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000
FXUS63 KLOT 011607
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1107 AM CDT WED JUL 1 2015

.SHORT TERM...
1101 AM CDT

THIS AFTERNOON AND EVENING...

SURFACE RIDGE CONTINUING TO BUILD SOUTH WITH ELONGATED HIGH PRESSURE
AREA LOCATED ACROSS CENTRAL AND WESTERN LAKE SUPERIOR. A
NORTHERLY LOW LEVEL FLOW IS HELPING TO SCOUR OUT RESIDUAL LOW
LEVEL MOISTURE AS EVIDENT BY THINNING LOW CLOUDS OVER NRN IL.
EXPECT THIS TREND TO CONTINUE THIS AFTERNOON WITH RAP/SREF/HRR
TRENDING DRIER IN THE LOW LEVELS. STILL CANT RULE OUT A SHOWER
FAR SOUTH CWFA BUT FEEL CHANCES OF THAT WILL HOLD OFF TILL EVENING
GIVEN CURRENT RADAR TRENDS AND RAP/HRR/SERF AND HAVE DROPPED
MENTION OF SUCH IN THE GRIDS/ZFP. GOING TEMPS ON TARGET WITH
ONSHORE FLOW HOLDING TEMPS SIGNIFICANTLY DOWN NEAR THE
LAKEFRONT... QUITE CHILLY BY JULY 1 STANDARDS. AVERAGE HIGH TEMP
FOR THE DAY IS 84 AT ORD AND RFD. SHAVED A DEGREE OR TWO OFF
MAXES WEST AND SOUTH CWFA AS TEMPS STRUGGLING COMPARED TO AVERAGE
DIRUNAL TREND FOR THE TIME OF YEAR AND MID-HIGH CLOUDINESS.

RAP PICKING UP ON LOW LEVEL MOISTURE ASSOCIATED WITH LOW CLOUDS
UPSTREAM OVER LAKE MICHIGAN AND LARGELY SHUNTS THIS MOISTURE OFF
TO THE EAST THIS EVENING. HENCE EXPECT MAINLY SCT-BKN MID-HIGH
CLOUDS TO CONTINUE THIS AFTERNOON AND EVENING AS MODEST DRYING IN
THE LOW LEVELS CONTINUES.

ED F

&&

.LONG TERM...
330 AM CDT

THURSDAY THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* PERIODIC MVFR CIGS.

* NE WINDS INCREASING TO 10-12 KT THIS AFTERNOON.

BMD/MM

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE LIES NORTH OF THE TERMINALS AND WILL PROVIDE MODEST
NORTHEAST WINDS AND DRY WEATHER THROUGH THE FORECAST PERIOD.
PATCHY MVFR WILL FLOAT ACROSS THE TERMINALS THROUGH MID
MORNING...THEN SHOULD LIFT AND SCATTER WITH VFR CONDITIONS THE
REMAINDER OF THE TAF PERIOD. WINDS ARE EXPECTED TO INCREASE AOA 10
KT FOR A FEW HOURS THIS AFTERNOON INTO EARLY EVENING.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 16Z...

* HIGH IN MVFR THROUGH 17-18Z.

* MEDIUM HIGH IN TIMING OF WINDS ABOVE 10KT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 011606
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1106 AM CDT WED JUL 1 2015

.SHORT TERM...
1101 AM CDT

THIS AFTERNOON AND EVENING...

SURFACE RIDGE CONTINUING TO BUILD SOUTH WITH ELONGATED HIGH PRESSURE
AREA LOCATED ACROSS CENTRAL AND WESTERN LAKE SUPERIOR. A
NORTHERLY LOW LEVEL FLOW IS HELPING TO SCOUR OUT RESIDUAL LOW
LEVEL MOISTURE AS EVIDENT BY THINNING LOW CLOUDS OVER NRN IL.
EXPECT THIS TREND TO CONTINUE THIS AFTERNOON WITH RAP/SREF/HRR
TRENDING DRIER IN THE LOW LEVELS. STILL CANT RULE OUT A SHOWER
FAR SOUTH CWFA BUT FEEL CHANCES OF THAT WILL HOLD OFF TILL EVENING
GIVEN CURRENT RADAR TRENDS AND RAP/HRR/SERF AND HAVE DROPPED
MENTION OF SUCH IN THE GRIDS/ZFP. GOING TEMPS ON TARGET WITH
ONSHORE FLOW HOLDING TEMPS SIGNIFICANTLY DOWN NEAR THE
LAKEFRONT... QUITE CHILLY BY JULY 1 STANDARDS. AVERAGE HIGH TEMP
FOR THE DAY IS 84 AT ORD AND RFD. SHAVED A DEGREE OR TWO OFF
MAXES WEST AND SOUTH CWFA AS TEMPS STRUGGLING COMPARED TO AVERAGE
DIRUNAL TREND FOR THE TIME OF YEAR AND MID-HIGH CLOUDINESS.

RAP PICKING UP ON LOW LEVEL MOISTURE ASSOCIATED WITH LOW CLOUDS
UPSTREAM OVER LAKE MICHIGAN AND LARGELY SHUNTS THIS MOISTURE OFF
TO THE EAST THIS EVENING. HENCE EXPECT MAINLY SCT-BKN MID-HIGH
CLOUDS TO CONTINUE THIS AFTERNOON AND EVENING AS MODEST DRYING IN
THE LOW LEVELS CONTINUES.

ED F

&&

.LONG TERM...
330 AM CDT

THURSDAY THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* PERIODIC MVFR CIGS THIS MORNING.
* NE WINDS INCREASING TO 10-12 KT THIS AFTERNOON.

BMD/MM

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE LIES NORTH OF THE TERMINALS AND WILL PROVIDE MODEST
NORTHEAST WINDS AND DRY WEATHER THROUGH THE FORECAST PERIOD.
PATCHY MVFR WILL FLOAT ACROSS THE TERMINALS THROUGH MID
MORNING...THEN SHOULD LIFT AND SCATTER WITH VFR CONDITIONS THE
REMAINDER OF THE TAF PERIOD. WINDS ARE EXPECTED TO INCREASE AOA 10
KT FOR A FEW HOURS THIS AFTERNOON INTO EARLY EVENING.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH IN MVFR THIS MORNING.

* MEDIUM HIGH IN TIMING OF WINDS ABOVE 10KT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 011606
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1106 AM CDT WED JUL 1 2015

.SHORT TERM...
1101 AM CDT

THIS AFTERNOON AND EVENING...

SURFACE RIDGE CONTINUING TO BUILD SOUTH WITH ELONGATED HIGH PRESSURE
AREA LOCATED ACROSS CENTRAL AND WESTERN LAKE SUPERIOR. A
NORTHERLY LOW LEVEL FLOW IS HELPING TO SCOUR OUT RESIDUAL LOW
LEVEL MOISTURE AS EVIDENT BY THINNING LOW CLOUDS OVER NRN IL.
EXPECT THIS TREND TO CONTINUE THIS AFTERNOON WITH RAP/SREF/HRR
TRENDING DRIER IN THE LOW LEVELS. STILL CANT RULE OUT A SHOWER
FAR SOUTH CWFA BUT FEEL CHANCES OF THAT WILL HOLD OFF TILL EVENING
GIVEN CURRENT RADAR TRENDS AND RAP/HRR/SERF AND HAVE DROPPED
MENTION OF SUCH IN THE GRIDS/ZFP. GOING TEMPS ON TARGET WITH
ONSHORE FLOW HOLDING TEMPS SIGNIFICANTLY DOWN NEAR THE
LAKEFRONT... QUITE CHILLY BY JULY 1 STANDARDS. AVERAGE HIGH TEMP
FOR THE DAY IS 84 AT ORD AND RFD. SHAVED A DEGREE OR TWO OFF
MAXES WEST AND SOUTH CWFA AS TEMPS STRUGGLING COMPARED TO AVERAGE
DIRUNAL TREND FOR THE TIME OF YEAR AND MID-HIGH CLOUDINESS.

RAP PICKING UP ON LOW LEVEL MOISTURE ASSOCIATED WITH LOW CLOUDS
UPSTREAM OVER LAKE MICHIGAN AND LARGELY SHUNTS THIS MOISTURE OFF
TO THE EAST THIS EVENING. HENCE EXPECT MAINLY SCT-BKN MID-HIGH
CLOUDS TO CONTINUE THIS AFTERNOON AND EVENING AS MODEST DRYING IN
THE LOW LEVELS CONTINUES.

ED F

&&

.LONG TERM...
330 AM CDT

THURSDAY THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* PERIODIC MVFR CIGS THIS MORNING.
* NE WINDS INCREASING TO 10-12 KT THIS AFTERNOON.

BMD/MM

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE LIES NORTH OF THE TERMINALS AND WILL PROVIDE MODEST
NORTHEAST WINDS AND DRY WEATHER THROUGH THE FORECAST PERIOD.
PATCHY MVFR WILL FLOAT ACROSS THE TERMINALS THROUGH MID
MORNING...THEN SHOULD LIFT AND SCATTER WITH VFR CONDITIONS THE
REMAINDER OF THE TAF PERIOD. WINDS ARE EXPECTED TO INCREASE AOA 10
KT FOR A FEW HOURS THIS AFTERNOON INTO EARLY EVENING.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH IN MVFR THIS MORNING.

* MEDIUM HIGH IN TIMING OF WINDS ABOVE 10KT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO


  [top]

000
FXUS63 KILX 011547
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1047 AM CDT WED JUL 1 2015

.UPDATE...
ISSUED AT 1047 AM CDT WED JUL 1 2015

MADE SOME QUICK UPDATES TO THE FORECAST...MAINLY TO LOWER POPS AND
REDUCE THUNDER MENTION TODAY. OVERNIGHT MCS HAS TRACKED WELL TO
THE S/SW OF CENTRAL ILLINOIS AND IS NOW PUSHING ACROSS SOUTHERN
MISSOURI INTO WESTERN KENTUCKY. FURTHER NORTH...PARTLY TO MOSTLY
CLOUDY BUT DRY CONDITIONS PREVAIL ACROSS THE KILX CWA. WILL KEEP
AN EYE ON SCATTERED SHOWERS UPSTREAM ACROSS MINNESOTA INTO
IOWA...AS THESE WILL LIKELY SPILL SOUTHEASTWARD INTO THE AREA
LATER TODAY...BUT OVERALL TREND IS DRIER THAN PREVIOUSLY FORECAST.
HAVE LOWERED OR ELIMINATED POPS THROUGH MIDDAY...THEN GONE WITH
MAINLY CHANCE POPS FOR SHOWERS/ISOLATED THUNDER FROM MID TO LATE
AFTERNOON. BEST RAIN CHANCES WILL HOLD OFF UNTIL TONIGHT AS LOW
PRESSURE TRACKS FROM ITS CURRENT POSITION OVER NORTHERN KANSAS
INTO WESTERN KENTUCKY.


&&

.SHORT TERM...(TODAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

SFC BOUNDARY EXTENDING FROM SOUTHWESTERN NEB TO CENTRAL MO WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. THIS WILL REMAIN WEST
OF THE CWA WITH MOST OF THE PCPN REMAINING SOUTHWEST OF THE AREA
THIS MORNING. HOWEVER...THE BOUNDARY WILL BEGIN TO LIFT NORTHWARD
DURING THE AFTERNOON...SO ADDITIONAL SHOWERS AND STORMS WILL DEVELOP
NORTH OF THE BOUNDARY AND EFFECT CENTRAL ILLINOIS DURING THE
AFTERNOON. HIGHER POPS IN THE FORECAST WILL BE TO THE SOUTHWEST WITH
JUST A CHANCE DURING THE MORNING HOURS SOUTHWEST OF A RUSHVILLE TO
TERRE HAUTE, IN LINE. DURING THE AFTERNOON THIS LINE WITH SHIFT
NORTHWARD TO I-74 WITH LIKELY POPS IN THE SOUTHWEST AND SOUTHEAST.
SHOULD BE PLENTY OF CLOUDS TO KEEP TEMPS ON THE COOLER SIDE...SO
LOOKING AT AFTERNOON HIGHS ONLY IN THE UPPER 70S. WINDS THIS MORNING
WILL BE LIGHT BUT THEN INCREASE SOME FOR THE REST OF THE DAY.
NORTHERN PARTS OF THE CWA WILL BE NORTH OF THE FRONT ALL DAY SO WILL
SEE EASTERLY WINDS. SOUTH OF THE FRONT WINDS WILL BE SOUTHERLY.

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

THIS RUN OF MODELS HAS MIXED NEWS.  THE NORTHERN HALF OF THE STATE
MAY IN FACT SEE SOME PARTLY CLOUDY AND DRY PDS OVER THE NEXT
WEEK...BUT THE SOUTHERN HALF OF THE STATE MAY NOT BE AS LUCKY. AS A
RESULT, THE FORECAST IS A BIT TROUBLESOME FROM A PERSISTENCE STAND
POINT. MAIN ISSUE WITH THE FORECAST IS THE LOCATION OF A QUASI-
STALLED BOUNDARY JUST TO THE SOUTH.  A SERIES OF SHORTWAVES INTERACT
AND KEEP PRECIPITATION OFF AND ON.  LOCATION OF THE BOUNDARY IS WHAT
REMAINS AN ISSUE. ALL MODELS ARE INCONSISTENT AND HAVE CONTINUITY
ISSUES BETWEEN THE QPF DEPICTION AND THE SFC FRONTAL ANALYSIS IN THE
WIND FIELDS.  OSCILLATING NORTH AND SOUTH IN SUBSEQUENT RUNS IS NOT
HELPING TO FIND ANY ABSOLUTES.  SO, FOR THIS FORECAST RUN, HAVE
WORKED THE FORECAST BEYOND TONIGHT INTO SLIGHTLY UPPING THE POPS
ACROSS THE SOUTH, PARTICULARLY SOUTH OF I70...BUT ALSO SOME MINOR
INCREASES IN CHANCE POPS SOUTH OF I72.

OVERNIGHT, THE HIGHEST POPS REMAIN IN THE SOUTH WITH BOUNDARY
DRIFTING SLOWLY SOUTHWARD OVERNIGHT AND SETTLING INTO THE OHIO RIVER
VALLEY.  FOR THURS THROUGH SAT, HAVE TRIED TO KEEP THE SILENT SLIGHT
POPS OR NONE FOR AREAS IMMEDIATELY ALONG AND NORTH OF LINE ROUGHLY
FROM SPRINGFIELD TO DANVILLE.  TO WRAP UP THE WEEKEND...THE
SUPERBLEND IS HANGING ONTO SOME CHANCE POPS BUT HAVE TRIED TO TEMPER
THEM SOMEWHAT AS THE WAVE AT 500MB IS BROAD, OPEN, AND PRODUCING
DIFF RESULTS BETWEEN THE ECMWF AND THE GFS.  MON NIGHT/TUESDAY TIME
FRAME IS WHEN THE AGREEMENT IS STARTING TO SHOW EVEN THIS FAR OUT
WITH A COLD FRONT SWEEPING THROUGH THE REGION AND MORE SIGNIFICANT
POPS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 647 AM CDT WED JUL 1 2015

SOME LIGHT FOG IS EFFECTING SOME SITES THIS MORNING...BUT WILL
EFFECT ALL SITES FOR A COUPLE HOURS...SO HAVE ADDED A TEMPO GROUP
FOR LIGHT FOG TIL 14Z. AFTER THIS...BASIC CONDITIONS FOR ALL SITES
WILL BE SOME SCATTERED CU AROUND 4KFT WITH AN OVERCAST MID DECK
AROUND 8KFT. MODELS ADVERTISING SCATTERED CONVECTION OVER SOME OF
THE SITES FOR THIS AFTERNOON AND INTO THIS EVENING. SO NOT THINK
THE CONVECTION WILL GET TO PIA AND BMI. SO HAVE A VCTS WITH A
BROKEN CIG AROUND 4KFT FOR SPI/DEC/CMI. DO NOT BELIEVE THIS WILL
LAST ALL NIGHT SO HAVE VCTS ENDING BETWEEN 03 AND 05Z...FROM WEST
TO EAST. WINDS WILL BE LIGHT THIS MORNING AT ALL SITES. BEYONDTHAT...WIND
DIRECTION WILL DEPEND ON WHERE THE FRONT WILL BE LATER TODAY. SO
HAVE PIA/BMI/CMI WITH EASTERLY WINDS THROUGH THE PERIOD. SPI AND
DEC WILL SEE SOUTHWEST WINDS THIS AFTERNOON AND THEN BECOMING
EASTERLY TONIGHT.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN



000
FXUS63 KILX 011547
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1047 AM CDT WED JUL 1 2015

.UPDATE...
ISSUED AT 1047 AM CDT WED JUL 1 2015

MADE SOME QUICK UPDATES TO THE FORECAST...MAINLY TO LOWER POPS AND
REDUCE THUNDER MENTION TODAY. OVERNIGHT MCS HAS TRACKED WELL TO
THE S/SW OF CENTRAL ILLINOIS AND IS NOW PUSHING ACROSS SOUTHERN
MISSOURI INTO WESTERN KENTUCKY. FURTHER NORTH...PARTLY TO MOSTLY
CLOUDY BUT DRY CONDITIONS PREVAIL ACROSS THE KILX CWA. WILL KEEP
AN EYE ON SCATTERED SHOWERS UPSTREAM ACROSS MINNESOTA INTO
IOWA...AS THESE WILL LIKELY SPILL SOUTHEASTWARD INTO THE AREA
LATER TODAY...BUT OVERALL TREND IS DRIER THAN PREVIOUSLY FORECAST.
HAVE LOWERED OR ELIMINATED POPS THROUGH MIDDAY...THEN GONE WITH
MAINLY CHANCE POPS FOR SHOWERS/ISOLATED THUNDER FROM MID TO LATE
AFTERNOON. BEST RAIN CHANCES WILL HOLD OFF UNTIL TONIGHT AS LOW
PRESSURE TRACKS FROM ITS CURRENT POSITION OVER NORTHERN KANSAS
INTO WESTERN KENTUCKY.


&&

.SHORT TERM...(TODAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

SFC BOUNDARY EXTENDING FROM SOUTHWESTERN NEB TO CENTRAL MO WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. THIS WILL REMAIN WEST
OF THE CWA WITH MOST OF THE PCPN REMAINING SOUTHWEST OF THE AREA
THIS MORNING. HOWEVER...THE BOUNDARY WILL BEGIN TO LIFT NORTHWARD
DURING THE AFTERNOON...SO ADDITIONAL SHOWERS AND STORMS WILL DEVELOP
NORTH OF THE BOUNDARY AND EFFECT CENTRAL ILLINOIS DURING THE
AFTERNOON. HIGHER POPS IN THE FORECAST WILL BE TO THE SOUTHWEST WITH
JUST A CHANCE DURING THE MORNING HOURS SOUTHWEST OF A RUSHVILLE TO
TERRE HAUTE, IN LINE. DURING THE AFTERNOON THIS LINE WITH SHIFT
NORTHWARD TO I-74 WITH LIKELY POPS IN THE SOUTHWEST AND SOUTHEAST.
SHOULD BE PLENTY OF CLOUDS TO KEEP TEMPS ON THE COOLER SIDE...SO
LOOKING AT AFTERNOON HIGHS ONLY IN THE UPPER 70S. WINDS THIS MORNING
WILL BE LIGHT BUT THEN INCREASE SOME FOR THE REST OF THE DAY.
NORTHERN PARTS OF THE CWA WILL BE NORTH OF THE FRONT ALL DAY SO WILL
SEE EASTERLY WINDS. SOUTH OF THE FRONT WINDS WILL BE SOUTHERLY.

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

THIS RUN OF MODELS HAS MIXED NEWS.  THE NORTHERN HALF OF THE STATE
MAY IN FACT SEE SOME PARTLY CLOUDY AND DRY PDS OVER THE NEXT
WEEK...BUT THE SOUTHERN HALF OF THE STATE MAY NOT BE AS LUCKY. AS A
RESULT, THE FORECAST IS A BIT TROUBLESOME FROM A PERSISTENCE STAND
POINT. MAIN ISSUE WITH THE FORECAST IS THE LOCATION OF A QUASI-
STALLED BOUNDARY JUST TO THE SOUTH.  A SERIES OF SHORTWAVES INTERACT
AND KEEP PRECIPITATION OFF AND ON.  LOCATION OF THE BOUNDARY IS WHAT
REMAINS AN ISSUE. ALL MODELS ARE INCONSISTENT AND HAVE CONTINUITY
ISSUES BETWEEN THE QPF DEPICTION AND THE SFC FRONTAL ANALYSIS IN THE
WIND FIELDS.  OSCILLATING NORTH AND SOUTH IN SUBSEQUENT RUNS IS NOT
HELPING TO FIND ANY ABSOLUTES.  SO, FOR THIS FORECAST RUN, HAVE
WORKED THE FORECAST BEYOND TONIGHT INTO SLIGHTLY UPPING THE POPS
ACROSS THE SOUTH, PARTICULARLY SOUTH OF I70...BUT ALSO SOME MINOR
INCREASES IN CHANCE POPS SOUTH OF I72.

OVERNIGHT, THE HIGHEST POPS REMAIN IN THE SOUTH WITH BOUNDARY
DRIFTING SLOWLY SOUTHWARD OVERNIGHT AND SETTLING INTO THE OHIO RIVER
VALLEY.  FOR THURS THROUGH SAT, HAVE TRIED TO KEEP THE SILENT SLIGHT
POPS OR NONE FOR AREAS IMMEDIATELY ALONG AND NORTH OF LINE ROUGHLY
FROM SPRINGFIELD TO DANVILLE.  TO WRAP UP THE WEEKEND...THE
SUPERBLEND IS HANGING ONTO SOME CHANCE POPS BUT HAVE TRIED TO TEMPER
THEM SOMEWHAT AS THE WAVE AT 500MB IS BROAD, OPEN, AND PRODUCING
DIFF RESULTS BETWEEN THE ECMWF AND THE GFS.  MON NIGHT/TUESDAY TIME
FRAME IS WHEN THE AGREEMENT IS STARTING TO SHOW EVEN THIS FAR OUT
WITH A COLD FRONT SWEEPING THROUGH THE REGION AND MORE SIGNIFICANT
POPS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 647 AM CDT WED JUL 1 2015

SOME LIGHT FOG IS EFFECTING SOME SITES THIS MORNING...BUT WILL
EFFECT ALL SITES FOR A COUPLE HOURS...SO HAVE ADDED A TEMPO GROUP
FOR LIGHT FOG TIL 14Z. AFTER THIS...BASIC CONDITIONS FOR ALL SITES
WILL BE SOME SCATTERED CU AROUND 4KFT WITH AN OVERCAST MID DECK
AROUND 8KFT. MODELS ADVERTISING SCATTERED CONVECTION OVER SOME OF
THE SITES FOR THIS AFTERNOON AND INTO THIS EVENING. SO NOT THINK
THE CONVECTION WILL GET TO PIA AND BMI. SO HAVE A VCTS WITH A
BROKEN CIG AROUND 4KFT FOR SPI/DEC/CMI. DO NOT BELIEVE THIS WILL
LAST ALL NIGHT SO HAVE VCTS ENDING BETWEEN 03 AND 05Z...FROM WEST
TO EAST. WINDS WILL BE LIGHT THIS MORNING AT ALL SITES. BEYONDTHAT...WIND
DIRECTION WILL DEPEND ON WHERE THE FRONT WILL BE LATER TODAY. SO
HAVE PIA/BMI/CMI WITH EASTERLY WINDS THROUGH THE PERIOD. SPI AND
DEC WILL SEE SOUTHWEST WINDS THIS AFTERNOON AND THEN BECOMING
EASTERLY TONIGHT.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN




000
FXUS63 KLOT 011409
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
909 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* PERIODIC MVFR CIGS THIS MORNING.
* NE WINDS INCREASING TO 10-12 KT THIS AFTERNOON.

BMD/MM

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE LIES NORTH OF THE TERMINALS AND WILL PROVIDE MODEST
NORTHEAST WINDS AND DRY WEATHER THROUGH THE FORECAST PERIOD.
PATCHY MVFR WILL FLOAT ACROSS THE TERMINALS THROUGH MID
MORNING...THEN SHOULD LIFT AND SCATTER WITH VFR CONDITIONS THE
REMAINDER OF THE TAF PERIOD. WINDS ARE EXPECTED TO INCREASE AOA 10
KT FOR A FEW HOURS THIS AFTERNOON INTO EARLY EVENING.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH IN MVFR THIS MORNING.

* MEDIUM HIGH IN TIMING OF WINDS ABOVE 10KT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 011409
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
909 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* PERIODIC MVFR CIGS THIS MORNING.
* NE WINDS INCREASING TO 10-12 KT THIS AFTERNOON.

BMD/MM

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE LIES NORTH OF THE TERMINALS AND WILL PROVIDE MODEST
NORTHEAST WINDS AND DRY WEATHER THROUGH THE FORECAST PERIOD.
PATCHY MVFR WILL FLOAT ACROSS THE TERMINALS THROUGH MID
MORNING...THEN SHOULD LIFT AND SCATTER WITH VFR CONDITIONS THE
REMAINDER OF THE TAF PERIOD. WINDS ARE EXPECTED TO INCREASE AOA 10
KT FOR A FEW HOURS THIS AFTERNOON INTO EARLY EVENING.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH IN MVFR THIS MORNING.

* MEDIUM HIGH IN TIMING OF WINDS ABOVE 10KT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KILX 011147
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
647 AM CDT WED JUL 1 2015

.SHORT TERM...(TODAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

SFC BOUNDARY EXTENDING FROM SOUTHWESTERN NEB TO CENTRAL MO WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. THIS WILL REMAIN WEST
OF THE CWA WITH MOST OF THE PCPN REMAINING SOUTHWEST OF THE AREA
THIS MORNING. HOWEVER...THE BOUNDARY WILL BEGIN TO LIFT NORTHWARD
DURING THE AFTERNOON...SO ADDITIONAL SHOWERS AND STORMS WILL DEVELOP
NORTH OF THE BOUNDARY AND EFFECT CENTRAL ILLINOIS DURING THE
AFTERNOON. HIGHER POPS IN THE FORECAST WILL BE TO THE SOUTHWEST WITH
JUST A CHANCE DURING THE MORNING HOURS SOUTHWEST OF A RUSHVILLE TO
TERRE HAUTE, IN LINE. DURING THE AFTERNOON THIS LINE WITH SHIFT
NORTHWARD TO I-74 WITH LIKELY POPS IN THE SOUTHWEST AND SOUTHEAST.
SHOULD BE PLENTY OF CLOUDS TO KEEP TEMPS ON THE COOLER SIDE...SO
LOOKING AT AFTERNOON HIGHS ONLY IN THE UPPER 70S. WINDS THIS MORNING
WILL BE LIGHT BUT THEN INCREASE SOME FOR THE REST OF THE DAY.
NORTHERN PARTS OF THE CWA WILL BE NORTH OF THE FRONT ALL DAY SO WILL
SEE EASTERLY WINDS. SOUTH OF THE FRONT WINDS WILL BE SOUTHERLY.

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

THIS RUN OF MODELS HAS MIXED NEWS.  THE NORTHERN HALF OF THE STATE
MAY IN FACT SEE SOME PARTLY CLOUDY AND DRY PDS OVER THE NEXT
WEEK...BUT THE SOUTHERN HALF OF THE STATE MAY NOT BE AS LUCKY. AS A
RESULT, THE FORECAST IS A BIT TROUBLESOME FROM A PERSISTENCE STAND
POINT. MAIN ISSUE WITH THE FORECAST IS THE LOCATION OF A QUASI-
STALLED BOUNDARY JUST TO THE SOUTH.  A SERIES OF SHORTWAVES INTERACT
AND KEEP PRECIPITATION OFF AND ON.  LOCATION OF THE BOUNDARY IS WHAT
REMAINS AN ISSUE. ALL MODELS ARE INCONSISTENT AND HAVE CONTINUITY
ISSUES BETWEEN THE QPF DEPICTION AND THE SFC FRONTAL ANALYSIS IN THE
WIND FIELDS.  OSCILLATING NORTH AND SOUTH IN SUBSEQUENT RUNS IS NOT
HELPING TO FIND ANY ABSOLUTES.  SO, FOR THIS FORECAST RUN, HAVE
WORKED THE FORECAST BEYOND TONIGHT INTO SLIGHTLY UPPING THE POPS
ACROSS THE SOUTH, PARTICULARLY SOUTH OF I70...BUT ALSO SOME MINOR
INCREASES IN CHANCE POPS SOUTH OF I72.

OVERNIGHT, THE HIGHEST POPS REMAIN IN THE SOUTH WITH BOUNDARY
DRIFTING SLOWLY SOUTHWARD OVERNIGHT AND SETTLING INTO THE OHIO RIVER
VALLEY.  FOR THURS THROUGH SAT, HAVE TRIED TO KEEP THE SILENT SLIGHT
POPS OR NONE FOR AREAS IMMEDIATELY ALONG AND NORTH OF LINE ROUGHLY
FROM SPRINGFIELD TO DANVILLE.  TO WRAP UP THE WEEKEND...THE
SUPERBLEND IS HANGING ONTO SOME CHANCE POPS BUT HAVE TRIED TO TEMPER
THEM SOMEWHAT AS THE WAVE AT 500MB IS BROAD, OPEN, AND PRODUCING
DIFF RESULTS BETWEEN THE ECMWF AND THE GFS.  MON NIGHT/TUESDAY TIME
FRAME IS WHEN THE AGREEMENT IS STARTING TO SHOW EVEN THIS FAR OUT
WITH A COLD FRONT SWEEPING THROUGH THE REGION AND MORE SIGNIFICANT
POPS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 647 AM CDT WED JUL 1 2015

SOME LIGHT FOG IS EFFECTING SOME SITES THIS MORNING...BUT WILL
EFFECT ALL SITES FOR A COUPLE HOURS...SO HAVE ADDED A TEMPO GROUP
FOR LIGHT FOG TIL 14Z. AFTER THIS...BASIC CONDITIONS FOR ALL SITES
WILL BE SOME SCATTERED CU AROUND 4KFT WITH AN OVERCAST MID DECK
AROUND 8KFT. MODELS ADVERTISING SCATTERED CONVECTION OVER SOME OF
THE SITES FOR THIS AFTERNOON AND INTO THIS EVENING. SO NOT THINK
THE CONVECTION WILL GET TO PIA AND BMI. SO HAVE A VCTS WITH A
BROKEN CIG AROUND 4KFT FOR SPI/DEC/CMI. DO NOT BELIEVE THIS WILL
LAST ALL NIGHT SO HAVE VCTS ENDING BETWEEN 03 AND 05Z...FROM WEST
TO EAST. WINDS WILL BE LIGHT THIS MORNING AT ALL SITES. BEYONDTHAT...WIND
DIRECTION WILL DEPEND ON WHERE THE FRONT WILL BE LATER TODAY. SO
HAVE PIA/BMI/CMI WITH EASTERLY WINDS THROUGH THE PERIOD. SPI AND
DEC WILL SEE SOUTHWEST WINDS THIS AFTERNOON AND THEN BECOMING
EASTERLY TONIGHT.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN



000
FXUS63 KILX 011147
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
647 AM CDT WED JUL 1 2015

.SHORT TERM...(TODAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

SFC BOUNDARY EXTENDING FROM SOUTHWESTERN NEB TO CENTRAL MO WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. THIS WILL REMAIN WEST
OF THE CWA WITH MOST OF THE PCPN REMAINING SOUTHWEST OF THE AREA
THIS MORNING. HOWEVER...THE BOUNDARY WILL BEGIN TO LIFT NORTHWARD
DURING THE AFTERNOON...SO ADDITIONAL SHOWERS AND STORMS WILL DEVELOP
NORTH OF THE BOUNDARY AND EFFECT CENTRAL ILLINOIS DURING THE
AFTERNOON. HIGHER POPS IN THE FORECAST WILL BE TO THE SOUTHWEST WITH
JUST A CHANCE DURING THE MORNING HOURS SOUTHWEST OF A RUSHVILLE TO
TERRE HAUTE, IN LINE. DURING THE AFTERNOON THIS LINE WITH SHIFT
NORTHWARD TO I-74 WITH LIKELY POPS IN THE SOUTHWEST AND SOUTHEAST.
SHOULD BE PLENTY OF CLOUDS TO KEEP TEMPS ON THE COOLER SIDE...SO
LOOKING AT AFTERNOON HIGHS ONLY IN THE UPPER 70S. WINDS THIS MORNING
WILL BE LIGHT BUT THEN INCREASE SOME FOR THE REST OF THE DAY.
NORTHERN PARTS OF THE CWA WILL BE NORTH OF THE FRONT ALL DAY SO WILL
SEE EASTERLY WINDS. SOUTH OF THE FRONT WINDS WILL BE SOUTHERLY.

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

THIS RUN OF MODELS HAS MIXED NEWS.  THE NORTHERN HALF OF THE STATE
MAY IN FACT SEE SOME PARTLY CLOUDY AND DRY PDS OVER THE NEXT
WEEK...BUT THE SOUTHERN HALF OF THE STATE MAY NOT BE AS LUCKY. AS A
RESULT, THE FORECAST IS A BIT TROUBLESOME FROM A PERSISTENCE STAND
POINT. MAIN ISSUE WITH THE FORECAST IS THE LOCATION OF A QUASI-
STALLED BOUNDARY JUST TO THE SOUTH.  A SERIES OF SHORTWAVES INTERACT
AND KEEP PRECIPITATION OFF AND ON.  LOCATION OF THE BOUNDARY IS WHAT
REMAINS AN ISSUE. ALL MODELS ARE INCONSISTENT AND HAVE CONTINUITY
ISSUES BETWEEN THE QPF DEPICTION AND THE SFC FRONTAL ANALYSIS IN THE
WIND FIELDS.  OSCILLATING NORTH AND SOUTH IN SUBSEQUENT RUNS IS NOT
HELPING TO FIND ANY ABSOLUTES.  SO, FOR THIS FORECAST RUN, HAVE
WORKED THE FORECAST BEYOND TONIGHT INTO SLIGHTLY UPPING THE POPS
ACROSS THE SOUTH, PARTICULARLY SOUTH OF I70...BUT ALSO SOME MINOR
INCREASES IN CHANCE POPS SOUTH OF I72.

OVERNIGHT, THE HIGHEST POPS REMAIN IN THE SOUTH WITH BOUNDARY
DRIFTING SLOWLY SOUTHWARD OVERNIGHT AND SETTLING INTO THE OHIO RIVER
VALLEY.  FOR THURS THROUGH SAT, HAVE TRIED TO KEEP THE SILENT SLIGHT
POPS OR NONE FOR AREAS IMMEDIATELY ALONG AND NORTH OF LINE ROUGHLY
FROM SPRINGFIELD TO DANVILLE.  TO WRAP UP THE WEEKEND...THE
SUPERBLEND IS HANGING ONTO SOME CHANCE POPS BUT HAVE TRIED TO TEMPER
THEM SOMEWHAT AS THE WAVE AT 500MB IS BROAD, OPEN, AND PRODUCING
DIFF RESULTS BETWEEN THE ECMWF AND THE GFS.  MON NIGHT/TUESDAY TIME
FRAME IS WHEN THE AGREEMENT IS STARTING TO SHOW EVEN THIS FAR OUT
WITH A COLD FRONT SWEEPING THROUGH THE REGION AND MORE SIGNIFICANT
POPS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 647 AM CDT WED JUL 1 2015

SOME LIGHT FOG IS EFFECTING SOME SITES THIS MORNING...BUT WILL
EFFECT ALL SITES FOR A COUPLE HOURS...SO HAVE ADDED A TEMPO GROUP
FOR LIGHT FOG TIL 14Z. AFTER THIS...BASIC CONDITIONS FOR ALL SITES
WILL BE SOME SCATTERED CU AROUND 4KFT WITH AN OVERCAST MID DECK
AROUND 8KFT. MODELS ADVERTISING SCATTERED CONVECTION OVER SOME OF
THE SITES FOR THIS AFTERNOON AND INTO THIS EVENING. SO NOT THINK
THE CONVECTION WILL GET TO PIA AND BMI. SO HAVE A VCTS WITH A
BROKEN CIG AROUND 4KFT FOR SPI/DEC/CMI. DO NOT BELIEVE THIS WILL
LAST ALL NIGHT SO HAVE VCTS ENDING BETWEEN 03 AND 05Z...FROM WEST
TO EAST. WINDS WILL BE LIGHT THIS MORNING AT ALL SITES. BEYONDTHAT...WIND
DIRECTION WILL DEPEND ON WHERE THE FRONT WILL BE LATER TODAY. SO
HAVE PIA/BMI/CMI WITH EASTERLY WINDS THROUGH THE PERIOD. SPI AND
DEC WILL SEE SOUTHWEST WINDS THIS AFTERNOON AND THEN BECOMING
EASTERLY TONIGHT.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN




000
FXUS63 KLOT 011117
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
617 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* PERIODIC MVFR CIGS THIS MORNING.
* NE WINDS INCREASING ABOVE 10 KT THIS AFTERNOON.

BMD

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE LIES NORTH OF THE TERMINALS AND WILL PROVIDE MODEST
NORTHEAST WINDS AND DRY WEATHER THROUGH THE FORECAST PERIOD.
PATCHY MVFR WILL FLOAT ACROSS THE TERMINALS THROUGH MID
MORNING...THEN SHOULD LIFT AND SCATTER WITH VFR CONDITIONS THE
REMAINDER OF THE TAF PERIOD. WINDS ARE EXPECTED TO INCREASE AOA 10
KT FOR A FEW HOURS THIS AFTERNOON INTO EARLY EVENING.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH IN ALL FORECAST ELEMENTS.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 011117
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
617 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* PERIODIC MVFR CIGS THIS MORNING.
* NE WINDS INCREASING ABOVE 10 KT THIS AFTERNOON.

BMD

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE LIES NORTH OF THE TERMINALS AND WILL PROVIDE MODEST
NORTHEAST WINDS AND DRY WEATHER THROUGH THE FORECAST PERIOD.
PATCHY MVFR WILL FLOAT ACROSS THE TERMINALS THROUGH MID
MORNING...THEN SHOULD LIFT AND SCATTER WITH VFR CONDITIONS THE
REMAINDER OF THE TAF PERIOD. WINDS ARE EXPECTED TO INCREASE AOA 10
KT FOR A FEW HOURS THIS AFTERNOON INTO EARLY EVENING.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH IN ALL FORECAST ELEMENTS.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 011117
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
617 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* PERIODIC MVFR CIGS THIS MORNING.
* NE WINDS INCREASING ABOVE 10 KT THIS AFTERNOON.

BMD

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE LIES NORTH OF THE TERMINALS AND WILL PROVIDE MODEST
NORTHEAST WINDS AND DRY WEATHER THROUGH THE FORECAST PERIOD.
PATCHY MVFR WILL FLOAT ACROSS THE TERMINALS THROUGH MID
MORNING...THEN SHOULD LIFT AND SCATTER WITH VFR CONDITIONS THE
REMAINDER OF THE TAF PERIOD. WINDS ARE EXPECTED TO INCREASE AOA 10
KT FOR A FEW HOURS THIS AFTERNOON INTO EARLY EVENING.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH IN ALL FORECAST ELEMENTS.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
402 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* MEDIUM CONFIDENCE IN END TIME OF MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 010902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
402 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* MEDIUM CONFIDENCE IN END TIME OF MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 010902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
402 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* MEDIUM CONFIDENCE IN END TIME OF MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 010902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
402 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* MEDIUM CONFIDENCE IN END TIME OF MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KILX 010837
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
337 AM CDT WED JUL 1 2015

.SHORT TERM...(TODAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

SFC BOUNDARY EXTENDING FROM SOUTHWESTERN NEB TO CENTRAL MO WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. THIS WILL REMAIN WEST
OF THE CWA WITH MOST OF THE PCPN REMAINING SOUTHWEST OF THE AREA
THIS MORNING. HOWEVER...THE BOUNDARY WILL BEGIN TO LIFT NORTHWARD
DURING THE AFTERNOON...SO ADDITIONAL SHOWERS AND STORMS WILL DEVELOP
NORTH OF THE BOUNDARY AND EFFECT CENTRAL ILLINOIS DURING THE
AFTERNOON. HIGHER POPS IN THE FORECAST WILL BE TO THE SOUTHWEST WITH
JUST A CHANCE DURING THE MORNING HOURS SOUTHWEST OF A RUSHVILLE TO
TERRE HAUTE, IN LINE. DURING THE AFTERNOON THIS LINE WITH SHIFT
NORTHWARD TO I-74 WITH LIKELY POPS IN THE SOUTHWEST AND SOUTHEAST.
SHOULD BE PLENTY OF CLOUDS TO KEEP TEMPS ON THE COOLER SIDE...SO
LOOKING AT AFTERNOON HIGHS ONLY IN THE UPPER 70S. WINDS THIS MORNING
WILL BE LIGHT BUT THEN INCREASE SOME FOR THE REST OF THE DAY.
NORTHERN PARTS OF THE CWA WILL BE NORTH OF THE FRONT ALL DAY SO WILL
SEE EASTERLY WINDS. SOUTH OF THE FRONT WINDS WILL BE SOUTHERLY.

&&

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

THIS RUN OF MODELS HAS MIXED NEWS.  THE NORTHERN HALF OF THE STATE
MAY IN FACT SEE SOME PARTLY CLOUDY AND DRY PDS OVER THE NEXT
WEEK...BUT THE SOUTHERN HALF OF THE STATE MAY NOT BE AS LUCKY. AS A
RESULT, THE FORECAST IS A BIT TROUBLESOME FROM A PERSISTENCE STAND
POINT. MAIN ISSUE WITH THE FORECAST IS THE LOCATION OF A QUASI-
STALLED BOUNDARY JUST TO THE SOUTH.  A SERIES OF SHORTWAVES INTERACT
AND KEEP PRECIPITATION OFF AND ON.  LOCATION OF THE BOUNDARY IS WHAT
REMAINS AN ISSUE. ALL MODELS ARE INCONSISTENT AND HAVE CONTINUITY
ISSUES BETWEEN THE QPF DEPICTION AND THE SFC FRONTAL ANALYSIS IN THE
WIND FIELDS.  OSCILLATING NORTH AND SOUTH IN SUBSEQUENT RUNS IS NOT
HELPING TO FIND ANY ABSOLUTES.  SO, FOR THIS FORECAST RUN, HAVE
WORKED THE FORECAST BEYOND TONIGHT INTO SLIGHTLY UPPING THE POPS
ACROSS THE SOUTH, PARTICULARLY SOUTH OF I70...BUT ALSO SOME MINOR
INCREASES IN CHANCE POPS SOUTH OF I72.

OVERNIGHT, THE HIGHEST POPS REMAIN IN THE SOUTH WITH BOUNDARY
DRIFTING SLOWLY SOUTHWARD OVERNIGHT AND SETTLING INTO THE OHIO RIVER
VALLEY.  FOR THURS THROUGH SAT, HAVE TRIED TO KEEP THE SILENT SLIGHT
POPS OR NONE FOR AREAS IMMEDIATELY ALONG AND NORTH OF LINE ROUGHLY
FROM SPRINGFIELD TO DANVILLE.  TO WRAP UP THE WEEKEND...THE
SUPERBLEND IS HANGING ONTO SOME CHANCE POPS BUT HAVE TRIED TO TEMPER
THEM SOMEWHAT AS THE WAVE AT 500MB IS BROAD, OPEN, AND PRODUCING
DIFF RESULTS BETWEEN THE ECMWF AND THE GFS.  MON NIGHT/TUESDAY TIME
FRAME IS WHEN THE AGREEMENT IS STARTING TO SHOW EVEN THIS FAR OUT
WITH A COLD FRONT SWEEPING THROUGH THE REGION AND MORE SIGNIFICANT
POPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1115 PM CDT TUE JUN 30 2015

MVFR VSBYS IN FOG/HZ OVERNIGHT WITH OUR NEXT WEATHER SYSTEM
PUSHING INTO MISSOURI BY MORNING. MODELS HAVE TRENDED FURTHER
WEST AND SOUTH WITH THE PRECIP SHIELD SO FOR NOW WILL CONTINUE
WITH VCSH OVER OUR SOUTHERN TAF SITES WITH LITTLE IF ANY PRECIP
FURTHER NORTH WITH LOW VFR CIGS SETTLING IN DURING THE MORNING
BASED ON THE LATEST FORECAST SOUNDINGS. SURFACE WINDS WILL NOT
BE MUCH OF A FACTOR THROUGH THIS FORECAST PERIOD WITH A LIGHT
AND VARIABLE WIND TONIGHT AND GENERALLY A LIGHT EASTERLY
DIRECTION ON WEDNESDAY WITH SPEEDS OF LESS THAN 10 KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...SMITH



000
FXUS63 KILX 010837
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
337 AM CDT WED JUL 1 2015

.SHORT TERM...(TODAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

SFC BOUNDARY EXTENDING FROM SOUTHWESTERN NEB TO CENTRAL MO WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. THIS WILL REMAIN WEST
OF THE CWA WITH MOST OF THE PCPN REMAINING SOUTHWEST OF THE AREA
THIS MORNING. HOWEVER...THE BOUNDARY WILL BEGIN TO LIFT NORTHWARD
DURING THE AFTERNOON...SO ADDITIONAL SHOWERS AND STORMS WILL DEVELOP
NORTH OF THE BOUNDARY AND EFFECT CENTRAL ILLINOIS DURING THE
AFTERNOON. HIGHER POPS IN THE FORECAST WILL BE TO THE SOUTHWEST WITH
JUST A CHANCE DURING THE MORNING HOURS SOUTHWEST OF A RUSHVILLE TO
TERRE HAUTE, IN LINE. DURING THE AFTERNOON THIS LINE WITH SHIFT
NORTHWARD TO I-74 WITH LIKELY POPS IN THE SOUTHWEST AND SOUTHEAST.
SHOULD BE PLENTY OF CLOUDS TO KEEP TEMPS ON THE COOLER SIDE...SO
LOOKING AT AFTERNOON HIGHS ONLY IN THE UPPER 70S. WINDS THIS MORNING
WILL BE LIGHT BUT THEN INCREASE SOME FOR THE REST OF THE DAY.
NORTHERN PARTS OF THE CWA WILL BE NORTH OF THE FRONT ALL DAY SO WILL
SEE EASTERLY WINDS. SOUTH OF THE FRONT WINDS WILL BE SOUTHERLY.

&&

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

THIS RUN OF MODELS HAS MIXED NEWS.  THE NORTHERN HALF OF THE STATE
MAY IN FACT SEE SOME PARTLY CLOUDY AND DRY PDS OVER THE NEXT
WEEK...BUT THE SOUTHERN HALF OF THE STATE MAY NOT BE AS LUCKY. AS A
RESULT, THE FORECAST IS A BIT TROUBLESOME FROM A PERSISTENCE STAND
POINT. MAIN ISSUE WITH THE FORECAST IS THE LOCATION OF A QUASI-
STALLED BOUNDARY JUST TO THE SOUTH.  A SERIES OF SHORTWAVES INTERACT
AND KEEP PRECIPITATION OFF AND ON.  LOCATION OF THE BOUNDARY IS WHAT
REMAINS AN ISSUE. ALL MODELS ARE INCONSISTENT AND HAVE CONTINUITY
ISSUES BETWEEN THE QPF DEPICTION AND THE SFC FRONTAL ANALYSIS IN THE
WIND FIELDS.  OSCILLATING NORTH AND SOUTH IN SUBSEQUENT RUNS IS NOT
HELPING TO FIND ANY ABSOLUTES.  SO, FOR THIS FORECAST RUN, HAVE
WORKED THE FORECAST BEYOND TONIGHT INTO SLIGHTLY UPPING THE POPS
ACROSS THE SOUTH, PARTICULARLY SOUTH OF I70...BUT ALSO SOME MINOR
INCREASES IN CHANCE POPS SOUTH OF I72.

OVERNIGHT, THE HIGHEST POPS REMAIN IN THE SOUTH WITH BOUNDARY
DRIFTING SLOWLY SOUTHWARD OVERNIGHT AND SETTLING INTO THE OHIO RIVER
VALLEY.  FOR THURS THROUGH SAT, HAVE TRIED TO KEEP THE SILENT SLIGHT
POPS OR NONE FOR AREAS IMMEDIATELY ALONG AND NORTH OF LINE ROUGHLY
FROM SPRINGFIELD TO DANVILLE.  TO WRAP UP THE WEEKEND...THE
SUPERBLEND IS HANGING ONTO SOME CHANCE POPS BUT HAVE TRIED TO TEMPER
THEM SOMEWHAT AS THE WAVE AT 500MB IS BROAD, OPEN, AND PRODUCING
DIFF RESULTS BETWEEN THE ECMWF AND THE GFS.  MON NIGHT/TUESDAY TIME
FRAME IS WHEN THE AGREEMENT IS STARTING TO SHOW EVEN THIS FAR OUT
WITH A COLD FRONT SWEEPING THROUGH THE REGION AND MORE SIGNIFICANT
POPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1115 PM CDT TUE JUN 30 2015

MVFR VSBYS IN FOG/HZ OVERNIGHT WITH OUR NEXT WEATHER SYSTEM
PUSHING INTO MISSOURI BY MORNING. MODELS HAVE TRENDED FURTHER
WEST AND SOUTH WITH THE PRECIP SHIELD SO FOR NOW WILL CONTINUE
WITH VCSH OVER OUR SOUTHERN TAF SITES WITH LITTLE IF ANY PRECIP
FURTHER NORTH WITH LOW VFR CIGS SETTLING IN DURING THE MORNING
BASED ON THE LATEST FORECAST SOUNDINGS. SURFACE WINDS WILL NOT
BE MUCH OF A FACTOR THROUGH THIS FORECAST PERIOD WITH A LIGHT
AND VARIABLE WIND TONIGHT AND GENERALLY A LIGHT EASTERLY
DIRECTION ON WEDNESDAY WITH SPEEDS OF LESS THAN 10 KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...SMITH



000
FXUS63 KILX 010837
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
337 AM CDT WED JUL 1 2015

.SHORT TERM...(TODAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

SFC BOUNDARY EXTENDING FROM SOUTHWESTERN NEB TO CENTRAL MO WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. THIS WILL REMAIN WEST
OF THE CWA WITH MOST OF THE PCPN REMAINING SOUTHWEST OF THE AREA
THIS MORNING. HOWEVER...THE BOUNDARY WILL BEGIN TO LIFT NORTHWARD
DURING THE AFTERNOON...SO ADDITIONAL SHOWERS AND STORMS WILL DEVELOP
NORTH OF THE BOUNDARY AND EFFECT CENTRAL ILLINOIS DURING THE
AFTERNOON. HIGHER POPS IN THE FORECAST WILL BE TO THE SOUTHWEST WITH
JUST A CHANCE DURING THE MORNING HOURS SOUTHWEST OF A RUSHVILLE TO
TERRE HAUTE, IN LINE. DURING THE AFTERNOON THIS LINE WITH SHIFT
NORTHWARD TO I-74 WITH LIKELY POPS IN THE SOUTHWEST AND SOUTHEAST.
SHOULD BE PLENTY OF CLOUDS TO KEEP TEMPS ON THE COOLER SIDE...SO
LOOKING AT AFTERNOON HIGHS ONLY IN THE UPPER 70S. WINDS THIS MORNING
WILL BE LIGHT BUT THEN INCREASE SOME FOR THE REST OF THE DAY.
NORTHERN PARTS OF THE CWA WILL BE NORTH OF THE FRONT ALL DAY SO WILL
SEE EASTERLY WINDS. SOUTH OF THE FRONT WINDS WILL BE SOUTHERLY.

&&

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

THIS RUN OF MODELS HAS MIXED NEWS.  THE NORTHERN HALF OF THE STATE
MAY IN FACT SEE SOME PARTLY CLOUDY AND DRY PDS OVER THE NEXT
WEEK...BUT THE SOUTHERN HALF OF THE STATE MAY NOT BE AS LUCKY. AS A
RESULT, THE FORECAST IS A BIT TROUBLESOME FROM A PERSISTENCE STAND
POINT. MAIN ISSUE WITH THE FORECAST IS THE LOCATION OF A QUASI-
STALLED BOUNDARY JUST TO THE SOUTH.  A SERIES OF SHORTWAVES INTERACT
AND KEEP PRECIPITATION OFF AND ON.  LOCATION OF THE BOUNDARY IS WHAT
REMAINS AN ISSUE. ALL MODELS ARE INCONSISTENT AND HAVE CONTINUITY
ISSUES BETWEEN THE QPF DEPICTION AND THE SFC FRONTAL ANALYSIS IN THE
WIND FIELDS.  OSCILLATING NORTH AND SOUTH IN SUBSEQUENT RUNS IS NOT
HELPING TO FIND ANY ABSOLUTES.  SO, FOR THIS FORECAST RUN, HAVE
WORKED THE FORECAST BEYOND TONIGHT INTO SLIGHTLY UPPING THE POPS
ACROSS THE SOUTH, PARTICULARLY SOUTH OF I70...BUT ALSO SOME MINOR
INCREASES IN CHANCE POPS SOUTH OF I72.

OVERNIGHT, THE HIGHEST POPS REMAIN IN THE SOUTH WITH BOUNDARY
DRIFTING SLOWLY SOUTHWARD OVERNIGHT AND SETTLING INTO THE OHIO RIVER
VALLEY.  FOR THURS THROUGH SAT, HAVE TRIED TO KEEP THE SILENT SLIGHT
POPS OR NONE FOR AREAS IMMEDIATELY ALONG AND NORTH OF LINE ROUGHLY
FROM SPRINGFIELD TO DANVILLE.  TO WRAP UP THE WEEKEND...THE
SUPERBLEND IS HANGING ONTO SOME CHANCE POPS BUT HAVE TRIED TO TEMPER
THEM SOMEWHAT AS THE WAVE AT 500MB IS BROAD, OPEN, AND PRODUCING
DIFF RESULTS BETWEEN THE ECMWF AND THE GFS.  MON NIGHT/TUESDAY TIME
FRAME IS WHEN THE AGREEMENT IS STARTING TO SHOW EVEN THIS FAR OUT
WITH A COLD FRONT SWEEPING THROUGH THE REGION AND MORE SIGNIFICANT
POPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1115 PM CDT TUE JUN 30 2015

MVFR VSBYS IN FOG/HZ OVERNIGHT WITH OUR NEXT WEATHER SYSTEM
PUSHING INTO MISSOURI BY MORNING. MODELS HAVE TRENDED FURTHER
WEST AND SOUTH WITH THE PRECIP SHIELD SO FOR NOW WILL CONTINUE
WITH VCSH OVER OUR SOUTHERN TAF SITES WITH LITTLE IF ANY PRECIP
FURTHER NORTH WITH LOW VFR CIGS SETTLING IN DURING THE MORNING
BASED ON THE LATEST FORECAST SOUNDINGS. SURFACE WINDS WILL NOT
BE MUCH OF A FACTOR THROUGH THIS FORECAST PERIOD WITH A LIGHT
AND VARIABLE WIND TONIGHT AND GENERALLY A LIGHT EASTERLY
DIRECTION ON WEDNESDAY WITH SPEEDS OF LESS THAN 10 KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...SMITH



000
FXUS63 KILX 010837
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
337 AM CDT WED JUL 1 2015

.SHORT TERM...(TODAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

SFC BOUNDARY EXTENDING FROM SOUTHWESTERN NEB TO CENTRAL MO WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. THIS WILL REMAIN WEST
OF THE CWA WITH MOST OF THE PCPN REMAINING SOUTHWEST OF THE AREA
THIS MORNING. HOWEVER...THE BOUNDARY WILL BEGIN TO LIFT NORTHWARD
DURING THE AFTERNOON...SO ADDITIONAL SHOWERS AND STORMS WILL DEVELOP
NORTH OF THE BOUNDARY AND EFFECT CENTRAL ILLINOIS DURING THE
AFTERNOON. HIGHER POPS IN THE FORECAST WILL BE TO THE SOUTHWEST WITH
JUST A CHANCE DURING THE MORNING HOURS SOUTHWEST OF A RUSHVILLE TO
TERRE HAUTE, IN LINE. DURING THE AFTERNOON THIS LINE WITH SHIFT
NORTHWARD TO I-74 WITH LIKELY POPS IN THE SOUTHWEST AND SOUTHEAST.
SHOULD BE PLENTY OF CLOUDS TO KEEP TEMPS ON THE COOLER SIDE...SO
LOOKING AT AFTERNOON HIGHS ONLY IN THE UPPER 70S. WINDS THIS MORNING
WILL BE LIGHT BUT THEN INCREASE SOME FOR THE REST OF THE DAY.
NORTHERN PARTS OF THE CWA WILL BE NORTH OF THE FRONT ALL DAY SO WILL
SEE EASTERLY WINDS. SOUTH OF THE FRONT WINDS WILL BE SOUTHERLY.

&&

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 1 2015

THIS RUN OF MODELS HAS MIXED NEWS.  THE NORTHERN HALF OF THE STATE
MAY IN FACT SEE SOME PARTLY CLOUDY AND DRY PDS OVER THE NEXT
WEEK...BUT THE SOUTHERN HALF OF THE STATE MAY NOT BE AS LUCKY. AS A
RESULT, THE FORECAST IS A BIT TROUBLESOME FROM A PERSISTENCE STAND
POINT. MAIN ISSUE WITH THE FORECAST IS THE LOCATION OF A QUASI-
STALLED BOUNDARY JUST TO THE SOUTH.  A SERIES OF SHORTWAVES INTERACT
AND KEEP PRECIPITATION OFF AND ON.  LOCATION OF THE BOUNDARY IS WHAT
REMAINS AN ISSUE. ALL MODELS ARE INCONSISTENT AND HAVE CONTINUITY
ISSUES BETWEEN THE QPF DEPICTION AND THE SFC FRONTAL ANALYSIS IN THE
WIND FIELDS.  OSCILLATING NORTH AND SOUTH IN SUBSEQUENT RUNS IS NOT
HELPING TO FIND ANY ABSOLUTES.  SO, FOR THIS FORECAST RUN, HAVE
WORKED THE FORECAST BEYOND TONIGHT INTO SLIGHTLY UPPING THE POPS
ACROSS THE SOUTH, PARTICULARLY SOUTH OF I70...BUT ALSO SOME MINOR
INCREASES IN CHANCE POPS SOUTH OF I72.

OVERNIGHT, THE HIGHEST POPS REMAIN IN THE SOUTH WITH BOUNDARY
DRIFTING SLOWLY SOUTHWARD OVERNIGHT AND SETTLING INTO THE OHIO RIVER
VALLEY.  FOR THURS THROUGH SAT, HAVE TRIED TO KEEP THE SILENT SLIGHT
POPS OR NONE FOR AREAS IMMEDIATELY ALONG AND NORTH OF LINE ROUGHLY
FROM SPRINGFIELD TO DANVILLE.  TO WRAP UP THE WEEKEND...THE
SUPERBLEND IS HANGING ONTO SOME CHANCE POPS BUT HAVE TRIED TO TEMPER
THEM SOMEWHAT AS THE WAVE AT 500MB IS BROAD, OPEN, AND PRODUCING
DIFF RESULTS BETWEEN THE ECMWF AND THE GFS.  MON NIGHT/TUESDAY TIME
FRAME IS WHEN THE AGREEMENT IS STARTING TO SHOW EVEN THIS FAR OUT
WITH A COLD FRONT SWEEPING THROUGH THE REGION AND MORE SIGNIFICANT
POPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1115 PM CDT TUE JUN 30 2015

MVFR VSBYS IN FOG/HZ OVERNIGHT WITH OUR NEXT WEATHER SYSTEM
PUSHING INTO MISSOURI BY MORNING. MODELS HAVE TRENDED FURTHER
WEST AND SOUTH WITH THE PRECIP SHIELD SO FOR NOW WILL CONTINUE
WITH VCSH OVER OUR SOUTHERN TAF SITES WITH LITTLE IF ANY PRECIP
FURTHER NORTH WITH LOW VFR CIGS SETTLING IN DURING THE MORNING
BASED ON THE LATEST FORECAST SOUNDINGS. SURFACE WINDS WILL NOT
BE MUCH OF A FACTOR THROUGH THIS FORECAST PERIOD WITH A LIGHT
AND VARIABLE WIND TONIGHT AND GENERALLY A LIGHT EASTERLY
DIRECTION ON WEDNESDAY WITH SPEEDS OF LESS THAN 10 KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...SMITH



000
FXUS63 KLOT 010830
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010830
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 AM CDT WED JUL 1 2015

.SHORT TERM...
330 AM CDT

THROUGH THURSDAY...

DRY AND SEASONABLY COOL WEATHER IS EXPECTED TODAY. PROBABLY
BIGGEST FORECAST QUESTION IS IN REGARDS TO THE EXTENT OF
CLOUDINESS AS WE REMAIN CLOSE TO THE FRINGES OF THE CLOUD COVER
ASSOCIATED WITH CONVECTION ASSOCIATED WITH THE NW FLOW TO OUR WEST
AND SOUTH. NOT TOTALLY OUT OF THE QUESTION THAT SHOWERS COULD
SNEAK INTO OUR FARTHER SOUTHERN FRINGES OF OUR CWA TODAY...BUT
CHANCES LOOK SLIM. MODERATE NORTHEAST WINDS OFF THE LAKE SHOULD
KEEP TEMPERATURES IN THE 60S AT THE BEACHES...WHICH IS PRETTY
CHILLY BY JULY STANDARDS...WHILE FARTHER INLAND AWAY FROM THE
COOLING INFLUENCES OF THE LAKE WARM INTO THE 70S.

IZZI

&&

.LONG TERM...
330 AM CDT

THURSDAY NIGHT THROUGH TUESDAY...

LITTLE CHANGE TO THE PATTERN IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. UPPER TROUGH RESPONSIBLE FOR OUR COOL AND DRY WEATHER
WILL GRADUALLY WEAKEN AND SURFACE RIDGE WILL SLOWLY MIGRATE
EASTWARD ALLOWING FOR VERY SLOWLY MODERATING TEMPERATURES AND
GRADUAL WEAKENING OF THE LAKE BREEZES AND ASSOCIATED LAKE COOLING.
BY THE WEEKEND...TEMPS SHOULD MODERATE BACK CLOSER TO SEASONAL
NORMS AS GRADIENT FLOW TURNS MORE SOUTHERLY AND WARM AIR ADVECTION
KICKS IN. FLOW LOOKS WEAK ENOUGH SATURDAY TO ALLOW WEAK ILLINOIS
LAKE BREEZE TO FORM...AND CAN`T EVEN RULE IT OUT SUNDAY
EITHER...THOUGH THE MAGNITUDE OF ANY POSSIBLE LAKE COOLING LOOKS
TO BE FAR LESS OVER THE WEEKEND.

MEDIUM RANGE MODELS HAVE SLOWED THE ARRIVAL OF COLD FRONT AND
ASSOCIATED SHOWER/STORM CHANCES UNTIL MONDAY/MONDAY NIGHT TIME
FRAME NOW...SO OUTSIDE OF A SLIGHT CHANCE OF A SHOWER OR TWO
SNEAKING INTO OUR FAR SOUTHERN CWA AT TIMES THROUGH FRIDAY...IT
LOOKS LIKE DRY WEATHER WILL BE THE RULE THROUGH THE HOLIDAY
WEEKEND.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 010815
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
315 AM CDT WED JUL 1 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010815
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
315 AM CDT WED JUL 1 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010815
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
315 AM CDT WED JUL 1 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010815
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
315 AM CDT WED JUL 1 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010524
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1224 AM CDT WED JUL 1 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010524
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1224 AM CDT WED JUL 1 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010524
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1224 AM CDT WED JUL 1 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* MVFR CIGS DEVELOPING OVERNIGHT.

BMD

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST THROUGH MUCH OF
THE TAF PERIOD PROVIDING NORTHEAST WINDS AND DRY WEATHER. SOME
MODELS HINT AT THE POSSIBILITY OF MVFR CIGS OVERSPREADING THE
TERMINALS OVERNIGHT INTO EARLY WEDNESDAY AND THERE ARE PATCHY MVFR
OBS UPSTREAM...SO WILL HAVE TO KEEP AN EYE ON TRENDS OVERNIGHT.
NOT CONFIDENT ENOUGH AT THE MOMENT TO INCLUDE...BUT 10Z-16Z SEEMS
LIKE THE MOST LIKELY TIMEFRAME IF IT DOES OCCUR. A LAKE BREEZE
WEDNESDAY AFTERNOON IS EXPECTED TO DRIVE WIND AOA 10 KT UNTIL THE
EVENING WHEN WINDS SHOULD BEGIN TO TAPER AGAIN.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* LOW CONFIDENCE IN MVFR CIGS.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KILX 010424
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1124 PM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 835 PM CDT TUE JUN 30 2015

8PM SURFACE ANALYSIS INDICATES A WEAK SURFACE TROF/WIND SHIFT LINE
FROM JUST NORTH OF PARIS WEST TO NEAR QUINCY. WIDELY SCATTERED
STORMS DEVELOPED ALONG THIS BOUNDARY LATE THIS AFTERNOON AND
EXCEPT FOR A FEW SHOWERS IN SOUTHEAST ILLINOIS...THE ACTIVITY
HAS DECREASED IN AREAL COVERAGE AND INTENSITY. OUR ATTENTION NOW
TURNS TO A COMPLEX OF STORMS FORECAST TO DEVELOP OUT TO OUR WEST
AND THEN IS FORECAST TO SHIFT EAST-SOUTHEAST INTO EAST CENTRAL
MO AND SOUTHWEST ILLINOIS BY DAWN. MOST OF THE MORE SIGNIFICANT
CONVECTION IS FORECAST TO REMAIN OUT TO OUR WEST AND SOUTHWEST
LATE TONIGHT NEAR THE NOSE OF THE LOW LEVEL JET WITH THE MORE
IMPRESSIVE SPEED CONVERGENCE AT 850 MB NOTED OVER NORTHWEST
MISSOURI AND SOUTHWEST IOWA.

BASED ON SEVERAL OF THE CONVECTIVE ALLOWING MODELS...IT APPEARS
OUR WEST AND SOUTHWEST AREAS STAND THE BEST CHANCE FOR SHOWERS AND
ISOLD STORMS BY MORNING WITH THE BULK OF THE ACTIVITY AFFECTING
MAINLY THE SOUTHERN HALF OF THE FORECAST AREA ON WEDNESDAY.
CURRENT FORECAST HAS THIS WELL IN HAND...SO OTHER THAN SOME MINOR
ADJUSTMENTS TO THE OVERNIGHT WORDING...NO MAJOR CHANGES WERE MADE
TO THE ZFP. WE SHOULD HAVE THE UPDATE OUT BY 900 PM ADDRESSING THE
WEAKENING TRENDS WITH THE SHOWERS IN THE SOUTHEAST.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1115 PM CDT TUE JUN 30 2015

MVFR VSBYS IN FOG/HZ OVERNIGHT WITH OUR NEXT WEATHER SYSTEM
PUSHING INTO MISSOURI BY MORNING. MODELS HAVE TRENDED FURTHER
WEST AND SOUTH WITH THE PRECIP SHIELD SO FOR NOW WILL CONTINUE
WITH VCSH OVER OUR SOUTHERN TAF SITES WITH LITTLE IF ANY PRECIP
FURTHER NORTH WITH LOW VFR CIGS SETTLING IN DURING THE MORNING
BASED ON THE LATEST FORECAST SOUNDINGS. SURFACE WINDS WILL NOT
BE MUCH OF A FACTOR THROUGH THIS FORECAST PERIOD WITH A LIGHT
AND VARIABLE WIND TONIGHT AND GENERALLY A LIGHT EASTERLY
DIRECTION ON WEDNESDAY WITH SPEEDS OF LESS THAN 10 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...SMITH



000
FXUS63 KLOT 010310
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1010 PM CDT TUE JUN 30 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* POSSIBLE MVFR CIGS OVERNIGHT/WEDNESDAY MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR MVFR CIGS OVERNIGHT/WEDNESDAY MORNING.
* HIGH FOR WINDS THRU THE PERIOD. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 010310
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1010 PM CDT TUE JUN 30 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* POSSIBLE MVFR CIGS OVERNIGHT/WEDNESDAY MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR MVFR CIGS OVERNIGHT/WEDNESDAY MORNING.
* HIGH FOR WINDS THRU THE PERIOD. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010310
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1010 PM CDT TUE JUN 30 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* POSSIBLE MVFR CIGS OVERNIGHT/WEDNESDAY MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR MVFR CIGS OVERNIGHT/WEDNESDAY MORNING.
* HIGH FOR WINDS THRU THE PERIOD. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 010243
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
943 PM CDT TUE JUN 30 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010243
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
943 PM CDT TUE JUN 30 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010243
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
943 PM CDT TUE JUN 30 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 010243
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
943 PM CDT TUE JUN 30 2015

.UPDATE...
943 PM CDT

FOR EVENING UPDATE...

MINOR TWEAKS TO GOING FORECAST THIS EVENING...MAINLY WITH RESPECT TO
HOURLY GRIDS FOR WIND AND TEMPS...AS WELL AS SKY COVER WITH EARLIER
LAKE BREEZE/SECONDARY COLD FRONTAL BOUNDARY.

WEAK SURFACE LOW PRESSURE WAS PULLING AWAY FROM THE FORECAST AREA
ACROSS THE CENTRAL GREAT LAKES THIS EVENING. PRIMARY TRAILING COLD
FRONT EXTENDED SOUTHWEST ACROSS SOUTHERN IN/IL...WHILE A COMBINED
LAKE BREEZE/SECONDARY COLD FRONT HAD SURGED INLAND ACROSS NE IL/NW
IND AND EAST CENTRAL IL SINCE LATE AFTERNOON. WHILE COOLER AND DRIER
AIR WAS SPREADING INTO THE AREA ON NORTH-NORTHEAST WINDS...AN AREA
OF FOG HAD INITIALLY DEVELOPED BEHIND THE BOUNDARY ACROSS THE LAKE
AND BRIEFLY IMPACTED AREAS NEAR THE LAKE SHORE. WEB CAMERAS INDICATE
THAT FOG HAS LARGELY DISSIPATED...LIFTING INTO A LOW CEILING AND
SCATTERING AS LOWER DEW POINT AIR ARRIVES. 11-3.9 MICRON IR IMAGERY
INDICATES ONLY SCATTERED LOW CLOUDS AROUND THE SOUTH END OF THE LAKE
AT THIS HOUR...WITH MORE EXTENSIVE CLOUDINESS LIMITED TO THE
NORTHERN HALF OR SO. FARTHER WEST...CIRRUS WAS SPILLING INTO THE
MISSISSIPPI VALLEY IN ASSOCIATION WITH THE UPPER JET STREAK ENTERING
THE WESTERN SIDE OF THE UPPER TROUGH OVER THE EASTERN CONUS...WHICH
WILL LIKELY KEEP SKIES PARTLY CLOUDY IN NATURE THROUGH THE NIGHT.

SURFACE HIGH PRESSURE SPREADING INTO THE NORTHERN GREAT LAKES AND
UPPER MIDWEST WILL BUILD SOUTH INTO THE MIDWEST WEDNESDAY...SETTING
THE STAGE FOR A FEW DAYS OF DRY WEATHER.

RATZER

&&

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

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000
FXUS63 KILX 010146
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
846 PM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 835 PM CDT TUE JUN 30 2015

8PM SURFACE ANALYSIS INDICATES A WEAK SURFACE TROF/WIND SHIFT LINE
FROM JUST NORTH OF PARIS WEST TO NEAR QUINCY. WIDELY SCATTERED
STORMS DEVELOPED ALONG THIS BOUNDARY LATE THIS AFTERNOON AND
EXCEPT FOR A FEW SHOWERS IN SOUTHEAST ILLINOIS...THE ACTIVITY
HAS DECREASED IN AREAL COVERAGE AND INTENSITY. OUR ATTENTION NOW
TURNS TO A COMPLEX OF STORMS FORECAST TO DEVELOP OUT TO OUR WEST
AND THEN IS FORECAST TO SHIFT EAST-SOUTHEAST INTO EAST CENTRAL
MO AND SOUTHWEST ILLINOIS BY DAWN. MOST OF THE MORE SIGNIFICANT
CONVECTION IS FORECAST TO REMAIN OUT TO OUR WEST AND SOUTHWEST
LATE TONIGHT NEAR THE NOSE OF THE LOW LEVEL JET WITH THE MORE
IMPRESSIVE SPEED CONVERGENCE AT 850 MB NOTED OVER NORTHWEST
MISSOURI AND SOUTHWEST IOWA.

BASED ON SEVERAL OF THE CONVECTIVE ALLOWING MODELS...IT APPEARS
OUR WEST AND SOUTHWEST AREAS STAND THE BEST CHANCE FOR SHOWERS AND
ISOLD STORMS BY MORNING WITH THE BULK OF THE ACTIVITY AFFECTING
MAINLY THE SOUTHERN HALF OF THE FORECAST AREA ON WEDNESDAY.
CURRENT FORECAST HAS THIS WELL IN HAND...SO OTHER THAN SOME MINOR
ADJUSTMENTS TO THE OVERNIGHT WORDING...NO MAJOR CHANGES WERE MADE
TO THE ZFP. WE SHOULD HAVE THE UPDATE OUT BY 900 PM ADDRESSING THE
WEAKENING TRENDS WITH THE SHOWERS IN THE SOUTHEAST.


&&

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM CDT TUE JUN 30 2015

MAIN FORECAST CONCERN WILL BE TIMING AND COVERAGE OF CONVECTION
EXPECTED TO DEVELOP OUT TO OUR WEST AND DROP SOUTHEAST ACROSS
MISSOURI LATE TONIGHT AND PORTIONS OF SOUTHWEST IL WED MORNING.
FURTHER NORTH...HZ/BR CONCERNS LATE TONIGHT INTO TOMORROW MORNING.
SMALL BAND OF CONVECTION FORMED FROM NEAR DECATUR TO SOUTH OF
CHAMPAIGN AND HAS CONTINUED TO DRIFT SOUTHEAST LATE THIS AFTERNOON
AND WILL STAY SOUTH OF ALL OF OUR TAF SITES THIS EVENING. THE
NEXT BATCH OF SHOWERS AND STORMS IS EXPECTED TO DEVELOP WELL TO
OUR WEST THIS EVE AND TRACK SOUTHEAST ACROSS MO OVERNIGHT WITH
SPI AND DEC ON THE EDGE OF THE RAIN BY 12Z WED MORNING. FURTHER
NORTH, FORECAST SOUNDINGS INDICATE MORE OF A LOWER VFR CIG
STARTING TOMORROW MORNING BUT NOT MUCH IN THE WAY OF RAIN THAT
FAR NORTH. WILL CONTINUE WITH 3-5SM BR IN THE TAFS DURING THE
EARLY MORNING HOURS WITH LIGHT WINDS TONIGHT AND WINDS MOSTLY
OUT OF AN EASTERLY DIRECTION WITH SPEEDS OF LESS THAN 10KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...SMITH



000
FXUS63 KILX 010146
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
846 PM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 835 PM CDT TUE JUN 30 2015

8PM SURFACE ANALYSIS INDICATES A WEAK SURFACE TROF/WIND SHIFT LINE
FROM JUST NORTH OF PARIS WEST TO NEAR QUINCY. WIDELY SCATTERED
STORMS DEVELOPED ALONG THIS BOUNDARY LATE THIS AFTERNOON AND
EXCEPT FOR A FEW SHOWERS IN SOUTHEAST ILLINOIS...THE ACTIVITY
HAS DECREASED IN AREAL COVERAGE AND INTENSITY. OUR ATTENTION NOW
TURNS TO A COMPLEX OF STORMS FORECAST TO DEVELOP OUT TO OUR WEST
AND THEN IS FORECAST TO SHIFT EAST-SOUTHEAST INTO EAST CENTRAL
MO AND SOUTHWEST ILLINOIS BY DAWN. MOST OF THE MORE SIGNIFICANT
CONVECTION IS FORECAST TO REMAIN OUT TO OUR WEST AND SOUTHWEST
LATE TONIGHT NEAR THE NOSE OF THE LOW LEVEL JET WITH THE MORE
IMPRESSIVE SPEED CONVERGENCE AT 850 MB NOTED OVER NORTHWEST
MISSOURI AND SOUTHWEST IOWA.

BASED ON SEVERAL OF THE CONVECTIVE ALLOWING MODELS...IT APPEARS
OUR WEST AND SOUTHWEST AREAS STAND THE BEST CHANCE FOR SHOWERS AND
ISOLD STORMS BY MORNING WITH THE BULK OF THE ACTIVITY AFFECTING
MAINLY THE SOUTHERN HALF OF THE FORECAST AREA ON WEDNESDAY.
CURRENT FORECAST HAS THIS WELL IN HAND...SO OTHER THAN SOME MINOR
ADJUSTMENTS TO THE OVERNIGHT WORDING...NO MAJOR CHANGES WERE MADE
TO THE ZFP. WE SHOULD HAVE THE UPDATE OUT BY 900 PM ADDRESSING THE
WEAKENING TRENDS WITH THE SHOWERS IN THE SOUTHEAST.


&&

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM CDT TUE JUN 30 2015

MAIN FORECAST CONCERN WILL BE TIMING AND COVERAGE OF CONVECTION
EXPECTED TO DEVELOP OUT TO OUR WEST AND DROP SOUTHEAST ACROSS
MISSOURI LATE TONIGHT AND PORTIONS OF SOUTHWEST IL WED MORNING.
FURTHER NORTH...HZ/BR CONCERNS LATE TONIGHT INTO TOMORROW MORNING.
SMALL BAND OF CONVECTION FORMED FROM NEAR DECATUR TO SOUTH OF
CHAMPAIGN AND HAS CONTINUED TO DRIFT SOUTHEAST LATE THIS AFTERNOON
AND WILL STAY SOUTH OF ALL OF OUR TAF SITES THIS EVENING. THE
NEXT BATCH OF SHOWERS AND STORMS IS EXPECTED TO DEVELOP WELL TO
OUR WEST THIS EVE AND TRACK SOUTHEAST ACROSS MO OVERNIGHT WITH
SPI AND DEC ON THE EDGE OF THE RAIN BY 12Z WED MORNING. FURTHER
NORTH, FORECAST SOUNDINGS INDICATE MORE OF A LOWER VFR CIG
STARTING TOMORROW MORNING BUT NOT MUCH IN THE WAY OF RAIN THAT
FAR NORTH. WILL CONTINUE WITH 3-5SM BR IN THE TAFS DURING THE
EARLY MORNING HOURS WITH LIGHT WINDS TONIGHT AND WINDS MOSTLY
OUT OF AN EASTERLY DIRECTION WITH SPEEDS OF LESS THAN 10KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...SMITH



000
FXUS63 KILX 010146
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
846 PM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 835 PM CDT TUE JUN 30 2015

8PM SURFACE ANALYSIS INDICATES A WEAK SURFACE TROF/WIND SHIFT LINE
FROM JUST NORTH OF PARIS WEST TO NEAR QUINCY. WIDELY SCATTERED
STORMS DEVELOPED ALONG THIS BOUNDARY LATE THIS AFTERNOON AND
EXCEPT FOR A FEW SHOWERS IN SOUTHEAST ILLINOIS...THE ACTIVITY
HAS DECREASED IN AREAL COVERAGE AND INTENSITY. OUR ATTENTION NOW
TURNS TO A COMPLEX OF STORMS FORECAST TO DEVELOP OUT TO OUR WEST
AND THEN IS FORECAST TO SHIFT EAST-SOUTHEAST INTO EAST CENTRAL
MO AND SOUTHWEST ILLINOIS BY DAWN. MOST OF THE MORE SIGNIFICANT
CONVECTION IS FORECAST TO REMAIN OUT TO OUR WEST AND SOUTHWEST
LATE TONIGHT NEAR THE NOSE OF THE LOW LEVEL JET WITH THE MORE
IMPRESSIVE SPEED CONVERGENCE AT 850 MB NOTED OVER NORTHWEST
MISSOURI AND SOUTHWEST IOWA.

BASED ON SEVERAL OF THE CONVECTIVE ALLOWING MODELS...IT APPEARS
OUR WEST AND SOUTHWEST AREAS STAND THE BEST CHANCE FOR SHOWERS AND
ISOLD STORMS BY MORNING WITH THE BULK OF THE ACTIVITY AFFECTING
MAINLY THE SOUTHERN HALF OF THE FORECAST AREA ON WEDNESDAY.
CURRENT FORECAST HAS THIS WELL IN HAND...SO OTHER THAN SOME MINOR
ADJUSTMENTS TO THE OVERNIGHT WORDING...NO MAJOR CHANGES WERE MADE
TO THE ZFP. WE SHOULD HAVE THE UPDATE OUT BY 900 PM ADDRESSING THE
WEAKENING TRENDS WITH THE SHOWERS IN THE SOUTHEAST.


&&

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM CDT TUE JUN 30 2015

MAIN FORECAST CONCERN WILL BE TIMING AND COVERAGE OF CONVECTION
EXPECTED TO DEVELOP OUT TO OUR WEST AND DROP SOUTHEAST ACROSS
MISSOURI LATE TONIGHT AND PORTIONS OF SOUTHWEST IL WED MORNING.
FURTHER NORTH...HZ/BR CONCERNS LATE TONIGHT INTO TOMORROW MORNING.
SMALL BAND OF CONVECTION FORMED FROM NEAR DECATUR TO SOUTH OF
CHAMPAIGN AND HAS CONTINUED TO DRIFT SOUTHEAST LATE THIS AFTERNOON
AND WILL STAY SOUTH OF ALL OF OUR TAF SITES THIS EVENING. THE
NEXT BATCH OF SHOWERS AND STORMS IS EXPECTED TO DEVELOP WELL TO
OUR WEST THIS EVE AND TRACK SOUTHEAST ACROSS MO OVERNIGHT WITH
SPI AND DEC ON THE EDGE OF THE RAIN BY 12Z WED MORNING. FURTHER
NORTH, FORECAST SOUNDINGS INDICATE MORE OF A LOWER VFR CIG
STARTING TOMORROW MORNING BUT NOT MUCH IN THE WAY OF RAIN THAT
FAR NORTH. WILL CONTINUE WITH 3-5SM BR IN THE TAFS DURING THE
EARLY MORNING HOURS WITH LIGHT WINDS TONIGHT AND WINDS MOSTLY
OUT OF AN EASTERLY DIRECTION WITH SPEEDS OF LESS THAN 10KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...SMITH




000
FXUS63 KILX 010146
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
846 PM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 835 PM CDT TUE JUN 30 2015

8PM SURFACE ANALYSIS INDICATES A WEAK SURFACE TROF/WIND SHIFT LINE
FROM JUST NORTH OF PARIS WEST TO NEAR QUINCY. WIDELY SCATTERED
STORMS DEVELOPED ALONG THIS BOUNDARY LATE THIS AFTERNOON AND
EXCEPT FOR A FEW SHOWERS IN SOUTHEAST ILLINOIS...THE ACTIVITY
HAS DECREASED IN AREAL COVERAGE AND INTENSITY. OUR ATTENTION NOW
TURNS TO A COMPLEX OF STORMS FORECAST TO DEVELOP OUT TO OUR WEST
AND THEN IS FORECAST TO SHIFT EAST-SOUTHEAST INTO EAST CENTRAL
MO AND SOUTHWEST ILLINOIS BY DAWN. MOST OF THE MORE SIGNIFICANT
CONVECTION IS FORECAST TO REMAIN OUT TO OUR WEST AND SOUTHWEST
LATE TONIGHT NEAR THE NOSE OF THE LOW LEVEL JET WITH THE MORE
IMPRESSIVE SPEED CONVERGENCE AT 850 MB NOTED OVER NORTHWEST
MISSOURI AND SOUTHWEST IOWA.

BASED ON SEVERAL OF THE CONVECTIVE ALLOWING MODELS...IT APPEARS
OUR WEST AND SOUTHWEST AREAS STAND THE BEST CHANCE FOR SHOWERS AND
ISOLD STORMS BY MORNING WITH THE BULK OF THE ACTIVITY AFFECTING
MAINLY THE SOUTHERN HALF OF THE FORECAST AREA ON WEDNESDAY.
CURRENT FORECAST HAS THIS WELL IN HAND...SO OTHER THAN SOME MINOR
ADJUSTMENTS TO THE OVERNIGHT WORDING...NO MAJOR CHANGES WERE MADE
TO THE ZFP. WE SHOULD HAVE THE UPDATE OUT BY 900 PM ADDRESSING THE
WEAKENING TRENDS WITH THE SHOWERS IN THE SOUTHEAST.


&&

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM CDT TUE JUN 30 2015

MAIN FORECAST CONCERN WILL BE TIMING AND COVERAGE OF CONVECTION
EXPECTED TO DEVELOP OUT TO OUR WEST AND DROP SOUTHEAST ACROSS
MISSOURI LATE TONIGHT AND PORTIONS OF SOUTHWEST IL WED MORNING.
FURTHER NORTH...HZ/BR CONCERNS LATE TONIGHT INTO TOMORROW MORNING.
SMALL BAND OF CONVECTION FORMED FROM NEAR DECATUR TO SOUTH OF
CHAMPAIGN AND HAS CONTINUED TO DRIFT SOUTHEAST LATE THIS AFTERNOON
AND WILL STAY SOUTH OF ALL OF OUR TAF SITES THIS EVENING. THE
NEXT BATCH OF SHOWERS AND STORMS IS EXPECTED TO DEVELOP WELL TO
OUR WEST THIS EVE AND TRACK SOUTHEAST ACROSS MO OVERNIGHT WITH
SPI AND DEC ON THE EDGE OF THE RAIN BY 12Z WED MORNING. FURTHER
NORTH, FORECAST SOUNDINGS INDICATE MORE OF A LOWER VFR CIG
STARTING TOMORROW MORNING BUT NOT MUCH IN THE WAY OF RAIN THAT
FAR NORTH. WILL CONTINUE WITH 3-5SM BR IN THE TAFS DURING THE
EARLY MORNING HOURS WITH LIGHT WINDS TONIGHT AND WINDS MOSTLY
OUT OF AN EASTERLY DIRECTION WITH SPEEDS OF LESS THAN 10KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...SMITH




000
FXUS63 KLOT 302348
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
648 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 302348
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
648 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 302348
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
648 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 302348
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
648 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 302348
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
648 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 302348
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
648 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* NORTHEAST WINDS AROUND 10KT EARLY THIS EVENING.
* POSSIBLE MVFR CIGS THIS EVENING...OVERNIGHT AND WEDNESDAY
  MORNING.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

AREA OF LOW CLOUDS/FOG OVER THE LAKE HAS BEEN HUGGING THE SHORE
LINE AND WILL SOON MOVE INTO NORTHWEST INDIANA. CONFIDENCE
REGARDING HOW LOW CIGS/VIS MAY DROP AT GYY IS LOW...BUT THERE IS
A POTENTIAL FOR A SHORT PERIOD OF LIFR/VLIFR CONDITIONS. LOWER
CIGS HAVE REMAINED GENERALLY EAST OF ORD/MDW BUT AS SUNSET
APPROACHES...ITS POSSIBLE SOME OF THIS MAY MOVE INLAND. OTHERWISE
MVFR CIGS OVER NORTHEAST WI AND NORTHERN LAKE MICHIGAN MAY MOVE
SOUTH LATER THIS EVENING AND OVERNIGHT. SOME GUIDANCE SUGGESTS
LOW CLOUDS DEVELOPING ACROSS THE AREA OVERNIGHT. STILL SOME
UNCERTAINTY REGARDING TRENDS AND HOW WIDESPREAD ANY LOWER CIGS
BECOME...SO BACKED OFF TO JUST SCATTERED MENTION WITH THIS
FORECAST AND TRENDS WILL NEED TO BE MONITORED.

NORTHEAST WINDS AROUND 10 KT WILL SLOWLY DIMINISH THIS EVENING
AND MAY TURN BACK MORE NORTH/NORTHWEST BY WEDNESDAY MORNING. WIND
DIRECTIONS WILL LIKELY TURN BACK NORTHEASTERLY WEDNESDAY AFTERNOON
WITH A POTENTIAL LAKE BREEZE PUSHING WIND SPEEDS BACK TO AROUND 10
KTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS EVENING THRU WEDNESDAY MORNING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

* THURSDAY THROUGH SATURDAY...DRY/VFR. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF TSRA. EASTERLY WINDS.
* MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KILX 302332
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
632 PM CDT TUE JUN 30 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM CDT TUE JUN 30 2015

MAIN FORECAST CONCERN WILL BE TIMING AND COVERAGE OF CONVECTION
EXPECTED TO DEVELOP OUT TO OUR WEST AND DROP SOUTHEAST ACROSS
MISSOURI LATE TONIGHT AND PORTIONS OF SOUTHWEST IL WED MORNING.
FURTHER NORTH...HZ/BR CONCERNS LATE TONIGHT INTO TOMORROW MORNING.
SMALL BAND OF CONVECTION FORMED FROM NEAR DECATUR TO SOUTH OF
CHAMPAIGN AND HAS CONTINUED TO DRIFT SOUTHEAST LATE THIS AFTERNOON
AND WILL STAY SOUTH OF ALL OF OUR TAF SITES THIS EVENING. THE
NEXT BATCH OF SHOWERS AND STORMS IS EXPECTED TO DEVELOP WELL TO
OUR WEST THIS EVE AND TRACK SOUTHEAST ACROSS MO OVERNIGHT WITH
SPI AND DEC ON THE EDGE OF THE RAIN BY 12Z WED MORNING. FURTHER
NORTH, FORECAST SOUNDINGS INDICATE MORE OF A LOWER VFR CIG
STARTING TOMORROW MORNING BUT NOT MUCH IN THE WAY OF RAIN THAT
FAR NORTH. WILL CONTINUE WITH 3-5SM BR IN THE TAFS DURING THE
EARLY MORNING HOURS WITH LIGHT WINDS TONIGHT AND WINDS MOSTLY
OUT OF AN EASTERLY DIRECTION WITH SPEEDS OF LESS THAN 10KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...SMITH



000
FXUS63 KILX 302332
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
632 PM CDT TUE JUN 30 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM CDT TUE JUN 30 2015

MAIN FORECAST CONCERN WILL BE TIMING AND COVERAGE OF CONVECTION
EXPECTED TO DEVELOP OUT TO OUR WEST AND DROP SOUTHEAST ACROSS
MISSOURI LATE TONIGHT AND PORTIONS OF SOUTHWEST IL WED MORNING.
FURTHER NORTH...HZ/BR CONCERNS LATE TONIGHT INTO TOMORROW MORNING.
SMALL BAND OF CONVECTION FORMED FROM NEAR DECATUR TO SOUTH OF
CHAMPAIGN AND HAS CONTINUED TO DRIFT SOUTHEAST LATE THIS AFTERNOON
AND WILL STAY SOUTH OF ALL OF OUR TAF SITES THIS EVENING. THE
NEXT BATCH OF SHOWERS AND STORMS IS EXPECTED TO DEVELOP WELL TO
OUR WEST THIS EVE AND TRACK SOUTHEAST ACROSS MO OVERNIGHT WITH
SPI AND DEC ON THE EDGE OF THE RAIN BY 12Z WED MORNING. FURTHER
NORTH, FORECAST SOUNDINGS INDICATE MORE OF A LOWER VFR CIG
STARTING TOMORROW MORNING BUT NOT MUCH IN THE WAY OF RAIN THAT
FAR NORTH. WILL CONTINUE WITH 3-5SM BR IN THE TAFS DURING THE
EARLY MORNING HOURS WITH LIGHT WINDS TONIGHT AND WINDS MOSTLY
OUT OF AN EASTERLY DIRECTION WITH SPEEDS OF LESS THAN 10KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...SMITH




000
FXUS63 KLOT 302210
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
510 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* NORTHEAST WINDS 10-15KT THRU THIS EVENING.
* POSSIBLE MVFR CIGS LATE THIS AFTERNOON/EARLY THIS EVENING AND
  AGAIN LATER THIS EVENING/OVERNIGHT.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 22Z...

LAKE BREEZE/COLD FRONT NOW SOUTHWEST OF ORD/MDW AND WILL CONTINUE
MOVING INLAND THRU THIS EVENING. NORTHEAST WINDS 10-15KT WILL
SLOWLY DIMINISH UNDER 10KTS THIS EVENING. IFR/LIFR CIGS NEAR LAKE
MICHIGAN WILL CONTINUE MOVING SOUTH THRU EARLY THIS EVENING.
FAIRLY LOW CONFIDENCE REGARDING IF THESE LOWER CIGS WILL MOVE AS
FAR INLAND AS ORD/MDW BUT INCLUDED A TEMPO WITH THIS UPDATE FOR
CIGS AROUND 1KFT. CMS

PREVIOUS 18Z DISCUSSION...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS LATE THIS AFTERNOON/THIS EVENING AND
  OVERNIGHT. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 302210
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
510 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* NORTHEAST WINDS 10-15KT THRU THIS EVENING.
* POSSIBLE MVFR CIGS LATE THIS AFTERNOON/EARLY THIS EVENING AND
  AGAIN LATER THIS EVENING/OVERNIGHT.
* NORTHEAST WINDS AROUND 10KT WEDNESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 22Z...

LAKE BREEZE/COLD FRONT NOW SOUTHWEST OF ORD/MDW AND WILL CONTINUE
MOVING INLAND THRU THIS EVENING. NORTHEAST WINDS 10-15KT WILL
SLOWLY DIMINISH UNDER 10KTS THIS EVENING. IFR/LIFR CIGS NEAR LAKE
MICHIGAN WILL CONTINUE MOVING SOUTH THRU EARLY THIS EVENING.
FAIRLY LOW CONFIDENCE REGARDING IF THESE LOWER CIGS WILL MOVE AS
FAR INLAND AS ORD/MDW BUT INCLUDED A TEMPO WITH THIS UPDATE FOR
CIGS AROUND 1KFT. CMS

PREVIOUS 18Z DISCUSSION...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS LATE THIS AFTERNOON/THIS EVENING AND
  OVERNIGHT. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 302105
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
405 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 302105
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
405 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
404 PM CDT

AS LOW PRESSURE DEPARTS THE LAKE THIS AFTERNOON...WINDS ARE
QUICKLY SHIFTING TO THE NORTH. AS THIS OCCURS...SPEEDS ARE ALSO
QUICKLY INCREASING TO THE 15 TO 25 KT RANGE OVER MUCH OF THE LAKE.
THESE SPEEDS WILL LIKELY SPREAD THROUGH THE REMAINING SOUTHERN
PORTIONS OF THE LAKE THROUGH EARLY THIS EVENING. ALTHOUGH THE
STRONGEST SPEEDS SHOULD REMAIN AWAY FROM THE NEARSHORE...DO THINK
10 TO 20 KT WINDS WILL BE POSSIBLE IN THESE AREAS THIS
AFTERNOON/EVENING. WITH HIGH PRESSURE SPANNING THE GREAT LAKES
REGION THROUGH THE END OF THE WORK WEEK...NORTHERLY WINDS WILL
PREVAIL.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 302017
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
317 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
313 PM CDT

WEDNESDAY NIGHT THROUGH TUESDAY...

MOST OF THE REMAINING FORECAST PERIOD WILL LIKELY SEE BELOW
NORMAL TEMPS AND WITH DRIER CONDITIONS. THIS WILL BE THE CASE
WEDNESDAY NIGHT AS EXPECTED SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL PLAINS LIKELY DRIFT EAST SOUTHEAST TOWARDS A MORE
MOIST/UNSTABLE AIRMASS...WHILE DRIER AIR AND LITTLE TO NO
INSTABILITY ARE PRESENT ACROSS THE CWA. DID LEAVE SLIGHT CHANCE
POPS FOR SHOWERS ACROSS THE FAR SOUTHERN CWA FOR SOME VARIABILITY
IN GUIDANCE TRYING TO INCH THIS PRECIP CLOSER TO THE CWA.
HOWEVER...A MORE LIKELY SCENARIO IS FOR THIS DEVELOPMENT TO REMAIN
TO THE SOUTH. THURSDAY AND THURSDAY NIGHT WILL LIKELY BE DRY AS
HIGH PRESSURE DOMINATES THE REGION...BUT THERE STILL IS SOME
VARIABILITY AMONG MODEL GUIDANCE HANDLING OF AN APPROACHING UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE REFLECTION...AND ASSOCIATED
PRECIP ON FRIDAY. ALTHOUGH THE BEST PRECIP AXIS SHOULD REMAIN JUST
SOUTH OF THE CWA...DID LEAVE SLIGHT CHANCE OF SHOWERS FOR THE
SOUTHERN HALF OF THE CWA DUE TO THIS UNCERTAINTY. THE REMAINDER OF
THE WEEKEND IS LOOKING DRY FOR MOST AREAS BUT TOWARDS SUNDAY AND
ESPECIALLY BY EARLY NEXT WEEK...A RETURN TO SOUTHERLY FLOW WILL
ALLOW A WARMER AND MORE MOIST ENVIRONMENT TO SPREAD BACK NORTH
ACROSS THE REGION. ISOLATED TO SCATTERED SHOWER/THUNDERSTORM
DEVELOPMENT IS APPEARING MORE PROBABLE ON SUNDAY...BUT WITH
CONTINUED MOIST ADVECTION AND INCREASING FLOW ALOFT EARLY NEXT
WEEK...MORE WIDESPREAD DEVELOPMENT WILL BECOME MORE LIKELY. TIMING
AND PLACEMENT ISSUES ARE PRESENT DURING THIS TIME....BUT MORE
ORGANIZED DEVELOPMENT DOES APPEAR POSSIBLE IN THE MONDAY TO
TUESDAY TIME FRAME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KILX 301946
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
246 PM CDT TUE JUN 30 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

&&

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1238 PM CDT TUE JUN 30 2015

MAIN AVIATION FORECAST CONCERN IS THE DEVELOPMENT AND TRACK OF A
POTENTIAL STORM COMPLEX LATE TONIGHT INTO WEDNESDAY MORNING. MODEL
TRENDS HAVE BEEN SLOWER AND FURTHER SOUTH WITH THE
TRACK...GENERALLY FROM THE SOUTH DAKOTA/NEBRASKA BORDER THIS
EVENING ACROSS CENTRAL MISSOURI INTO SOUTHERN ILLINOIS BY
WEDNESDAY MORNING. BELIEVE THE CENTRAL ILLINOIS TERMINALS WILL BE
ON THE NORTHERN FRINGE OF THE PRECIP...SO HAVE ONLY INCLUDED MVFR
CEILINGS AND VCTS AFTER 13/14Z AT KSPI AND KDEC. FURTHER
NORTH...HAVE MAINTAINED DRY CONDITIONS AT THE I-74 TAF SITES. THE
ONLY OTHER ISSUE WOULD BE POSSIBLE FOG TONIGHT AS SKIES CLEAR AND
WINDS BECOME LIGHT/VARIABLE. FORECAST SOUNDINGS AND NUMERIC
GUIDANCE BOTH INDICATE SOME LIGHT FOG OVERNIGHT...SO HAVE LOWERED
VSBYS TO AROUND 3SM AFTER 09Z ACCORDINGLY.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...BARNES




000
FXUS63 KILX 301946
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
246 PM CDT TUE JUN 30 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 246 PM CDT TUE JUN 30 2015

18Z/1PM WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP TROUGH OVER THE
GREAT LAKES/OHIO RIVER VALLEY...WITH NORTHWESTERLY FLOW PREVAILING
FROM THE NORTHERN PLAINS TO THE TENNESSEE RIVER VALLEY.  TWO
DISTINCT SHORT-WAVES ARE EMBEDDED WITHIN THE FLOW...ONE OVER INDIANA
AND ANOTHER FURTHER UPSTREAM ACROSS SOUTHERN SASKATCHEWAN.  DESPITE
WEAK FRONTAL BOUNDARY DROPPING INTO NORTH-CENTRAL ILLINOIS THIS
AFTERNOON...UPPER SUPPORT IS VERY WEAK IN THE WAKE OF THE INDIANA
WAVE.  AS A RESULT...AM ONLY EXPECTING ISOLATED SHOWERS/THUNDER
AHEAD OF THE APPROACHING FRONT LATE THIS AFTERNOON INTO THE EARLY
EVENING.  MOST HIGH-RES MODELS SUGGEST THE GREATEST AREAL COVERAGE
OF PRECIP WILL BE ACROSS EAST-CENTRAL ILLINOIS.  HAVE INCLUDED 20-30
POPS EARLY THIS EVENING TO COVER ANY POTENTIAL CONVECTION ALONG THE
FRONT...BUT THINK THIS WILL QUICKLY DISSIPATE AFTER SUNSET.  FURTHER
NORTHWEST...A LARGE COMPLEX OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AHEAD OF THE SASKATCHEWAN WAVE THIS EVENING...THEN TRACK
SOUTHEASTWARD TOWARD THE REGION OVERNIGHT INTO WEDNESDAY MORNING.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM AND TRACKING IT FURTHER
S/SW ACROSS MAINLY CENTRAL MISSOURI INTO SOUTHERN ILLINOIS.  HAVE
TRIMMED POPS CONSIDERABLY AFTER MIDNIGHT...WITH ONLY SLIGHT CHANCES
ALONG/SOUTHWEST OF A MACOMB...TO SPRINGFIELD...TO OLNEY LINE TOWARD
DAWN WEDNESDAY.  ELSEWHERE AROUND CENTRAL ILLINOIS...DRY CONDITIONS
WILL PREVAIL WITH PERHAPS SOME PATCHY FOG DEVELOPING.

&&

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUN 30 2015

DESPITE A LONG WAVE TROUGH REMAINING ACROSS THE EASTERN HALF OF THE
CONUS FOR MUCH OF THE NEXT WEEK, THERE STILL APPEAR TO BE A FEW DRY
PERIODS, ESPECIALLY FOR THE NORTHERN HALF OF ILLINOIS.

WEDNESDAY WILL START OUT WITH A STRONG MCS DEVELOPING IN NEBRASKA
AND A WARM FRONT EXTENDING EAST AHEAD OF THE LOW ACROSS MISSOURI AND
SOUTHERN ILLINOIS. THE 12Z MODELS HAVE ALL SLOWED DOWN THE
PROGRESSION OF THE LOW CENTER, WITH THE LOW PASSAGE NOW DELAYED
UNTIL THURSDAY. INCREASING WARM FRONTAL CIRCULATION ACROSS SOUTH-
CENTRAL ILLINOIS WILL BE THE FOCUS FOR SHOWERS AND STORMS TO DEVELOP
WELL AHEAD OF THE LOW, AS EARLY AS 12Z/7AM WEDNESDAY IN OUR SW
COUNTIES. SHOWERS AND STORMS WILL EXPAND EASTWARD DURING THE DAY,
WITH THE BEST CHANCES OF RAIN COMING WED NIGHT AS LOW CENTER REACHES
FAR SW IL BY 12Z/7AM THURSDAY. SHOWERS WILL BE CONFINED TO AREAS
SOUTH OF I-70 THURSDAY, AS THE LOW PROGRESSES INTO WESTERN KENTUCKY.

A STATIONARY FRONT LINGERING BEHIND THE LOW ACROSS SOUTHERN IL WILL
KEEP PRECIP CHANCES ACROSS OUR FAR SOUTHEASTERN COUNTIES FRIDAY
THROUGH SATURDAY NIGHT, WHILE THE REMAINDER OF OUR COUNTIES SEE A
POTENTIALLY DRY START TO THE WEEKEND. THE DRY TREND MAY END ON
SUNDAY AS A LOBE OF THE UPPER TROUGH SWINGS ACROSS IL. THE 12Z
ECMWF IS MORE AGGRESSIVE WITH PRECIP WITH THAT FEATURE, WITH THE
CANADIAN DRY AND THE GFS IN THE MIDDLE, SHOWING SCATTERED
AFTERNOON CONVECTION. WE KEPT CHANCE POPS FOR AREAS SOUTHEAST OF
THE IL RIVER FOR NOW.

A COLD FRONT ARRIVING FROM THE NORTHWEST ON MONDAY WILL PROMPT STORM
CHANCES ACROSS ALL OF IL. AS THE FRONT STALLS OUT ACROSS THE AREA,
RAIN CHANCES WILL LINGER THROUGH TUESDAY.

TEMPS ARE PROJECTED TO REMAIN BELOW NORMAL THROUGH FRIDAY, THEN
THE GFS ADVERTISES A WARMING TREND THIS WEEKEND INTO EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE TRIES TO BUILD INTO ILLINOIS. THE
ECMWF HAS CONTINUED TO DIFFER WITH THAT SOLUTION, INDICATING THE
ARRIVAL OF ANOTHER TROUGH FROM THE NORTHERN PLAINS EARLY NEXT
WEEK, AND A CONTINUATION OF BELOW NORMAL TEMPS. THE END RESULT IN
HIGHS WAS TO CLIMB TOWARD NORMAL EACH DAY SATURDAY THROUGH MONDAY,
WITH NORMAL BEING MID 80S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1238 PM CDT TUE JUN 30 2015

MAIN AVIATION FORECAST CONCERN IS THE DEVELOPMENT AND TRACK OF A
POTENTIAL STORM COMPLEX LATE TONIGHT INTO WEDNESDAY MORNING. MODEL
TRENDS HAVE BEEN SLOWER AND FURTHER SOUTH WITH THE
TRACK...GENERALLY FROM THE SOUTH DAKOTA/NEBRASKA BORDER THIS
EVENING ACROSS CENTRAL MISSOURI INTO SOUTHERN ILLINOIS BY
WEDNESDAY MORNING. BELIEVE THE CENTRAL ILLINOIS TERMINALS WILL BE
ON THE NORTHERN FRINGE OF THE PRECIP...SO HAVE ONLY INCLUDED MVFR
CEILINGS AND VCTS AFTER 13/14Z AT KSPI AND KDEC. FURTHER
NORTH...HAVE MAINTAINED DRY CONDITIONS AT THE I-74 TAF SITES. THE
ONLY OTHER ISSUE WOULD BE POSSIBLE FOG TONIGHT AS SKIES CLEAR AND
WINDS BECOME LIGHT/VARIABLE. FORECAST SOUNDINGS AND NUMERIC
GUIDANCE BOTH INDICATE SOME LIGHT FOG OVERNIGHT...SO HAVE LOWERED
VSBYS TO AROUND 3SM AFTER 09Z ACCORDINGLY.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...BARNES



000
FXUS63 KLOT 301911
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
211 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 301900
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
200 PM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 301900
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
200 PM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 301900
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
200 PM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 301900
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
200 PM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KILX 301739
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1239 PM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 922 AM CDT TUE JUN 30 2015

MADE SOME UPDATES TO THE FORECAST THIS MORNING...MAINLY TO LOWER
POPS. SHORT-WAVE TROUGH THAT BROUGHT A FEW SHOWERS AND
THUNDERSTORMS TO THE AREA LAST NIGHT IS CURRENTLY PUSHING INTO
INDIANA. SUBSIDENCE ON THE BACK SIDE OF THE WAVE WILL LEAD TO DRY
CONDITIONS FOR THE REMAINDER OF THE MORNING INTO THE EARLY
AFTERNOON BEFORE AN APPROACHING SURFACE TROUGH POTENTIALLY
TRIGGERS A FEW ADDITIONAL STORMS THIS AFTERNOON. MOST MODELS
REMAIN FAIRLY DRY...WITH BOTH THE HRRR AND NAM SUGGESTING THE BEST
AREAL COVERAGE WILL LIKELY BE ACROSS EAST-CENTRAL ILLINOIS DURING
THE LATE AFTERNOON. HAVE THEREFORE GONE WITH A DRY FORECAST FOR
THE REMAINDER OF THE MORNING...WITH LOW CHANCE POPS ALONG/SOUTH OF
A RUSHVILLE TO DANVILLE LINE DURING THE AFTERNOON. UNDER MOSTLY
SUNNY SKIES...TEMPERATURES WILL BE A FEW DEGREES WARMER THAN
YESTERDAY...WITH AFTERNOON HIGHS REACHING THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1238 PM CDT TUE JUN 30 2015

MAIN AVIATION FORECAST CONCERN IS THE DEVELOPMENT AND TRACK OF A
POTENTIAL STORM COMPLEX LATE TONIGHT INTO WEDNESDAY MORNING. MODEL
TRENDS HAVE BEEN SLOWER AND FURTHER SOUTH WITH THE
TRACK...GENERALLY FROM THE SOUTH DAKOTA/NEBRASKA BORDER THIS
EVENING ACROSS CENTRAL MISSOURI INTO SOUTHERN ILLINOIS BY
WEDNESDAY MORNING. BELIEVE THE CENTRAL ILLINOIS TERMINALS WILL BE
ON THE NORTHERN FRINGE OF THE PRECIP...SO HAVE ONLY INCLUDED MVFR
CEILINGS AND VCTS AFTER 13/14Z AT KSPI AND KDEC. FURTHER
NORTH...HAVE MAINTAINED DRY CONDITIONS AT THE I-74 TAF SITES. THE
ONLY OTHER ISSUE WOULD BE POSSIBLE FOG TONIGHT AS SKIES CLEAR AND
WINDS BECOME LIGHT/VARIABLE. FORECAST SOUNDINGS AND NUMERIC
GUIDANCE BOTH INDICATE SOME LIGHT FOG OVERNIGHT...SO HAVE LOWERED
VISBYS TO AROUND 3SM AFTER 09Z ACCORDINGLY.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...BARNES



000
FXUS63 KILX 301739
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1239 PM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 922 AM CDT TUE JUN 30 2015

MADE SOME UPDATES TO THE FORECAST THIS MORNING...MAINLY TO LOWER
POPS. SHORT-WAVE TROUGH THAT BROUGHT A FEW SHOWERS AND
THUNDERSTORMS TO THE AREA LAST NIGHT IS CURRENTLY PUSHING INTO
INDIANA. SUBSIDENCE ON THE BACK SIDE OF THE WAVE WILL LEAD TO DRY
CONDITIONS FOR THE REMAINDER OF THE MORNING INTO THE EARLY
AFTERNOON BEFORE AN APPROACHING SURFACE TROUGH POTENTIALLY
TRIGGERS A FEW ADDITIONAL STORMS THIS AFTERNOON. MOST MODELS
REMAIN FAIRLY DRY...WITH BOTH THE HRRR AND NAM SUGGESTING THE BEST
AREAL COVERAGE WILL LIKELY BE ACROSS EAST-CENTRAL ILLINOIS DURING
THE LATE AFTERNOON. HAVE THEREFORE GONE WITH A DRY FORECAST FOR
THE REMAINDER OF THE MORNING...WITH LOW CHANCE POPS ALONG/SOUTH OF
A RUSHVILLE TO DANVILLE LINE DURING THE AFTERNOON. UNDER MOSTLY
SUNNY SKIES...TEMPERATURES WILL BE A FEW DEGREES WARMER THAN
YESTERDAY...WITH AFTERNOON HIGHS REACHING THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1238 PM CDT TUE JUN 30 2015

MAIN AVIATION FORECAST CONCERN IS THE DEVELOPMENT AND TRACK OF A
POTENTIAL STORM COMPLEX LATE TONIGHT INTO WEDNESDAY MORNING. MODEL
TRENDS HAVE BEEN SLOWER AND FURTHER SOUTH WITH THE
TRACK...GENERALLY FROM THE SOUTH DAKOTA/NEBRASKA BORDER THIS
EVENING ACROSS CENTRAL MISSOURI INTO SOUTHERN ILLINOIS BY
WEDNESDAY MORNING. BELIEVE THE CENTRAL ILLINOIS TERMINALS WILL BE
ON THE NORTHERN FRINGE OF THE PRECIP...SO HAVE ONLY INCLUDED MVFR
CEILINGS AND VCTS AFTER 13/14Z AT KSPI AND KDEC. FURTHER
NORTH...HAVE MAINTAINED DRY CONDITIONS AT THE I-74 TAF SITES. THE
ONLY OTHER ISSUE WOULD BE POSSIBLE FOG TONIGHT AS SKIES CLEAR AND
WINDS BECOME LIGHT/VARIABLE. FORECAST SOUNDINGS AND NUMERIC
GUIDANCE BOTH INDICATE SOME LIGHT FOG OVERNIGHT...SO HAVE LOWERED
VISBYS TO AROUND 3SM AFTER 09Z ACCORDINGLY.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...BARNES




000
FXUS63 KLOT 301728
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1228 PM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* MVFR CEILINGS THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 18Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF NE WINDS HAS BEEN PUSHED BACK TO 21Z
AND MAY ACTUALLY DEVELOP AS LATE AS 22Z. REMNANT LOW LEVEL
MOISTURE WILL KEEP 1500 FOOT CEILINGS LIKELY LATE TONIGHT. ONCE
THE SURFACE HIGH GETS CLOSER WEDNESDAY MORNING...CLOUD COVER WILL
SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH IN MVFR CIGS THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP OR IMPACT TERMINALS.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 301728
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1228 PM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* MVFR CEILINGS THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 18Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF NE WINDS HAS BEEN PUSHED BACK TO 21Z
AND MAY ACTUALLY DEVELOP AS LATE AS 22Z. REMNANT LOW LEVEL
MOISTURE WILL KEEP 1500 FOOT CEILINGS LIKELY LATE TONIGHT. ONCE
THE SURFACE HIGH GETS CLOSER WEDNESDAY MORNING...CLOUD COVER WILL
SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH IN MVFR CIGS THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP OR IMPACT TERMINALS.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 301604
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1104 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* LAKE BREEZE AND THIS AFTERNOON.
* VICINITY SHOWERS THIS AFTERNOON.
* MVFR CIGS POSSIBLE AGAIN OVERNIGHT.

BMD/MM

//DISCUSSION...UPDATED 12Z...

PATCHY FOG THIS MORNING WILL CONTINUE TO IMPROVE OVER THE NEXT
COUPLE HOURS WITH SUNRISE WITH VFR CONDITIONS AND MODEST NORTHWEST
WINDS EXPECTED THROUGH THE REMAINDER OF THE MORNING AND MUCH OF
THE AFTERNOON. A LAKE BREEZE IS EXPECTED TO PUSH INLAND THIS
AFTERNOON TURNING WINDS TO THE NORTHEAST FOR THE CHICAGO
TERMINALS. CANNOT RULE OUT A FEW ISOLATED SHOWERS OR THUNDERSTORMS
DEVELOPING ALONG THE BOUNDARY HOWEVER CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAF. WINDS WILL SETTLE TO THE EAST
TONIGHT. NAM/MET GUIDANCE INDICATES THAT MVFR CIGS MAY DEVELOP
OVERNIGHT...HOWEVER OTHER MODELS INDICATE VFR CONDITIONS WILL
PREVAIL AND GIVEN THE MOIST BIAS OF THE NAM...THOUGHT IT WAS ONLY
WORTH A SCT020 AND MENTION IN THE CONCERN SECTION.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 16Z...

* MEDIUM IN LAKE BREEZE THIS AFTERNOON.
* LOW TO MEDIUM ON SHOWERS THIS AFTERNOON.
* LOW ON MVFR CIGS OVERNIGHT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 301604
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1104 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* LAKE BREEZE AND THIS AFTERNOON.
* VICINITY SHOWERS THIS AFTERNOON.
* MVFR CIGS POSSIBLE AGAIN OVERNIGHT.

BMD/MM

//DISCUSSION...UPDATED 12Z...

PATCHY FOG THIS MORNING WILL CONTINUE TO IMPROVE OVER THE NEXT
COUPLE HOURS WITH SUNRISE WITH VFR CONDITIONS AND MODEST NORTHWEST
WINDS EXPECTED THROUGH THE REMAINDER OF THE MORNING AND MUCH OF
THE AFTERNOON. A LAKE BREEZE IS EXPECTED TO PUSH INLAND THIS
AFTERNOON TURNING WINDS TO THE NORTHEAST FOR THE CHICAGO
TERMINALS. CANNOT RULE OUT A FEW ISOLATED SHOWERS OR THUNDERSTORMS
DEVELOPING ALONG THE BOUNDARY HOWEVER CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAF. WINDS WILL SETTLE TO THE EAST
TONIGHT. NAM/MET GUIDANCE INDICATES THAT MVFR CIGS MAY DEVELOP
OVERNIGHT...HOWEVER OTHER MODELS INDICATE VFR CONDITIONS WILL
PREVAIL AND GIVEN THE MOIST BIAS OF THE NAM...THOUGHT IT WAS ONLY
WORTH A SCT020 AND MENTION IN THE CONCERN SECTION.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 16Z...

* MEDIUM IN LAKE BREEZE THIS AFTERNOON.
* LOW TO MEDIUM ON SHOWERS THIS AFTERNOON.
* LOW ON MVFR CIGS OVERNIGHT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KILX 301430
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
930 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 922 AM CDT TUE JUN 30 2015

MADE SOME UPDATES TO THE FORECAST THIS MORNING...MAINLY TO LOWER
POPS. SHORT-WAVE TROUGH THAT BROUGHT A FEW SHOWERS AND
THUNDERSTORMS TO THE AREA LAST NIGHT IS CURRENTLY PUSHING INTO
INDIANA. SUBSIDENCE ON THE BACK SIDE OF THE WAVE WILL LEAD TO DRY
CONDITIONS FOR THE REMAINDER OF THE MORNING INTO THE EARLY
AFTERNOON BEFORE AN APPROACHING SURFACE TROUGH POTENTIALLY
TRIGGERS A FEW ADDITIONAL STORMS THIS AFTERNOON. MOST MODELS
REMAIN FAIRLY DRY...WITH BOTH THE HRRR AND NAM SUGGESTING THE BEST
AREAL COVERAGE WILL LIKELY BE ACROSS EAST-CENTRAL ILLINOIS DURING
THE LATE AFTERNOON. HAVE THEREFORE GONE WITH A DRY FORECAST FOR
THE REMAINDER OF THE MORNING...WITH LOW CHANCE POPS ALONG/SOUTH OF
A RUSHVILLE TO DANVILLE LINE DURING THE AFTERNOON. UNDER MOSTLY
SUNNY SKIES...TEMPERATURES WILL BE A FEW DEGREES WARMER THAN
YESTERDAY...WITH AFTERNOON HIGHS REACHING THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE JUN 30 2015

VFR CONDITIONS WILL PREVAIL AT ALL SITES FOR MOST OF THE PERIOD.
WILL HAVE SOME LIGHT FOG AT ALL SITES FOR COUPLE HOURS THIS
MORNING. THEN SKIES SHOULD BE SCATTERED WITH JUST SOME CU AROUND.
ONE ISOLATED T-STORM WILL EFFECT DEC FOR AN HOUR SO WILL HAVE
TEMPO GROUP FOR IT WITH VCTS FOR COUPLE OF HOURS OTHERWISE. HIRES
MODELS FORECAST SCATTERED CONVECTION OVER THE AREA FOR THIS
AFTERNOON SO HAVE VCTS WITH SCATTERED CU AT ALL SITES STARTING AT
18Z...AND LASTING TIL AROUND 00Z. SCATTERED CLOUDS WILL CONTINUE
INTO THE EVENING BUT THEN HAVE ADDED CHANCE OF FOG WITH CLEAR
SKIES AND LIGHTER WINDS OVERNIGHT. WINDS WILL BE WESTERLY THIS
MORNING AND THEN BECOME NORTHWEST THIS AFTERNOON...AND THEN
NORTHERLY THIS EVENING.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN




000
FXUS63 KILX 301430
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
930 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 922 AM CDT TUE JUN 30 2015

MADE SOME UPDATES TO THE FORECAST THIS MORNING...MAINLY TO LOWER
POPS. SHORT-WAVE TROUGH THAT BROUGHT A FEW SHOWERS AND
THUNDERSTORMS TO THE AREA LAST NIGHT IS CURRENTLY PUSHING INTO
INDIANA. SUBSIDENCE ON THE BACK SIDE OF THE WAVE WILL LEAD TO DRY
CONDITIONS FOR THE REMAINDER OF THE MORNING INTO THE EARLY
AFTERNOON BEFORE AN APPROACHING SURFACE TROUGH POTENTIALLY
TRIGGERS A FEW ADDITIONAL STORMS THIS AFTERNOON. MOST MODELS
REMAIN FAIRLY DRY...WITH BOTH THE HRRR AND NAM SUGGESTING THE BEST
AREAL COVERAGE WILL LIKELY BE ACROSS EAST-CENTRAL ILLINOIS DURING
THE LATE AFTERNOON. HAVE THEREFORE GONE WITH A DRY FORECAST FOR
THE REMAINDER OF THE MORNING...WITH LOW CHANCE POPS ALONG/SOUTH OF
A RUSHVILLE TO DANVILLE LINE DURING THE AFTERNOON. UNDER MOSTLY
SUNNY SKIES...TEMPERATURES WILL BE A FEW DEGREES WARMER THAN
YESTERDAY...WITH AFTERNOON HIGHS REACHING THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE JUN 30 2015

VFR CONDITIONS WILL PREVAIL AT ALL SITES FOR MOST OF THE PERIOD.
WILL HAVE SOME LIGHT FOG AT ALL SITES FOR COUPLE HOURS THIS
MORNING. THEN SKIES SHOULD BE SCATTERED WITH JUST SOME CU AROUND.
ONE ISOLATED T-STORM WILL EFFECT DEC FOR AN HOUR SO WILL HAVE
TEMPO GROUP FOR IT WITH VCTS FOR COUPLE OF HOURS OTHERWISE. HIRES
MODELS FORECAST SCATTERED CONVECTION OVER THE AREA FOR THIS
AFTERNOON SO HAVE VCTS WITH SCATTERED CU AT ALL SITES STARTING AT
18Z...AND LASTING TIL AROUND 00Z. SCATTERED CLOUDS WILL CONTINUE
INTO THE EVENING BUT THEN HAVE ADDED CHANCE OF FOG WITH CLEAR
SKIES AND LIGHTER WINDS OVERNIGHT. WINDS WILL BE WESTERLY THIS
MORNING AND THEN BECOME NORTHWEST THIS AFTERNOON...AND THEN
NORTHERLY THIS EVENING.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN



000
FXUS63 KILX 301430
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
930 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 922 AM CDT TUE JUN 30 2015

MADE SOME UPDATES TO THE FORECAST THIS MORNING...MAINLY TO LOWER
POPS. SHORT-WAVE TROUGH THAT BROUGHT A FEW SHOWERS AND
THUNDERSTORMS TO THE AREA LAST NIGHT IS CURRENTLY PUSHING INTO
INDIANA. SUBSIDENCE ON THE BACK SIDE OF THE WAVE WILL LEAD TO DRY
CONDITIONS FOR THE REMAINDER OF THE MORNING INTO THE EARLY
AFTERNOON BEFORE AN APPROACHING SURFACE TROUGH POTENTIALLY
TRIGGERS A FEW ADDITIONAL STORMS THIS AFTERNOON. MOST MODELS
REMAIN FAIRLY DRY...WITH BOTH THE HRRR AND NAM SUGGESTING THE BEST
AREAL COVERAGE WILL LIKELY BE ACROSS EAST-CENTRAL ILLINOIS DURING
THE LATE AFTERNOON. HAVE THEREFORE GONE WITH A DRY FORECAST FOR
THE REMAINDER OF THE MORNING...WITH LOW CHANCE POPS ALONG/SOUTH OF
A RUSHVILLE TO DANVILLE LINE DURING THE AFTERNOON. UNDER MOSTLY
SUNNY SKIES...TEMPERATURES WILL BE A FEW DEGREES WARMER THAN
YESTERDAY...WITH AFTERNOON HIGHS REACHING THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE JUN 30 2015

VFR CONDITIONS WILL PREVAIL AT ALL SITES FOR MOST OF THE PERIOD.
WILL HAVE SOME LIGHT FOG AT ALL SITES FOR COUPLE HOURS THIS
MORNING. THEN SKIES SHOULD BE SCATTERED WITH JUST SOME CU AROUND.
ONE ISOLATED T-STORM WILL EFFECT DEC FOR AN HOUR SO WILL HAVE
TEMPO GROUP FOR IT WITH VCTS FOR COUPLE OF HOURS OTHERWISE. HIRES
MODELS FORECAST SCATTERED CONVECTION OVER THE AREA FOR THIS
AFTERNOON SO HAVE VCTS WITH SCATTERED CU AT ALL SITES STARTING AT
18Z...AND LASTING TIL AROUND 00Z. SCATTERED CLOUDS WILL CONTINUE
INTO THE EVENING BUT THEN HAVE ADDED CHANCE OF FOG WITH CLEAR
SKIES AND LIGHTER WINDS OVERNIGHT. WINDS WILL BE WESTERLY THIS
MORNING AND THEN BECOME NORTHWEST THIS AFTERNOON...AND THEN
NORTHERLY THIS EVENING.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN



000
FXUS63 KILX 301430
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
930 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 922 AM CDT TUE JUN 30 2015

MADE SOME UPDATES TO THE FORECAST THIS MORNING...MAINLY TO LOWER
POPS. SHORT-WAVE TROUGH THAT BROUGHT A FEW SHOWERS AND
THUNDERSTORMS TO THE AREA LAST NIGHT IS CURRENTLY PUSHING INTO
INDIANA. SUBSIDENCE ON THE BACK SIDE OF THE WAVE WILL LEAD TO DRY
CONDITIONS FOR THE REMAINDER OF THE MORNING INTO THE EARLY
AFTERNOON BEFORE AN APPROACHING SURFACE TROUGH POTENTIALLY
TRIGGERS A FEW ADDITIONAL STORMS THIS AFTERNOON. MOST MODELS
REMAIN FAIRLY DRY...WITH BOTH THE HRRR AND NAM SUGGESTING THE BEST
AREAL COVERAGE WILL LIKELY BE ACROSS EAST-CENTRAL ILLINOIS DURING
THE LATE AFTERNOON. HAVE THEREFORE GONE WITH A DRY FORECAST FOR
THE REMAINDER OF THE MORNING...WITH LOW CHANCE POPS ALONG/SOUTH OF
A RUSHVILLE TO DANVILLE LINE DURING THE AFTERNOON. UNDER MOSTLY
SUNNY SKIES...TEMPERATURES WILL BE A FEW DEGREES WARMER THAN
YESTERDAY...WITH AFTERNOON HIGHS REACHING THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE JUN 30 2015

VFR CONDITIONS WILL PREVAIL AT ALL SITES FOR MOST OF THE PERIOD.
WILL HAVE SOME LIGHT FOG AT ALL SITES FOR COUPLE HOURS THIS
MORNING. THEN SKIES SHOULD BE SCATTERED WITH JUST SOME CU AROUND.
ONE ISOLATED T-STORM WILL EFFECT DEC FOR AN HOUR SO WILL HAVE
TEMPO GROUP FOR IT WITH VCTS FOR COUPLE OF HOURS OTHERWISE. HIRES
MODELS FORECAST SCATTERED CONVECTION OVER THE AREA FOR THIS
AFTERNOON SO HAVE VCTS WITH SCATTERED CU AT ALL SITES STARTING AT
18Z...AND LASTING TIL AROUND 00Z. SCATTERED CLOUDS WILL CONTINUE
INTO THE EVENING BUT THEN HAVE ADDED CHANCE OF FOG WITH CLEAR
SKIES AND LIGHTER WINDS OVERNIGHT. WINDS WILL BE WESTERLY THIS
MORNING AND THEN BECOME NORTHWEST THIS AFTERNOON...AND THEN
NORTHERLY THIS EVENING.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN



000
FXUS63 KILX 301430
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
930 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 922 AM CDT TUE JUN 30 2015

MADE SOME UPDATES TO THE FORECAST THIS MORNING...MAINLY TO LOWER
POPS. SHORT-WAVE TROUGH THAT BROUGHT A FEW SHOWERS AND
THUNDERSTORMS TO THE AREA LAST NIGHT IS CURRENTLY PUSHING INTO
INDIANA. SUBSIDENCE ON THE BACK SIDE OF THE WAVE WILL LEAD TO DRY
CONDITIONS FOR THE REMAINDER OF THE MORNING INTO THE EARLY
AFTERNOON BEFORE AN APPROACHING SURFACE TROUGH POTENTIALLY
TRIGGERS A FEW ADDITIONAL STORMS THIS AFTERNOON. MOST MODELS
REMAIN FAIRLY DRY...WITH BOTH THE HRRR AND NAM SUGGESTING THE BEST
AREAL COVERAGE WILL LIKELY BE ACROSS EAST-CENTRAL ILLINOIS DURING
THE LATE AFTERNOON. HAVE THEREFORE GONE WITH A DRY FORECAST FOR
THE REMAINDER OF THE MORNING...WITH LOW CHANCE POPS ALONG/SOUTH OF
A RUSHVILLE TO DANVILLE LINE DURING THE AFTERNOON. UNDER MOSTLY
SUNNY SKIES...TEMPERATURES WILL BE A FEW DEGREES WARMER THAN
YESTERDAY...WITH AFTERNOON HIGHS REACHING THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE JUN 30 2015

VFR CONDITIONS WILL PREVAIL AT ALL SITES FOR MOST OF THE PERIOD.
WILL HAVE SOME LIGHT FOG AT ALL SITES FOR COUPLE HOURS THIS
MORNING. THEN SKIES SHOULD BE SCATTERED WITH JUST SOME CU AROUND.
ONE ISOLATED T-STORM WILL EFFECT DEC FOR AN HOUR SO WILL HAVE
TEMPO GROUP FOR IT WITH VCTS FOR COUPLE OF HOURS OTHERWISE. HIRES
MODELS FORECAST SCATTERED CONVECTION OVER THE AREA FOR THIS
AFTERNOON SO HAVE VCTS WITH SCATTERED CU AT ALL SITES STARTING AT
18Z...AND LASTING TIL AROUND 00Z. SCATTERED CLOUDS WILL CONTINUE
INTO THE EVENING BUT THEN HAVE ADDED CHANCE OF FOG WITH CLEAR
SKIES AND LIGHTER WINDS OVERNIGHT. WINDS WILL BE WESTERLY THIS
MORNING AND THEN BECOME NORTHWEST THIS AFTERNOON...AND THEN
NORTHERLY THIS EVENING.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN



000
FXUS63 KILX 301430
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
930 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 922 AM CDT TUE JUN 30 2015

MADE SOME UPDATES TO THE FORECAST THIS MORNING...MAINLY TO LOWER
POPS. SHORT-WAVE TROUGH THAT BROUGHT A FEW SHOWERS AND
THUNDERSTORMS TO THE AREA LAST NIGHT IS CURRENTLY PUSHING INTO
INDIANA. SUBSIDENCE ON THE BACK SIDE OF THE WAVE WILL LEAD TO DRY
CONDITIONS FOR THE REMAINDER OF THE MORNING INTO THE EARLY
AFTERNOON BEFORE AN APPROACHING SURFACE TROUGH POTENTIALLY
TRIGGERS A FEW ADDITIONAL STORMS THIS AFTERNOON. MOST MODELS
REMAIN FAIRLY DRY...WITH BOTH THE HRRR AND NAM SUGGESTING THE BEST
AREAL COVERAGE WILL LIKELY BE ACROSS EAST-CENTRAL ILLINOIS DURING
THE LATE AFTERNOON. HAVE THEREFORE GONE WITH A DRY FORECAST FOR
THE REMAINDER OF THE MORNING...WITH LOW CHANCE POPS ALONG/SOUTH OF
A RUSHVILLE TO DANVILLE LINE DURING THE AFTERNOON. UNDER MOSTLY
SUNNY SKIES...TEMPERATURES WILL BE A FEW DEGREES WARMER THAN
YESTERDAY...WITH AFTERNOON HIGHS REACHING THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE JUN 30 2015

VFR CONDITIONS WILL PREVAIL AT ALL SITES FOR MOST OF THE PERIOD.
WILL HAVE SOME LIGHT FOG AT ALL SITES FOR COUPLE HOURS THIS
MORNING. THEN SKIES SHOULD BE SCATTERED WITH JUST SOME CU AROUND.
ONE ISOLATED T-STORM WILL EFFECT DEC FOR AN HOUR SO WILL HAVE
TEMPO GROUP FOR IT WITH VCTS FOR COUPLE OF HOURS OTHERWISE. HIRES
MODELS FORECAST SCATTERED CONVECTION OVER THE AREA FOR THIS
AFTERNOON SO HAVE VCTS WITH SCATTERED CU AT ALL SITES STARTING AT
18Z...AND LASTING TIL AROUND 00Z. SCATTERED CLOUDS WILL CONTINUE
INTO THE EVENING BUT THEN HAVE ADDED CHANCE OF FOG WITH CLEAR
SKIES AND LIGHTER WINDS OVERNIGHT. WINDS WILL BE WESTERLY THIS
MORNING AND THEN BECOME NORTHWEST THIS AFTERNOON...AND THEN
NORTHERLY THIS EVENING.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN



000
FXUS63 KLOT 301406
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
906 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* LAKE BREEZE AND THIS AFTERNOON.
* VICINITY SHOWERS THIS AFTERNOON.
* MVFR CIGS POSSIBLE AGAIN OVERNIGHT.

BMD/MM

//DISCUSSION...UPDATED 12Z...

PATCHY FOG THIS MORNING WILL CONTINUE TO IMPROVE OVER THE NEXT
COUPLE HOURS WITH SUNRISE WITH VFR CONDITIONS AND MODEST NORTHWEST
WINDS EXPECTED THROUGH THE REMAINDER OF THE MORNING AND MUCH OF
THE AFTERNOON. A LAKE BREEZE IS EXPECTED TO PUSH INLAND THIS
AFTERNOON TURNING WINDS TO THE NORTHEAST FOR THE CHICAGO
TERMINALS. CANNOT RULE OUT A FEW ISOLATED SHOWERS OR THUNDERSTORMS
DEVELOPING ALONG THE BOUNDARY HOWEVER CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAF. WINDS WILL SETTLE TO THE EAST
TONIGHT. NAM/MET GUIDANCE INDICATES THAT MVFR CIGS MAY DEVELOP
OVERNIGHT...HOWEVER OTHER MODELS INDICATE VFR CONDITIONS WILL
PREVAIL AND GIVEN THE MOIST BIAS OF THE NAM...THOUGHT IT WAS ONLY
WORTH A SCT020 AND MENTION IN THE CONCERN SECTION.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* MEDIUM IN LAKE BREEZE THIS AFTERNOON.
* LOW TO MEDIUM ON SHOWERS THIS AFTERNOON.
* LOW ON MVFR CIGS OVERNIGHT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 301406
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
906 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* LAKE BREEZE AND THIS AFTERNOON.
* VICINITY SHOWERS THIS AFTERNOON.
* MVFR CIGS POSSIBLE AGAIN OVERNIGHT.

BMD/MM

//DISCUSSION...UPDATED 12Z...

PATCHY FOG THIS MORNING WILL CONTINUE TO IMPROVE OVER THE NEXT
COUPLE HOURS WITH SUNRISE WITH VFR CONDITIONS AND MODEST NORTHWEST
WINDS EXPECTED THROUGH THE REMAINDER OF THE MORNING AND MUCH OF
THE AFTERNOON. A LAKE BREEZE IS EXPECTED TO PUSH INLAND THIS
AFTERNOON TURNING WINDS TO THE NORTHEAST FOR THE CHICAGO
TERMINALS. CANNOT RULE OUT A FEW ISOLATED SHOWERS OR THUNDERSTORMS
DEVELOPING ALONG THE BOUNDARY HOWEVER CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAF. WINDS WILL SETTLE TO THE EAST
TONIGHT. NAM/MET GUIDANCE INDICATES THAT MVFR CIGS MAY DEVELOP
OVERNIGHT...HOWEVER OTHER MODELS INDICATE VFR CONDITIONS WILL
PREVAIL AND GIVEN THE MOIST BIAS OF THE NAM...THOUGHT IT WAS ONLY
WORTH A SCT020 AND MENTION IN THE CONCERN SECTION.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* MEDIUM IN LAKE BREEZE THIS AFTERNOON.
* LOW TO MEDIUM ON SHOWERS THIS AFTERNOON.
* LOW ON MVFR CIGS OVERNIGHT.

BMD/MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 301135
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
635 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* PATCHY FOG THIS MORNING
* LAKE BREEZE THIS AFTERNOON.
* MVFR CIGS POSSIBLE AGAIN OVERNIGHT.

BMD

//DISCUSSION...UPDATED 12Z...

PATCHY FOG THIS MORNING WILL CONTINUE TO IMPROVE OVER THE NEXT
COUPLE HOURS WITH SUNRISE WITH VFR CONDITIONS AND MODEST NORTHWEST
WINDS EXPECTED THROUGH THE REMAINDER OF THE MORNING AND MUCH OF
THE AFTERNOON. A LAKE BREEZE IS EXPECTED TO PUSH INLAND THIS
AFTERNOON TURNING WINDS TO THE NORTHEAST FOR THE CHICAGO
TERMINALS. CANNOT RULE OUT A FEW ISOLATED SHOWERS OR THUNDERSTORMS
DEVELOPING ALONG THE BOUNDARY HOWEVER CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAF. WINDS WILL SETTLE TO THE EAST
TONIGHT. NAM/MET GUIDANCE INDICATES THAT MVFR CIGS MAY DEVELOP
OVERNIGHT...HOWEVER OTHER MODELS INDICATE VFR CONDITIONS WILL
PREVAIL AND GIVEN THE MOIST BIAS OF THE NAM...THOUGHT IT WAS ONLY
WORTH A SCT020 AND MENTION IN THE CONCERN SECTION.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH THAT VFR CONDITIONS WILL BE IN PLACE FROM AROUND 14Z
  THROUGH THE REMAINDER OF TODAY.
* MEDIUM IN LAKE BREEZE THIS AFTERNOON OR EVENING.
* LOW ON MVFR CIGS OVERNIGHT.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 301135
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
635 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* PATCHY FOG THIS MORNING
* LAKE BREEZE THIS AFTERNOON.
* MVFR CIGS POSSIBLE AGAIN OVERNIGHT.

BMD

//DISCUSSION...UPDATED 12Z...

PATCHY FOG THIS MORNING WILL CONTINUE TO IMPROVE OVER THE NEXT
COUPLE HOURS WITH SUNRISE WITH VFR CONDITIONS AND MODEST NORTHWEST
WINDS EXPECTED THROUGH THE REMAINDER OF THE MORNING AND MUCH OF
THE AFTERNOON. A LAKE BREEZE IS EXPECTED TO PUSH INLAND THIS
AFTERNOON TURNING WINDS TO THE NORTHEAST FOR THE CHICAGO
TERMINALS. CANNOT RULE OUT A FEW ISOLATED SHOWERS OR THUNDERSTORMS
DEVELOPING ALONG THE BOUNDARY HOWEVER CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAF. WINDS WILL SETTLE TO THE EAST
TONIGHT. NAM/MET GUIDANCE INDICATES THAT MVFR CIGS MAY DEVELOP
OVERNIGHT...HOWEVER OTHER MODELS INDICATE VFR CONDITIONS WILL
PREVAIL AND GIVEN THE MOIST BIAS OF THE NAM...THOUGHT IT WAS ONLY
WORTH A SCT020 AND MENTION IN THE CONCERN SECTION.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH THAT VFR CONDITIONS WILL BE IN PLACE FROM AROUND 14Z
  THROUGH THE REMAINDER OF TODAY.
* MEDIUM IN LAKE BREEZE THIS AFTERNOON OR EVENING.
* LOW ON MVFR CIGS OVERNIGHT.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 301135
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
635 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* PATCHY FOG THIS MORNING
* LAKE BREEZE THIS AFTERNOON.
* MVFR CIGS POSSIBLE AGAIN OVERNIGHT.

BMD

//DISCUSSION...UPDATED 12Z...

PATCHY FOG THIS MORNING WILL CONTINUE TO IMPROVE OVER THE NEXT
COUPLE HOURS WITH SUNRISE WITH VFR CONDITIONS AND MODEST NORTHWEST
WINDS EXPECTED THROUGH THE REMAINDER OF THE MORNING AND MUCH OF
THE AFTERNOON. A LAKE BREEZE IS EXPECTED TO PUSH INLAND THIS
AFTERNOON TURNING WINDS TO THE NORTHEAST FOR THE CHICAGO
TERMINALS. CANNOT RULE OUT A FEW ISOLATED SHOWERS OR THUNDERSTORMS
DEVELOPING ALONG THE BOUNDARY HOWEVER CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAF. WINDS WILL SETTLE TO THE EAST
TONIGHT. NAM/MET GUIDANCE INDICATES THAT MVFR CIGS MAY DEVELOP
OVERNIGHT...HOWEVER OTHER MODELS INDICATE VFR CONDITIONS WILL
PREVAIL AND GIVEN THE MOIST BIAS OF THE NAM...THOUGHT IT WAS ONLY
WORTH A SCT020 AND MENTION IN THE CONCERN SECTION.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH THAT VFR CONDITIONS WILL BE IN PLACE FROM AROUND 14Z
  THROUGH THE REMAINDER OF TODAY.
* MEDIUM IN LAKE BREEZE THIS AFTERNOON OR EVENING.
* LOW ON MVFR CIGS OVERNIGHT.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 301135
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
635 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* PATCHY FOG THIS MORNING
* LAKE BREEZE THIS AFTERNOON.
* MVFR CIGS POSSIBLE AGAIN OVERNIGHT.

BMD

//DISCUSSION...UPDATED 12Z...

PATCHY FOG THIS MORNING WILL CONTINUE TO IMPROVE OVER THE NEXT
COUPLE HOURS WITH SUNRISE WITH VFR CONDITIONS AND MODEST NORTHWEST
WINDS EXPECTED THROUGH THE REMAINDER OF THE MORNING AND MUCH OF
THE AFTERNOON. A LAKE BREEZE IS EXPECTED TO PUSH INLAND THIS
AFTERNOON TURNING WINDS TO THE NORTHEAST FOR THE CHICAGO
TERMINALS. CANNOT RULE OUT A FEW ISOLATED SHOWERS OR THUNDERSTORMS
DEVELOPING ALONG THE BOUNDARY HOWEVER CONFIDENCE IS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAF. WINDS WILL SETTLE TO THE EAST
TONIGHT. NAM/MET GUIDANCE INDICATES THAT MVFR CIGS MAY DEVELOP
OVERNIGHT...HOWEVER OTHER MODELS INDICATE VFR CONDITIONS WILL
PREVAIL AND GIVEN THE MOIST BIAS OF THE NAM...THOUGHT IT WAS ONLY
WORTH A SCT020 AND MENTION IN THE CONCERN SECTION.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH THAT VFR CONDITIONS WILL BE IN PLACE FROM AROUND 14Z
  THROUGH THE REMAINDER OF TODAY.
* MEDIUM IN LAKE BREEZE THIS AFTERNOON OR EVENING.
* LOW ON MVFR CIGS OVERNIGHT.

BMD

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KILX 301130
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
630 AM CDT TUE JUN 30 2015

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE JUN 30 2015

VFR CONDITIONS WILL PREVAIL AT ALL SITES FOR MOST OF THE PERIOD.
WILL HAVE SOME LIGHT FOG AT ALL SITES FOR COUPLE HOURS THIS
MORNING. THEN SKIES SHOULD BE SCATTERED WITH JUST SOME CU AROUND.
ONE ISOLATED T-STORM WILL EFFECT DEC FOR AN HOUR SO WILL HAVE
TEMPO GROUP FOR IT WITH VCTS FOR COUPLE OF HOURS OTHERWISE. HIRES
MODELS FORECAST SCATTERED CONVECTION OVER THE AREA FOR THIS
AFTERNOON SO HAVE VCTS WITH SCATTERED CU AT ALL SITES STARTING AT
18Z...AND LASTING TIL AROUND 00Z. SCATTERED CLOUDS WILL CONTINUE
INTO THE EVENING BUT THEN HAVE ADDED CHANCE OF FOG WITH CLEAR
SKIES AND LIGHTER WINDS OVERNIGHT. WINDS WILL BE WESTERLY THIS
MORNING AND THEN BECOME NORTHWEST THIS AFTERNOON...AND THEN
NORTHERLY THIS EVENING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN



000
FXUS63 KILX 301130
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
630 AM CDT TUE JUN 30 2015

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE JUN 30 2015

VFR CONDITIONS WILL PREVAIL AT ALL SITES FOR MOST OF THE PERIOD.
WILL HAVE SOME LIGHT FOG AT ALL SITES FOR COUPLE HOURS THIS
MORNING. THEN SKIES SHOULD BE SCATTERED WITH JUST SOME CU AROUND.
ONE ISOLATED T-STORM WILL EFFECT DEC FOR AN HOUR SO WILL HAVE
TEMPO GROUP FOR IT WITH VCTS FOR COUPLE OF HOURS OTHERWISE. HIRES
MODELS FORECAST SCATTERED CONVECTION OVER THE AREA FOR THIS
AFTERNOON SO HAVE VCTS WITH SCATTERED CU AT ALL SITES STARTING AT
18Z...AND LASTING TIL AROUND 00Z. SCATTERED CLOUDS WILL CONTINUE
INTO THE EVENING BUT THEN HAVE ADDED CHANCE OF FOG WITH CLEAR
SKIES AND LIGHTER WINDS OVERNIGHT. WINDS WILL BE WESTERLY THIS
MORNING AND THEN BECOME NORTHWEST THIS AFTERNOON...AND THEN
NORTHERLY THIS EVENING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...AUTEN




000
FXUS63 KLOT 300907
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
407 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* FOG EARLY THIS MORNING.
* SCATTERED SHRA/ISOL TSRA THIS AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* MEDIUM CONFIDENCE IN MVFR/IFR FOG AROUND SUNRISE.
* LOW CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300907
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
407 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* FOG EARLY THIS MORNING.
* SCATTERED SHRA/ISOL TSRA THIS AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* MEDIUM CONFIDENCE IN MVFR/IFR FOG AROUND SUNRISE.
* LOW CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300907
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
407 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* FOG EARLY THIS MORNING.
* SCATTERED SHRA/ISOL TSRA THIS AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* MEDIUM CONFIDENCE IN MVFR/IFR FOG AROUND SUNRISE.
* LOW CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KILX 300833
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
333 AM CDT TUE JUN 30 2015

.SHORT TERM...(TODAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

LOW PRESSURE AREA OVER LAKE MICH WILL SLOWLY DRIFT EAST ACROSS THE
GREAT LAKES REGION TODAY. AN ASSOCIATED WEAK SFC TROUGH WILL ROTATE
ACROSS THE AREA AS WELL. SFC PATTERN WILL PREVENT AN INCREASE OF LOW
LEVEL MOISTURE FROM OUTSIDE THE AREA...SO ANY MOISTURE AVAILABLE FOR
THE SFC TROUGH WILL BE FROM WHAT IS ALREADY IN PLACE OR FROM
EVAPOTRANSPIRATION FROM THE FAST GROWING CORN/BEAN FIELDS. EVEN
THOUGH FORCING ALONG THE FRONT COULD BE WEAK AS WELL...STILL THINK
THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY LATE THIS MORNING AND
CONTINUE THROUGH THIS AFTERNOON. SO WILL MAINTAIN CHANCE POPS ACROSS
THE AREA IN THE FORECAST. WINDS WILL WEST WEST TO NORTHWEST THROUGH
THE DAY PARTLY SUNNY SKIES. AFTERNOON HIGHS SHOULD BE A DEGREE OR
TWO WARMER THAN YESTERDAY.

&&

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE JUN 30 2015

ACTUALLY THE GOOD NEWS CONTINUES IN THIS ROUND OF MODEL SOLUTIONS
FOR A COUPLE OF DRY PERIODS THIS WEEK...PARTICULARLY IN THE NORTHERN
HALF OF THE STATE.  IN THE SHORTER TERM, TONIGHT WILL SEE THE
DWINDLING OF ANY ACTIVITY LEFT OVER FROM POTENTIAL CONVECTION THIS
AFTERNOON, BUT AFTER MIDNIGHT THE HIGHER POPS SHIFT TO THE SOUTHWEST
AS ANOTHER WAVE DIVES ALMOST STRAIGHT SOUTH FROM THE UPPER MIDWEST
AND DOWN ALONG THE MID MISS RIVER VALLEY.  MODELS SLOW THE WAVE AND
CONTINUE ITS IMPACT INTO TOMORROW AND TOMORROW EVENING, PARTICULARLY
IN THE SOUTHERN TIER OF THE STATE. PRECIP ALMOST SKIRTING THE
BUILDING SFC RIDGE JUST TO THE NORTH AND KEEP THE POPS CLOSE.
HOWEVER, THU-SAT...THE MODELS ARE STARTING TO CLEAR A BIT WITH THE
POPS AND PUT CENTRAL AND NORTHERN IL IN A DRY SPOT WITH THAT SFC
RIDGE BUILDING.  GFS AND ECMWF ARE BOTH TRENDING DRIER...EVEN
PUSHING THE FRI SHORTWAVE MUCH FURTHER TO THE SOUTH...WITH THE ECMWF
NOT QUITE AS DRY. HAVE CONTINUED TO DRY OUT THE GRIDDED FORECAST AS
THE SUPERBLEND IS STILL WORKING OUT ITS PREV GUESS AND DEALING WITH
THE WETTER ECMWF. UNFORTUNATELY AT THIS TIME, ANOTHER WAVE IS
SHOWING UP FOR THE LATTER HALF OF THE WEEKEND AND POPS RETURNING SAT
NIGHT/SUN.  WITH A MAJOR PATTERN SHIFT, WOULD NOT BE SURPRISED TO
SEE THIS SHIFT AS WELL. BUT FOR NOW...STARTING THE DRIER TREND FOR
THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...ONTON



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300826
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
326 AM CDT TUE JUN 30 2015

.SHORT TERM...
325 AM CDT

THROUGH WEDNESDAY...

PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND PRECIP CHANCES
TODAY. NORTHWEST FLOW ALOFT CONTINUES WITH SERIES OF DISTURBANCES
PIVOTING AROUND EASTERN NOAM UPPER TROUGH. ONE SUCH VORT EVIDENT ON
WATER VAPOR IMAGERY OVER NORTHERN WISCONSIN WILL DROP SOUTH INTO THE
AREA LATER TODAY AND COULD SPARK SOME ISOLATED SHOWER AND PERHAPS T-
STORM DEVELOPMENT THIS AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE OVER WESTERN LAKES WILL BEGIN SLOWLY BEGIN MOVING EASTWARD
ALLOWING WEAK NORTHWESTERLY WINDS AT THE SURFACE TO BEGIN PROCESS OF
ADVECTING IN DRIER AIR MASS TODAY...WHICH SHOULD RESULT IN BEST
INSTABILITY OVER SOUTHEASTERN CWA. WATER VAPOR ALSO SHOWS DRY MID-
UPPER LEVEL AIR ADVECTING SE INTO THE AREA WHICH SHOULD ALSO TEND TO
LIMIT THE COVERAGE AND INTENSITY OF SHOWERS THIS AFTERNOON.
GENERALLY FOCUSED CHANCE POPS TODAY IN SE CWA WHERE BEST COMBO OF
INSTABILITY AND MOISTURE WILL EXIST...THOUGH DO HOLD ONTO A TONGUE
OF SLIGHT CHANCE POPS NORTH INTO NORTHEAST ILLINOIS IN CASE MORE
FOCUSED LOW LEVEL CONVERGENCE ALONG THE LAKE BREEZE ENDS UP BEING
ENOUGH TO POP SOME WEAK AFTERNOON CONVECTION.

STRONGER SHORTWAVE WILL RIDE THE NORTHWEST FLOW INTO THE MISSOURI
AND LOWER OHIO VALLEY REGION TONIGHT...BUT LOOKS TO PASS FAR ENOUGH
SOUTHWEST OF OUR REGION TO PROVIDE LITTLE THREAT OF PRECIPITATION.
DRY AND SEASONABLY COOL WEATHER WILL BE THE DOMINANT WEATHER STORY
TOMORROW WITH WINDS OFF THE LAKE KEEPING TEMPS AT THE BEACHES PRETTY
CHILLY BY JULY STANDARDS.

IZZI

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300800
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
300 AM CDT TUE JUN 30 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT


A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300800
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
300 AM CDT TUE JUN 30 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
259 AM CDT


A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300607
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
107 AM CDT TUE JUN 30 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300607
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
107 AM CDT TUE JUN 30 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300607
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
107 AM CDT TUE JUN 30 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300607
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
107 AM CDT TUE JUN 30 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* FOG OVERNIGHT.
* SCATTERED SHRA/ISOL TSRA TUESDAY AFTERNOON.

BMD

//DISCUSSION...UPDATED 06Z...

SCATTERED SHOWERS SHOULD CONTINUE TO DIMINISH OVER THE NEXT
COUPLE HOURS ACROSS NORTHERN ILLINOIS AS A WEAK SURFACE TROUGH
DROPS SOUTHEAST ACROSS THE REGION. WINDS WILL BE LIGHT WITHIN THE
FRONTAL TROUGH THEN SHOULD TURN NORTHWESTERLY LATER OVERNIGHT OR
EARLY TUESDAY. MAIN CONCERN OVERNIGHT SEEMS TO BE FOG DEVELOPMENT
WITH CONDITIONS ALREADY NEAR SATURATION AND MID LEVEL CLOUD COVER
PROGGED TO CLEAR THE TERMINALS IN THE NEXT 3-4 HOURS. THE
COMBINATION OF LIGHT WINDS AND CLEARING SKIES WILL SET THE STAGE
FOR RADIATION FOG DEVELOPING. AT THIS POINT...NONE OF THE MOS
GUIDANCE IS PICKING UP ON FOG AND THE RAW VSBY GUIDANCE FROM THE
MODELS IS HIT OR MISS. TRENDED VSBY DOWN IN THE LATEST VERSION OF
THE TAFS...BUT CONCERNED AT LEAST PATCHY DENSE FOG OF 1/2 TO 1/4
OF A MILE WILL BE IN PLACE IF NOT MORE WIDESPREAD. WILL WATCH
TRENDS OVER NEXT COUPLE HOURS TO SEE IF FURTHER REDUCTION OF VSBY
IS NEEDED IN THE FORECAST.

TUESDAY SHOULD START OUT WITH NORTHWEST FLOW AND EXPECT TO
GRADUALLY IMPROVE BACK TO VFR BY AROUND MID MORNING. A LAKE BREEZE
IS EXPECTED TO TURN WINDS NE LATE AFTERNOON OR EARLY EVENING FOR
ORD/MDW...AND EARLY AFTERNOON AT GYY. COULD BE SOME SCATTERED
SHOWERS WITH ISOLATED THUNDERSTORMS AGAIN TOMORROW...MAINLY IN THE
AFTERNOON WHEN INSTABILITY PEAKS.

BMD


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* INCREASING CONFIDENCE IN MVFR/IFR FOG OVERNIGHT. LOW CONFIDENCE
  IN LIFR VSBY.
* LOW-MEDIUM CONFIDENCE IN PRECIP AT TERMINALS TUESDAY AFTERNOON.

BMD

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KILX 300507
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300507
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300507
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300507
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300507
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300507
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300507
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300507
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1207 AM CDT TUE JUN 30 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1207 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH ISOLATED
THUNDERSTORMS KCMI-KPIA NORTHWARD. THUNDERSTORMS WILL CONTINUE
SLOW MOVEMENT TO THE SOUTH OVERNIGHT. INITIAL BROKEN LINE OF
THUNDERSTORMS SHOULD PASS BY CENTRAL IL TERMINALS BY 11-14Z SO
HAVE INCORPORATED A BREAK IN VCTS AT THAT POINT...BUT SHOULD
RETURN WITH AFTERNOON HEATING SO HAVE BROUGHT VCTS BACK INTO TAFS
17-18Z. EXPECTING LOW VFR CEILINGS WITH MOST
SHOWERS/STORMS...HOWEVER STRONGER STORMS COULD PRODUCE LOCAL MVFR
CIGS/VSBYS. TIMING/LOCATION UNCERTAINTIES REMAIN WITH REGARD TO
STRONGER STORMS THAT MAY PRODUCE MVFR CONDITIONS...SO NOT
MENTIONED IN TAFS AT THIS TIME. WINDS SW-NW 5-10 KTS
OVERNIGHT...VEERING SLIGHTLY NW AND INCREASING TO 10-12 KTS AFTER
17Z. WINDS CONTINUING TO VEER NORTHERLY AROUND 00Z AND WEAKEN TO
5-8 KTS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KLOT 300323
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1023 PM CDT MON JUN 29 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* SCATTERED SHRA OVERNIGHT.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 03Z...

SHOWERS AND A FEW THUNDERSTORMS CONTINUE MOVING SOUTHEAST ACROSS
NORTHWEST IL LATE THIS EVENING. SHORT RANGE GUIDANCE INDICATES
ISOLATED TO SCATTERED COVERAGE DEVELOPING INTO SOUTHEAST WI AND
THEN SPREADING SOUTHEAST ACROSS THE CHICAGO AREA TERMINALS.
ADJUSTED TIMING ACCORDINGLY...THOUGH LOW CONFIDENCE REGARDING
OVERALL COVERAGE. CMS

PREVIOUS 00Z DISCUSSION...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR SHRA OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR LAKE BREEZE/SHIFT TO NORTHEAST TUESDAY AFTERNOON...
  LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300323
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1023 PM CDT MON JUN 29 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* SCATTERED SHRA OVERNIGHT.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 03Z...

SHOWERS AND A FEW THUNDERSTORMS CONTINUE MOVING SOUTHEAST ACROSS
NORTHWEST IL LATE THIS EVENING. SHORT RANGE GUIDANCE INDICATES
ISOLATED TO SCATTERED COVERAGE DEVELOPING INTO SOUTHEAST WI AND
THEN SPREADING SOUTHEAST ACROSS THE CHICAGO AREA TERMINALS.
ADJUSTED TIMING ACCORDINGLY...THOUGH LOW CONFIDENCE REGARDING
OVERALL COVERAGE. CMS

PREVIOUS 00Z DISCUSSION...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR SHRA OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR LAKE BREEZE/SHIFT TO NORTHEAST TUESDAY AFTERNOON...
  LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300323
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1023 PM CDT MON JUN 29 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* SCATTERED SHRA OVERNIGHT.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 03Z...

SHOWERS AND A FEW THUNDERSTORMS CONTINUE MOVING SOUTHEAST ACROSS
NORTHWEST IL LATE THIS EVENING. SHORT RANGE GUIDANCE INDICATES
ISOLATED TO SCATTERED COVERAGE DEVELOPING INTO SOUTHEAST WI AND
THEN SPREADING SOUTHEAST ACROSS THE CHICAGO AREA TERMINALS.
ADJUSTED TIMING ACCORDINGLY...THOUGH LOW CONFIDENCE REGARDING
OVERALL COVERAGE. CMS

PREVIOUS 00Z DISCUSSION...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR SHRA OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR LAKE BREEZE/SHIFT TO NORTHEAST TUESDAY AFTERNOON...
  LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300323
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1023 PM CDT MON JUN 29 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* SCATTERED SHRA OVERNIGHT.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 03Z...

SHOWERS AND A FEW THUNDERSTORMS CONTINUE MOVING SOUTHEAST ACROSS
NORTHWEST IL LATE THIS EVENING. SHORT RANGE GUIDANCE INDICATES
ISOLATED TO SCATTERED COVERAGE DEVELOPING INTO SOUTHEAST WI AND
THEN SPREADING SOUTHEAST ACROSS THE CHICAGO AREA TERMINALS.
ADJUSTED TIMING ACCORDINGLY...THOUGH LOW CONFIDENCE REGARDING
OVERALL COVERAGE. CMS

PREVIOUS 00Z DISCUSSION...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR SHRA OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR LAKE BREEZE/SHIFT TO NORTHEAST TUESDAY AFTERNOON...
  LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300323
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1023 PM CDT MON JUN 29 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* SCATTERED SHRA OVERNIGHT.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 03Z...

SHOWERS AND A FEW THUNDERSTORMS CONTINUE MOVING SOUTHEAST ACROSS
NORTHWEST IL LATE THIS EVENING. SHORT RANGE GUIDANCE INDICATES
ISOLATED TO SCATTERED COVERAGE DEVELOPING INTO SOUTHEAST WI AND
THEN SPREADING SOUTHEAST ACROSS THE CHICAGO AREA TERMINALS.
ADJUSTED TIMING ACCORDINGLY...THOUGH LOW CONFIDENCE REGARDING
OVERALL COVERAGE. CMS

PREVIOUS 00Z DISCUSSION...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR SHRA OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR LAKE BREEZE/SHIFT TO NORTHEAST TUESDAY AFTERNOON...
  LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300323
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1023 PM CDT MON JUN 29 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* SCATTERED SHRA OVERNIGHT.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 03Z...

SHOWERS AND A FEW THUNDERSTORMS CONTINUE MOVING SOUTHEAST ACROSS
NORTHWEST IL LATE THIS EVENING. SHORT RANGE GUIDANCE INDICATES
ISOLATED TO SCATTERED COVERAGE DEVELOPING INTO SOUTHEAST WI AND
THEN SPREADING SOUTHEAST ACROSS THE CHICAGO AREA TERMINALS.
ADJUSTED TIMING ACCORDINGLY...THOUGH LOW CONFIDENCE REGARDING
OVERALL COVERAGE. CMS

PREVIOUS 00Z DISCUSSION...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* LOW FOR SHRA OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR LAKE BREEZE/SHIFT TO NORTHEAST TUESDAY AFTERNOON...
  LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KILX 300224
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
924 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 756 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH SCATTERED FEW-SCT
CLOUD COVER ABOVE 3.5 KFT AGL THIS EVENING WHILE ISOLATED
THUNDERSTORMS CONTINUE ACROSS NORTHERN IL. THUNDERSTORMS ARE
SHOWING SOME SLOW MOVEMENT TO THE SOUTH...BUT ARE STRUGGLING TO
MAINTAIN STRENGTH OVER CENTRAL IL WHERE GENERAL SUBSIDENCE ALOFT
CONTINUES. STORMS SHOULD TEND TO DISSIPATE AFTER SUNSET AS
WELL...SO HAVE NOT INCLUDED MENTION IN 00Z TAFS. SHORTWAVE TROUGH
CURRENTLY OVER SE MN/WI WILL DROP SOUTHWARD INTO THE AREA EARLY
TUESDAY MORNING...TRIGGERING SCATTERED SHOWERS/THUNDER. EXPECTING
LOW VFR CEILINGS AND VCTS SPREADING ACROSS TERMINALS
11-14Z...CONTINUING FOR MUCH OF REMAINDER OF TAF PERIOD. STRONGER
STORMS COULD PRODUCE LOCAL MVFR CIGS/VSBYS...ALTHOUGH
TIMING/LOCATION UNCERTAINTIES PREVENT EXPLICIT MENTION IN TAFS AT
THIS TIME. WINDS W-NW 5-10 KTS OVERNIGHT...VEERING SLIGHTLY NW AND
INCREASING TO 10-12 KTS AFTER 17Z.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300224
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
924 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 924 PM CDT MON JUN 29 2015

THUNDERSTORMS ACROSS NORTHERN IL HAVING A HARD TIME MAINTAINING
STRENGTH AS THEY SPREAD SLOWLY SOUTHWARD TOWARD CENTRAL IL. THIS
IS DUE TO GENERAL SUBSIDENCE OVER CENTRAL IL THIS EVENING IN THE
WAKE OF A DEPARTING SHORTWAVE HEADING TOWARD EASTERN GREAT LAKES
WITH ANOTHER APPROACHING FROM NNW VIA SE MINNESOTA/SW WISCONSIN.
WITH SURFACE COOLING AFTER SUNSET...INSTABILITY DRIVING THE
THUNDERSTORMS JUST NORTH OF CENTRAL IL WILL DIMINISH...FURTHER
DECREASING THUNDERSTORM ACTIVITY. HAVE MADE SOME MINOR
ADJUSTMENTS TO EVENING THUNDERSTORM CHANCES IN EARLIER
UPDATES...BUT FORECAST LARGELY ON TRACK OVERNIGHT AS THE
APPROACHING SHORTWAVE REMAINS ON TRACK TO ARRIVE EARLY IN THE
MORNING...SPREADING SHOWERS AND THUNDERSTORMS INTO THE AREA. LOWS
EXPECTED IN THE MID 60S WITH LIGHT WEST WINDS TONIGHT.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 756 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH SCATTERED FEW-SCT
CLOUD COVER ABOVE 3.5 KFT AGL THIS EVENING WHILE ISOLATED
THUNDERSTORMS CONTINUE ACROSS NORTHERN IL. THUNDERSTORMS ARE
SHOWING SOME SLOW MOVEMENT TO THE SOUTH...BUT ARE STRUGGLING TO
MAINTAIN STRENGTH OVER CENTRAL IL WHERE GENERAL SUBSIDENCE ALOFT
CONTINUES. STORMS SHOULD TEND TO DISSIPATE AFTER SUNSET AS
WELL...SO HAVE NOT INCLUDED MENTION IN 00Z TAFS. SHORTWAVE TROUGH
CURRENTLY OVER SE MN/WI WILL DROP SOUTHWARD INTO THE AREA EARLY
TUESDAY MORNING...TRIGGERING SCATTERED SHOWERS/THUNDER. EXPECTING
LOW VFR CEILINGS AND VCTS SPREADING ACROSS TERMINALS
11-14Z...CONTINUING FOR MUCH OF REMAINDER OF TAF PERIOD. STRONGER
STORMS COULD PRODUCE LOCAL MVFR CIGS/VSBYS...ALTHOUGH
TIMING/LOCATION UNCERTAINTIES PREVENT EXPLICIT MENTION IN TAFS AT
THIS TIME. WINDS W-NW 5-10 KTS OVERNIGHT...VEERING SLIGHTLY NW AND
INCREASING TO 10-12 KTS AFTER 17Z.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ONTON
SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON




000
FXUS63 KLOT 300154
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
854 PM CDT MON JUN 29 2015

.UPDATE...
854 PM CDT

FOR EVENING UPDATE...

ONLY A FEW MINOR CHANGES MADE TO HOURLY POP/WX GRIDS INTO THE
OVERNIGHT HOURS TO ADJUST FOR RADAR TRENDS/EXTRAPOLATION OF MID-
LEVEL SHORT WAVE TROUGH AXIS CURRENTLY UPSTREAM OVER NORTHWEST
WI/EAST CENTRAL MN PER VAPOR IMAGERY. ZONE UPDATE SHORTLY.

ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS HAVE DECREASED IN
COVERAGE AND WERE MAINLY LOCATED PRIMARILY ALONG SOUTHERN PORTIONS
OF THE I-39 CORRIDOR IN LASALLE AND LIVINGSTON COUNTIES AT 845 PM.
THESE CELLS CONTINUE TO PULSE AND EXHIBIT MID-LEVEL ROTATION AT
TIMES ALONG EASTERN GRADIENT OF A REGION OF 25-30 KT 0-6 KM BULK
SHEAR AXIS JUST WEST OF THE CWA. SHOULD CONTINUE TO SEE A GRADUAL
DIURNAL WEAKENING IN THESE CELLS AS THEY CONTINUE TO DRIFT SLOWLY
SOUTH-SOUTHEAST ACROSS LIVINGSTON COUNTY THIS EVENING. FARTHER
UPSTREAM HOWEVER...AREA OF SHOWERS/THUNDERSTORMS ACROSS SOUTH
CENTRAL AND SOUTHWEST WI WERE ADVANCING TO THE SOUTH-SOUTHEAST AS
WELL...IN ASSOCIATION WITH THE AFOREMENTIONED MID-LEVEL WAVE. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO PROPAGATE INTO THE CWA LATE
THIS EVENING...ALTHOUGH THE STRONGEST CONVECTION IS EXPECTED TO
REMAIN ALONG/WEST OF THE MISSISSIPPI RIVER WHERE POOL MID-UPPER
60S SURFACE DEW POINTS AND 2000 J/KG MUCAPE AXIS IS LOCATED PER
SPC/RAP MESOANALYSIS. RECENT RUNS OF THE HRRR DEPICT THIS...WITH
EROSION OF MUCH OF THE DEEPER CONVECTION FARTHER EAST ACROSS OUR
CWA. STILL... THE POTENTIAL FOR SHOWERS/ISOLATED THUNDER WILL
LINGER INTO THE PRE-DAWN HOURS AS THE SHORT WAVE PROGRESSES
SOUTHEAST ACROSS THE AREA. A FEW SHOWERS MAY LINGER PAST SUNRISE
ACROSS THE SOUTHEAST CORNER OF THE CWA.

RATZER

&&

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KILX 300056
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
756 PM CDT MON JUN 29 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 756 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH SCATTERED FEW-SCT
CLOUD COVER ABOVE 3.5 KFT AGL THIS EVENING WHILE ISOLATED
THUNDERSTORMS CONTINUE ACROSS NORTHERN IL. THUNDERSTORMS ARE
SHOWING SOME SLOW MOVEMENT TO THE SOUTH...BUT ARE STRUGGLING TO
MAINTAIN STRENGTH OVER CENTRAL IL WHERE GENERAL SUBSIDENCE ALOFT
CONTINUES. STORMS SHOULD TEND TO DISSIPATE AFTER SUNSET AS
WELL...SO HAVE NOT INCLUDED MENTION IN 00Z TAFS. SHORTWAVE TROUGH
CURRENTLY OVER SE MN/WI WILL DROP SOUTHWARD INTO THE AREA EARLY
TUESDAY MORNING...TRIGGERING SCATTERED SHOWERS/THUNDER. EXPECTING
LOW VFR CEILINGS AND VCTS SPREADING ACROSS TERMINALS
11-14Z...CONTINUING FOR MUCH OF REMAINDER OF TAF PERIOD. STRONGER
STORMS COULD PRODUCE LOCAL MVFR CIGS/VSBYS...ALTHOUGH
TIMING/LOCATION UNCERTAINTIES PREVENT EXPLICIT MENTION IN TAFS AT
THIS TIME. WINDS W-NW 5-10 KTS OVERNIGHT...VEERING SLIGHTLY NW AND
INCREASING TO 10-12 KTS AFTER 17Z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON



000
FXUS63 KILX 300056
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
756 PM CDT MON JUN 29 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 756 PM CDT MON JUN 29 2015

VFR CONDITIONS ACROSS CENTRAL IL TERMINALS WITH SCATTERED FEW-SCT
CLOUD COVER ABOVE 3.5 KFT AGL THIS EVENING WHILE ISOLATED
THUNDERSTORMS CONTINUE ACROSS NORTHERN IL. THUNDERSTORMS ARE
SHOWING SOME SLOW MOVEMENT TO THE SOUTH...BUT ARE STRUGGLING TO
MAINTAIN STRENGTH OVER CENTRAL IL WHERE GENERAL SUBSIDENCE ALOFT
CONTINUES. STORMS SHOULD TEND TO DISSIPATE AFTER SUNSET AS
WELL...SO HAVE NOT INCLUDED MENTION IN 00Z TAFS. SHORTWAVE TROUGH
CURRENTLY OVER SE MN/WI WILL DROP SOUTHWARD INTO THE AREA EARLY
TUESDAY MORNING...TRIGGERING SCATTERED SHOWERS/THUNDER. EXPECTING
LOW VFR CEILINGS AND VCTS SPREADING ACROSS TERMINALS
11-14Z...CONTINUING FOR MUCH OF REMAINDER OF TAF PERIOD. STRONGER
STORMS COULD PRODUCE LOCAL MVFR CIGS/VSBYS...ALTHOUGH
TIMING/LOCATION UNCERTAINTIES PREVENT EXPLICIT MENTION IN TAFS AT
THIS TIME. WINDS W-NW 5-10 KTS OVERNIGHT...VEERING SLIGHTLY NW AND
INCREASING TO 10-12 KTS AFTER 17Z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...ONTON




000
FXUS63 KLOT 300005
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
705 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300005
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
705 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300005
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
705 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300005
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
705 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
705 PM CDT

WEAKER SURFACE PATTERN IN PLACE SITUATED ACROSS THE REGION
TODAY...WITH SOUTHERLY WINDS IN PLACE. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE TONIGHT INTO TUESDAY BUT AS AN AREA OF LOW
PRESSURE PUSHES EAST THROUGH THE GREAT LAKES REGION ON
TUESDAY...EXPECT WINDS TO TURN MORE NORTHERLY. INCREASING SPEEDS
ARE LIKELY ALL ACROSS THE LAKE AND INTO THE NEARSHORE TUESDAY
AFTERNOON INTO THE EVENING...WITH NORTH WINDS OF 10 TO 20 KT
EXPECTED AT THIS TIME. HOWEVER...WILL NEED TO MONITOR THE
POTENTIAL FOR SLIGHTLY STRONGER WINDS DURING THIS PERIOD WITH A
WINDOW OF 15 TO 25 KT WINDS A POSSIBILITY...ESPECIALLY AS COOLER
AIR WORKS DOWN THE LAKE. THESE CONCERNS ARE FOR THE NEARSHORE AS
WELL AND IF THE HIGHER SPEEDS AND THEN HIGHER WAVES DO
OCCUR...THEN SMALL CRAFT CONDITIONS COULD BE POSSIBLE. WITH HIGH
PRESSURE THEN EXPECTED TO SPAN THE GREAT LAKES REGION...NORTHERLY
WINDS ARE EXPECTED TO PREVAIL THROUGH MUCH OF THE REMAINING WORK
WEEK.

RODRIGUEZ

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300000
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
700 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 300000
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
700 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300000
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
700 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 300000
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
700 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* SCATTERED SHRA LATE THIS EVENING/EARLY MORNING.
* CHANCE OF SHRA TUESDAY AFTERNOON.
* POSSIBLE MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LAKE BREEZE/SHIFT TO NORTHEAST LATE TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 00Z...

SHOWER ACTIVITY CONTINUES TO DECREASE IN COVERAGE ACROSS THE
CHICAGO AREA TERMINALS WHILE SHOWERS AND A FEW THUNDERSTORMS
CONTINUE FURTHER WEST AND SOUTH OF THE TERMINALS. THIS ACTIVITY
WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS WITH LOSS OF DAYTIME
HEATING. ADDITIONAL SHOWERS/THUNDERSTORMS ACROSS SOUTH/CENTRAL WI
WILL MOVE SOUTH LATER THIS EVENING. SHORT TERM/HI RES GUIDANCE
SHOWS THIS ACTIVITY SLOWLY WEAKENING BUT STILL ARRIVING INTO
NORTHERN IL. HOW MUCH CONTINUES ACROSS THE TERMINALS INTO THE
EARLY MORNING HOURS REMAINS SOMEWHAT UNCERTAIN...BUT MAINTAINED
CURRENT SHOWER MENTION AND WILL NEED TO MONITOR TRENDS THRU THE
EVENING.

A WEAK GRADIENT HAS ALLOWED WINDS TO BECOME LIGHT AND VARIABLE
WHICH WILL TEND TO FAVOR CALM THIS EVENING. EVENTUALLY WINDS WILL
SHIFT MORE LIGHT WESTERLY OR NORTHWESTERLY OVERNIGHT...THEN
INCREASE IN SPEED LATER TUESDAY MORNING. WINDS WILL SHIFT MORE
NORTHERLY IN THE AFTERNOON AND LIKELY TURN NORTHEAST OFF THE LAKE
BY LATE TUESDAY AFTERNOON/EARLY EVENING.

PREVAILING VFR CIGS...OUTSIDE ANY PRECIP AREAS...SHOULD CONTINUE
THIS EVENING...WITH MVFR CIGS POSSIBLE OVERNIGHT INTO TUESDAY
MORNING. CONFIDENCE IS PRETTY LOW REGARDING SPECIFIC HEIGHTS SO
DIDN/T MAKE ANY SIGNIFICANT CHANGES. FOG WILL ALSO BE POSSIBLE
OVERNIGHT DEPENDING ON EXTENT OF CLOUD COVER. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* LOW FOR SHRA LATE THIS EVENING/OVERNIGHT.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA TUESDAY AFTERNOON.
* MEDIUM FOR WINDS THRU THE PERIOD...MEDIUM FOR SHIFT TO NORTHEAST
  TUESDAY AFTERNOON...LOW FOR TIMING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY AND THURSDAY...DRY/VFR. NORTHEAST WINDS.
* FRIDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* SATURDAY...SLIGHT CHANCE OF SHRA. EAST WINDS.
* SUNDAY...SLIGHT SHRA/TSRA. SOUTHEAST WINDS.

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 292219
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
519 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* SCATTERED SHRA/ISOLATED TSRA THRU EARLY EVENING.
* MVFR CIGS...POSSIBLE IFR CIGS OVERNIGHT/TUESDAY MORNING.
* SCATTERED SHRA LATE THIS EVENING/EARLY OVERNIGHT.
* CHANCE OF SHRA TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 22Z...

SCATTERED SHOWERS ALONG WITH ISOLATED THUNDERSTORMS CONTINUE TO
SLOWLY MOVE SOUTHEAST ACROSS THE AREA THIS AFTERNOON. MUCH OF THE
THUNDER ACTIVITY CURRENTLY EXTENDS WEST AND SOUTH OF THE CHICAGO
AREA TERMINALS AND SHOULD REMAIN IN THESE AREAS THRU EARLY EVENING
WHEN ACTIVITY SHOULD SLOWLY BEGIN TO DIMINISH WITH LOST OF
DAYTIME HEATING. SURFACE WINDS REMAIN QUITE LIGHT WITH VARIABLE
DIRECTIONS DUE TO OUTFLOW BOUNDARIES. STRONGER CELLS MAY PRODUCE
SOME LOCALLY HIGHER WIND SPEEDS/GUSTS. CMS

PREVIOUS 18Z DISCUSSION...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH FOR SCATTERED SHRA...MEDIUM FOR COVERAGE...LOW FOR ISOLATED
  TSRA.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA LATE THIS EVENING/EARLY OVERNIGHT AND AGAIN TUESDAY
  AFTERNOON. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 292219
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
519 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* SCATTERED SHRA/ISOLATED TSRA THRU EARLY EVENING.
* MVFR CIGS...POSSIBLE IFR CIGS OVERNIGHT/TUESDAY MORNING.
* SCATTERED SHRA LATE THIS EVENING/EARLY OVERNIGHT.
* CHANCE OF SHRA TUESDAY AFTERNOON. CMS

//DISCUSSION...UPDATED 22Z...

SCATTERED SHOWERS ALONG WITH ISOLATED THUNDERSTORMS CONTINUE TO
SLOWLY MOVE SOUTHEAST ACROSS THE AREA THIS AFTERNOON. MUCH OF THE
THUNDER ACTIVITY CURRENTLY EXTENDS WEST AND SOUTH OF THE CHICAGO
AREA TERMINALS AND SHOULD REMAIN IN THESE AREAS THRU EARLY EVENING
WHEN ACTIVITY SHOULD SLOWLY BEGIN TO DIMINISH WITH LOST OF
DAYTIME HEATING. SURFACE WINDS REMAIN QUITE LIGHT WITH VARIABLE
DIRECTIONS DUE TO OUTFLOW BOUNDARIES. STRONGER CELLS MAY PRODUCE
SOME LOCALLY HIGHER WIND SPEEDS/GUSTS. CMS

PREVIOUS 18Z DISCUSSION...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH FOR SCATTERED SHRA...MEDIUM FOR COVERAGE...LOW FOR ISOLATED
  TSRA.
* MEDIUM FOR MVFR CIGS OVERNIGHT/TUESDAY MORNING.
* LOW FOR SHRA LATE THIS EVENING/EARLY OVERNIGHT AND AGAIN TUESDAY
  AFTERNOON. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 292020
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
320 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 292020
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
320 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 292020
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
320 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 292020
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
320 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 292020
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
320 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 292020
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
320 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 292020
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
320 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 292020
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
320 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
319 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

THE BEGINNING OF THE PERIOD TUESDAY EVENING MAY BEGIN WITH
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL ACROSS THE
CWA...BUT EXPECT WHATEVER LINGERING DEVELOPMENT TO DIMINISH.
DEPARTING LARGE SCALE ASCENT AND A GOOD PUSH OF COOLER/DRIER AIR
ACROSS THE CWA TUESDAY NIGHT...WILL ALLOW FOR ANY FURTHER PRECIP
DEVELOPMENT ACROSS THE REGION TO REMAIN SOUTH OF THE CWA. WITH
THIS COOLER/DRIER AIRMASS IN PLACE AND WITH DIMINISHING
WINDS/CLEARING SKIES...DID LOWER LOW TEMPS TUESDAY NIGHT WITH
TEMPS DROPPING INTO THE 50S FOR MOST AREAS. ALTHOUGH NORTHWEST
FLOW ALOFT WILL PREVAIL ON WEDNESDAY...IT IS BECOMING MORE LIKELY
THAT THE BEST DEVELOPMENT FOR FURTHER PRECIP WILL BE TO THE
SOUTHWEST/SOUTH OF THE CWA. SO DID REMOVE POPS FOR MOST LOCATIONS
DURING THIS TIME BUT DID LEAVE SLIGHT CHANCE WORDING FOR THE FAR
SOUTHWEST CWA OWING TO SOME SLIGHT VARIABILITY AMONG MODEL
GUIDANCE. HOWEVER...COULD SEE THESE SLIGHT CHANCE POPS BEING
REMOVED WITH DRIER CONDITIONS THE MORE LIKELY TREND. ALSO LOWERED
SKY COVER TUESDAY NIGHT INTO WEDNESDAY WITH CLEARER SKIES BECOMING
MORE LIKELY BUT WITH SEVERAL MID LEVEL IMPULSES TRAVERSING THE
FLOW...COULD SEE SOME PERIODIC MID/HIGH LEVEL CLOUD COVER.

THE DRIER TREND WITH A MORE SOUTHWARD PLACEMENT OF BEST PRECIP
DEVELOPMENT WILL LIKELY CONTINUE WEDNESDAY NIGHT INTO
THURSDAY...WITH HIGH PRESSURE EXPANDING ACROSS MUCH OF THE REGION.
BELOW NORMAL TEMPS LOOK TO CONTINUE DURING THIS PERIOD AS WELL
WITH TEMPS FALLING TO THE 50S AGAIN. LOWERED TEMPS DURING THIS
PERIOD AND MAY NOT HAVE LOWERED ENOUGH ESPECIALLY ACROSS FAR
NORTHERN ILLINOIS WHERE TEMPS COULD FALL INTO THE 40S. WITH
STEERING FLOW KEEPING GENERAL MOVEMENT OF APPROACHING MID LEVEL
IMPULSES TO THE SOUTH AND WITH DOMINATING HIGH PRESSURE IN
PLACE...SUNNY SKIES WILL BE IN PLACE THURSDAY. HOWEVER...COOLER
AIRMASS AND ONSHORE FLOW WILL HELP KEEP TEMPS BELOW NORMAL...IN
THE 70S AND THE UPPER 60S NEAR THE LAKE. DRY CONDITIONS SHOULD
CONTINUE THURSDAY NIGHT BUT WITH CONFIDENCE LOWERING INTO
FRIDAY...AS GUIDANCE VARIES WITH A POSSIBLE SYSTEM PUSHING ACROSS
THE CWA. HAVE MAINTAINED CHANCE POPS FOR SHOWERS/THUNDERSTORMS ON
FRIDAY...BUT WILL NEED TO MONITOR THIS PERIOD FOR ANOTHER POSSIBLE
DRY DAY. GOING INTO THE WEEKEND...GUIDANCE DOES VARY BUT AT THIS
TIME...SATURDAY IS APPEARING TO BE ANOTHER DRY PERIOD FOR MOST
AREAS.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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000
FXUS63 KILX 292009
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
309 PM CDT MON JUN 29 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 300 PM CDT MON JUN 29 2015

19Z/2PM SURFACE ANALYSIS SHOWS 1008MB LOW OVER EASTERN
INDIANA...WITH COLD FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS.
ALOFT...A DEEP TROUGH WITH SEVERAL EMBEDDED SHORT-WAVES REMAINS IN
PLACE ACROSS THE EASTERN CONUS.  WHILE ONE IMPULSE ASSOCIATED WITH
THE SURFACE LOW HAS PASSED WELL EAST OF ILLINOIS...TWO ADDITIONAL
FEATURES ARE NOTED ON UPSTREAM WATER VAPOR IMAGERY...ONE OVER
SOUTHERN LAKE MICHIGAN AND ANOTHER OVER EASTERN MINNESOTA/NORTHERN
WISCONSIN.  THE GREAT LAKES WAVE IS CURRENTLY TRIGGERING WIDELY
SCATTERED CONVECTION ACROSS MAINLY NORTHERN ILLINOIS INTO
NORTHERN/CENTRAL INDIANA.  A FEW SHOWERS ASSOCIATED WITH THIS
FEATURE WILL DRIFT SOUTHWARD INTO THE NORTHERN KILX CWA THIS
AFTERNOON INTO THE EARLY EVENING BEFORE DISSIPATING TOWARD SUNSET.
WILL INCLUDE LOW CHANCE POPS ALONG/NORTHEAST OF A RUSHVILLE...TO
DECATUR...TO PARIS LINE THROUGH MID-EVENING ACCORDINGLY. AFTER
THAT...THINK THERE WILL BE A LULL IN PRECIP CHANCES BEFORE THE
MINNESOTA WAVE APPROACHES FROM THE NORTH LATE TONIGHT.  HAVE
THEREFORE BROUGHT LOW CHANCE POPS AS FAR SOUTH AS I-70 WELL AFTER
MIDNIGHT TOWARD DAWN TUESDAY.  FURTHER SOUTHEAST...HAVE GONE WITH A
DRY FORECAST THROUGH THE ENTIRE NIGHT SOUTH OF THE I-70 CORRIDOR.

&&

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 300 PM CDT MON JUN 29 2015

THE 12Z EXTENDED MODELS ARE STARTING TO GIVE SOME HOPE TO LONGER DRY
PERIODS THIS WEEK, ESPECIALLY THE NORTHERN HALF OF ILLINOIS.

IN THE EARLY EXTENDED FOR TUESDAY, THE UPPER TROUGH IN THE EASTERN
CONUS AND THE RIDGE IN THE WEST WILL ALLOW A SHORTWAVE TO DROP SOUTH
THROUGH ILLINOIS LATE TONIGHT INTO TUESDAY, TRIGGERING SHOWERS AND A
FEW THUNDERSTORMS.

SOME WEAK RIDGING ALOFT MID WEEK OVER ILLINOIS COULD PUSH THE STORM
TRACK FOR THE WEDNESDAY NIGHT SYSTEM JUST SOUTHWEST OF OUR COUNTIES.
THE BETTER CHANCES FOR STORMS FROM THAT SYSTEM SHOULD REMAIN S OF I-
70, ALTHOUGH MODEL DIFFERENCES KEEP AT LEAST CHANCE POPS AS FAR
NORTH AS I-74. WE REMAIN IN THE SPC DAY 3 MARGINAL RISK FOR STORMS
SOUTH OF I-74, BUT OVERALL CHANCES OF SEVERE ARE RELATIVELY LOW.

THE NEXT STRONGER SHORTWAVE IS PROJECTED TO AFFECT OUR FORECAST AREA
ON FRIDAY, WITH THE ECMWF/GFS/CANADIAN HAVING RELATIVELY SIMILAR
TIMING AND LOCATION OF THAT SYSTEM. THE GFS IS THE OUTLIER WITH
PRECIP, GOING NEARLY DRY DURING THAT TIME. BETTER CHANCES FOR STORMS
FRIDAY APPEAR TO BE SOUTH OF I-74.

BEYOND THAT, MODEL DIFFERENCES BECOME MORE PROMINENT, WITH
VARIATIONS ON TIMING OF UPPER LEVEL RIDGING OR TROUGHING. GENERAL
CONSENSUS IS FOR SCATTERED SHOWERS/STORMS TO BE POSSIBLE AS THE
UPPER TROUGH AXIS REMAINS CLOSE-BY IF NOT DIRECTLY ACROSS ILLINOIS
FROM SW TO NE. FROM FRIDAY NIGHT THROUGH THE WEEKEND, WE TRENDED
DOWN WITH POPS TO SLIGHT CHANCE IN THE WEST, AND LOW CHANCE IN THE
EAST CLOSER TO THE POTENTIAL TRACK OF ANY SHORTWAVES.

IN THE FAR EXTENDED, THE GFS IS ADVERTISING A POTENTIAL SHIFT TO
LONG WAVE RIDGING ALOFT STARTING MONDAY, WHICH COULD TRANSLATE INTO
A SHIFT IN THE STORM TRACK NORTH OF ILLINOIS AND BUILDING OF SOME
HEAT IN OUR AREA. THE 12Z ECMWF HAS THE OPPOSITE SOLUTION, WITH
ANOTHER TROUGH PROGRESSING FROM THE NORTHERN PLAINS AND DIGGING INTO
ILLINOIS FOR THE FIRST HALF OF NEXT WEEK. HOPEFULLY THE DRIER GFS
PANS OUT SO WE CAN GIVE THE RIVERS A CHANCE TO RECEDE FROM NEAR
RECORD FLOODING IN SOME AREAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VFR CEILINGS AND VCTS COMING INTO
THE PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BARNES
LONG TERM...SHIMON
AVIATION...BARNES




000
FXUS63 KLOT 291955
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
255 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

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000
FXUS63 KLOT 291955
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
255 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 291955
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
255 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 291955
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
255 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... LOWERING TO MVFR
  WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 05Z-09Z OVERNIGHT/EARLY TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES OVERNIGHT/EARLY TUESDAY AND
  AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 291925
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
225 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... BRIEF LOWERING TO
  MVFR WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 09Z-13Z TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES LATE TONIGHT/EARLY TUESDAY
  AND AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 291925
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
225 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... BRIEF LOWERING TO
  MVFR WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 09Z-13Z TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES LATE TONIGHT/EARLY TUESDAY
  AND AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 291925
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
225 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... BRIEF LOWERING TO
  MVFR WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 09Z-13Z TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES LATE TONIGHT/EARLY TUESDAY
  AND AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 291925
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
225 PM CDT MON JUN 29 2015

.SHORT TERM...
224 PM CDT

THROUGH TUESDAY...

TONIGHT...SHOWER/THUNDER TRENDS WILL BE THE MAIN FOCUS TONIGHT AS
ANOTHER IN A SERIES OF UPPER WAVES TRAVERSES THE AREA. LATE
AFTERNOON SHOWER/THUNDER ACTIVITY WILL FADE AS THE PRIMARY WAVE
DRIVING THE ACTIVITY SHIFTS TO THE EAST AND DAYLIGHT BEGINS TO WANE.
WATER VAPOR IMAGERY SHOWS ADDITIONAL WAVES MOVING SOUTHEAST ACROSS
MINNESOTA WITH THE MOST PRONOUNCED WAVE APPROACHING NORTHWEST
WISCONSIN. SHOWERS AND STORMS CONTINUE TO MARCH SOUTHEASTWARD WITH
THIS SECOND WAVE WHILE NEW SCATTERED ACTIVITY IS DEVELOPING TO THE
SOUTH ACROSS EXTREME SOUTHEAST MN AND SOUTHWEST WI IN CONJUNCTION
WITH THE SE MN WAVE. GUIDANCE IS MIXED ON HOW LONG ALL OF THIS
ACTIVITY WILL CONTINUE INTO THE NIGHT AND THEREFORE HOW MUCH IMPACT
THE CWA WILL SEE. BASED ON LATEST TRENDS AND NEAR TERM
GUIDANCE...SHOWERS AND STORMS COULD REACH THE NORTHWEST CWA BY MID
EVENING THEN CONTINUE ACROSS THE AREA OVERNIGHT IF THEY HOLD
TOGETHER. SOME OF THE ACTIVITY WITH THE SE MN WAVE MAY BE MORE
DIURNALLY DRIVEN SO IT MAY FADE AS IT MOVES CLOSER TO THE AREA EARLY
THIS EVENING. EXPECT THE MORE ORGANIZED NORTHERN ACTIVITY TO MAKE
BETTER PROGRESS AND HOLD TOGETHER LONGER SO WILL WORK A BAND OF LOW
LIKELY/HIGH CHANCE POPS ACROSS THE AREA FROM MID EVENING THROUGH THE
OVERNIGHT HOURS THEN EXIT THEM TO THE EAST EARLY TOMORROW MORNING.
AM A BIT CONCERNED THAT THE ARRIVAL OF POPS MAY BE JUST A BIT SLOW
SO MAY NEED TO SPEED THE PROGRESSION UP BY AN HOUR OR TWO GOING INTO
EARLY EVENING SO STAY TUNED. WOULD EXPECT ANY WIND THREAT WITH THIS
ACTIVITY TO BE DIMINISHING AS IT APPROACHES LEAVING HEAVY
DOWNPOURS/ISOLATED FLOODING AS THE PRIMARY CONCERN.

TUESDAY...ANY LEFTOVER OVERNIGHT PRECIP WILL EXIT TO THE EAST BY MID
TUESDAY MORNING AS AN UPPER TROUGH AXIS CLEARS TO THE EAST. THE MAIN
SURFACE LOW WILL LAG BEHIND THE UPPER WAVE BUT WILL DRAG A COOL
FRONTAL BOUNDARY ACROSS THE AREA THROUGH THE MORNING. THERE DOES NOT
APPEAR TO BE MUCH OF A COHERENT FOCUS FOR ADDITIONAL ORGANIZED
DEVELOPMENT THROUGH THE MORNING BUT WITH BROADER ASCENT IN PLACE
ISOLATED ACTIVITY IS POSSIBLE. HIGH PRESSURE WILL BE BUILDING ACROSS
WESTERN LAKE SUPERIOR WHILE BRINGING A STRONGER PRESSURE GRADIENT TO
NORTHERN SECTIONS OF LAKE MICHIGAN AHEAD OF IT. A SECONDARY COOL
FRONTAL BOUNDARY LOOKS TO DEVELOP AND DROP DOWN LAKE MICHIGAN
TUESDAY AFTERNOON WHICH MAY SERVE TO TRIGGER ISOLATED/SCATTERED
SHRA/TSRA DEVELOPMENT DURING THE AFTERNOON...ESPECIALLY LATER...
GIVEN THAT THE AIRMASS BEHIND THE INITIAL FRONT WILL STILL BE MOIST
AND UNSTABLE. WILL CARRY CHANCE POPS DURING THE MID/LATE AFTERNOON
INTO THE EARLY EVENING HOURS ACROSS NORTHEAST IL AND FAR NORTHWEST
IN. HIGH TEMPS WILL BE IN THE UPPER 70S TO AROUND 80 WITH LAKEFRONT
AREAS COOLING LATE IN THE DAY AS WINDS SHIFT NORTHEAST WITH THE
SECONDARY FRONTAL PASSAGE.

MDB

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... BRIEF LOWERING TO
  MVFR WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 09Z-13Z TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES LATE TONIGHT/EARLY TUESDAY
  AND AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KLOT 291757
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1257 PM CDT MON JUN 29 2015

.UPDATE...
1143 AM CDT

SHOWER/THUNDER CHANCES AND COVERAGE REMAIN THE FOCUS FOR THE REST
OF THE DAY. LATEST SURFACE ANALYSIS CONTINUES TO SHOW A WEAK
TROUGH AXIS STRETCHING FROM CENTRAL WISCONSIN SOUTHWARD ACROSS THE
CHICAGO METRO AREA THEN INTO EAST-CENTRAL ILLINOIS. WATER VAPOR
IMAGERY SHOWS ONE UPPER TROUGH WHICH BROUGHT THE MORNING RAIN TO
THE AREA NOW TO THE EAST BUT SEVERAL ADDITIONAL WAVES ARE ON THE
WAY. THE NEXT IS FAIRLY SUBTLE AND IS OVER FAR SOUTHEAST MINNESOTA
WITH ANOTHER MORE ORGANIZED WAVE TRACKING SOUTHEAST ACROSS CENTRAL
MINNESOTA. THE FIRST WAVE IS HELPING TO GENERATE SHOWERS ACROSS
CENTRAL WISCONSIN WITH ADDITIONAL SHOWERS NOW JUST STARTING TO
POP OVER NORTHERN ILLINOIS. EXPECT THAT COVERAGE WILL INCREASE
INTO THE AFTERNOON AS THE WAVE MOVES OVERHEAD AND COMBINES WITH
CONVERGENCE ALONG THE WEAK TROUGH.

WHILE ISOLATED TO SCATTERED COVERAGE IS EXPECTED ACROSS JUST
ABOUT THE ENTIRE FORECAST AREA...THE MOST CONCENTRATED ACTIVITY
WILL LIKELY BE ALONG THE TROUGH AXIS. VISIBLE SATELLITE IS
STARTING TO SHOW WHERE THIS MAY LINE UP WITH BEST CU DEVELOPMENT
ARCHING FROM JUST EAST OF MADISON AND JANESVILLE ACROSS THE
CENTRAL CHICAGO METRO AND INTO FAR NORTHWEST INDIANA. LAKE
INFLUENCES MAY ALSO HELP REINFORCE THE CONVERGENCE ACROSS THESE
SAME AREAS WHICH ALSO SUPPORTS BEST COVERAGE. WILL CONTINUE WITH
HIGHEST POPS ACROSS THE EASTERN TWO-THIRDS OF THE AREA THIS
AFTERNOON AND MAY END UP RAISING THEM TO LIKELY OR BETTER BEFORE
LONG. INSTABILITY IS INCREASING SO THUNDER RISK WILL INCREASE.
HEAVY DOWNPOURS AND LOCALIZED FLOODING LOOK TO BE THE GREATEST
RISK GIVEN THE MOIST ATMOSPHERE AND SLOW STORM MOVEMENT. THE
SEVERE RISK IS PRETTY LOW BUT A FEW STRONGER WIND GUSTS COULD
OCCUR.

MDB

&&

.SHORT TERM...
253 AM CDT

THROUGH TONIGHT...

IR IMAGERY EARLY THIS MORNING HAS THICKER CLOUD COVER STRETCHING
FROM CENTRAL/EASTERN WISC SOUTHEAST ACROSS NORTHEAST IL INTO CENTRAL
IN. SFC ANALYSIS HAS A WEAK LOW CENTERED OVER CENTRAL IL...AND WILL
EVENTUALLY LIFT NORTHEAST ACROSS CENTRAL IN LATER THIS AFTN. THE
NOTABLE FEATURE IS THE LACK OF A GRADIENT WITH THIS WAVE...AS
WINDS ACROSS THE REGION EARLY THIS MORNING ARE GENERALLY LESS THAN
10KT. SOME CLEARING HAS TAKEN PLACE IN THE CLOUD SHIELD ALONG THE
WESTERN PORTIONS OF THE CWFA...WHICH COUPLED WITH THE DEW PTS IN
THE LOW 60S HAS ALLOWED FOG TO PATCHY DENSE FOG TO DEVELOP. EXPECT
FOG TO LINGER A COUPLE HOURS AFTER DAYBREAK GIVEN THE LACK OF
MIXING...BUT BY MID- MORNING THE FOG SHUD ERODE. CLOUDS ARE POISED
TO THICKEN YET AGAIN...WITH MARGINAL INSTABILITY LATE MORNING THRU
THE AFTN/EVE. HAVE OPTED TO HOLD THE MENTION OF THUNDER THRU THE
MORNING...THEN HAVE GONE WITH JUST A SLIGHT CHANCE OF THUNDER. THE
COVERAGE FROM SHOWERS/THUNDER WILL NOT BE GREAT...SO ONLY MINOR
ADJUSTMENTS TO THE GOING POPS.

TEMPS WILL HINGE ON CLOUD COVER AND WIND DIR...ESPECIALLY TRUE FOR
AREAS ADJACENT TO LAKE MICHIGAN. GUIDANCE HAS CONTINUED TO POINT
TOWARDS A NORTHEAST WIND OFF OF THE LAKE...WHICH WILL LIKELY HOLD
TEMPS IN THE UPR 60S TO LOW 70S. ELSEWHERE THE INLAND AREAS SHUD
SLOWLY WARM GIVEN THE BUOYANT ATMOSPHERE INTO THE LOW/MID 70S.

LATER THIS EVENING WITH THE 500MB TROUGH AXIS STILL
OVERHEAD...ANOTHER LOBE OF MID-LVL VORTICITY IS POISED TO DROP SOUTH
FROM THE UPPER MIDWEST ACROSS THE WESTERN GREAT LAKES. THIS SHUD
PROVIDE A BRIEF LULL IN SHOWERS/THUNDER THIS EVE...BEFORE
SHOWERS/THUNDER REDEVELOP LATE TONIGHT AS THE VORT MAX ARRIVES. WITH
DEW POINTS REMAINING IN THE LOW/MID 60S OVERNIGHT...AS THE NEXT SFC
LOW DEVELOPS TONIGHT...SOME OF THE PRECIP COULD BE BRIEF DOWNPOURS
AND SLOW MOVING. THIS COULD RESULT IN RENEWED FLOODING CONCERNS FOR
AREAS THAT CONTINUE TO SEE NEARLY SATURATED SOILS.

BEACHLER

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... BRIEF LOWERING TO
  MVFR WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 09Z-13Z TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES LATE TONIGHT/EARLY TUESDAY
  AND AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 291757
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1257 PM CDT MON JUN 29 2015

.UPDATE...
1143 AM CDT

SHOWER/THUNDER CHANCES AND COVERAGE REMAIN THE FOCUS FOR THE REST
OF THE DAY. LATEST SURFACE ANALYSIS CONTINUES TO SHOW A WEAK
TROUGH AXIS STRETCHING FROM CENTRAL WISCONSIN SOUTHWARD ACROSS THE
CHICAGO METRO AREA THEN INTO EAST-CENTRAL ILLINOIS. WATER VAPOR
IMAGERY SHOWS ONE UPPER TROUGH WHICH BROUGHT THE MORNING RAIN TO
THE AREA NOW TO THE EAST BUT SEVERAL ADDITIONAL WAVES ARE ON THE
WAY. THE NEXT IS FAIRLY SUBTLE AND IS OVER FAR SOUTHEAST MINNESOTA
WITH ANOTHER MORE ORGANIZED WAVE TRACKING SOUTHEAST ACROSS CENTRAL
MINNESOTA. THE FIRST WAVE IS HELPING TO GENERATE SHOWERS ACROSS
CENTRAL WISCONSIN WITH ADDITIONAL SHOWERS NOW JUST STARTING TO
POP OVER NORTHERN ILLINOIS. EXPECT THAT COVERAGE WILL INCREASE
INTO THE AFTERNOON AS THE WAVE MOVES OVERHEAD AND COMBINES WITH
CONVERGENCE ALONG THE WEAK TROUGH.

WHILE ISOLATED TO SCATTERED COVERAGE IS EXPECTED ACROSS JUST
ABOUT THE ENTIRE FORECAST AREA...THE MOST CONCENTRATED ACTIVITY
WILL LIKELY BE ALONG THE TROUGH AXIS. VISIBLE SATELLITE IS
STARTING TO SHOW WHERE THIS MAY LINE UP WITH BEST CU DEVELOPMENT
ARCHING FROM JUST EAST OF MADISON AND JANESVILLE ACROSS THE
CENTRAL CHICAGO METRO AND INTO FAR NORTHWEST INDIANA. LAKE
INFLUENCES MAY ALSO HELP REINFORCE THE CONVERGENCE ACROSS THESE
SAME AREAS WHICH ALSO SUPPORTS BEST COVERAGE. WILL CONTINUE WITH
HIGHEST POPS ACROSS THE EASTERN TWO-THIRDS OF THE AREA THIS
AFTERNOON AND MAY END UP RAISING THEM TO LIKELY OR BETTER BEFORE
LONG. INSTABILITY IS INCREASING SO THUNDER RISK WILL INCREASE.
HEAVY DOWNPOURS AND LOCALIZED FLOODING LOOK TO BE THE GREATEST
RISK GIVEN THE MOIST ATMOSPHERE AND SLOW STORM MOVEMENT. THE
SEVERE RISK IS PRETTY LOW BUT A FEW STRONGER WIND GUSTS COULD
OCCUR.

MDB

&&

.SHORT TERM...
253 AM CDT

THROUGH TONIGHT...

IR IMAGERY EARLY THIS MORNING HAS THICKER CLOUD COVER STRETCHING
FROM CENTRAL/EASTERN WISC SOUTHEAST ACROSS NORTHEAST IL INTO CENTRAL
IN. SFC ANALYSIS HAS A WEAK LOW CENTERED OVER CENTRAL IL...AND WILL
EVENTUALLY LIFT NORTHEAST ACROSS CENTRAL IN LATER THIS AFTN. THE
NOTABLE FEATURE IS THE LACK OF A GRADIENT WITH THIS WAVE...AS
WINDS ACROSS THE REGION EARLY THIS MORNING ARE GENERALLY LESS THAN
10KT. SOME CLEARING HAS TAKEN PLACE IN THE CLOUD SHIELD ALONG THE
WESTERN PORTIONS OF THE CWFA...WHICH COUPLED WITH THE DEW PTS IN
THE LOW 60S HAS ALLOWED FOG TO PATCHY DENSE FOG TO DEVELOP. EXPECT
FOG TO LINGER A COUPLE HOURS AFTER DAYBREAK GIVEN THE LACK OF
MIXING...BUT BY MID- MORNING THE FOG SHUD ERODE. CLOUDS ARE POISED
TO THICKEN YET AGAIN...WITH MARGINAL INSTABILITY LATE MORNING THRU
THE AFTN/EVE. HAVE OPTED TO HOLD THE MENTION OF THUNDER THRU THE
MORNING...THEN HAVE GONE WITH JUST A SLIGHT CHANCE OF THUNDER. THE
COVERAGE FROM SHOWERS/THUNDER WILL NOT BE GREAT...SO ONLY MINOR
ADJUSTMENTS TO THE GOING POPS.

TEMPS WILL HINGE ON CLOUD COVER AND WIND DIR...ESPECIALLY TRUE FOR
AREAS ADJACENT TO LAKE MICHIGAN. GUIDANCE HAS CONTINUED TO POINT
TOWARDS A NORTHEAST WIND OFF OF THE LAKE...WHICH WILL LIKELY HOLD
TEMPS IN THE UPR 60S TO LOW 70S. ELSEWHERE THE INLAND AREAS SHUD
SLOWLY WARM GIVEN THE BUOYANT ATMOSPHERE INTO THE LOW/MID 70S.

LATER THIS EVENING WITH THE 500MB TROUGH AXIS STILL
OVERHEAD...ANOTHER LOBE OF MID-LVL VORTICITY IS POISED TO DROP SOUTH
FROM THE UPPER MIDWEST ACROSS THE WESTERN GREAT LAKES. THIS SHUD
PROVIDE A BRIEF LULL IN SHOWERS/THUNDER THIS EVE...BEFORE
SHOWERS/THUNDER REDEVELOP LATE TONIGHT AS THE VORT MAX ARRIVES. WITH
DEW POINTS REMAINING IN THE LOW/MID 60S OVERNIGHT...AS THE NEXT SFC
LOW DEVELOPS TONIGHT...SOME OF THE PRECIP COULD BE BRIEF DOWNPOURS
AND SLOW MOVING. THIS COULD RESULT IN RENEWED FLOODING CONCERNS FOR
AREAS THAT CONTINUE TO SEE NEARLY SATURATED SOILS.

BEACHLER

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... BRIEF LOWERING TO
  MVFR WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 09Z-13Z TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES LATE TONIGHT/EARLY TUESDAY
  AND AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO



000
FXUS63 KLOT 291757
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1257 PM CDT MON JUN 29 2015

.UPDATE...
1143 AM CDT

SHOWER/THUNDER CHANCES AND COVERAGE REMAIN THE FOCUS FOR THE REST
OF THE DAY. LATEST SURFACE ANALYSIS CONTINUES TO SHOW A WEAK
TROUGH AXIS STRETCHING FROM CENTRAL WISCONSIN SOUTHWARD ACROSS THE
CHICAGO METRO AREA THEN INTO EAST-CENTRAL ILLINOIS. WATER VAPOR
IMAGERY SHOWS ONE UPPER TROUGH WHICH BROUGHT THE MORNING RAIN TO
THE AREA NOW TO THE EAST BUT SEVERAL ADDITIONAL WAVES ARE ON THE
WAY. THE NEXT IS FAIRLY SUBTLE AND IS OVER FAR SOUTHEAST MINNESOTA
WITH ANOTHER MORE ORGANIZED WAVE TRACKING SOUTHEAST ACROSS CENTRAL
MINNESOTA. THE FIRST WAVE IS HELPING TO GENERATE SHOWERS ACROSS
CENTRAL WISCONSIN WITH ADDITIONAL SHOWERS NOW JUST STARTING TO
POP OVER NORTHERN ILLINOIS. EXPECT THAT COVERAGE WILL INCREASE
INTO THE AFTERNOON AS THE WAVE MOVES OVERHEAD AND COMBINES WITH
CONVERGENCE ALONG THE WEAK TROUGH.

WHILE ISOLATED TO SCATTERED COVERAGE IS EXPECTED ACROSS JUST
ABOUT THE ENTIRE FORECAST AREA...THE MOST CONCENTRATED ACTIVITY
WILL LIKELY BE ALONG THE TROUGH AXIS. VISIBLE SATELLITE IS
STARTING TO SHOW WHERE THIS MAY LINE UP WITH BEST CU DEVELOPMENT
ARCHING FROM JUST EAST OF MADISON AND JANESVILLE ACROSS THE
CENTRAL CHICAGO METRO AND INTO FAR NORTHWEST INDIANA. LAKE
INFLUENCES MAY ALSO HELP REINFORCE THE CONVERGENCE ACROSS THESE
SAME AREAS WHICH ALSO SUPPORTS BEST COVERAGE. WILL CONTINUE WITH
HIGHEST POPS ACROSS THE EASTERN TWO-THIRDS OF THE AREA THIS
AFTERNOON AND MAY END UP RAISING THEM TO LIKELY OR BETTER BEFORE
LONG. INSTABILITY IS INCREASING SO THUNDER RISK WILL INCREASE.
HEAVY DOWNPOURS AND LOCALIZED FLOODING LOOK TO BE THE GREATEST
RISK GIVEN THE MOIST ATMOSPHERE AND SLOW STORM MOVEMENT. THE
SEVERE RISK IS PRETTY LOW BUT A FEW STRONGER WIND GUSTS COULD
OCCUR.

MDB

&&

.SHORT TERM...
253 AM CDT

THROUGH TONIGHT...

IR IMAGERY EARLY THIS MORNING HAS THICKER CLOUD COVER STRETCHING
FROM CENTRAL/EASTERN WISC SOUTHEAST ACROSS NORTHEAST IL INTO CENTRAL
IN. SFC ANALYSIS HAS A WEAK LOW CENTERED OVER CENTRAL IL...AND WILL
EVENTUALLY LIFT NORTHEAST ACROSS CENTRAL IN LATER THIS AFTN. THE
NOTABLE FEATURE IS THE LACK OF A GRADIENT WITH THIS WAVE...AS
WINDS ACROSS THE REGION EARLY THIS MORNING ARE GENERALLY LESS THAN
10KT. SOME CLEARING HAS TAKEN PLACE IN THE CLOUD SHIELD ALONG THE
WESTERN PORTIONS OF THE CWFA...WHICH COUPLED WITH THE DEW PTS IN
THE LOW 60S HAS ALLOWED FOG TO PATCHY DENSE FOG TO DEVELOP. EXPECT
FOG TO LINGER A COUPLE HOURS AFTER DAYBREAK GIVEN THE LACK OF
MIXING...BUT BY MID- MORNING THE FOG SHUD ERODE. CLOUDS ARE POISED
TO THICKEN YET AGAIN...WITH MARGINAL INSTABILITY LATE MORNING THRU
THE AFTN/EVE. HAVE OPTED TO HOLD THE MENTION OF THUNDER THRU THE
MORNING...THEN HAVE GONE WITH JUST A SLIGHT CHANCE OF THUNDER. THE
COVERAGE FROM SHOWERS/THUNDER WILL NOT BE GREAT...SO ONLY MINOR
ADJUSTMENTS TO THE GOING POPS.

TEMPS WILL HINGE ON CLOUD COVER AND WIND DIR...ESPECIALLY TRUE FOR
AREAS ADJACENT TO LAKE MICHIGAN. GUIDANCE HAS CONTINUED TO POINT
TOWARDS A NORTHEAST WIND OFF OF THE LAKE...WHICH WILL LIKELY HOLD
TEMPS IN THE UPR 60S TO LOW 70S. ELSEWHERE THE INLAND AREAS SHUD
SLOWLY WARM GIVEN THE BUOYANT ATMOSPHERE INTO THE LOW/MID 70S.

LATER THIS EVENING WITH THE 500MB TROUGH AXIS STILL
OVERHEAD...ANOTHER LOBE OF MID-LVL VORTICITY IS POISED TO DROP SOUTH
FROM THE UPPER MIDWEST ACROSS THE WESTERN GREAT LAKES. THIS SHUD
PROVIDE A BRIEF LULL IN SHOWERS/THUNDER THIS EVE...BEFORE
SHOWERS/THUNDER REDEVELOP LATE TONIGHT AS THE VORT MAX ARRIVES. WITH
DEW POINTS REMAINING IN THE LOW/MID 60S OVERNIGHT...AS THE NEXT SFC
LOW DEVELOPS TONIGHT...SOME OF THE PRECIP COULD BE BRIEF DOWNPOURS
AND SLOW MOVING. THIS COULD RESULT IN RENEWED FLOODING CONCERNS FOR
AREAS THAT CONTINUE TO SEE NEARLY SATURATED SOILS.

BEACHLER

&&

.LONG TERM...
253 AM CDT

TUESDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL BE SLOWLY PIVOTING EAST...WITH GUIDANCE
SUGGESTING MID-LVL HEIGHTS MAY TRY TO RISE AND ALLOW FOR A BREAK
IN THE PRECIP TUE AFTN/EVE. ADDITIONALLY A QUASI- STATIONARY
BOUNDARY WILL BECOME ORIENTED FROM THE OHIO RIVER STRETCHING
WEST/NORTHWEST TO EASTERN NEBRASKA. THIS BOUNDARY WILL BECOME A
FOCAL POINT MID-WEEK AS A LOW ACROSS THE PLAINS WILL RIDE ALONG
THE BOUNDARY AND MAY BUCKLE NORTH TOWARDS THE SOUTHERN CWFA. PRIOR
TO THIS SCENARIO...AN AREA OF ANTI- CYCLONIC FLOW WILL TRY TO DROP
SOUTH FROM ONTARIO AND PUSH A BACKDOOR FRONT SOUTH ACROSS THE LAKE
TUE NGT/EARLY WED. THIS WILL SHARPEN THE BAROCLINIC ZONE WED...BUT
SHUD STILL REMAIN WELL SOUTH OF THE FORECAST AREA. TEMPS TUE PRIOR
TO THE FRONT MAY BE ABLE TO WARM INTO THE UPR 70S OR NEAR 80...BUT
THEN A NORTH/NORTHEAST LLVL FLOW WED WILL KEEP TEMPS IN THE UPR
60S TO NEAR 70 FOR AREAS ADJACENT TO LAKE MI. FURTHER INLAND
CLOUDS WILL THICKEN WED WITH TEMPS GENERALLY IN THE LOW/MID 70S.

THERE IS SOME DISCREPANCIES AMONGST THE GUIDANCE MEMBERS FOR
WED...WHICH INDICATE THE SFC LOW PATCH AND BOUNDARY MAY BE FURTHER
SOUTH AS A RESULT OF A SLIGHTLY STRONGER SFC RIDGE DROPPING SOUTH
FROM ONTARIO. THIS WILL ALSO DRIVE PRECIP PLACEMENT WED
NGT/THUR...ALONG WITH TEMPS THUR. HAVE NUDGED POPS DRIER FOR THE
NORTHERN CWFA BOTH WED/THUR. TEMPS THUR WILL CONTINUE TO BE IN THE
70S...WITH LIKELY THE UPR 60S FOR AREAS ADJACENT TO LAKE MICHIGAN.

FRIDAY THROUGH SUNDAY... WESTERN CONUS HIGH AMPLITUDE RIDGE WILL
REMAIN THROUGH SAT WITH THE DOWNSTREAM TROUGH OVER THE GREAT LAKES
SLOWLY WEAKENING OVER THE WEEKEND. SIMULTANEOUSLY HEIGHTS WILL BEGIN
TO RISE ACROSS THE SOUTHEASTERN CONUS...WHICH COULD HELP TO PUSH
WARMER TEMPS BACK NORTH ACROSS THE CENTRAL STATES LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. OPER GUIDANCE SUGGESTS THE MID-LVL
RIDGE MAY RELAX EARLIER IN THE WEEKEND...WITH A QUASI-NORTHWEST FLOW
INTO THE GREAT LAKES BY SUN. SO PERIODIC CHANCES FOR
SHOWERS/THUNDERSTORMS MAY RETURN FOR THE SECOND HALF OF THE HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. TEMPS WILL RETURN TO MORE SEASONAL
CONDS BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* CIGS REMAINING MAINLY VFR THIS AFTERNOON... BRIEF LOWERING TO
  MVFR WITH SHOWERS/TSRA.
* MVFR/IFR CIGS/VSBYS PSBL AGAIN OVERNIGHT TONIGHT.
* SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MUCH OF THE
  TAF PERIOD... BEST WINDOWS FOR THIS ARE 20-00Z THIS AFTERNOON
  AND AGAIN 09Z-13Z TUESDAY MORNING.

ED F

//DISCUSSION...UPDATED 18Z...

SHOWERS INCREASING IN COVERAGE AND INTENSITY PAST 1-2 HOURS SINCE
16Z... WITH ACTIVITY FOCUSING ON AREA OF LOW LEVEL CONVERGING AIR
ALONG AN INVERTED TROUGH OF LOW PRESSURE ARCING FROM THE SOUTH
SUBURBS TO THE FOX RIVER VALLEY NORTHWARD INTO SOUTH CENTRAL WI
EAST OF MSN. WITH THE ENTIRE SYSTEM DRIFTING ESE EXPECT SHOWERS TO
MOVE SE SLOWLY AWAY FROM MDW WITH A BRIEF BREAK ONLY TO BE
REPLACED BY ADDITIONAL SHOWERS AND THUNDERSTORMS LATER THIS
AFTERNOON ORD TO MDW AS THE FOX VALLEY TO S CENTRAL WISC SEGMENT
OF THIS PRECIPITATION AREA DRIFTS SLOWLY SE.

MAY SEE AN EXTENSION OF THIS RAIN PERIOD INTO THE EVENING HOURS
DEPENDING ON THE TIMING OF AN UPPER LEVEL DISTURBANCE CURRENTLY
OVER NW WISC AND WILL BE TWEAKING THE FORECAST THIS AFTERNOON
BASED ON TRENDS AND MONITORING AND MODEL PREDICTIONS OF THIS
FEATURE... WHICH HAS BEEN VERY CONSISTENT BASED ON SATELLITE AND
LIGHTNING DATA.

THEN YET ANOTHER WINDOW OF PRECIPITATION APPEARS IN THE OFFERING
LATE TONIGHT/EARLY TUESDAY AS YET ANOTHER WEAK IMPULSE DROPS SOUTH.
A WEAK COLD FRONT THEN SAGS SE ACROSS THE AREA TUESDAY
AFTERNOON... BRINGING YET ANOTHER OPPORTUNITY FOR SHOWERS IN AN
OTHERWISE CONTINUED VERY MOIST AND RELATIVELY UNSTABLE ATMOSPHERE.

ED F

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN SCATTERED SHRA/ISOL TSRA THIS AFTERNOON INTO
  EVENING...LOW CONFIDENCE IN SPECIFIC TIMING AT TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WINDS STAYING AT OR BELOW 10KT.
* LOW-MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN SHOWER CHANCES LATE TONIGHT/EARLY TUESDAY
  AND AGAIN TUES AFTERNOON.

ED F

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...DRY. NE WINDS. MVFR/IFR PSBL.
WEDNESDAY...DRY. NE WINDS. MVFR/IFR PSBL.
THURSDAY...DRY. NE WINDS. MVFR/IFR PSBL.
FRIDAY...CHC SHRA/SLT CHC TSRA. NE WINDS. PRIMARILY VFR.
SATURDAY...CHC SHRA. NE WINDS. PRIMARILY VFR.
SUNDAY...SLT CHC TSRA. S WINDS. PRIMARILY VFR.

BMD

&&

.MARINE...
301 AM CDT

EXPECT A WEAK GRADIENT MUCH OF THE UPCOMING WEEK WITH THE
EXCEPTION OF TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT
GENERALLY LIGHT WINDS TODAY AND TONIGHT AS LAKE MICHIGAN LIES
BETWEEN TWO AREAS OF LOW PRESSURE WHICH WILL EVENTUALLY MERGE OVER
THE EASTERN GREAT LAKES LATER ON TUESDAY. WINDS BRIEFLY PICK UP
MAINLY IN THE 15 TO 20 KT OCCASIONALLY 25 KT RANGE OUT OF THE
NORTH BEHIND THE DEPARTING LOW AND AHEAD OF A RIDGE BUILDING SOUTH
INTO THE REGION. EXPECT LIGHT WINDS TO RETURN TO CLOSE OUT THE
WEEK AND CONTINUE INTO THE WEEKEND.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO




000
FXUS63 KILX 291747
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 1039 AM CDT MON JUN 29 2015

MORNING SURFACE ANALYSIS SHOWS 1008MB LOW NEAR KHUF...WITH COLD
FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS. DESPITE PROXIMITY
OF LOW...15Z/10AM RADAR IMAGE IS NEARLY CLEAR EXCEPT FOR A FEW
SHOWERS ACROSS IROQUOIS COUNTY. SKIES REMAIN CLOUDY FOR THE MOST
PART...HOWEVER PARTIAL CLEARING HAS OCCURRED WEST OF THE I-55
CORRIDOR. HRRR CONTINUES TO DEVELOP SCATTERED CONVECTION ACROSS
NEARLY THE ENTIRE AREA WITH ITS 1 AND 2-HOUR FORECAST...HOWEVER
THIS HAS PROVEN TO BE WAY OVERBLOWN. MEANWHILE THE 12Z NAM IS
ALMOST ENTIRELY DRY FOR THE REMAINDER OF THE DAY UNTIL AN UPPER-
LEVEL WAVE CURRENTLY OVER MINNESOTA ARRIVES TONIGHT. GIVEN AMPLE
LOW-LEVEL MOISTURE AND PRESENCE OF LOW PRESSURE NEARBY...CANNOT
COMPLETELY RULE OUT A STRAY SHOWER THIS AFTERNOON. HAVE UPDATED
POPS TO GO DRY THROUGH MIDDAY...THEN JUST SLIGHT CHANCES THIS
AFTERNOON. DUE TO THE CLOUD COVER AND A LIGHT NORTHERLY
BREEZE...HIGH TEMPS WILL BE SEVERAL DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR IN THE UPPER 70S TO AROUND 80 DEGREES.

&&

.SHORT TERM...(TODAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

SURFACE LOW IN WEST CENTRAL ILLINOIS AND MAJORITY OF PRECIP
ASSOCIATED WITH VIGOROUS SHORT WAVE HAS MOVED OUT TO THE EAST THIS
MORNING.  ENHANCED LLVL MOISTURE FROM EXITING TS RESULTING IN SOME
FOG THIS MORNING AND HAVE ADDED IN A COUPLE HOURS MAINLY IN THE
WEST. UPPER LEVEL TROF AXIS STILL OVER EASTERN ILX THIS MORNING AND
WILL KEEP CENTRAL ILLINOIS IN NWRLY FLOW/SLIGHTLY CYCLONIC FLOW
ALOFT.  SHOULD KEEP SOME OF THE CLOUDS OVER THE FA FOR MUCH OF THE
DAY AND INCREASE THE CHANCES FOR SOME INSTABILITY SHOWERS WITH SOME
POSSIBLE THUNDER LATER THIS AFTERNOON.  TEMPERATURES STILL A BIT
BELOW NORMAL TODAY, WITH THE COOLEST TEMPS IN THE NE, CLOSER TO THE
UPPER LEVEL TROF AND COOLER MID LEVELS.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

FORECAST DISCUSSION SEEMING A BIT REPETITIVE AS CENTRAL ILLINOIS
REMAINS IN A LARGELY NORTHWESTERLY FLOW PATTERN FOR THE FCST PD.  A
STEADY STREAM OF SHORT WAVES INTO THE REGION KEEP POPS FOR
OCCASIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. SOME TIMING
ISSUES REMAIN FROM RUN TO RUN. FORECAST KEEPS SOME POPS IN TONIGHT,
MAINLY FOR THE NORTH AND EAST CLOSER TO THE SFC LOW...AND INCREASING
TOWARDS MORNING WITH ANOTHER WAVE DIVING INTO THE MIDWEST IN NAM AND
GFS SOLUTIONS, WITH A BREAK TUES NIGHT POSSIBLE FOR THE NORTH BEFORE
ANOTHER WAVE ON WED AND SO ON THROUGH MOST OF THE FORECAST. WED/WED
NIGHT IS CURRENTLY SOME OF THE MORE FOCUSED POPS AS A BOUNDARY IS
APPARENT IN SFC WIND FIELDS IN THE MODELS.  ANY BOUNDARY LIKELY TO
SET UP IN THE REGION WILL PROVIDE MORE FOCUS/DYNAMICS FOR ANY SHORT
WAVE ASSISTED CONVECTION THAT DOES FORM.  THE SERIES OF WAVES STARTS
TO HAVE A LITTLE MORE DISSONANCE FROM MODEL TO MODEL GOING INTO THE
EXTENDED AS EXPECTED WITH REGARDS TO TIMING. OVERALL THE FORECAST
REMAINS WET AND STORMY WITH TEMPS SLIGHTLY BELOW NORMAL WITH
NORTHWESTERLY FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VRF CEILINGS AND VCTS COMING INTO THE
PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...BARNES




000
FXUS63 KILX 291747
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 1039 AM CDT MON JUN 29 2015

MORNING SURFACE ANALYSIS SHOWS 1008MB LOW NEAR KHUF...WITH COLD
FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS. DESPITE PROXIMITY
OF LOW...15Z/10AM RADAR IMAGE IS NEARLY CLEAR EXCEPT FOR A FEW
SHOWERS ACROSS IROQUOIS COUNTY. SKIES REMAIN CLOUDY FOR THE MOST
PART...HOWEVER PARTIAL CLEARING HAS OCCURRED WEST OF THE I-55
CORRIDOR. HRRR CONTINUES TO DEVELOP SCATTERED CONVECTION ACROSS
NEARLY THE ENTIRE AREA WITH ITS 1 AND 2-HOUR FORECAST...HOWEVER
THIS HAS PROVEN TO BE WAY OVERBLOWN. MEANWHILE THE 12Z NAM IS
ALMOST ENTIRELY DRY FOR THE REMAINDER OF THE DAY UNTIL AN UPPER-
LEVEL WAVE CURRENTLY OVER MINNESOTA ARRIVES TONIGHT. GIVEN AMPLE
LOW-LEVEL MOISTURE AND PRESENCE OF LOW PRESSURE NEARBY...CANNOT
COMPLETELY RULE OUT A STRAY SHOWER THIS AFTERNOON. HAVE UPDATED
POPS TO GO DRY THROUGH MIDDAY...THEN JUST SLIGHT CHANCES THIS
AFTERNOON. DUE TO THE CLOUD COVER AND A LIGHT NORTHERLY
BREEZE...HIGH TEMPS WILL BE SEVERAL DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR IN THE UPPER 70S TO AROUND 80 DEGREES.

&&

.SHORT TERM...(TODAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

SURFACE LOW IN WEST CENTRAL ILLINOIS AND MAJORITY OF PRECIP
ASSOCIATED WITH VIGOROUS SHORT WAVE HAS MOVED OUT TO THE EAST THIS
MORNING.  ENHANCED LLVL MOISTURE FROM EXITING TS RESULTING IN SOME
FOG THIS MORNING AND HAVE ADDED IN A COUPLE HOURS MAINLY IN THE
WEST. UPPER LEVEL TROF AXIS STILL OVER EASTERN ILX THIS MORNING AND
WILL KEEP CENTRAL ILLINOIS IN NWRLY FLOW/SLIGHTLY CYCLONIC FLOW
ALOFT.  SHOULD KEEP SOME OF THE CLOUDS OVER THE FA FOR MUCH OF THE
DAY AND INCREASE THE CHANCES FOR SOME INSTABILITY SHOWERS WITH SOME
POSSIBLE THUNDER LATER THIS AFTERNOON.  TEMPERATURES STILL A BIT
BELOW NORMAL TODAY, WITH THE COOLEST TEMPS IN THE NE, CLOSER TO THE
UPPER LEVEL TROF AND COOLER MID LEVELS.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

FORECAST DISCUSSION SEEMING A BIT REPETITIVE AS CENTRAL ILLINOIS
REMAINS IN A LARGELY NORTHWESTERLY FLOW PATTERN FOR THE FCST PD.  A
STEADY STREAM OF SHORT WAVES INTO THE REGION KEEP POPS FOR
OCCASIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. SOME TIMING
ISSUES REMAIN FROM RUN TO RUN. FORECAST KEEPS SOME POPS IN TONIGHT,
MAINLY FOR THE NORTH AND EAST CLOSER TO THE SFC LOW...AND INCREASING
TOWARDS MORNING WITH ANOTHER WAVE DIVING INTO THE MIDWEST IN NAM AND
GFS SOLUTIONS, WITH A BREAK TUES NIGHT POSSIBLE FOR THE NORTH BEFORE
ANOTHER WAVE ON WED AND SO ON THROUGH MOST OF THE FORECAST. WED/WED
NIGHT IS CURRENTLY SOME OF THE MORE FOCUSED POPS AS A BOUNDARY IS
APPARENT IN SFC WIND FIELDS IN THE MODELS.  ANY BOUNDARY LIKELY TO
SET UP IN THE REGION WILL PROVIDE MORE FOCUS/DYNAMICS FOR ANY SHORT
WAVE ASSISTED CONVECTION THAT DOES FORM.  THE SERIES OF WAVES STARTS
TO HAVE A LITTLE MORE DISSONANCE FROM MODEL TO MODEL GOING INTO THE
EXTENDED AS EXPECTED WITH REGARDS TO TIMING. OVERALL THE FORECAST
REMAINS WET AND STORMY WITH TEMPS SLIGHTLY BELOW NORMAL WITH
NORTHWESTERLY FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VRF CEILINGS AND VCTS COMING INTO THE
PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...BARNES




000
FXUS63 KILX 291747
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 1039 AM CDT MON JUN 29 2015

MORNING SURFACE ANALYSIS SHOWS 1008MB LOW NEAR KHUF...WITH COLD
FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS. DESPITE PROXIMITY
OF LOW...15Z/10AM RADAR IMAGE IS NEARLY CLEAR EXCEPT FOR A FEW
SHOWERS ACROSS IROQUOIS COUNTY. SKIES REMAIN CLOUDY FOR THE MOST
PART...HOWEVER PARTIAL CLEARING HAS OCCURRED WEST OF THE I-55
CORRIDOR. HRRR CONTINUES TO DEVELOP SCATTERED CONVECTION ACROSS
NEARLY THE ENTIRE AREA WITH ITS 1 AND 2-HOUR FORECAST...HOWEVER
THIS HAS PROVEN TO BE WAY OVERBLOWN. MEANWHILE THE 12Z NAM IS
ALMOST ENTIRELY DRY FOR THE REMAINDER OF THE DAY UNTIL AN UPPER-
LEVEL WAVE CURRENTLY OVER MINNESOTA ARRIVES TONIGHT. GIVEN AMPLE
LOW-LEVEL MOISTURE AND PRESENCE OF LOW PRESSURE NEARBY...CANNOT
COMPLETELY RULE OUT A STRAY SHOWER THIS AFTERNOON. HAVE UPDATED
POPS TO GO DRY THROUGH MIDDAY...THEN JUST SLIGHT CHANCES THIS
AFTERNOON. DUE TO THE CLOUD COVER AND A LIGHT NORTHERLY
BREEZE...HIGH TEMPS WILL BE SEVERAL DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR IN THE UPPER 70S TO AROUND 80 DEGREES.

&&

.SHORT TERM...(TODAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

SURFACE LOW IN WEST CENTRAL ILLINOIS AND MAJORITY OF PRECIP
ASSOCIATED WITH VIGOROUS SHORT WAVE HAS MOVED OUT TO THE EAST THIS
MORNING.  ENHANCED LLVL MOISTURE FROM EXITING TS RESULTING IN SOME
FOG THIS MORNING AND HAVE ADDED IN A COUPLE HOURS MAINLY IN THE
WEST. UPPER LEVEL TROF AXIS STILL OVER EASTERN ILX THIS MORNING AND
WILL KEEP CENTRAL ILLINOIS IN NWRLY FLOW/SLIGHTLY CYCLONIC FLOW
ALOFT.  SHOULD KEEP SOME OF THE CLOUDS OVER THE FA FOR MUCH OF THE
DAY AND INCREASE THE CHANCES FOR SOME INSTABILITY SHOWERS WITH SOME
POSSIBLE THUNDER LATER THIS AFTERNOON.  TEMPERATURES STILL A BIT
BELOW NORMAL TODAY, WITH THE COOLEST TEMPS IN THE NE, CLOSER TO THE
UPPER LEVEL TROF AND COOLER MID LEVELS.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

FORECAST DISCUSSION SEEMING A BIT REPETITIVE AS CENTRAL ILLINOIS
REMAINS IN A LARGELY NORTHWESTERLY FLOW PATTERN FOR THE FCST PD.  A
STEADY STREAM OF SHORT WAVES INTO THE REGION KEEP POPS FOR
OCCASIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. SOME TIMING
ISSUES REMAIN FROM RUN TO RUN. FORECAST KEEPS SOME POPS IN TONIGHT,
MAINLY FOR THE NORTH AND EAST CLOSER TO THE SFC LOW...AND INCREASING
TOWARDS MORNING WITH ANOTHER WAVE DIVING INTO THE MIDWEST IN NAM AND
GFS SOLUTIONS, WITH A BREAK TUES NIGHT POSSIBLE FOR THE NORTH BEFORE
ANOTHER WAVE ON WED AND SO ON THROUGH MOST OF THE FORECAST. WED/WED
NIGHT IS CURRENTLY SOME OF THE MORE FOCUSED POPS AS A BOUNDARY IS
APPARENT IN SFC WIND FIELDS IN THE MODELS.  ANY BOUNDARY LIKELY TO
SET UP IN THE REGION WILL PROVIDE MORE FOCUS/DYNAMICS FOR ANY SHORT
WAVE ASSISTED CONVECTION THAT DOES FORM.  THE SERIES OF WAVES STARTS
TO HAVE A LITTLE MORE DISSONANCE FROM MODEL TO MODEL GOING INTO THE
EXTENDED AS EXPECTED WITH REGARDS TO TIMING. OVERALL THE FORECAST
REMAINS WET AND STORMY WITH TEMPS SLIGHTLY BELOW NORMAL WITH
NORTHWESTERLY FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VRF CEILINGS AND VCTS COMING INTO THE
PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...BARNES




000
FXUS63 KILX 291747
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 1039 AM CDT MON JUN 29 2015

MORNING SURFACE ANALYSIS SHOWS 1008MB LOW NEAR KHUF...WITH COLD
FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS. DESPITE PROXIMITY
OF LOW...15Z/10AM RADAR IMAGE IS NEARLY CLEAR EXCEPT FOR A FEW
SHOWERS ACROSS IROQUOIS COUNTY. SKIES REMAIN CLOUDY FOR THE MOST
PART...HOWEVER PARTIAL CLEARING HAS OCCURRED WEST OF THE I-55
CORRIDOR. HRRR CONTINUES TO DEVELOP SCATTERED CONVECTION ACROSS
NEARLY THE ENTIRE AREA WITH ITS 1 AND 2-HOUR FORECAST...HOWEVER
THIS HAS PROVEN TO BE WAY OVERBLOWN. MEANWHILE THE 12Z NAM IS
ALMOST ENTIRELY DRY FOR THE REMAINDER OF THE DAY UNTIL AN UPPER-
LEVEL WAVE CURRENTLY OVER MINNESOTA ARRIVES TONIGHT. GIVEN AMPLE
LOW-LEVEL MOISTURE AND PRESENCE OF LOW PRESSURE NEARBY...CANNOT
COMPLETELY RULE OUT A STRAY SHOWER THIS AFTERNOON. HAVE UPDATED
POPS TO GO DRY THROUGH MIDDAY...THEN JUST SLIGHT CHANCES THIS
AFTERNOON. DUE TO THE CLOUD COVER AND A LIGHT NORTHERLY
BREEZE...HIGH TEMPS WILL BE SEVERAL DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR IN THE UPPER 70S TO AROUND 80 DEGREES.

&&

.SHORT TERM...(TODAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

SURFACE LOW IN WEST CENTRAL ILLINOIS AND MAJORITY OF PRECIP
ASSOCIATED WITH VIGOROUS SHORT WAVE HAS MOVED OUT TO THE EAST THIS
MORNING.  ENHANCED LLVL MOISTURE FROM EXITING TS RESULTING IN SOME
FOG THIS MORNING AND HAVE ADDED IN A COUPLE HOURS MAINLY IN THE
WEST. UPPER LEVEL TROF AXIS STILL OVER EASTERN ILX THIS MORNING AND
WILL KEEP CENTRAL ILLINOIS IN NWRLY FLOW/SLIGHTLY CYCLONIC FLOW
ALOFT.  SHOULD KEEP SOME OF THE CLOUDS OVER THE FA FOR MUCH OF THE
DAY AND INCREASE THE CHANCES FOR SOME INSTABILITY SHOWERS WITH SOME
POSSIBLE THUNDER LATER THIS AFTERNOON.  TEMPERATURES STILL A BIT
BELOW NORMAL TODAY, WITH THE COOLEST TEMPS IN THE NE, CLOSER TO THE
UPPER LEVEL TROF AND COOLER MID LEVELS.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

FORECAST DISCUSSION SEEMING A BIT REPETITIVE AS CENTRAL ILLINOIS
REMAINS IN A LARGELY NORTHWESTERLY FLOW PATTERN FOR THE FCST PD.  A
STEADY STREAM OF SHORT WAVES INTO THE REGION KEEP POPS FOR
OCCASIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. SOME TIMING
ISSUES REMAIN FROM RUN TO RUN. FORECAST KEEPS SOME POPS IN TONIGHT,
MAINLY FOR THE NORTH AND EAST CLOSER TO THE SFC LOW...AND INCREASING
TOWARDS MORNING WITH ANOTHER WAVE DIVING INTO THE MIDWEST IN NAM AND
GFS SOLUTIONS, WITH A BREAK TUES NIGHT POSSIBLE FOR THE NORTH BEFORE
ANOTHER WAVE ON WED AND SO ON THROUGH MOST OF THE FORECAST. WED/WED
NIGHT IS CURRENTLY SOME OF THE MORE FOCUSED POPS AS A BOUNDARY IS
APPARENT IN SFC WIND FIELDS IN THE MODELS.  ANY BOUNDARY LIKELY TO
SET UP IN THE REGION WILL PROVIDE MORE FOCUS/DYNAMICS FOR ANY SHORT
WAVE ASSISTED CONVECTION THAT DOES FORM.  THE SERIES OF WAVES STARTS
TO HAVE A LITTLE MORE DISSONANCE FROM MODEL TO MODEL GOING INTO THE
EXTENDED AS EXPECTED WITH REGARDS TO TIMING. OVERALL THE FORECAST
REMAINS WET AND STORMY WITH TEMPS SLIGHTLY BELOW NORMAL WITH
NORTHWESTERLY FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VRF CEILINGS AND VCTS COMING INTO THE
PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...BARNES




000
FXUS63 KILX 291747
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 1039 AM CDT MON JUN 29 2015

MORNING SURFACE ANALYSIS SHOWS 1008MB LOW NEAR KHUF...WITH COLD
FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS. DESPITE PROXIMITY
OF LOW...15Z/10AM RADAR IMAGE IS NEARLY CLEAR EXCEPT FOR A FEW
SHOWERS ACROSS IROQUOIS COUNTY. SKIES REMAIN CLOUDY FOR THE MOST
PART...HOWEVER PARTIAL CLEARING HAS OCCURRED WEST OF THE I-55
CORRIDOR. HRRR CONTINUES TO DEVELOP SCATTERED CONVECTION ACROSS
NEARLY THE ENTIRE AREA WITH ITS 1 AND 2-HOUR FORECAST...HOWEVER
THIS HAS PROVEN TO BE WAY OVERBLOWN. MEANWHILE THE 12Z NAM IS
ALMOST ENTIRELY DRY FOR THE REMAINDER OF THE DAY UNTIL AN UPPER-
LEVEL WAVE CURRENTLY OVER MINNESOTA ARRIVES TONIGHT. GIVEN AMPLE
LOW-LEVEL MOISTURE AND PRESENCE OF LOW PRESSURE NEARBY...CANNOT
COMPLETELY RULE OUT A STRAY SHOWER THIS AFTERNOON. HAVE UPDATED
POPS TO GO DRY THROUGH MIDDAY...THEN JUST SLIGHT CHANCES THIS
AFTERNOON. DUE TO THE CLOUD COVER AND A LIGHT NORTHERLY
BREEZE...HIGH TEMPS WILL BE SEVERAL DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR IN THE UPPER 70S TO AROUND 80 DEGREES.

&&

.SHORT TERM...(TODAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

SURFACE LOW IN WEST CENTRAL ILLINOIS AND MAJORITY OF PRECIP
ASSOCIATED WITH VIGOROUS SHORT WAVE HAS MOVED OUT TO THE EAST THIS
MORNING.  ENHANCED LLVL MOISTURE FROM EXITING TS RESULTING IN SOME
FOG THIS MORNING AND HAVE ADDED IN A COUPLE HOURS MAINLY IN THE
WEST. UPPER LEVEL TROF AXIS STILL OVER EASTERN ILX THIS MORNING AND
WILL KEEP CENTRAL ILLINOIS IN NWRLY FLOW/SLIGHTLY CYCLONIC FLOW
ALOFT.  SHOULD KEEP SOME OF THE CLOUDS OVER THE FA FOR MUCH OF THE
DAY AND INCREASE THE CHANCES FOR SOME INSTABILITY SHOWERS WITH SOME
POSSIBLE THUNDER LATER THIS AFTERNOON.  TEMPERATURES STILL A BIT
BELOW NORMAL TODAY, WITH THE COOLEST TEMPS IN THE NE, CLOSER TO THE
UPPER LEVEL TROF AND COOLER MID LEVELS.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

FORECAST DISCUSSION SEEMING A BIT REPETITIVE AS CENTRAL ILLINOIS
REMAINS IN A LARGELY NORTHWESTERLY FLOW PATTERN FOR THE FCST PD.  A
STEADY STREAM OF SHORT WAVES INTO THE REGION KEEP POPS FOR
OCCASIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. SOME TIMING
ISSUES REMAIN FROM RUN TO RUN. FORECAST KEEPS SOME POPS IN TONIGHT,
MAINLY FOR THE NORTH AND EAST CLOSER TO THE SFC LOW...AND INCREASING
TOWARDS MORNING WITH ANOTHER WAVE DIVING INTO THE MIDWEST IN NAM AND
GFS SOLUTIONS, WITH A BREAK TUES NIGHT POSSIBLE FOR THE NORTH BEFORE
ANOTHER WAVE ON WED AND SO ON THROUGH MOST OF THE FORECAST. WED/WED
NIGHT IS CURRENTLY SOME OF THE MORE FOCUSED POPS AS A BOUNDARY IS
APPARENT IN SFC WIND FIELDS IN THE MODELS.  ANY BOUNDARY LIKELY TO
SET UP IN THE REGION WILL PROVIDE MORE FOCUS/DYNAMICS FOR ANY SHORT
WAVE ASSISTED CONVECTION THAT DOES FORM.  THE SERIES OF WAVES STARTS
TO HAVE A LITTLE MORE DISSONANCE FROM MODEL TO MODEL GOING INTO THE
EXTENDED AS EXPECTED WITH REGARDS TO TIMING. OVERALL THE FORECAST
REMAINS WET AND STORMY WITH TEMPS SLIGHTLY BELOW NORMAL WITH
NORTHWESTERLY FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VRF CEILINGS AND VCTS COMING INTO THE
PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...BARNES



000
FXUS63 KILX 291747
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 1039 AM CDT MON JUN 29 2015

MORNING SURFACE ANALYSIS SHOWS 1008MB LOW NEAR KHUF...WITH COLD
FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS. DESPITE PROXIMITY
OF LOW...15Z/10AM RADAR IMAGE IS NEARLY CLEAR EXCEPT FOR A FEW
SHOWERS ACROSS IROQUOIS COUNTY. SKIES REMAIN CLOUDY FOR THE MOST
PART...HOWEVER PARTIAL CLEARING HAS OCCURRED WEST OF THE I-55
CORRIDOR. HRRR CONTINUES TO DEVELOP SCATTERED CONVECTION ACROSS
NEARLY THE ENTIRE AREA WITH ITS 1 AND 2-HOUR FORECAST...HOWEVER
THIS HAS PROVEN TO BE WAY OVERBLOWN. MEANWHILE THE 12Z NAM IS
ALMOST ENTIRELY DRY FOR THE REMAINDER OF THE DAY UNTIL AN UPPER-
LEVEL WAVE CURRENTLY OVER MINNESOTA ARRIVES TONIGHT. GIVEN AMPLE
LOW-LEVEL MOISTURE AND PRESENCE OF LOW PRESSURE NEARBY...CANNOT
COMPLETELY RULE OUT A STRAY SHOWER THIS AFTERNOON. HAVE UPDATED
POPS TO GO DRY THROUGH MIDDAY...THEN JUST SLIGHT CHANCES THIS
AFTERNOON. DUE TO THE CLOUD COVER AND A LIGHT NORTHERLY
BREEZE...HIGH TEMPS WILL BE SEVERAL DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR IN THE UPPER 70S TO AROUND 80 DEGREES.

&&

.SHORT TERM...(TODAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

SURFACE LOW IN WEST CENTRAL ILLINOIS AND MAJORITY OF PRECIP
ASSOCIATED WITH VIGOROUS SHORT WAVE HAS MOVED OUT TO THE EAST THIS
MORNING.  ENHANCED LLVL MOISTURE FROM EXITING TS RESULTING IN SOME
FOG THIS MORNING AND HAVE ADDED IN A COUPLE HOURS MAINLY IN THE
WEST. UPPER LEVEL TROF AXIS STILL OVER EASTERN ILX THIS MORNING AND
WILL KEEP CENTRAL ILLINOIS IN NWRLY FLOW/SLIGHTLY CYCLONIC FLOW
ALOFT.  SHOULD KEEP SOME OF THE CLOUDS OVER THE FA FOR MUCH OF THE
DAY AND INCREASE THE CHANCES FOR SOME INSTABILITY SHOWERS WITH SOME
POSSIBLE THUNDER LATER THIS AFTERNOON.  TEMPERATURES STILL A BIT
BELOW NORMAL TODAY, WITH THE COOLEST TEMPS IN THE NE, CLOSER TO THE
UPPER LEVEL TROF AND COOLER MID LEVELS.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

FORECAST DISCUSSION SEEMING A BIT REPETITIVE AS CENTRAL ILLINOIS
REMAINS IN A LARGELY NORTHWESTERLY FLOW PATTERN FOR THE FCST PD.  A
STEADY STREAM OF SHORT WAVES INTO THE REGION KEEP POPS FOR
OCCASIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. SOME TIMING
ISSUES REMAIN FROM RUN TO RUN. FORECAST KEEPS SOME POPS IN TONIGHT,
MAINLY FOR THE NORTH AND EAST CLOSER TO THE SFC LOW...AND INCREASING
TOWARDS MORNING WITH ANOTHER WAVE DIVING INTO THE MIDWEST IN NAM AND
GFS SOLUTIONS, WITH A BREAK TUES NIGHT POSSIBLE FOR THE NORTH BEFORE
ANOTHER WAVE ON WED AND SO ON THROUGH MOST OF THE FORECAST. WED/WED
NIGHT IS CURRENTLY SOME OF THE MORE FOCUSED POPS AS A BOUNDARY IS
APPARENT IN SFC WIND FIELDS IN THE MODELS.  ANY BOUNDARY LIKELY TO
SET UP IN THE REGION WILL PROVIDE MORE FOCUS/DYNAMICS FOR ANY SHORT
WAVE ASSISTED CONVECTION THAT DOES FORM.  THE SERIES OF WAVES STARTS
TO HAVE A LITTLE MORE DISSONANCE FROM MODEL TO MODEL GOING INTO THE
EXTENDED AS EXPECTED WITH REGARDS TO TIMING. OVERALL THE FORECAST
REMAINS WET AND STORMY WITH TEMPS SLIGHTLY BELOW NORMAL WITH
NORTHWESTERLY FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VRF CEILINGS AND VCTS COMING INTO THE
PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...BARNES



000
FXUS63 KILX 291747
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 1039 AM CDT MON JUN 29 2015

MORNING SURFACE ANALYSIS SHOWS 1008MB LOW NEAR KHUF...WITH COLD
FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS. DESPITE PROXIMITY
OF LOW...15Z/10AM RADAR IMAGE IS NEARLY CLEAR EXCEPT FOR A FEW
SHOWERS ACROSS IROQUOIS COUNTY. SKIES REMAIN CLOUDY FOR THE MOST
PART...HOWEVER PARTIAL CLEARING HAS OCCURRED WEST OF THE I-55
CORRIDOR. HRRR CONTINUES TO DEVELOP SCATTERED CONVECTION ACROSS
NEARLY THE ENTIRE AREA WITH ITS 1 AND 2-HOUR FORECAST...HOWEVER
THIS HAS PROVEN TO BE WAY OVERBLOWN. MEANWHILE THE 12Z NAM IS
ALMOST ENTIRELY DRY FOR THE REMAINDER OF THE DAY UNTIL AN UPPER-
LEVEL WAVE CURRENTLY OVER MINNESOTA ARRIVES TONIGHT. GIVEN AMPLE
LOW-LEVEL MOISTURE AND PRESENCE OF LOW PRESSURE NEARBY...CANNOT
COMPLETELY RULE OUT A STRAY SHOWER THIS AFTERNOON. HAVE UPDATED
POPS TO GO DRY THROUGH MIDDAY...THEN JUST SLIGHT CHANCES THIS
AFTERNOON. DUE TO THE CLOUD COVER AND A LIGHT NORTHERLY
BREEZE...HIGH TEMPS WILL BE SEVERAL DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR IN THE UPPER 70S TO AROUND 80 DEGREES.

&&

.SHORT TERM...(TODAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

SURFACE LOW IN WEST CENTRAL ILLINOIS AND MAJORITY OF PRECIP
ASSOCIATED WITH VIGOROUS SHORT WAVE HAS MOVED OUT TO THE EAST THIS
MORNING.  ENHANCED LLVL MOISTURE FROM EXITING TS RESULTING IN SOME
FOG THIS MORNING AND HAVE ADDED IN A COUPLE HOURS MAINLY IN THE
WEST. UPPER LEVEL TROF AXIS STILL OVER EASTERN ILX THIS MORNING AND
WILL KEEP CENTRAL ILLINOIS IN NWRLY FLOW/SLIGHTLY CYCLONIC FLOW
ALOFT.  SHOULD KEEP SOME OF THE CLOUDS OVER THE FA FOR MUCH OF THE
DAY AND INCREASE THE CHANCES FOR SOME INSTABILITY SHOWERS WITH SOME
POSSIBLE THUNDER LATER THIS AFTERNOON.  TEMPERATURES STILL A BIT
BELOW NORMAL TODAY, WITH THE COOLEST TEMPS IN THE NE, CLOSER TO THE
UPPER LEVEL TROF AND COOLER MID LEVELS.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

FORECAST DISCUSSION SEEMING A BIT REPETITIVE AS CENTRAL ILLINOIS
REMAINS IN A LARGELY NORTHWESTERLY FLOW PATTERN FOR THE FCST PD.  A
STEADY STREAM OF SHORT WAVES INTO THE REGION KEEP POPS FOR
OCCASIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. SOME TIMING
ISSUES REMAIN FROM RUN TO RUN. FORECAST KEEPS SOME POPS IN TONIGHT,
MAINLY FOR THE NORTH AND EAST CLOSER TO THE SFC LOW...AND INCREASING
TOWARDS MORNING WITH ANOTHER WAVE DIVING INTO THE MIDWEST IN NAM AND
GFS SOLUTIONS, WITH A BREAK TUES NIGHT POSSIBLE FOR THE NORTH BEFORE
ANOTHER WAVE ON WED AND SO ON THROUGH MOST OF THE FORECAST. WED/WED
NIGHT IS CURRENTLY SOME OF THE MORE FOCUSED POPS AS A BOUNDARY IS
APPARENT IN SFC WIND FIELDS IN THE MODELS.  ANY BOUNDARY LIKELY TO
SET UP IN THE REGION WILL PROVIDE MORE FOCUS/DYNAMICS FOR ANY SHORT
WAVE ASSISTED CONVECTION THAT DOES FORM.  THE SERIES OF WAVES STARTS
TO HAVE A LITTLE MORE DISSONANCE FROM MODEL TO MODEL GOING INTO THE
EXTENDED AS EXPECTED WITH REGARDS TO TIMING. OVERALL THE FORECAST
REMAINS WET AND STORMY WITH TEMPS SLIGHTLY BELOW NORMAL WITH
NORTHWESTERLY FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VRF CEILINGS AND VCTS COMING INTO THE
PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...BARNES



000
FXUS63 KILX 291747
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 1039 AM CDT MON JUN 29 2015

MORNING SURFACE ANALYSIS SHOWS 1008MB LOW NEAR KHUF...WITH COLD
FRONT EXTENDING SOUTHWESTWARD INTO THE OZARKS. DESPITE PROXIMITY
OF LOW...15Z/10AM RADAR IMAGE IS NEARLY CLEAR EXCEPT FOR A FEW
SHOWERS ACROSS IROQUOIS COUNTY. SKIES REMAIN CLOUDY FOR THE MOST
PART...HOWEVER PARTIAL CLEARING HAS OCCURRED WEST OF THE I-55
CORRIDOR. HRRR CONTINUES TO DEVELOP SCATTERED CONVECTION ACROSS
NEARLY THE ENTIRE AREA WITH ITS 1 AND 2-HOUR FORECAST...HOWEVER
THIS HAS PROVEN TO BE WAY OVERBLOWN. MEANWHILE THE 12Z NAM IS
ALMOST ENTIRELY DRY FOR THE REMAINDER OF THE DAY UNTIL AN UPPER-
LEVEL WAVE CURRENTLY OVER MINNESOTA ARRIVES TONIGHT. GIVEN AMPLE
LOW-LEVEL MOISTURE AND PRESENCE OF LOW PRESSURE NEARBY...CANNOT
COMPLETELY RULE OUT A STRAY SHOWER THIS AFTERNOON. HAVE UPDATED
POPS TO GO DRY THROUGH MIDDAY...THEN JUST SLIGHT CHANCES THIS
AFTERNOON. DUE TO THE CLOUD COVER AND A LIGHT NORTHERLY
BREEZE...HIGH TEMPS WILL BE SEVERAL DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR IN THE UPPER 70S TO AROUND 80 DEGREES.

&&

.SHORT TERM...(TODAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

SURFACE LOW IN WEST CENTRAL ILLINOIS AND MAJORITY OF PRECIP
ASSOCIATED WITH VIGOROUS SHORT WAVE HAS MOVED OUT TO THE EAST THIS
MORNING.  ENHANCED LLVL MOISTURE FROM EXITING TS RESULTING IN SOME
FOG THIS MORNING AND HAVE ADDED IN A COUPLE HOURS MAINLY IN THE
WEST. UPPER LEVEL TROF AXIS STILL OVER EASTERN ILX THIS MORNING AND
WILL KEEP CENTRAL ILLINOIS IN NWRLY FLOW/SLIGHTLY CYCLONIC FLOW
ALOFT.  SHOULD KEEP SOME OF THE CLOUDS OVER THE FA FOR MUCH OF THE
DAY AND INCREASE THE CHANCES FOR SOME INSTABILITY SHOWERS WITH SOME
POSSIBLE THUNDER LATER THIS AFTERNOON.  TEMPERATURES STILL A BIT
BELOW NORMAL TODAY, WITH THE COOLEST TEMPS IN THE NE, CLOSER TO THE
UPPER LEVEL TROF AND COOLER MID LEVELS.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUN 29 2015

FORECAST DISCUSSION SEEMING A BIT REPETITIVE AS CENTRAL ILLINOIS
REMAINS IN A LARGELY NORTHWESTERLY FLOW PATTERN FOR THE FCST PD.  A
STEADY STREAM OF SHORT WAVES INTO THE REGION KEEP POPS FOR
OCCASIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. SOME TIMING
ISSUES REMAIN FROM RUN TO RUN. FORECAST KEEPS SOME POPS IN TONIGHT,
MAINLY FOR THE NORTH AND EAST CLOSER TO THE SFC LOW...AND INCREASING
TOWARDS MORNING WITH ANOTHER WAVE DIVING INTO THE MIDWEST IN NAM AND
GFS SOLUTIONS, WITH A BREAK TUES NIGHT POSSIBLE FOR THE NORTH BEFORE
ANOTHER WAVE ON WED AND SO ON THROUGH MOST OF THE FORECAST. WED/WED
NIGHT IS CURRENTLY SOME OF THE MORE FOCUSED POPS AS A BOUNDARY IS
APPARENT IN SFC WIND FIELDS IN THE MODELS.  ANY BOUNDARY LIKELY TO
SET UP IN THE REGION WILL PROVIDE MORE FOCUS/DYNAMICS FOR ANY SHORT
WAVE ASSISTED CONVECTION THAT DOES FORM.  THE SERIES OF WAVES STARTS
TO HAVE A LITTLE MORE DISSONANCE FROM MODEL TO MODEL GOING INTO THE
EXTENDED AS EXPECTED WITH REGARDS TO TIMING. OVERALL THE FORECAST
REMAINS WET AND STORMY WITH TEMPS SLIGHTLY BELOW NORMAL WITH
NORTHWESTERLY FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUN 29 2015

EARLY MORNING OVERCAST CONTINUES TO THIN/DISSIPATE EARLY THIS
AFTERNOON...WITH LATEST OBS GENERALLY SHOWING SCT-BKN CLOUD COVER
AT AROUND 3500FT. GIVEN AMPLE LOW-LEVEL MOISTURE AND DECENT LAPSE
RATES...WILL CARRY LOW VFR CEILINGS THROUGH THE BALANCE OF THE
AFTERNOON FOLLOWED BY PARTIAL CLEARING TOWARD SUNSET. SHORT-WAVE
TROUGH CURRENTLY OVER MINNESOTA WILL DROP SOUTHWARD INTO THE AREA
LATE TONIGHT INTO TUESDAY MORNING...TRIGGERING SCATTERED
SHOWERS/THUNDER. SOME TIMING DIFFERENCES EXIST AMONG THE 12Z
MODELS...BUT PREFER THE SLOWER GFS. AS SUCH...KEPT FORECAST DRY
THROUGH THE NIGHT...WITH LOW VRF CEILINGS AND VCTS COMING INTO THE
PICTURE BETWEEN 13Z AND 15Z. WINDS WILL INITIALLY BE FROM THE
NORTHWEST AT 5 TO 10KT THIS AFTERNOON...THEN WILL BACK TO WESTERLY
TONIGHT INTO TUESDAY MORNING.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...BARNES
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...BARNES



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