Forecast Discussion - NOAA's National Weather Service

[top]


000
FXUS63 KLOT 191607
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1107 AM CDT WED JUN 19 2013

.DISCUSSION...
330 AM CDT

METEOROLOGICALLY BORING WEATHER ON TAP FOR THE NEXT COUPLE OF DAYS
WITH THE ONLY REAL FORECAST CHALLENGE THIS MORNING BEING TEMPS AND
CONVECTIVE CHANCES FRIDAY THROUGH THE WEEKEND AND INTO NEXT WEEK.

HIGH PRESSURE OVER THE REGION TODAY WILL SET THE STAGE FOR A STELLAR
DAY WITH AMPLE SUNSHINE...LOW HUMIDITY...MILD TEMPERATURES (ALBEIT
COOLER LAKESIDE) AND FAIRLY LIGHT WINDS. HIGH PRESSURE WILL MOVE OFF
TO THE EAST THE NEXT COUPLE DAYS WITH WINDS GRADUALLY TURNING MORE
SOUTHERLY ON THE BACK SIDE OF THE HIGH AND ALLOWING FOR A STEADY
WARM UP EACH OF THE NEXT FEW DAYS.

POWER-HOUSE UPPER LOW OFF THE PAC NW COAST WILL MOVE SLOWLY INLAND
AND GRADUALLY INCH ITS WAY EASTWARD INTO THE NORTHERN ROCKIES LATER
THIS WEEK AND INTO THE WEEKEND. DOWNSTREAM OF THIS UPPER LOW LOOK
FOR RIDGING ALOFT TO BUILD...THOUGH HOW FAR NORTH THE HEART OF THE
UPPER RIDGE BUILDS IS UP FOR DEBATE AMONG THE VARIOUS MODELS. GFS
HAS BEEN AND CONTINUES TO BE THE STRONGEST/FARTHEST NORTH WITH THE
UPPER RIDGE AND WOULD LIKELY SPELL HOT...HUMID AND RELATIVELY RAIN
FREE WX THROUGH THE WEEKEND. ECMWF CONTINUES TO BE A BIT WEAKER WITH
UPPER RIDGE WITH STRONGER BELT OF WESTERLIES CLOSER TO THE AREA AND
POSSIBLY LEAVING OUR CWA IN THE LINE OF FIRE FOR THE RING OF FIRE
PATTERN AND POTENTIAL FOR A COUPLE MCS TO ROLL THROUGH THE AREA.

PREVIOUS FEW FORECASTS HAVE BEEN LEANING A BIT TOWARD THE DRIER AND
STEAMIER GFS SOLUTION...AND WITH NO APPRECIABLE CHANGE IN THE MODEL
GUIDANCE THIS SET OF RUNS DIDNT SEE ANY GOOD REASON TO CHANGE
COURSE FROM OUR GOING FORECAST. CERTAINLY LOWER THAN AVERAGE
CONFIDENCE AND SHOULD MCS TRAIN COME ROLLING THROUGH THEN HIGHS
WOULD LIKELY BE MUCH COOLER AND IN THE 80S...HOWEVER SHOULD THE
RING `O FIRE STAY TO OUR NORTH AND WE STAY CAPPED THEN HIGHS IN
THE 90S WOULD BE LIKELY. DOES APPEAR AS THOUGH THE GEM IS MORE IN
THE ECMWF`S MCS CAMP...SO IF THIS TREND CONTINUES LATER FORECASTS
MAY NEED TO BEEF UP POPS AND TRIM TEMPS SOMEWHAT.

IZZI

&&

.AVIATION...

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

* NONE

TRS

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

VERY LITTLE GOING ON WEATHER-WISE TODAY. HIGH PRESSURE SPANS ACROSS
THE GREAT LAKES REGION AND WILL GRADUALLY MOVE SOUTHEAST TOWARDS THE
MID ATLANTIC COAST BY TOMORROW. THIS CAUSE NORTHEASTERLY WINDS THIS
MORNING TO VEER TO THE EAST AND SOUTHEAST TODAY...AND EVENTUALLY
SOUTH TOMORROW. GIVEN WINDS ARE ALREADY OFF OF LAKE MICHIGAN
TODAY...A LAKE BREEZE WILL LIKELY HAVE LITTLE IMPACT ON THE WINDS
EXCEPT FOR A MODEST INCREASE IN SPEEDS AND POSSIBLY A SHIFT BACK TO
A SLIGHTLY MORE NORTH OF EAST DIRECTION. OTHERWISE EXPECT VFR
CONDITIONS AND WINDS SHOULD GENERALLY STAY BELOW 10 KT OUTSIDE OF A
POSSIBLE BRIEF INCREASE WITH A LAKE BREEZE THIS AFTERNOON.

BMD

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

* MEDIUM CONFIDENCE WIND DIRECTION +/- 20 DEG...HIGH CONFIDENCE
  WIND SPEED.
* HIGH CONFIDENCE ALL OTHER ELEMENTS.

TRS

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

THURSDAY NIGHT THROUGH FRIDAY NIGHT...VFR.
SATURDAY THROUGH TUESDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE
VFR.

BMD

&&

.MARINE...
243 AM CDT

HIGH PRESSURE IS CENTERED OVER THE CENTRAL GREAT LAKES REGION EARLY
THIS MORNING AND IS FORECAST TO MOVE SOUTHEAST TOWARDS THE MID
ATLANTIC COAST BY THURSDAY. MEANWHILE...WINDS AND WAVES HAVE ALREADY
DIMINISHED UNDER THE INFLUENCE OF THE HIGH...THUS WILL ALLOW
REMAINING SMALL CRAFT ADVISORIES TO EXPIRE WITH THE MORNING FORECAST
PACKAGE. WITH LIGHT FLOW IN PLACE TODAY...WINDS WILL BECOME OFFSHORE
THIS AFTERNOON AS LAKE BREEZES DEVELOP ACROSS THE ENTIRE LAKE. AS
THE HIGH SETTLES TO OUR EAST THURSDAY...AND LOW PRESSURE OVER THE
PLAINS...WINDS WILL BEGIN TO TURN SOUTHERLY...AND FRESHEN UP FRIDAY
AS THE LOW LIFTS INTO THE UPPER MIDWEST. SOUTHERLY FLOW WILL
DOMINATE THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK. 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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO

[top]


000
FXUS63 KILX 191541
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1041 AM CDT WED JUN 19 2013

.DISCUSSION...
ISSUED 1038 AM CDT WED JUN 19 2013

ONLY MINOR GRID EDITS WERE NEEDED TO THE GOING FORECAST. SKIES
LARGELY SUNNY ASIDE FROM SOME CIRRUS SPREADING IN FROM THE
WEST...AND TEMPERATURES WERE ON TRACK TO REACH THE LOWER 80S
ACROSS THE FORECAST AREA.

GEELHART

&&

.AVIATION...
ISSUED 645 AM CDT WED JUN 19 2013

VFR CONDITIONS ARE FORECAST TO CONTINUE ACROSS THE CENTRAL IL
TERMINAL AIRPORTS NEXT 24 HOURS THROUGH 12Z/7 AM THU. FAIR WX DUE
TO 1023 MB SURFACE HIGH PRESSURE OVER MICHIGAN AND RIDGING SW
INTO MO...AND TO DRIFT EAST INTO THE EASTERN GREAT LAKES AND
SOUTHERN NEW ENGLAND BY DAWN THU. PATCHY SHALLOW/GROUND FOG OVER SE
IL TO LIFT BY 13Z/8 AM AND STAY SE OF THE CENTRAL IL TAF SITES.
SCATTERED-BROKEN MID/HIGH CLOUDS STREAMING SE OVER IA/MO WILL
PUSH SE ACROSS THE SW HALF OF IL THIS MORNING AND AFFECT SPI AND
POSSIBLY AS FAR NE AS PIA AND DEC BUT ANY CEILINGS WOULD STAY
ABOVE 10K FT. SCATTERED CUMULUS CLOUDS 4-5K FT TO DEVELOP AFTER
15Z/10 AM AND CONTINUE THIS AFTERNOON WITH BROKEN CEILINGS MAINLY
STAYING SOUTH OF I-72 OVER SE IL THIS AFTERNOON. CUMULUS CLOUDS TO
DISSIPATE EARLY THIS EVENING BY SUNSET LEAVING CLEAR SKIES
TONIGHT. FOG NOT EXPECTED TONIGHT DUE TO DRY AIR MASS IN PLACE. NE
WINDS 4-8 KTS EARLY THIS MORNING TO TURN EAST LATER THIS MORNING
AND AFTERNOON IN 6-10 KT RANGE...THEN BECOME LIGHT ESE AFTER
SUNSET TONIGHT.

07

&&

.PREV DISCUSSION...
ISSUED 251 AM CDT WED JUN 19 2013

SHORT TERM...TODAY THROUGH FRIDAY

COLD FRONT THAT BROUGHT A FEW STRONG THUNDERSTORMS TO PORTIONS OF
EAST-CENTRAL AND SOUTHEAST ILLINOIS YESTERDAY AFTERNOON/EVENING
HAS NOW SAGGED SOUTHWARD TO NEAR THE OHIO RIVER. COOL/DRY
NORTHEASTERLY FLOW BEHIND THE FRONT HAS SPREAD ACROSS CENTRAL
ILLINOIS EARLY THIS MORNING...WITH 07Z/2AM DEWPOINTS DIPPING INTO
THE UPPER 40S ACROSS THE FAR NORTHERN KILX CWA. THIS DRY AIR MASS
WILL LEAD TO MOSTLY SUNNY AND PLEASANT CONDITIONS TODAY...WITH
AFTERNOON HIGHS ONLY REACHING THE LOWER 80S. THE ONLY POTENTIAL
FLY IN THE OINTMENT WILL BE FURTHER SOUTH IN CLOSER PROXIMITY TO
THE FRONTAL BOUNDARY...WHERE SEVERAL ITERATIONS OF THE WRF MODEL
ARE SUGGESTING ISOLATED CONVECTION ALONG THE I-64 CORRIDOR LATE
THIS AFTERNOON. BASED ON STRONG PUSH OF DRY AIR FROM THE
NORTHEAST...THINK IF ANY CONVECTION DEVELOPS...IT WILL REMAIN
JUST S/SW OF THE KILX CWA.

DRY WEATHER WILL CONTINUE THROUGH THURSDAY MORNING...BEFORE WARM
FRONT LIFTING NORTHWARD INTO THE AREA POTENTIALLY TRIGGERS ISOLATED
SHOWERS/THUNDER ACROSS WEST-CENTRAL ILLINOIS THURSDAY AFTERNOON.
WEAKENING UPPER WAVE APPROACHING FROM THE PLAINS WILL PROVIDE
LIMITED SYNOPTIC LIFT ALONG THE BOUNDARY...HOWEVER THINK AIR MASS
WILL BE TOO DRY TO SUPPORT MUCH IN THE WAY OF PRECIP. WILL CARRY
JUST A 20 POP ALONG/WEST OF THE ILLINOIS RIVER THURSDAY
AFTERNOON...AND EVEN THAT MAY BE OVERDOING IT. ANY SHOWERS THAT
DEVELOP IN ADVANCE OF THE FRONT WILL QUICKLY DISSIPATE THURSDAY
EVENING AS MEAGER DAYTIME INSTABILITY IS LOST.

UPPER RIDGE BEGINS TO BUILD ACROSS THE MIDWEST ON FRIDAY...IN
RESPONSE TO UPSTREAM DEEP TROUGH WEST OF THE ROCKIES. MODELS ARE
STILL HAVING DIFFICULTY DETERMINING THE EXACT STRENGTH OF THE
RIDGE AND WHETHER OR NOT ANY POTENTIAL MCS ACTIVITY COULD IMPACT
PARTS OF CENTRAL ILLINOIS. GFS HAS SHOWN A CONSISTENT SIGNAL OVER
THE PAST SEVERAL RUNS...KEEPING BULK OF PRECIP WELL TO THE NORTH
ACROSS THE UPPER MIDWEST INTO THE GREAT LAKES. WILL CONTINUE TO
FOLLOW THIS SOLUTION...WHICH LEADS TO A VERY WARM/DRY DAY ON
FRIDAY WITH HIGHS WELL INTO THE 80S.

LONG TERM...SATURDAY THROUGH TUESDAY

HOT AND GENERALLY DRY WEATHER WILL PERSIST OVER THE WEEKEND...WITH
UPPER RIDGING FIRMLY IN PLACE AND ANY SIGNIFICANT CONVECTION
STAYING NORTH OF CENTRAL ILLINOIS. MAY SEE SOME ISOLATED
SHOWERS/STORMS AROUND THE AREA SATURDAY AFTERNOON DEPENDING ON
STRENGTH OF MID-LEVEL CAPPING...BUT NOT ENOUGH TO MENTION IN THE
FORECAST AT THIS TIME. MAIN STORY FOR THE WEEKEND WILL BE THE
HOT/HUMID WEATHER...WITH HIGHS IN THE UPPER 80S/LOWER 90S AND HEAT
INDEX VALUES APPROACHING 100 ON BOTH SATURDAY AND SUNDAY. RIDGE
BEGINS TO FLATTEN EARLY NEXT WEEK...GRADUALLY ALLOWING A FRONTAL
BOUNDARY TO SETTLE SOUTHWARD INTO CENTRAL ILLINOIS. SPEED IN WHICH
THIS PROCESS OCCURS IS STILL IN QUESTION...AS MODEL SOLUTIONS VARY
FROM RUN TO RUN. BOTTOM LINE WITH BOTH THE GFS AND ECMWF IS THAT
RIDGE AXIS WILL SHIFT INTO THE ROCKIES BY THE MIDDLE/END OF NEXT
WEEK...RESULTING IN A COOLER NORTHWESTERLY FLOW ACROSS THE
MIDWEST. AT THIS POINT...WILL BRING LOW CHANCE POPS INTO THE
NORTHERN CWA ON MONDAY...HOWEVER WIDESPREAD PRECIP WILL LIKELY
HOLD OFF UNTIL WEDNESDAY/THURSDAY WHEN RIDGE RE-POSITIONS ITSELF
FURTHER WEST.

BARNES

&&

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

$$


000
FXUS63 KILX 191145
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
645 AM CDT WED JUN 19 2013

.DISCUSSION...
ISSUED 251 AM CDT WED JUN 19 2013

SHORT TERM...TODAY THROUGH FRIDAY

COLD FRONT THAT BROUGHT A FEW STRONG THUNDERSTORMS TO PORTIONS OF
EAST-CENTRAL AND SOUTHEAST ILLINOIS YESTERDAY AFTERNOON/EVENING
HAS NOW SAGGED SOUTHWARD TO NEAR THE OHIO RIVER. COOL/DRY
NORTHEASTERLY FLOW BEHIND THE FRONT HAS SPREAD ACROSS CENTRAL
ILLINOIS EARLY THIS MORNING...WITH 07Z/2AM DEWPOINTS DIPPING INTO
THE UPPER 40S ACROSS THE FAR NORTHERN KILX CWA. THIS DRY AIRMASS
WILL LEAD TO MOSTLY SUNNY AND PLEASANT CONDITIONS TODAY...WITH
AFTERNOON HIGHS ONLY REACHING THE LOWER 80S. THE ONLY POTENTIAL
FLY IN THE OINTMENT WILL BE FURTHER SOUTH IN CLOSER PROXIMITY TO
THE FRONTAL BOUNDARY...WHERE SEVERAL ITERATIONS OF THE WRF MODEL
ARE SUGGESTING ISOLATED CONVECTION ALONG THE I-64 CORRIDOR LATE
THIS AFTERNOON. BASED ON STRONG PUSH OF DRY AIR FROM THE
NORTHEAST...THINK IF ANY CONVECTION DEVELOPS...IT WILL REMAIN
JUST S/SW OF THE KILX CWA.

DRY WEATHER WILL CONTINUE THROUGH THURSDAY MORNING...BEFORE WARM
FRONT LIFTING NORTHWARD INTO THE AREA POTENTIALLY TRIGGERS ISOLATED
SHOWERS/THUNDER ACROSS WEST-CENTRAL ILLINOIS THURSDAY AFTERNOON.
WEAKENING UPPER WAVE APPROACHING FROM THE PLAINS WILL PROVIDE
LIMITED SYNOPTIC LIFT ALONG THE BOUNDARY...HOWEVER THINK AIRMASS
WILL BE TOO DRY TO SUPPORT MUCH IN THE WAY OF PRECIP. WILL CARRY
JUST A 20 POP ALONG/WEST OF THE ILLINOIS RIVER THURSDAY
AFTERNOON...AND EVEN THAT MAY BE OVERDOING IT. ANY SHOWERS THAT
DEVELOP IN ADVANCE OF THE FRONT WILL QUICKLY DISSIPATE THURSDAY
EVENING AS MEAGER DAYTIME INSTABILITY IS LOST.

UPPER RIDGE BEGINS TO BUILD ACROSS THE MIDWEST ON FRIDAY...IN
RESPONSE TO UPSTREAM DEEP TROUGH WEST OF THE ROCKIES. MODELS ARE
STILL HAVING DIFFICULTY DETERMINING THE EXACT STRENGTH OF THE
RIDGE AND WHETHER OR NOT ANY POTENTIAL MCS ACTIVITY COULD IMPACT
PARTS OF CENTRAL ILLINOIS. GFS HAS SHOWN A CONSISTENT SIGNAL OVER
THE PAST SEVERAL RUNS...KEEPING BULK OF PRECIP WELL TO THE NORTH
ACROSS THE UPPER MIDWEST INTO THE GREAT LAKES. WILL CONTINUE TO
FOLLOW THIS SOLUTION...WHICH LEADS TO A VERY WARM/DRY DAY ON
FRIDAY WITH HIGHS WELL INTO THE 80S.

LONG TERM...SATURDAY THROUGH TUESDAY

HOT AND GENERALLY DRY WEATHER WILL PERSIST OVER THE WEEKEND...WITH
UPPER RIDGING FIRMLY IN PLACE AND ANY SIGNIFICANT CONVECTION
STAYING NORTH OF CENTRAL ILLINOIS. MAY SEE SOME ISOLATED
SHOWERS/STORMS AROUND THE AREA SATURDAY AFTERNOON DEPENDING ON
STRENGTH OF MID-LEVEL CAPPING...BUT NOT ENOUGH TO MENTION IN THE
FORECAST AT THIS TIME. MAIN STORY FOR THE WEEKEND WILL BE THE
HOT/HUMID WEATHER...WITH HIGHS IN THE UPPER 80S/LOWER 90S AND HEAT
INDEX VALUES APPROACHING 100 ON BOTH SATURDAY AND SUNDAY. RIDGE
BEGINS TO FLATTEN EARLY NEXT WEEK...GRADUALLY ALLOWING A FRONTAL
BOUNDARY TO SETTLE SOUTHWARD INTO CENTRAL ILLINOIS. SPEED IN WHICH
THIS PROCESS OCCURS IS STILL IN QUESTION...AS MODEL SOLUTIONS VARY
FROM RUN TO RUN. BOTTOM LINE WITH BOTH THE GFS AND ECMWF IS THAT
RIDGE AXIS WILL SHIFT INTO THE ROCKIES BY THE MIDDLE/END OF NEXT
WEEK...RESULTING IN A COOLER NORTHWESTERLY FLOW ACROSS THE
MIDWEST. AT THIS POINT...WILL BRING LOW CHANCE POPS INTO THE
NORTHERN CWA ON MONDAY...HOWEVER WIDESPREAD PRECIP WILL LIKELY
HOLD OFF UNTIL WEDNESDAY/THURSDAY WHEN RIDGE RE-POSITIONS ITSELF
FURTHER WEST.

BARNES

&&

.AVIATION...
ISSUED 645 AM CDT WED JUN 19 2013

VFR CONDITIONS ARE FORECAST TO CONTINUE ACROSS THE CENTRAL IL
TERMINAL AIRPORTS NEXT 24 HOURS THROUGH 12Z/7 AM THU. FAIR WX DUE
TO 1023 MB SURFACE HIGH PRESSURE OVER MICHIGAN AND RIDGING SW
INTO MO...AND TO DRIFT EAST INTO THE EASTERN GREAT LAKES AND
SOUTHERN NEW ENGLAND BY DAWN THU. PATCHY SHALLOW/GROUND FOG OVER SE
IL TO LIFT BY 13Z/8 AM AND STAY SE OF THE CENTRAL IL TAF SITES.
SCATTERED-BROKEN MID/HIGH CLOUDS STREAMING SE OVER IA/MO WILL
PUSH SE ACROSS THE SW HALF OF IL THIS MORNING AND AFFECT SPI AND
POSSIBLY AS FAR NE AS PIA AND DEC BUT ANY CEILINGS WOULD STAY
ABOVE 10K FT. SCATTERED CUMULUS CLOUDS 4-5K FT TO DEVELOP AFTER
15Z/10 AM AND CONTINUE THIS AFTERNOON WITH BROKEN CEILINGS MAINLY
STAYING SOUTH OF I-72 OVER SE IL THIS AFTERNOON. CUMULUS CLOUDS TO
DISSIPATE EARLY THIS EVENING BY SUNSET LEAVING CLEAR SKIES
TONIGHT. FOG NOT EXPECTED TONIGHT DUE TO DRY AIRMASS IN PLACE. NE
WINDS 4-8 KTS EARLY THIS MORNING TO TURN EAST LATER THIS MORNING
AND AFTERNOON IN 6-10 KT RANGE...THEN BECOME LIGHT ESE AFTER
SUNSET TONIGHT.

07

&&

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

&&

$$


000
FXUS63 KLOT 191129
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
629 AM CDT WED JUN 19 2013

.DISCUSSION...
330 AM CDT

METEOROLOGICALLY BORING WEATHER ON TAP FOR THE NEXT COUPLE OF DAYS
WITH THE ONLY REAL FORECAST CHALLENGE THIS MORNING BEING TEMPS AND
CONVECTIVE CHANCES FRIDAY THROUGH THE WEEKEND AND INTO NEXT WEEK.

HIGH PRESSURE OVER THE REGION TODAY WILL SET THE STAGE FOR A STELLAR
DAY WITH AMPLE SUNSHINE...LOW HUMIDITY...MILD TEMPERATURES (ALBEIT
COOLER LAKESIDE) AND FAIRLY LIGHT WINDS. HIGH PRESSURE WILL MOVE OFF
TO THE EAST THE NEXT COUPLE DAYS WITH WINDS GRADUALLY TURNING MORE
SOUTHERLY ON THE BACK SIDE OF THE HIGH AND ALLOWING FOR A STEADY
WARM UP EACH OF THE NEXT FEW DAYS.

POWER-HOUSE UPPER LOW OFF THE PAC NW COAST WILL MOVE SLOWLY INLAND
AND GRADUALLY INCH ITS WAY EASTWARD INTO THE NORTHERN ROCKIES LATER
THIS WEEK AND INTO THE WEEKEND. DOWNSTREAM OF THIS UPPER LOW LOOK
FOR RIDGING ALOFT TO BUILD...THOUGH HOW FAR NORTH THE HEART OF THE
UPPER RIDGE BUILDS IS UP FOR DEBATE AMONG THE VARIOUS MODELS. GFS
HAS BEEN AND CONTINUES TO BE THE STRONGEST/FARTHEST NORTH WITH THE
UPPER RIDGE AND WOULD LIKELY SPELL HOT...HUMID AND RELATIVELY RAIN
FREE WX THROUGH THE WEEKEND. ECMWF CONTINUES TO BE A BIT WEAKER WITH
UPPER RIDGE WITH STRONGER BELT OF WESTERLIES CLOSER TO THE AREA AND
POSSIBLY LEAVING OUR CWA IN THE LINE OF FIRE FOR THE RING OF FIRE
PATTERN AND POTENTIAL FOR A COUPLE MCS TO ROLL THROUGH THE AREA.

PREVIOUS FEW FORECASTS HAVE BEEN LEANING A BIT TOWARD THE DRIER AND
STEAMIER GFS SOLUTION...AND WITH NO APPRECIABLE CHANGE IN THE MODEL
GUIDANCE THIS SET OF RUNS DIDNT SEE ANY GOOD REASON TO CHANGE
COURSE FROM OUR GOING FORECAST. CERTAINLY LOWER THAN AVERAGE
CONFIDENCE AND SHOULD MCS TRAIN COME ROLLING THROUGH THEN HIGHS
WOULD LIKELY BE MUCH COOLER AND IN THE 80S...HOWEVER SHOULD THE
RING `O FIRE STAY TO OUR NORTH AND WE STAY CAPPED THEN HIGHS IN
THE 90S WOULD BE LIKELY. DOES APPEAR AS THOUGH THE GEM IS MORE IN
THE ECMWF`S MCS CAMP...SO IF THIS TREND CONTINUES LATER FORECASTS
MAY NEED TO BEEF UP POPS AND TRIM TEMPS SOMEWHAT.

IZZI

&&

.AVIATION...

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

* NONE

BMD

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

VERY LITTLE GOING ON WEATHER-WISE TODAY. HIGH PRESSURE SPANS ACROSS
THE GREAT LAKES REGION AND WILL GRADUALLY MOVE SOUTHEAST TOWARDS THE
MID ATLANTIC COAST BY TOMORROW. THIS CAUSE NORTHEASTERLY WINDS THIS
MORNING TO VEER TO THE EAST AND SOUTHEAST TODAY...AND EVENTUALLY
SOUTH TOMORROW. GIVEN WINDS ARE ALREADY OFF OF LAKE MICHIGAN
TODAY...A LAKE BREEZE WILL LIKELY HAVE LITTLE IMPACT ON THE WINDS
EXCEPT FOR A MODEST INCREASE IN SPEEDS AND POSSIBLY A SHIFT BACK TO
A SLIGHTLY MORE NORTH OF EAST DIRECTION. OTHERWISE EXPECT VFR
CONDITIONS AND WINDS SHOULD GENERALLY STAY BELOW 10 KT OUTSIDE OF A
POSSIBLE BRIEF INCREASE WITH A LAKE BREEZE THIS AFTERNOON.

BMD


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

* MEDIUM CONFIDENCE IN WIND DIRECTION...HIGH CONFIDENCE IN WIND
  SPEEDS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

BMD

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

THURSDAY NIGHT THROUGH FRIDAY NIGHT...VFR.
SATURDAY THROUGH TUESDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE
VFR.

BMD

&&

.MARINE...
243 AM CDT

HIGH PRESSURE IS CENTERED OVER THE CENTRAL GREAT LAKES REGION EARLY
THIS MORNING AND IS FORECAST TO MOVE SOUTHEAST TOWARDS THE MID
ATLANTIC COAST BY THURSDAY. MEANWHILE...WINDS AND WAVES HAVE ALREADY
DIMINISHED UNDER THE INFLUENCE OF THE HIGH...THUS WILL ALLOW
REMAINING SMALL CRAFT ADVISORIES TO EXPIRE WITH THE MORNING FORECAST
PACKAGE. WITH LIGHT FLOW IN PLACE TODAY...WINDS WILL BECOME OFFSHORE
THIS AFTERNOON AS LAKE BREEZES DEVELOP ACROSS THE ENTIRE LAKE. AS
THE HIGH SETTLES TO OUR EAST THURSDAY...AND LOW PRESSURE OVER THE
PLAINS...WINDS WILL BEGIN TO TURN SOUTHERLY...AND FRESHEN UP FRIDAY
AS THE LOW LIFTS INTO THE UPPER MIDWEST. SOUTHERLY FLOW WILL
DOMINATE THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK. 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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO


000
FXUS63 KLOT 190901
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
401 AM CDT WED JUN 19 2013

.DISCUSSION...
330 AM CDT

METEOROLOGICALLY BORING WEATHER ON TAP FOR THE NEXT COUPLE OF DAYS
WITH THE ONLY REAL FORECAST CHALLENGE THIS MORNING BEING TEMPS AND
CONVECTIVE CHANCES FRIDAY THROUGH THE WEEKEND AND INTO NEXT WEEK.

HIGH PRESSURE OVER THE REGION TODAY WILL SET THE STAGE FOR A STELLAR
DAY WITH AMPLE SUNSHINE...LOW HUMIDITY...MILD TEMPERATURES (ALBEIT
COOLER LAKESIDE) AND FAIRLY LIGHT WINDS. HIGH PRESSURE WILL MOVE OFF
TO THE EAST THE NEXT COUPLE DAYS WITH WINDS GRADUALLY TURNING MORE
SOUTHERLY ON THE BACK SIDE OF THE HIGH AND ALLOWING FOR A STEADY
WARM UP EACH OF THE NEXT FEW DAYS.

POWER-HOUSE UPPER LOW OFF THE PAC NW COAST WILL MOVE SLOWLY INLAND
AND GRADUALLY INCH ITS WAY EASTWARD INTO THE NORTHERN ROCKIES LATER
THIS WEEK AND INTO THE WEEKEND. DOWNSTREAM OF THIS UPPER LOW LOOK
FOR RIDGING ALOFT TO BUILD...THOUGH HOW FAR NORTH THE HEART OF THE
UPPER RIDGE BUILDS IS UP FOR DEBATE AMONG THE VARIOUS MODELS. GFS
HAS BEEN AND CONTINUES TO BE THE STRONGEST/FARTHEST NORTH WITH THE
UPPER RIDGE AND WOULD LIKELY SPELL HOT...HUMID AND RELATIVELY RAIN
FREE WX THROUGH THE WEEKEND. ECMWF CONTINUES TO BE A BIT WEAKER WITH
UPPER RIDGE WITH STRONGER BELT OF WESTERLIES CLOSER TO THE AREA AND
POSSIBLY LEAVING OUR CWA IN THE LINE OF FIRE FOR THE RING OF FIRE
PATTERN AND POTENTIAL FOR A COUPLE MCS TO ROLL THROUGH THE AREA.

PREVIOUS FEW FORECASTS HAVE BEEN LEANING A BIT TOWARD THE DRIER AND
STEAMIER GFS SOLUTION...AND WITH NO APPRECIABLE CHANGE IN THE MODEL
GUIDANCE THIS SET OF RUNS DIDNT SEE ANY GOOD REASON TO CHANGE
COURSE FROM OUR GOING FORECAST. CERTAINLY LOWER THAN AVERAGE
CONFIDENCE AND SHOULD MCS TRAIN COME ROLLING THROUGH THEN HIGHS
WOULD LIKELY BE MUCH COOLER AND IN THE 80S...HOWEVER SHOULD THE
RING `O FIRE STAY TO OUR NORTH AND WE STAY CAPPED THEN HIGHS IN
THE 90S WOULD BE LIKELY. DOES APPEAR AS THOUGH THE GEM IS MORE IN
THE ECMWF`S MCS CAMP...SO IF THIS TREND CONTINUES LATER FORECASTS
MAY NEED TO BEEF UP POPS AND TRIM TEMPS SOMEWHAT.

IZZI

&&

.AVIATION...

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

* LAKE BREEZE WEDNESDAY AFTERNOON.

BMD

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

HIGH PRESSURE SPANS THE GREAT LAKES REGION TONIGHT WITH LIGHT FLOW
EXPECTED THROUGH THE TAF PERIOD. WINDS SHOULD SYNOPTICALLY VEER EAST
THEN SOUTHEAST...BUT A LAKE BREEZE MAY INTERRUPT THIS PROCESS
WEDNESDAY AFTERNOON TURNING WINDS BACK TO NORTHEAST FOR A PERIOD.
WITH SUNSET...WINDS SHOULD THEN VEER AGAIN TO THE SOUTHEAST AS THE
HIGH CONTINUES TO SETTLE SOUTHEAST TOWARDS THE MID ATLANTIC COAST.
OUTSIDE OF THE INFLUENCE OF THE LAKE BREEZE WEDNESDAY
AFTERNOON...EXPECT WINDS TO REMAIN LESS THAN 10 KT. VFR CONDITIONS
ARE ALSO EXPECTED TO PREVAIL THROUGH THE PERIOD.

BMD

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

* MEDIUM CONFIDENCE IN WIND DIRECTION FORECAST...HIGH CONFIDENCE
  IN WIND SPEEDS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

BMD

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

THURSDAY...VFR.

FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR TSRA...OTHERWISE VFR.

LENNING

&&

.MARINE...
243 AM CDT

HIGH PRESSURE IS CENTERED OVER THE CENTRAL GREAT LAKES REGION EARLY
THIS MORNING AND IS FORECAST TO MOVE SOUTHEAST TOWARDS THE MID
ATLANTIC COAST BY THURSDAY. MEANWHILE...WINDS AND WAVES HAVE ALREADY
DIMINISHED UNDER THE INFLUDENCE OF THE HIGH...THUS WILL ALLOW
REMAINING SMALL CRAFT ADVISORIES TO EXPIRE WITH THE MORNING FORECAST
PACKAGE. WITH LIGHT FLOW IN PLACE TODAY...WINDS WILL BECOME OFFSHORE
THIS AFTERNOON AS LAKE BREEZES DEVELOP ACROSS THE ENTIRE LAKE. AS
THE HIGH SETTLES TO OUR EAST THURSDAY...AND LOW PRESSURE OVER THE
PLAINS...WINDS WILL BEGIN TO TURN SOUTHERLY...AND FRESHEN UP FRIDAY
AS THE LOW LIFTS INTO THE UPPER MIDWEST. SOUTHERLY FLOW WILL
DOMINATE THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK. 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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO


000
FXUS63 KLOT 190830
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 AM CDT WED JUN 19 2013

.DISCUSSION...
330 AM CDT

METEOROLOGICALLY BORING WEATHER ON TAP FOR THE NEXT COUPLE OF DAYS
WITH THE ONLY REAL FORECAST CHALLENGE THIS MORNING BEING TEMPS AND
CONVECTIVE CHANCES FRIDAY THROUGH THE WEEKEND AND INTO NEXT WEEK.

HIGH PRESSURE OVER THE REGION TODAY WILL SET THE STAGE FOR A STELLAR
DAY WITH AMPLE SUNSHINE...LOW HUMIDITY...MILD TEMPERATURES (ALBEIT
COOLER LAKESIDE) AND FAIRLY LIGHT WINDS. HIGH PRESSURE WILL MOVE OFF
TO THE EAST THE NEXT COUPLE DAYS WITH WINDS GRADUALLY TURNING MORE
SOUTHERLY ON THE BACK SIDE OF THE HIGH AND ALLOWING FOR A STEADY
WARM UP EACH OF THE NEXT FEW DAYS.

POWER-HOUSE UPPER LOW OFF THE PAC NW COAST WILL MOVE SLOWLY INLAND
AND GRADUALLY INCH ITS WAY EASTWARD INTO THE NORTHERN ROCKIES LATER
THIS WEEK AND INTO THE WEEKEND. DOWNSTREAM OF THIS UPPER LOW LOOK
FOR RIDGING ALOFT TO BUILD...THOUGH HOW FAR NORTH THE HEART OF THE
UPPER RIDGE BUILDS IS UP FOR DEBATE AMONG THE VARIOUS MODELS. GFS
HAS BEEN AND CONTINUES TO BE THE STRONGEST/FARTHEST NORTH WITH THE
UPPER RIDGE AND WOULD LIKELY SPELL HOT...HUMID AND RELATIVELY RAIN
FREE WX THROUGH THE WEEKEND. ECMWF CONTINUES TO BE A BIT WEAKER WITH
UPPER RIDGE WITH STRONGER BELT OF WESTERLIES CLOSER TO THE AREA AND
POSSIBLY LEAVING OUR CWA IN THE LINE OF FIRE FOR THE RING OF FIRE
PATTERN AND POTENTIAL FOR A COUPLE MCS TO ROLL THROUGH THE AREA.

PREVIOUS FEW FORECASTS HAVE BEEN LEANING A BIT TOWARD THE DRIER AND
STEAMIER GFS SOLUTION...AND WITH NO APPRECIABLE CHANGE IN THE MODEL
GUIDANCE THIS SET OF RUNS DIDNT SEE ANY GOOD REASON TO CHANGE
COURSE FROM OUR GOING FORECAST. CERTAINLY LOWER THAN AVERAGE
CONFIDENCE AND SHOULD MCS TRAIN COME ROLLING THROUGH THEN HIGHS
WOULD LIKELY BE MUCH COOLER AND IN THE 80S...HOWEVER SHOULD THE
RING `O FIRE STAY TO OUR NORTH AND WE STAY CAPPED THEN HIGHS IN
THE 90S WOULD BE LIKELY. DOES APPEAR AS THOUGH THE GEM IS MORE IN
THE ECMWF`S MCS CAMP...SO IF THIS TREND CONTINUES LATER FORECASTS
MAY NEED TO BEEF UP POPS AND TRIM TEMPS SOMEWHAT.

IZZI

&&

.AVIATION...

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

* LAKE BREEZE WEDNESDAY AFTERNOON.

BMD

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

HIGH PRESSURE SPANS THE GREAT LAKES REGION TONIGHT WITH LIGHT FLOW
EXPECTED THROUGH THE TAF PERIOD. WINDS SHOULD SYNOPTICALLY VEER EAST
THEN SOUTHEAST...BUT A LAKE BREEZE MAY INTERRUPT THIS PROCESS
WEDNESDAY AFTERNOON TURNING WINDS BACK TO NORTHEAST FOR A PERIOD.
WITH SUNSET...WINDS SHOULD THEN VEER AGAIN TO THE SOUTHEAST AS THE
HIGH CONTINUES TO SETTLE SOUTHEAST TOWARDS THE MID ATLANTIC COAST.
OUTSIDE OF THE INFLUENCE OF THE LAKE BREEZE WEDNESDAY
AFTERNOON...EXPECT WINDS TO REMAIN LESS THAN 10 KT. VFR CONDITIONS
ARE ALSO EXPECTED TO PREVAIL THROUGH THE PERIOD.

BMD

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

* MEDIUM CONFIDENCE IN WIND DIRECTION FORECAST...HIGH CONFIDENCE
  IN WIND SPEEDS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

BMD

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

THURSDAY...VFR.

FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR TSRA...OTHERWISE VFR.

LENNING

&&

.MARINE...
243 AM CDT

HIGH PRESSURE IS CENTERED OVER THE CENTRAL GREAT LAKES REGION EARLY
THIS MORNING AND IS FORECAST TO MOVE SOUTHEAST TOWARDS THE MID
ATLANTIC COAST BY THURSDAY. MEANWHILE...WINDS AND WAVES HAVE ALREADY
DIMINISHED UNDER THE INFLUDENCE OF THE HIGH...THUS WILL ALLOW
REMAINING SMALL CRAFT ADVISORIES TO EXPIRE WITH THE MORNING FORECAST
PACKAGE. WITH LIGHT FLOW IN PLACE TODAY...WINDS WILL BECOME OFFSHORE
THIS AFTERNOON AS LAKE BREEZES DEVELOP ACROSS THE ENTIRE LAKE. AS
THE HIGH SETTLES TO OUR EAST THURSDAY...AND LOW PRESSURE OVER THE
PLAINS...WINDS WILL BEGIN TO TURN SOUTHERLY...AND FRESHEN UP FRIDAY
AS THE LOW LIFTS INTO THE UPPER MIDWEST. SOUTHERLY FLOW WILL
DOMINATE THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KILX 190751
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
251 AM CDT WED JUN 19 2013

.DISCUSSION...
ISSUED 251 AM CDT WED JUN 19 2013

SHORT TERM...TODAY THROUGH FRIDAY

COLD FRONT THAT BROUGHT A FEW STRONG THUNDERSTORMS TO PORTIONS OF
EAST-CENTRAL AND SOUTHEAST ILLINOIS YESTERDAY AFTERNOON/EVENING
HAS NOW SAGGED SOUTHWARD TO NEAR THE OHIO RIVER. COOL/DRY
NORTHEASTERLY FLOW BEHIND THE FRONT HAS SPREAD ACROSS CENTRAL
ILLINOIS EARLY THIS MORNING...WITH 07Z/2AM DEWPOINTS DIPPING INTO
THE UPPER 40S ACROSS THE FAR NORTHERN KILX CWA. THIS DRY AIRMASS
WILL LEAD TO MOSTLY SUNNY AND PLEASANT CONDITIONS TODAY...WITH
AFTERNOON HIGHS ONLY REACHING THE LOWER 80S. THE ONLY POTENTIAL
FLY IN THE OINTMENT WILL BE FURTHER SOUTH IN CLOSER PROXIMITY TO
THE FRONTAL BOUNDARY...WHERE SEVERAL ITERATIONS OF THE WRF MODEL
ARE SUGGESTING ISOLATED CONVECTION ALONG THE I-64 CORRIDOR LATE
THIS AFTERNOON. BASED ON STRONG PUSH OF DRY AIR FROM THE
NORTHEAST...THINK IF ANY CONVECTION DEVELOPS...IT WILL REMAIN
JUST S/SW OF THE KILX CWA.

DRY WEATHER WILL CONTINUE THROUGH THURSDAY MORNING...BEFORE WARM
FRONT LIFTING NORTHWARD INTO THE AREA POTENTIALLY TRIGGERS ISOLATED
SHOWERS/THUNDER ACROSS WEST-CENTRAL ILLINOIS THURSDAY AFTERNOON.
WEAKENING UPPER WAVE APPROACHING FROM THE PLAINS WILL PROVIDE
LIMITED SYNOPTIC LIFT ALONG THE BOUNDARY...HOWEVER THINK AIRMASS
WILL BE TOO DRY TO SUPPORT MUCH IN THE WAY OF PRECIP. WILL CARRY
JUST A 20 POP ALONG/WEST OF THE ILLINOIS RIVER THURSDAY
AFTERNOON...AND EVEN THAT MAY BE OVERDOING IT. ANY SHOWERS THAT
DEVELOP IN ADVANCE OF THE FRONT WILL QUICKLY DISSIPATE THURSDAY
EVENING AS MEAGER DAYTIME INSTABILITY IS LOST.

UPPER RIDGE BEGINS TO BUILD ACROSS THE MIDWEST ON FRIDAY...IN
RESPONSE TO UPSTREAM DEEP TROUGH WEST OF THE ROCKIES. MODELS ARE
STILL HAVING DIFFICULTY DETERMINING THE EXACT STRENGTH OF THE
RIDGE AND WHETHER OR NOT ANY POTENTIAL MCS ACTIVITY COULD IMPACT
PARTS OF CENTRAL ILLINOIS. GFS HAS SHOWN A CONSISTENT SIGNAL OVER
THE PAST SEVERAL RUNS...KEEPING BULK OF PRECIP WELL TO THE NORTH
ACROSS THE UPPER MIDWEST INTO THE GREAT LAKES. WILL CONTINUE TO
FOLLOW THIS SOLUTION...WHICH LEADS TO A VERY WARM/DRY DAY ON
FRIDAY WITH HIGHS WELL INTO THE 80S.

LONG TERM...SATURDAY THROUGH TUESDAY

HOT AND GENERALLY DRY WEATHER WILL PERSIST OVER THE WEEKEND...WITH
UPPER RIDGING FIRMLY IN PLACE AND ANY SIGNIFICANT CONVECTION
STAYING NORTH OF CENTRAL ILLINOIS. MAY SEE SOME ISOLATED
SHOWERS/STORMS AROUND THE AREA SATURDAY AFTERNOON DEPENDING ON
STRENGTH OF MID-LEVEL CAPPING...BUT NOT ENOUGH TO MENTION IN THE
FORECAST AT THIS TIME. MAIN STORY FOR THE WEEKEND WILL BE THE
HOT/HUMID WEATHER...WITH HIGHS IN THE UPPER 80S/LOWER 90S AND HEAT
INDEX VALUES APPROACHING 100 ON BOTH SATURDAY AND SUNDAY. RIDGE
BEGINS TO FLATTEN EARLY NEXT WEEK...GRADUALLY ALLOWING A FRONTAL
BOUNDARY TO SETTLE SOUTHWARD INTO CENTRAL ILLINOIS. SPEED IN WHICH
THIS PROCESS OCCURS IS STILL IN QUESTION...AS MODEL SOLUTIONS VARY
FROM RUN TO RUN. BOTTOM LINE WITH BOTH THE GFS AND ECMWF IS THAT
RIDGE AXIS WILL SHIFT INTO THE ROCKIES BY THE MIDDLE/END OF NEXT
WEEK...RESULTING IN A COOLER NORTHWESTERLY FLOW ACROSS THE
MIDWEST. AT THIS POINT...WILL BRING LOW CHANCE POPS INTO THE
NORTHERN CWA ON MONDAY...HOWEVER WIDESPREAD PRECIP WILL LIKELY
HOLD OFF UNTIL WEDNESDAY/THURSDAY WHEN RIDGE RE-POSITIONS ITSELF
FURTHER WEST.

BARNES
&&

.AVIATION...
ISSUED 1154 PM CDT TUE JUN 18 2013

VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. SKIES
SHOULD REMAIN CLEAR OVERNIGHT AND THEN ONLY EXPECTING SOME
SCATTERED CU TOMORROW AT AROUND 4KFT. THIS CU WILL NOT BE DIURNAL
SO AM EXPECTING IT TO CONTINUE INTO THE EVENING HOURS TOMORROW.
WINDS WILL BE NORTHEASTERLY OVERNIGHT AND THEN BECOME EASTERLY
TOMORROW. THEN EXPECTING VARIABLE WINDS TOMORROW EVENING AS THEY
SHIFT FROM SOUTHEAST TO SOUTH BACK TO SOUTHEAST. WIND SPEEDS
TOMORROW EVENING SHOULD BE LIGHT.

AUTEN
&&

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

$$


000
FXUS63 KLOT 190744
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
244 AM CDT WED JUN 19 2013

.DISCUSSION...
849 PM CDT

VERY LITTLE CHANGE MADE TO THE GOING FORECAST FOR THE REST OF
TONIGHT. THE HIGH PRESSURE RIDGE CONTINUES TO BUILD DOWN THE LAKE
RESULTING IN A PRESSURE GRADIENT ACROSS NE IL AND NW IN. THIS
COUPLED WITH THE LONG NNE FETCH OF THE WINDS OVER THE LAKE HAS
CONTINUED TO ALLOW FOR 20+ MPH GUSTS EARLY THIS EVE. THESE LOOK
SLOW TO SUBSIDE PER OBSERVATIONAL TRENDS AND THE RAP BUFKIT
SOUNDINGS. SO THESE WILL ADD A LITTLE NIP IN THE AIR...BY JUNE
STANDARDS...ACROSS CHICAGO WITH TEMPS FALLING SLOWLY THROUGH THE
MID-UPPER 50S. THE COOLEST TEMPS TONIGHT STILL LOOK TO BE ALONG
THE STATE LINE WHERE CONDITIONS SHOULD DECOUPLE. UPPER 40S SHOULD
BE REALIZED THERE.

MTF

//PREV DISCUSSION...
239 PM CDT

STRATUS LAYER THAT WAS ANCHORED OVER FAR NORTHEAST IL/NORTHWEST IN
THIS MORNING HAS ERODED WITH THE WARM AIR HEATING THE SFC. VISIBLE
IMAGERY INDICATES A FEW AREAS OF CUMULUS CLOUDS THAT HAVE DEVELOPED
THIS AFTERNOON ACROSS NORTHERN IL. IN ADDITION SOME BUILDING CUMULUS
CLOUDS WERE NOTED ALONG A PONTIAC TO KANKAKEE LINE...IN AN AREA OF A
STRONGER THERMAL DIFFERENTIAL. HOWEVER THE LIFT MECHANISM IN THIS
AREA IS MINIMAL...AND SO A FEW ISOLATED SHOWERS/THUNDERSTORMS MAY
DEVELOP BUT QUICKLY DISSIPATE. ALL PRECIPITATION OVER THE CWFA WILL
BE DIURNALLY DRIVEN...THUS BY SUNSET OR IMMEDIATELY AFTER SUNSET
PRECIP WILL COME TO AN END. FURTHER SOUTH STRONGER INSTABILITY WAS
POSITIONED ACROSS CENTRAL IL STRETCHING WEST THROUGH NORTHERN
MISSOURI. MID-LVL WAVE CONTINUES TO PIVOT EAST ACROSS FAR NORTHWEST
IL THIS AFTERNOON...AND WILL MAINTAIN THE NORTHEAST FLOW ACROSS MUCH
OF THE CWFA. AS A RESULT COOL TEMPS WILL PERSIST THIS EVENING...WITH
MINIMAL CLOUD COVER FROM THE DIFFLUENT FLOW ALOFT. SKIES WILL BECOME
MOSTLY CLEAR TONIGHT...WITH THE LLVL FLOW WEAKENING. THIS SHOULD
PROVIDE DECENT RADIATIONAL COOLING WITH TEMPS OVERNIGHT EXPECTED TO
BE IN THE MID 50S SOUTH OF I-80. FURTHER NORTH TEMPS WILL BE MUCH
COOLER TO ARND 50...POSSIBLY THE UPR 40S FOR AREAS ALONG AND NORTH
OF A ROCKFORD...AURORA...WAUKEGAN LINE.

CONFIDENCE...HIGH.

WEDNESDAY THROUGH THURSDAY...

500MB TROUGH AXIS SLOWLY PIVOTS TO THE EASTERN GREAT LAKES WED...AND
WILL CONTINUE TO PUSH EAST THUR. THE SFC RIDGE WILL ALSO BEGIN TO
PUSH EAST...HOWEVER AN ONSHORE OR NORTHEAST TO EAST FLOW WILL
PERSIST INTO WED FOR MUCH OF NORTHERN IL. THE DIFFERENCE FOR WED
WILL BE THAT THE 850MB THERMAL TROUGH WILL LINGER OVERHEAD. WITH
ABUNDANT SUNSHINE AND SFC HEATING...TEMPS SHUD WARM INTO THE MID/UPR
70S OR POSSIBLY THE LOW 80S FROM LASALLE TO IROQUOIS COUNTY.

FOR THUR 500MB HEIGHTS WILL BEGIN TO RISE WITH FLOW BEGINNING TO
TURN TO THE SOUTHEAST IN THE LLVLS. A WEAK LAKE BREEZE MAY DEVELOP
AND PUSH INTO LAKE COUNTY IL...WHICH WOULD MOST LIKELY PROVIDE A
COOLING TREND IN THE AFTN HOURS. 850MB TEMPS WILL STEADILY WARM FOR
THUR TO ARND 14 TO 16 DEG C...WITH CONTINUED THIN CLOUD COVER. THIS
WILL ALLOW TEMPS TO WARM INTO THE LOW/MID 80S. THE CAVEAT WILL BE
AREAS OF LAKE COUNTY IL POST FRONTAL PASSAGE THAT WILL ALLOW TEMPS
TO FALL INTO THE 60S IN THE AFTN.

IT DOES APPEAR THAT ENOUGH DRY AIR WILL LINGER THRU THUR
AFTN/EVE...THUS HAVE HELD ONTO A DRY FORECAST IN THIS TIMEFRAME.
THIS PATTERN WILL BE CHANGING AS WE MIGRATE INTO THE EXTENDED
PERIODS.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN DRY WEATHER THROUGH THUR...MEDIUM/HIGH.

FRIDAY THROUGH MONDAY...
MINIMAL CHANGES FROM PREVIOUS FORECAST IN REGARDS TO THE EXTENDED
PERIODS. POSSIBLY THE FIRST STRETCH OF 90 DEG DAYS IS UPON US FOR
SUN/MON/TUE.

GUIDANCE HAS A WARM FRONTAL BOUNDARY LIFTING OVERHEAD FRI WITH
SOUTHERLY FLOW USHERING IN ADDTL LLVL MOISTURE. IT DOES APPEAR A
WAVE WILL ALSO PUSH OVER THE CWFA FRI...WITH POTENTIAL FOR
SHOWERS/THUNDERSTORMS. TEMPS WILL BE SLIGHTLY WARM FOR FRI INTO THE
UPR 80S...WITH A FEW 90 DEGREE POINTS ACROSS THE CWFA.

ENSEMBLES FOR SEVERAL DAYS HAVE CONTINUED TO INDICATE THAT A 500MB
RIDGE ACROSS THE CENTRAL CONUS WILL ADVECT EAST AND BECOME ANCHORED
ACROSS THE EASTERN HALF OF THE CONUS BY THE WEEKEND AND POSSIBLY
PERSIST THROUGH EARLY NEXT WEEK. ADDITIONALLY...GUIDANCE HAS PROGGED
850MB TEMPS TO RISE TO ARND 20-22 DEG C FOR THE WEEKEND THRU EARLY
NEXT WEEK. CONSISTENCY FROM PREVIOUS RUNS SUGGESTS HIGH CONFIDENCE
IN THIS WARM STRETCH ARRIVING. THEN SUN/MON/TUE APPEAR TO BE NEAR
CARBON COPIES WITH TEMPS EASILY WARMING TO 90 DEGREES...POSSIBLY THE
LOW 90S. CLIMATOLOGY BASED ON THE 850MB TEMPS PROGGED AND TIME OF
YEAR WOULD SUGGEST TEMPS TO BE WARMER AS FORECASTED. A COUPLE
LIMITING FACTORS MIGHT BE THE POTENTIAL FOR A SERIES OF WAVES
BRINGING INSTABILITY AND THUNDERSTORM POTENTIAL EACH DAY OF THE
EXTENDED...ALONG WITH DEW PTS PROGGED TO BE ARND 70 DEG.
THIS COULD POTENTIALLY KEEP TEMPS IN CHECK IN THE MID/UPR 80S.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN PRECIP/CONVECTIVE FORECAST...MEDIUM/HIGH.

BEACHLER

&&

.AVIATION...

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

* LAKE BREEZE WEDNESDAY AFTERNOON.

BMD

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

HIGH PRESSURE SPANS THE GREAT LAKES REGION TONIGHT WITH LIGHT FLOW
EXPECTED THROUGH THE TAF PERIOD. WINDS SHOULD SYNOPTICALLY VEER EAST
THEN SOUTHEAST...BUT A LAKE BREEZE MAY INTERRUPT THIS PROCESS
WEDNESDAY AFTERNOON TURNING WINDS BACK TO NORTHEAST FOR A PERIOD.
WITH SUNSET...WINDS SHOULD THEN VEER AGAIN TO THE SOUTHEAST AS THE
HIGH CONTINUES TO SETTLE SOUTHEAST TOWARDS THE MID ATLANTIC COAST.
OUTSIDE OF THE INFLUENCE OF THE LAKE BREEZE WEDNESDAY
AFTERNOON...EXPECT WINDS TO REMAIN LESS THAN 10 KT. VFR CONDITIONS
ARE ALSO EXPECTED TO PREVAIL THROUGH THE PERIOD.

BMD

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

* MEDIUM CONFIDENCE IN WIND DIRECTION FORECAST...HIGH CONFIDENCE
  IN WIND SPEEDS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

BMD

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

THURSDAY...VFR.

FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR TSRA...OTHERWISE VFR.

LENNING

&&

.MARINE...
243 AM CDT

HIGH PRESSURE IS CENTERED OVER THE CENTRAL GREAT LAKES REGION EARLY
THIS MORNING AND IS FORECAST TO MOVE SOUTHEAST TOWARDS THE MID
ATLANTIC COAST BY THURSDAY. MEANWHILE...WINDS AND WAVES HAVE ALREADY
DIMINISHED UNDER THE INFLUDENCE OF THE HIGH...THUS WILL ALLOW
REMAINING SMALL CRAFT ADVISORIES TO EXPIRE WITH THE MORNING FORECAST
PACKAGE. WITH LIGHT FLOW IN PLACE TODAY...WINDS WILL BECOME OFFSHORE
THIS AFTERNOON AS LAKE BREEZES DEVELOP ACROSS THE ENTIRE LAKE. AS
THE HIGH SETTLES TO OUR EAST THURSDAY...AND LOW PRESSURE OVER THE
PLAINS...WINDS WILL BEGIN TO TURN SOUTHERLY...AND FRESHEN UP FRIDAY
AS THE LOW LIFTS INTO THE UPPER MIDWEST. SOUTHERLY FLOW WILL
DOMINATE THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KLOT 190600
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
100 AM CDT WED JUN 19 2013

.DISCUSSION...
849 PM CDT

VERY LITTLE CHANGE MADE TO THE GOING FORECAST FOR THE REST OF
TONIGHT. THE HIGH PRESSURE RIDGE CONTINUES TO BUILD DOWN THE LAKE
RESULTING IN A PRESSURE GRADIENT ACROSS NE IL AND NW IN. THIS
COUPLED WITH THE LONG NNE FETCH OF THE WINDS OVER THE LAKE HAS
CONTINUED TO ALLOW FOR 20+ MPH GUSTS EARLY THIS EVE. THESE LOOK
SLOW TO SUBSIDE PER OBSERVATIONAL TRENDS AND THE RAP BUFKIT
SOUNDINGS. SO THESE WILL ADD A LITTLE NIP IN THE AIR...BY JUNE
STANDARDS...ACROSS CHICAGO WITH TEMPS FALLING SLOWLY THROUGH THE
MID-UPPER 50S. THE COOLEST TEMPS TONIGHT STILL LOOK TO BE ALONG
THE STATE LINE WHERE CONDITIONS SHOULD DECOUPLE. UPPER 40S SHOULD
BE REALIZED THERE.

MTF

//PREV DISCUSSION...
239 PM CDT

STRATUS LAYER THAT WAS ANCHORED OVER FAR NORTHEAST IL/NORTHWEST IN
THIS MORNING HAS ERODED WITH THE WARM AIR HEATING THE SFC. VISIBLE
IMAGERY INDICATES A FEW AREAS OF CUMULUS CLOUDS THAT HAVE DEVELOPED
THIS AFTERNOON ACROSS NORTHERN IL. IN ADDITION SOME BUILDING CUMULUS
CLOUDS WERE NOTED ALONG A PONTIAC TO KANKAKEE LINE...IN AN AREA OF A
STRONGER THERMAL DIFFERENTIAL. HOWEVER THE LIFT MECHANISM IN THIS
AREA IS MINIMAL...AND SO A FEW ISOLATED SHOWERS/THUNDERSTORMS MAY
DEVELOP BUT QUICKLY DISSIPATE. ALL PRECIPITATION OVER THE CWFA WILL
BE DIURNALLY DRIVEN...THUS BY SUNSET OR IMMEDIATELY AFTER SUNSET
PRECIP WILL COME TO AN END. FURTHER SOUTH STRONGER INSTABILITY WAS
POSITIONED ACROSS CENTRAL IL STRETCHING WEST THROUGH NORTHERN
MISSOURI. MID-LVL WAVE CONTINUES TO PIVOT EAST ACROSS FAR NORTHWEST
IL THIS AFTERNOON...AND WILL MAINTAIN THE NORTHEAST FLOW ACROSS MUCH
OF THE CWFA. AS A RESULT COOL TEMPS WILL PERSIST THIS EVENING...WITH
MINIMAL CLOUD COVER FROM THE DIFFLUENT FLOW ALOFT. SKIES WILL BECOME
MOSTLY CLEAR TONIGHT...WITH THE LLVL FLOW WEAKENING. THIS SHOULD
PROVIDE DECENT RADIATIONAL COOLING WITH TEMPS OVERNIGHT EXPECTED TO
BE IN THE MID 50S SOUTH OF I-80. FURTHER NORTH TEMPS WILL BE MUCH
COOLER TO ARND 50...POSSIBLY THE UPR 40S FOR AREAS ALONG AND NORTH
OF A ROCKFORD...AURORA...WAUKEGAN LINE.

CONFIDENCE...HIGH.

WEDNESDAY THROUGH THURSDAY...

500MB TROUGH AXIS SLOWLY PIVOTS TO THE EASTERN GREAT LAKES WED...AND
WILL CONTINUE TO PUSH EAST THUR. THE SFC RIDGE WILL ALSO BEGIN TO
PUSH EAST...HOWEVER AN ONSHORE OR NORTHEAST TO EAST FLOW WILL
PERSIST INTO WED FOR MUCH OF NORTHERN IL. THE DIFFERENCE FOR WED
WILL BE THAT THE 850MB THERMAL TROUGH WILL LINGER OVERHEAD. WITH
ABUNDANT SUNSHINE AND SFC HEATING...TEMPS SHUD WARM INTO THE MID/UPR
70S OR POSSIBLY THE LOW 80S FROM LASALLE TO IROQUOIS COUNTY.

FOR THUR 500MB HEIGHTS WILL BEGIN TO RISE WITH FLOW BEGINNING TO
TURN TO THE SOUTHEAST IN THE LLVLS. A WEAK LAKE BREEZE MAY DEVELOP
AND PUSH INTO LAKE COUNTY IL...WHICH WOULD MOST LIKELY PROVIDE A
COOLING TREND IN THE AFTN HOURS. 850MB TEMPS WILL STEADILY WARM FOR
THUR TO ARND 14 TO 16 DEG C...WITH CONTINUED THIN CLOUD COVER. THIS
WILL ALLOW TEMPS TO WARM INTO THE LOW/MID 80S. THE CAVEAT WILL BE
AREAS OF LAKE COUNTY IL POST FRONTAL PASSAGE THAT WILL ALLOW TEMPS
TO FALL INTO THE 60S IN THE AFTN.

IT DOES APPEAR THAT ENOUGH DRY AIR WILL LINGER THRU THUR
AFTN/EVE...THUS HAVE HELD ONTO A DRY FORECAST IN THIS TIMEFRAME.
THIS PATTERN WILL BE CHANGING AS WE MIGRATE INTO THE EXTENDED
PERIODS.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN DRY WEATHER THROUGH THUR...MEDIUM/HIGH.

FRIDAY THROUGH MONDAY...
MINIMAL CHANGES FROM PREVIOUS FORECAST IN REGARDS TO THE EXTENDED
PERIODS. POSSIBLY THE FIRST STRETCH OF 90 DEG DAYS IS UPON US FOR
SUN/MON/TUE.

GUIDANCE HAS A WARM FRONTAL BOUNDARY LIFTING OVERHEAD FRI WITH
SOUTHERLY FLOW USHERING IN ADDTL LLVL MOISTURE. IT DOES APPEAR A
WAVE WILL ALSO PUSH OVER THE CWFA FRI...WITH POTENTIAL FOR
SHOWERS/THUNDERSTORMS. TEMPS WILL BE SLIGHTLY WARM FOR FRI INTO THE
UPR 80S...WITH A FEW 90 DEGREE POINTS ACROSS THE CWFA.

ENSEMBLES FOR SEVERAL DAYS HAVE CONTINUED TO INDICATE THAT A 500MB
RIDGE ACROSS THE CENTRAL CONUS WILL ADVECT EAST AND BECOME ANCHORED
ACROSS THE EASTERN HALF OF THE CONUS BY THE WEEKEND AND POSSIBLY
PERSIST THROUGH EARLY NEXT WEEK. ADDITIONALLY...GUIDANCE HAS PROGGED
850MB TEMPS TO RISE TO ARND 20-22 DEG C FOR THE WEEKEND THRU EARLY
NEXT WEEK. CONSISTENCY FROM PREVIOUS RUNS SUGGESTS HIGH CONFIDENCE
IN THIS WARM STRETCH ARRIVING. THEN SUN/MON/TUE APPEAR TO BE NEAR
CARBON COPIES WITH TEMPS EASILY WARMING TO 90 DEGREES...POSSIBLY THE
LOW 90S. CLIMATOLOGY BASED ON THE 850MB TEMPS PROGGED AND TIME OF
YEAR WOULD SUGGEST TEMPS TO BE WARMER AS FORECASTED. A COUPLE
LIMITING FACTORS MIGHT BE THE POTENTIAL FOR A SERIES OF WAVES
BRINGING INSTABILITY AND THUNDERSTORM POTENTIAL EACH DAY OF THE
EXTENDED...ALONG WITH DEW PTS PROGGED TO BE ARND 70 DEG.
THIS COULD POTENTIALLY KEEP TEMPS IN CHECK IN THE MID/UPR 80S.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN PRECIP/CONVECTIVE FORECAST...MEDIUM/HIGH.

BEACHLER

&&

.AVIATION...

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

* LAKE BREEZE WEDNESDAY AFTERNOON.

BMD

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

HIGH PRESSURE SPANS THE GREAT LAKES REGION TONIGHT WITH LIGHT FLOW
EXPECTED THROUGH THE TAF PERIOD. WINDS SHOULD SYNOPTICALLY VEER EAST
THEN SOUTHEAST...BUT A LAKE BREEZE MAY INTERRUPT THIS PROCESS
WEDNESDAY AFTERNOON TURNING WINDS BACK TO NORTHEAST FOR A PERIOD.
WITH SUNSET...WINDS SHOULD THEN VEER AGAIN TO THE SOUTHEAST AS THE
HIGH CONTINUES TO SETTLE SOUTHEAST TOWARDS THE MID ATLANTIC COAST.
OUTSIDE OF THE INFLUENCE OF THE LAKE BREEZE WEDNESDAY
AFTERNOON...EXPECT WINDS TO REMAIN LESS THAN 10 KT. VFR CONDITIONS
ARE ALSO EXPECTED TO PREVAIL THROUGH THE PERIOD.

BMD


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

* MEDIUM CONFIDENCE IN WIND DIRECTION FORECAST...HIGH CONFIDENCE
  IN WIND SPEEDS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

BMD

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

THURSDAY...VFR.

FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR TSRA...OTHERWISE VFR.

LENNING

&&

.MARINE...
137 PM CDT

A SURFACE RIDGE OF HIGH PRESSURE ACROSS THE UPPER GREAT LAKES
REGION...WILL SHIFT EASTWARD TOWARDS NEW ENGLAND BY WEDNESDAY
EVENING. MEANWHILE...LOW PRESSURE IS EXPECTED TO TAKE SHAPE ACROSS
THE PLAINS STATES. THIS PRESSURE PATTERN WILL REMAIN IN PLACE FOR A
FEW DAYS INTO THE WEEKEND. OVERALL...THIS WILL RESULT IN A PROLONGED
PERIOD OF SOUTHERLY WINDS ACROSS THE LAKE. WIND MAGNITUDES GENERALLY
LOOK TO BE IN THE 10 TO 20 KT RANGE...WITH A FEW PERIODS OF 15 TO 25
KT SOUTHERLY WINDS...ESPECIALLY LATER IN THE PERIOD.

THERE WILL ALSO BE INCREASING CHANCES FOR A FEW PERIODS OF
THUNDERSTORM ACTIVITY FRIDAY AND INTO THE WEEKEND OVER THE LAKE. A
FAIRLY ACTIVE WEATHER PATTERN LOOKS TO SETUP UP ACROSS THE GREAT
THE NORTHERN CONUS AND GREAT LAKES REGION.

IN THE SHORTER TERM...I HAVE EXTENDED THE SMALL CRAFT ADVISORY INTO
THIS EVENING FOR THE ILLINOIS SHORES AND MAINTAINED THE ADVISORY
THROUGH LATE TONIGHT FOR THE INDIANA SHORES. LOCAL BUOY OBS INDICATE
WAVES AROUND 4 FT...AND WITH THE ONSHORE FLOW CONTINUING TO BE IN THE
15 TO 20 KT RANGE AHEAD OF THE SURFACE HIGH...I DO NOT SEE ANY
IMPROVEMENT IN THE WAVE CONDITIONS FOR SEVERAL MORE HOURS.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KILX 190454
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1154 PM CDT TUE JUN 18 2013

.DISCUSSION...
ISSUED 858 PM CDT TUE JUN 18 2013

SHOWERS AND THUNDERSTORMS HAVE GREATLY DECREASED AND SEVERE THREAT
IS GONE. HOWEVER...SOME SCATTERED TO ISOLATED SHOWERS AND
THUNDERSTORMS ARE STILL POSSIBLE IN THE SOUTHEAST THROUGH ABOUT
MIDNIGHT. SO WILL BE UPDATING FORECAST TO REFLECT CURRENT RADAR
TRENDS. UPDATE SHOULD BE OUT SHORTLY.

AUTEN
&&

.AVIATION...
ISSUED 1154 PM CDT TUE JUN 18 2013

VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. SKIES
SHOULD REMAIN CLEAR OVERNIGHT AND THEN ONLY EXPECTING SOME
SCATTERED CU TOMORROW AT AROUND 4KFT. THIS CU WILL NOT BE DIURNAL
SO AM EXPECTING IT TO CONTINUE INTO THE EVENING HOURS TOMORROW.
WINDS WILL BE NORTHEASTERLY OVERNIGHT AND THEN BECOME EASTERLY
TOMORROW. THEN EXPECTING VARIABLE WINDS TOMORROW EVENING AS THEY
SHIFT FROM SOUTHEAST TO SOUTH BACK TO SOUTHEAST. WIND SPEEDS
TOMORROW EVENING SHOULD BE LIGHT.

AUTEN
&&

.PREV DISCUSSION...
ISSUED 133 PM CDT TUE JUN 18 2013

LATEST MODEL SUITE IN REASONABLE AGREEMENT THROUGH THE FORECAST
PERIOD AS HEIGHTS BUILD AND SUMMER MOVES INTO FULL SWING.

SHORT TERM...TONIGHT THROUGH WEDNESDAY

COLD FRONT AT 18Z EXTENDS FROM NEAR MACOMB...ACROSS DECATUR...TO
NEAR TERRE HAUTE. INSTABILITY ALONG THE FRONT WILL LIKELY BE SUFFICIENT
FOR CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON AND EARLY EVENING ALONG
THE BOUNDARY WHERE CONVERGENCE AND POOLING DEW POINTS ARE
OCCURRING. HIGH PRESSURE CENTERED OVER THE UPPER GREAT LAKES IS
EXPECTED TO CONTINUE TO PUSH THE BOUNDARY SOUTHWARD THROUGH
TONIGHT. DIURNAL STABILITY COMBINED WITH DRIER AIR BEING ADVECTED
INTO ILLINOIS SHOULD END RAIN CHANCES BY MIDNIGHT.

WEDNESDAY SHOULD BE DRY AS HIGH PRESSURE DOMINATES. TEMPERATURES
SHOULD BE COOLER THAN NORMAL.  THAT WILL CHANGE AS THE WEEK GOES ON.

LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

STRONG UPPER LOW IN THE NORTHEAST PACIFIC IS EXPECTED TO MAKE
LANDFALL ACROSS THE NORTHWEST IN THE NEXT 24 HOURS. AS THIS
FEATURE PUSHES EAST...RIDGE SHOULD BUILD AHEAD OF IT. MODELS ARE
CONSISTENT IN DEVELOPING RISING HEIGHTS ACROSS THE MISSISSIPPI
VALLEY WITH RISES OF 160 METERS AT 500MB BETWEEN NOW AND FRIDAY
EVENING. TEMPERATURES SHOULD RESPOND BY MOVING ABOVE NORMAL FOR
THE LATE JUNE. LOW-LEVEL FLOW SHOULD ALSO COME AROUND TO SOUTH-
SOUTHWEST BY FRIDAY ALLOWING DEW POINTS TO CLIMB. COMBINATION OF
HUMIDITY AND TEMPS SHOULD BRING HEAT INDEX VALUES BETWEEN 95 AND
102 ACROSS THE AREA FOR THE WEEKEND AND INTO EARLY NEXT WEEK.

BIGGEST DIFFERENCE BETWEEN THE MAJOR MODELS IS WHETHER RIDGING
WILL BE SUFFICIENT TO KEEP PRECIP TO OUR NORTH. 00Z ECMWF/12Z NAM
ARE WEAKEST AND DEVELOP A PATTERN THAT IS MOST CONDUCIVE TO
DIURNAL CONVECTION. 12Z GFS/GEM IS STRONGER WITH RIDGE AND SUGGEST
THAT ANY ACTIVITY SHOULD REMAIN ISOLATED AT LEAST THROUGH THE WEEKEND.

MODELS IN GOOD AGREEMENT IN REDEVELOPING THE UPPER RIDGE BACK OVER
THE SOUTHERN ROCKIES BY NEXT TUESDAY WHICH WILL DEVELOP A LITTLE
MORE IN THE WAY OF FLOW ACROSS ILLINOIS AND HIGHER RAIN CHANCES.
THIS TRANSITION MAY BE A LITTLE FAST AND WILL KEEP TUESDAY DOWN TO
SLIGHT CHC FOR NOW BUT LATER SHIFTS WILL HAVE TO WATCH CAREFULLY
FOR MODEL TRENDS.


&&

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

$$


000
FXUS63 KLOT 190304
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1004 PM CDT TUE JUN 18 2013

.DISCUSSION...
849 PM CDT

VERY LITTLE CHANGE MADE TO THE GOING FORECAST FOR THE REST OF
TONIGHT. THE HIGH PRESSURE RIDGE CONTINUES TO BUILD DOWN THE LAKE
RESULTING IN A PRESSURE GRADIENT ACROSS NE IL AND NW IN. THIS
COUPLED WITH THE LONG NNE FETCH OF THE WINDS OVER THE LAKE HAS
CONTINUED TO ALLOW FOR 20+ MPH GUSTS EARLY THIS EVE. THESE LOOK
SLOW TO SUBSIDE PER OBSERVATIONAL TRENDS AND THE RAP BUFKIT
SOUNDINGS. SO THESE WILL ADD A LITTLE NIP IN THE AIR...BY JUNE
STANDARDS...ACROSS CHICAGO WITH TEMPS FALLING SLOWLY THROUGH THE
MID-UPPER 50S. THE COOLEST TEMPS TONIGHT STILL LOOK TO BE ALONG
THE STATE LINE WHERE CONDITIONS SHOULD DECOUPLE. UPPER 40S SHOULD
BE REALIZED THERE.

MTF

//PREV DISCUSSION...
239 PM CDT

STRATUS LAYER THAT WAS ANCHORED OVER FAR NORTHEAST IL/NORTHWEST IN
THIS MORNING HAS ERODED WITH THE WARM AIR HEATING THE SFC. VISIBLE
IMAGERY INDICATES A FEW AREAS OF CUMULUS CLOUDS THAT HAVE DEVELOPED
THIS AFTERNOON ACROSS NORTHERN IL. IN ADDITION SOME BUILDING CUMULUS
CLOUDS WERE NOTED ALONG A PONTIAC TO KANKAKEE LINE...IN AN AREA OF A
STRONGER THERMAL DIFFERENTIAL. HOWEVER THE LIFT MECHANISM IN THIS
AREA IS MINIMAL...AND SO A FEW ISOLATED SHOWERS/THUNDERSTORMS MAY
DEVELOP BUT QUICKLY DISSIPATE. ALL PRECIPITATION OVER THE CWFA WILL
BE DIURNALLY DRIVEN...THUS BY SUNSET OR IMMEDIATELY AFTER SUNSET
PRECIP WILL COME TO AN END. FURTHER SOUTH STRONGER INSTABILITY WAS
POSITIONED ACROSS CENTRAL IL STRETCHING WEST THROUGH NORTHERN
MISSOURI. MID-LVL WAVE CONTINUES TO PIVOT EAST ACROSS FAR NORTHWEST
IL THIS AFTERNOON...AND WILL MAINTAIN THE NORTHEAST FLOW ACROSS MUCH
OF THE CWFA. AS A RESULT COOL TEMPS WILL PERSIST THIS EVENING...WITH
MINIMAL CLOUD COVER FROM THE DIFFLUENT FLOW ALOFT. SKIES WILL BECOME
MOSTLY CLEAR TONIGHT...WITH THE LLVL FLOW WEAKENING. THIS SHOULD
PROVIDE DECENT RADIATIONAL COOLING WITH TEMPS OVERNIGHT EXPECTED TO
BE IN THE MID 50S SOUTH OF I-80. FURTHER NORTH TEMPS WILL BE MUCH
COOLER TO ARND 50...POSSIBLY THE UPR 40S FOR AREAS ALONG AND NORTH
OF A ROCKFORD...AURORA...WAUKEGAN LINE.

CONFIDENCE...HIGH.

WEDNESDAY THROUGH THURSDAY...

500MB TROUGH AXIS SLOWLY PIVOTS TO THE EASTERN GREAT LAKES WED...AND
WILL CONTINUE TO PUSH EAST THUR. THE SFC RIDGE WILL ALSO BEGIN TO
PUSH EAST...HOWEVER AN ONSHORE OR NORTHEAST TO EAST FLOW WILL
PERSIST INTO WED FOR MUCH OF NORTHERN IL. THE DIFFERENCE FOR WED
WILL BE THAT THE 850MB THERMAL TROUGH WILL LINGER OVERHEAD. WITH
ABUNDANT SUNSHINE AND SFC HEATING...TEMPS SHUD WARM INTO THE MID/UPR
70S OR POSSIBLY THE LOW 80S FROM LASALLE TO IROQUOIS COUNTY.

FOR THUR 500MB HEIGHTS WILL BEGIN TO RISE WITH FLOW BEGINNING TO
TURN TO THE SOUTHEAST IN THE LLVLS. A WEAK LAKE BREEZE MAY DEVELOP
AND PUSH INTO LAKE COUNTY IL...WHICH WOULD MOST LIKELY PROVIDE A
COOLING TREND IN THE AFTN HOURS. 850MB TEMPS WILL STEADILY WARM FOR
THUR TO ARND 14 TO 16 DEG C...WITH CONTINUED THIN CLOUD COVER. THIS
WILL ALLOW TEMPS TO WARM INTO THE LOW/MID 80S. THE CAVEAT WILL BE
AREAS OF LAKE COUNTY IL POST FRONTAL PASSAGE THAT WILL ALLOW TEMPS
TO FALL INTO THE 60S IN THE AFTN.

IT DOES APPEAR THAT ENOUGH DRY AIR WILL LINGER THRU THUR
AFTN/EVE...THUS HAVE HELD ONTO A DRY FORECAST IN THIS TIMEFRAME.
THIS PATTERN WILL BE CHANGING AS WE MIGRATE INTO THE EXTENDED
PERIODS.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN DRY WEATHER THROUGH THUR...MEDIUM/HIGH.

FRIDAY THROUGH MONDAY...
MINIMAL CHANGES FROM PREVIOUS FORECAST IN REGARDS TO THE EXTENDED
PERIODS. POSSIBLY THE FIRST STRETCH OF 90 DEG DAYS IS UPON US FOR
SUN/MON/TUE.

GUIDANCE HAS A WARM FRONTAL BOUNDARY LIFTING OVERHEAD FRI WITH
SOUTHERLY FLOW USHERING IN ADDTL LLVL MOISTURE. IT DOES APPEAR A
WAVE WILL ALSO PUSH OVER THE CWFA FRI...WITH POTENTIAL FOR
SHOWERS/THUNDERSTORMS. TEMPS WILL BE SLIGHTLY WARM FOR FRI INTO THE
UPR 80S...WITH A FEW 90 DEGREE POINTS ACROSS THE CWFA.

ENSEMBLES FOR SEVERAL DAYS HAVE CONTINUED TO INDICATE THAT A 500MB
RIDGE ACROSS THE CENTRAL CONUS WILL ADVECT EAST AND BECOME ANCHORED
ACROSS THE EASTERN HALF OF THE CONUS BY THE WEEKEND AND POSSIBLY
PERSIST THROUGH EARLY NEXT WEEK. ADDITIONALLY...GUIDANCE HAS PROGGED
850MB TEMPS TO RISE TO ARND 20-22 DEG C FOR THE WEEKEND THRU EARLY
NEXT WEEK. CONSISTENCY FROM PREVIOUS RUNS SUGGESTS HIGH CONFIDENCE
IN THIS WARM STRETCH ARRIVING. THEN SUN/MON/TUE APPEAR TO BE NEAR
CARBON COPIES WITH TEMPS EASILY WARMING TO 90 DEGREES...POSSIBLY THE
LOW 90S. CLIMATOLOGY BASED ON THE 850MB TEMPS PROGGED AND TIME OF
YEAR WOULD SUGGEST TEMPS TO BE WARMER AS FORECASTED. A COUPLE
LIMITING FACTORS MIGHT BE THE POTENTIAL FOR A SERIES OF WAVES
BRINGING INSTABILITY AND THUNDERSTORM POTENTIAL EACH DAY OF THE
EXTENDED...ALONG WITH DEW PTS PROGGED TO BE ARND 70 DEG.
THIS COULD POTENTIALLY KEEP TEMPS IN CHECK IN THE MID/UPR 80S.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN PRECIP/CONVECTIVE FORECAST...MEDIUM/HIGH.

BEACHLER

&&

.AVIATION...

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

* A FEW GUSTS INTO THE MID TEENS STILL POSSIBLE OVERNIGHT.

* WIND TRENDS TOMORROW...LIKELY VARYING BETWEEN NORTHEAST AND EAST.

LENNING

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

HIGH PRESSURE SITTING OVER LAKE MICHIGAN THIS EVENING WILL VERY
GRADUALLY SLIDE EAST OVER THE NEXT TWO DAYS...SLOWLY VEERING WINDS
FROM NORTHEAST TO SOUTHEAST AND EVENTUALLY BY THURSDAY AROUND TO
THE SOUTH. THIS PATTERN SHOULD KEEP PRECIPITATION OUT OF THE AREA
FOR A WHILE AND MAINTAIN GENERALLY CLEAR AND QUIET CONDITIONS.

LENNING

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

* MEDIUM CONFIDENCE IN WIND TRENDS. HIGH CONFIDENCE IN OTHER ELEMENTS.

LENNING

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

THURSDAY...VFR.

FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR TSRA...OTHERWISE VFR.

LENNING

&&

.MARINE...
137 PM CDT

A SURFACE RIDGE OF HIGH PRESSURE ACROSS THE UPPER GREAT LAKES
REGION...WILL SHIFT EASTWARD TOWARDS NEW ENGLAND BY WEDNESDAY
EVENING. MEANWHILE...LOW PRESSURE IS EXPECTED TO TAKE SHAPE ACROSS
THE PLAINS STATES. THIS PRESSURE PATTERN WILL REMAIN IN PLACE FOR A
FEW DAYS INTO THE WEEKEND. OVERALL...THIS WILL RESULT IN A PROLONGED
PERIOD OF SOUTHERLY WINDS ACROSS THE LAKE. WIND MAGNITUDES GENERALLY
LOOK TO BE IN THE 10 TO 20 KT RANGE...WITH A FEW PERIODS OF 15 TO 25
KT SOUTHERLY WINDS...ESPECIALLY LATER IN THE PERIOD.

THERE WILL ALSO BE INCREASING CHANCES FOR A FEW PERIODS OF
THUNDERSTORM ACTIVITY FRIDAY AND INTO THE WEEKEND OVER THE LAKE. A
FAIRLY ACTIVE WEATHER PATTERN LOOKS TO SETUP UP ACROSS THE GREAT
THE NORTHERN CONUS AND GREAT LAKES REGION.

IN THE SHORTER TERM...I HAVE EXTENDED THE SMALL CRAFT ADVISORY INTO
THIS EVENING FOR THE ILLINOIS SHORES AND MAINTAINED THE ADVISORY
THROUGH LATE TONIGHT FOR THE INDIANA SHORES. LOCAL BUOY OBS INDICATE
WAVES AROUND 4 FT...AND WITH THE ONSHORE FLOW CONTINUING TO BE IN THE
15 TO 20 KT RANGE AHEAD OF THE SURFACE HIGH...I DO NOT SEE ANY
IMPROVEMENT IN THE WAVE CONDITIONS FOR SEVERAL MORE HOURS.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KILX 190158
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
858 PM CDT TUE JUN 18 2013

.DISCUSSION...
ISSUED 858 PM CDT TUE JUN 18 2013

SHOWERS AND THUNDERSTORMS HAVE GREATLY DECREASED AND SEVERE THREAT
IS GONE. HOWEVER...SOME SCATTERED TO ISOLATED SHOWERS AND
THUNDERSTORMS ARE STILL POSSIBLE IN THE SOUTHEAST THROUGH ABOUT
MIDNIGHT. SO WILL BE UPDATING FORECAST TO REFLECT CURRENT RADAR
TRENDS. UPDATE SHOULD BE OUT SHORTLY.

AUTEN
&&

.AVIATION...
ISSUED 603 PM CDT TUE JUN 18 2013

THUNDERSTORMS CONTINUE TO IMPACT KDEC AS OUTFLOW BOUNDARY FROM
EARLIER CONVECTION CONTINUES TO INTERACT WITH NORTHWEST FLOW OFF
OF THE SURFACE. A COLD FRONT IS ALSO BISECTING THE AREA.
KPIA...KBMI...AND KCMI ARE ALL NORTH OF THE FRONT AND HAVE
NORTHEAST WINDS. KSPI IS STILL SOUTH OF THE FRONT WITH NORTHWEST
WINDS...BUT PASSAGE SHOULD BE WITHIN THE NEXT HOUR OR TWO BRINGING
THE WINDS TO NORTHEAST THERE AS WELL. BY 01Z CONVECTION IS ALSO
EXPECTED TO BE OVER IN THE KDEC AREA AS THE COLD FRONT MOVES SOUTH
AND SCOURES OUT THE OUTFLOW THAT HAS BEEN REJUVINATING CONVECTION.

ONCE FRONT CLEARS SOUTHERN TERMINALS...SKC-SCT CAN BE EXPECTED
THROUGH THE REMAINDER OF THE TAF VALID PERIOD WITH LIGHT NORTHEAST
WINDS BECOMING EASTERLY WEDNESDAY.

BARKER
&&

.PREV DISCUSSION...
ISSUED 133 PM CDT TUE JUN 18 2013

LATEST MODEL SUITE IN REASONABLE AGREEMENT THROUGH THE FORECAST
PERIOD AS HEIGHTS BUILD AND SUMMER MOVES INTO FULL SWING.

SHORT TERM...TONIGHT THROUGH WEDNESDAY

COLD FRONT AT 18Z EXTENDS FROM NEAR MACOMB...ACROSS DECATUR...TO
NEAR TERRE HAUTE. INSTABILITY ALONG THE FRONT WILL LIKELY BE SUFFICIENT
FOR CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON AND EARLY EVENING ALONG
THE BOUNDARY WHERE CONVERGENCE AND POOLING DEW POINTS ARE
OCCURRING. HIGH PRESSURE CENTERED OVER THE UPPER GREAT LAKES IS
EXPECTED TO CONTINUE TO PUSH THE BOUNDARY SOUTHWARD THROUGH
TONIGHT. DIURNAL STABILITY COMBINED WITH DRIER AIR BEING ADVECTED
INTO ILLINOIS SHOULD END RAIN CHANCES BY MIDNIGHT.

WEDNESDAY SHOULD BE DRY AS HIGH PRESSURE DOMINATES. TEMPERATURES
SHOULD BE COOLER THAN NORMAL.  THAT WILL CHANGE AS THE WEEK GOES ON.

LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

STRONG UPPER LOW IN THE NORTHEAST PACIFIC IS EXPECTED TO MAKE
LANDFALL ACROSS THE NORTHWEST IN THE NEXT 24 HOURS. AS THIS
FEATURE PUSHES EAST...RIDGE SHOULD BUILD AHEAD OF IT. MODELS ARE
CONSISTENT IN DEVELOPING RISING HEIGHTS ACROSS THE MISSISSIPPI
VALLEY WITH RISES OF 160 METERS AT 500MB BETWEEN NOW AND FRIDAY
EVENING. TEMPERATURES SHOULD RESPOND BY MOVING ABOVE NORMAL FOR
THE LATE JUNE. LOW-LEVEL FLOW SHOULD ALSO COME AROUND TO SOUTH-
SOUTHWEST BY FRIDAY ALLOWING DEW POINTS TO CLIMB. COMBINATION OF
HUMIDITY AND TEMPS SHOULD BRING HEAT INDEX VALUES BETWEEN 95 AND
102 ACROSS THE AREA FOR THE WEEKEND AND INTO EARLY NEXT WEEK.

BIGGEST DIFFERENCE BETWEEN THE MAJOR MODELS IS WHETHER RIDGING
WILL BE SUFFICIENT TO KEEP PRECIP TO OUR NORTH. 00Z ECMWF/12Z NAM
ARE WEAKEST AND DEVELOP A PATTERN THAT IS MOST CONDUCIVE TO
DIURNAL CONVECTION. 12Z GFS/GEM IS STRONGER WITH RIDGE AND SUGGEST
THAT ANY ACTIVITY SHOULD REMAIN ISOLATED AT LEAST THROUGH THE WEEKEND.

MODELS IN GOOD AGREEMENT IN REDEVELOPING THE UPPER RIDGE BACK OVER
THE SOUTHERN ROCKIES BY NEXT TUESDAY WHICH WILL DEVELOP A LITTLE
MORE IN THE WAY OF FLOW ACROSS ILLINOIS AND HIGHER RAIN CHANCES.
THIS TRANSITION MAY BE A LITTLE FAST AND WILL KEEP TUESDAY DOWN TO
SLIGHT CHC FOR NOW BUT LATER SHIFTS WILL HAVE TO WATCH CAREFULLY
FOR MODEL TRENDS.

&&

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

$$

000
FXUS63 KLOT 190149 AAA
AFDLOT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
849 PM CDT TUE JUN 18 2013

.DISCUSSION...
849 PM CDT

VERY LITTLE CHANGE MADE TO THE GOING FORECAST FOR THE REST OF
TONIGHT. THE HIGH PRESSURE RIDGE CONTINUES TO BUILD DOWN THE LAKE
RESULTING IN A PRESSURE GRADIENT ACROSS NE IL AND NW IN. THIS
COUPLED WITH THE LONG NNE FETCH OF THE WINDS OVER THE LAKE HAS
CONTINUED TO ALLOW FOR 20+ MPH GUSTS EARLY THIS EVE. THESE LOOK
SLOW TO SUBSIDE PER OBSERVATIONAL TRENDS AND THE RAP BUFKIT
SOUNDINGS. SO THESE WILL ADD A LITTLE NIP IN THE AIR...BY JUNE
STANDARDS...ACROSS CHICAGO WITH TEMPS FALLING SLOWLY THROUGH THE
MID-UPPER 50S. THE COOLEST TEMPS TONIGHT STILL LOOK TO BE ALONG
THE STATE LINE WHERE CONDITIONS SHOULD DECOUPLE. UPPER 40S SHOULD
BE REALIZED THERE.

MTF

.PREV DISCUSSION...
239 PM CDT

STRATUS LAYER THAT WAS ANCHORED OVER FAR NORTHEAST IL/NORTHWEST IN
THIS MORNING HAS ERODED WITH THE WARM AIR HEATING THE SFC. VISIBLE
IMAGERY INDICATES A FEW AREAS OF CUMULUS CLOUDS THAT HAVE DEVELOPED
THIS AFTERNOON ACROSS NORTHERN IL. IN ADDITION SOME BUILDING CUMULUS
CLOUDS WERE NOTED ALONG A PONTIAC TO KANKAKEE LINE...IN AN AREA OF A
STRONGER THERMAL DIFFERENTIAL. HOWEVER THE LIFT MECHANISM IN THIS
AREA IS MINIMAL...AND SO A FEW ISOLATED SHOWERS/THUNDERSTORMS MAY
DEVELOP BUT QUICKLY DISSIPATE. ALL PRECIPITATION OVER THE CWFA WILL
BE DIURNALLY DRIVEN...THUS BY SUNSET OR IMMEDIATELY AFTER SUNSET
PRECIP WILL COME TO AN END. FURTHER SOUTH STRONGER INSTABILITY WAS
POSITIONED ACROSS CENTRAL IL STRETCHING WEST THROUGH NORTHERN
MISSOURI. MID-LVL WAVE CONTINUES TO PIVOT EAST ACROSS FAR NORTHWEST
IL THIS AFTERNOON...AND WILL MAINTAIN THE NORTHEAST FLOW ACROSS MUCH
OF THE CWFA. AS A RESULT COOL TEMPS WILL PERSIST THIS EVENING...WITH
MINIMAL CLOUD COVER FROM THE DIFFLUENT FLOW ALOFT. SKIES WILL BECOME
MOSTLY CLEAR TONIGHT...WITH THE LLVL FLOW WEAKENING. THIS SHOULD
PROVIDE DECENT RADIATIONAL COOLING WITH TEMPS OVERNIGHT EXPECTED TO
BE IN THE MID 50S SOUTH OF I-80. FURTHER NORTH TEMPS WILL BE MUCH
COOLER TO ARND 50...POSSIBLY THE UPR 40S FOR AREAS ALONG AND NORTH
OF A ROCKFORD...AURORA...WAUKEGAN LINE.

CONFIDENCE...HIGH.

WEDNESDAY THROUGH THURSDAY...

500MB TROUGH AXIS SLOWLY PIVOTS TO THE EASTERN GREAT LAKES WED...AND
WILL CONTINUE TO PUSH EAST THUR. THE SFC RIDGE WILL ALSO BEGIN TO
PUSH EAST...HOWEVER AN ONSHORE OR NORTHEAST TO EAST FLOW WILL
PERSIST INTO WED FOR MUCH OF NORTHERN IL. THE DIFFERENCE FOR WED
WILL BE THAT THE 850MB THERMAL TROUGH WILL LINGER OVERHEAD. WITH
ABUNDANT SUNSHINE AND SFC HEATING...TEMPS SHUD WARM INTO THE MID/UPR
70S OR POSSIBLY THE LOW 80S FROM LASALLE TO IROQUOIS COUNTY.

FOR THUR 500MB HEIGHTS WILL BEGIN TO RISE WITH FLOW BEGINNING TO
TURN TO THE SOUTHEAST IN THE LLVLS. A WEAK LAKE BREEZE MAY DEVELOP
AND PUSH INTO LAKE COUNTY IL...WHICH WOULD MOST LIKELY PROVIDE A
COOLING TREND IN THE AFTN HOURS. 850MB TEMPS WILL STEADILY WARM FOR
THUR TO ARND 14 TO 16 DEG C...WITH CONTINUED THIN CLOUD COVER. THIS
WILL ALLOW TEMPS TO WARM INTO THE LOW/MID 80S. THE CAVEAT WILL BE
AREAS OF LAKE COUNTY IL POST FRONTAL PASSAGE THAT WILL ALLOW TEMPS
TO FALL INTO THE 60S IN THE AFTN.

IT DOES APPEAR THAT ENOUGH DRY AIR WILL LINGER THRU THUR
AFTN/EVE...THUS HAVE HELD ONTO A DRY FORECAST IN THIS TIMEFRAME.
THIS PATTERN WILL BE CHANGING AS WE MIGRATE INTO THE EXTENDED
PERIODS.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN DRY WEATHER THROUGH THUR...MEDIUM/HIGH.

FRIDAY THROUGH MONDAY...
MINIMAL CHANGES FROM PREVIOUS FORECAST IN REGARDS TO THE EXTENDED
PERIODS. POSSIBLY THE FIRST STRETCH OF 90 DEG DAYS IS UPON US FOR
SUN/MON/TUE.

GUIDANCE HAS A WARM FRONTAL BOUNDARY LIFTING OVERHEAD FRI WITH
SOUTHERLY FLOW USHERING IN ADDTL LLVL MOISTURE. IT DOES APPEAR A
WAVE WILL ALSO PUSH OVER THE CWFA FRI...WITH POTENTIAL FOR
SHOWERS/THUNDERSTORMS. TEMPS WILL BE SLIGHTLY WARM FOR FRI INTO THE
UPR 80S...WITH A FEW 90 DEGREE POINTS ACROSS THE CWFA.

ENSEMBLES FOR SEVERAL DAYS HAVE CONTINUED TO INDICATE THAT A 500MB
RIDGE ACROSS THE CENTRAL CONUS WILL ADVECT EAST AND BECOME ANCHORED
ACROSS THE EASTERN HALF OF THE CONUS BY THE WEEKEND AND POSSIBLY
PERSIST THROUGH EARLY NEXT WEEK. ADDITIONALLY...GUIDANCE HAS PROGGED
850MB TEMPS TO RISE TO ARND 20-22 DEG C FOR THE WEEKEND THRU EARLY
NEXT WEEK. CONSISTENCY FROM PREVIOUS RUNS SUGGESTS HIGH CONFIDENCE
IN THIS WARM STRETCH ARRIVING. THEN SUN/MON/TUE APPEAR TO BE NEAR
CARBON COPIES WITH TEMPS EASILY WARMING TO 90 DEGREES...POSSIBLY THE
LOW 90S. CLIMATOLOGY BASED ON THE 850MB TEMPS PROGGED AND TIME OF
YEAR WOULD SUGGEST TEMPS TO BE WARMER AS FORECASTED. A COUPLE
LIMITING FACTORS MIGHT BE THE POTENTIAL FOR A SERIES OF WAVES
BRINGING INSTABILITY AND THUNDERSTORM POTENTIAL EACH DAY OF THE
EXTENDED...ALONG WITH DEW PTS PROGGED TO BE ARND 70 DEG.
THIS COULD POTENTIALLY KEEP TEMPS IN CHECK IN THE MID/UPR 80S.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN PRECIP/CONVECTIVE FORECAST...MEDIUM/HIGH.

BEACHLER

.AVIATION...

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

* TIMING OF DIMINISHING GUSTS THIS EVENING.

* WIND TRENDS TOMORROW...LIKELY VARYING BETWEEN NORTHEAST AND EAST.

LENNING

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

HIGH PRESSURE SITTING OVER LAKE MICHIGAN THIS EVENING WILL VERY
GRADUALLY SLIDE EAST OVER THE NEXT TWO DAYS...SLOWLY VEERING WINDS
FROM NORTHEAST TO SOUTHEAST AND EVENTUALLY BY THURSDAY AROUND TO
THE SOUTH. THIS PATTERN SHOULD KEEP PRECIPITATION OUT OF THE AREA
FOR A WHILE AND MAINTAIN GENERALLY CLEAR AND QUIET CONDITIONS.

LENNING

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

* MEDIUM CONFIDENCE IN WIND TRENDS. HIGH CONFIDENCE IN OTHER ELEMENTS.

LENNING

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

THURSDAY...VFR.

FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR TSRA...OTHERWISE VFR.

LENNING

.MARINE...
137 PM CDT

A SURFACE RIDGE OF HIGH PRESSURE ACROSS THE UPPER GREAT LAKES
REGION...WILL SHIFT EASTWARD TOWARDS NEW ENGLAND BY WEDNESDAY
EVENING. MEANWHILE...LOW PRESSURE IS EXPECTED TO TAKE SHAPE ACROSS
THE PLAINS STATES. THIS PRESSURE PATTERN WILL REMAIN IN PLACE FOR A
FEW DAYS INTO THE WEEKEND. OVERALL...THIS WILL RESULT IN A PROLONGED
PERIOD OF SOUTHERLY WINDS ACROSS THE LAKE. WIND MAGNITUDES GENERALLY
LOOK TO BE IN THE 10 TO 20 KT RANGE...WITH A FEW PERIODS OF 15 TO 25
KT SOUTHERLY WINDS...ESPECIALLY LATER IN THE PERIOD.

THERE WILL ALSO BE INCREASING CHANCES FOR A FEW PERIODS OF
THUNDERSTORM ACTIVITY FRIDAY AND INTO THE WEEKEND OVER THE LAKE. A
FAIRLY ACTIVE WEATHER PATTERN LOOKS TO SETUP UP ACROSS THE GREAT
THE NORTHERN CONUS AND GREAT LAKES REGION.

IN THE SHORTER TERM...I HAVE EXTENDED THE SMALL CRAFT ADVISORY INTO
THIS EVENING FOR THE ILLINOIS SHORES AND MAINTAINED THE ADVISORY
THROUGH LATE TONIGHT FOR THE INDIANA SHORES. LOCAL BUOY OBS INDICATE
WAVES AROUND 4 FT...AND WITH THE ONSHORE FLOW CONTINUING TO BE IN THE
15 TO 20 KT RANGE AHEAD OF THE SURFACE HIGH...I DO NOT SEE ANY
IMPROVEMENT IN THE WAVE CONDITIONS FOR SEVERAL MORE HOURS.

KJB

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM TUESDAY.

SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 4 AM
WEDNESDAY.

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

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

000
FXUS63 KLOT 182349
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
649 PM CDT TUE JUN 18 2013

.DISCUSSION...
239 PM CDT

CONFIDENCE...HIGH.

WEDNESDAY THROUGH THURSDAY...

IT DOES APPEAR THAT ENOUGH DRY AIR WILL LINGER THRU THUR
AFTN/EVE...THUS HAVE HELD ONTO A DRY FORECAST IN THIS TIMEFRAME.
THIS PATTERN WILL BE CHANGING AS WE MIGRATE INTO THE EXTENDED
PERIODS.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN DRY WEATHER THROUGH THUR...MEDIUM/HIGH.

FRIDAY THROUGH MONDAY...
MINIMAL CHANGES FROM PREVIOUS FORECAST IN REGARDS TO THE EXTENDED
PERIODS. POSSIBLY THE FIRST STRETCH OF 90 DEG DAYS IS UPON US FOR
SUN/MON/TUE.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN PRECIP/CONVECTIVE FORECAST...MEDIUM/HIGH.

BEACHLER

.AVIATION...

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

* TIMING OF DIMINISHING GUSTS THIS EVENING.

* WIND TRENDS TOMORROW...LIKELY VARYING BETWEEN NORTHEAST AND EAST.

LENNING

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

LENNING

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

* MEDIUM CONFIDENCE IN WIND TRENDS. HIGH CONFIDENCE IN OTHER ELEMENTS.

LENNING

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

THURSDAY...VFR.

FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR TSRA...OTHERWISE VFR.

LENNING

.MARINE...
137 PM CDT

KJB

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM TUESDAY.

SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 4 AM
WEDNESDAY.

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

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


000
FXUS63 KILX 182304
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
604 PM CDT TUE JUN 18 2013

.DISCUSSION...
ISSUED 133 PM CDT TUE JUN 18 2013

LATEST MODEL SUITE IN REASONABLE AGREEMENT THROUGH THE FORECAST
PERIOD AS HEIGHTS BUILD AND SUMMER MOVES INTO FULL SWING.

SHORT TERM...TONIGHT THROUGH WEDNESDAY

COLD FRONT AT 18Z EXTENDS FROM NEAR MACOMB...ACROSS DECATUR...TO
NEAR TERRE HAUTE. INSTABILITY ALONG THE FRONT WILL LIKELY BE SUFFICIENT
FOR CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON AND EARLY EVENING ALONG
THE BOUNDARY WHERE CONVERGENCE AND POOLING DEW POINTS ARE
OCCURRING. HIGH PRESSURE CENTERED OVER THE UPPER GREAT LAKES IS
EXPECTED TO CONTINUE TO PUSH THE BOUNDARY SOUTHWARD THROUGH
TONIGHT. DIURNAL STABILITY COMBINED WITH DRIER AIR BEING ADVECTED
INTO ILLINOIS SHOULD END RAIN CHANCES BY MIDNIGHT.

WEDNESDAY SHOULD BE DRY AS HIGH PRESSURE DOMINATES. TEMPERATURES
SHOULD BE COOLER THAN NORMAL.  THAT WILL CHANGE AS THE WEEK GOES ON.

LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

STRONG UPPER LOW IN THE NORTHEAST PACIFIC IS EXPECTED TO MAKE
LANDFALL ACROSS THE NORTHWEST IN THE NEXT 24 HOURS. AS THIS
FEATURE PUSHES EAST...RIDGE SHOULD BUILD AHEAD OF IT. MODELS ARE
CONSISTENT IN DEVELOPING RISING HEIGHTS ACROSS THE MISSISSIPPI
VALLEY WITH RISES OF 160 METERS AT 500MB BETWEEN NOW AND FRIDAY
EVENING. TEMPERATURES SHOULD RESPOND BY MOVING ABOVE NORMAL FOR
THE LATE JUNE. LOW-LEVEL FLOW SHOULD ALSO COME AROUND TO SOUTH-
SOUTHWEST BY FRIDAY ALLOWING DEW POINTS TO CLIMB. COMBINATION OF
HUMIDITY AND TEMPS SHOULD BRING HEAT INDEX VALUES BETWEEN 95 AND
102 ACROSS THE AREA FOR THE WEEKEND AND INTO EARLY NEXT WEEK.

BIGGEST DIFFERENCE BETWEEN THE MAJOR MODELS IS WHETHER RIDGING
WILL BE SUFFICIENT TO KEEP PRECIP TO OUR NORTH. 00Z ECMWF/12Z NAM
ARE WEAKEST AND DEVELOP A PATTERN THAT IS MOST CONDUCIVE TO
DIURNAL CONVECTION. 12Z GFS/GEM IS STRONGER WITH RIDGE AND SUGGEST
THAT ANY ACTIVITY SHOULD REMAIN ISOLATED AT LEAST THROUGH THE WEEKEND.

MODELS IN GOOD AGREEMENT IN REDEVELOPING THE UPPER RIDGE BACK OVER
THE SOUTHERN ROCKIES BY NEXT TUESDAY WHICH WILL DEVELOP A LITTLE
MORE IN THE WAY OF FLOW ACROSS ILLINOIS AND HIGHER RAIN CHANCES.
THIS TRANSITION MAY BE A LITTLE FAST AND WILL KEEP TUESDAY DOWN TO
SLIGHT CHC FOR NOW BUT LATER SHIFTS WILL HAVE TO WATCH CAREFULLY
FOR MODEL TRENDS.



&&

.AVIATION...
ISSUED 603 PM CDT TUE JUN 18 2013

THUNDERSTORMS CONTINUE TO IMPACT KDEC AS OUTFLOW BOUNDARY FROM
EARLIER CONVECTION CONTINUES TO INTERACT WITH NORTHWEST FLOW OFF
OF THE SURFACE. A COLD FRONT IS ALSO BISECTING THE AREA.
KPIA...KBMI...AND KCMI ARE ALL NORTH OF THE FRONT AND HAVE
NORTHEAST WINDS. KSPI IS STILL SOUTH OF THE FRONT WITH NORTHWEST
WINDS...BUT PASSAGE SHOULD BE WITHIN THE NEXT HOUR OR TWO BRINGING
THE WINDS TO NORTHEAST THERE AS WELL. BY 01Z CONVECTION IS ALSO
EXPECTED TO BE OVER IN THE KDEC AREA AS THE COLD FRONT MOVES SOUTH
AND SCOURES OUT THE OUTFLOW THAT HAS BEEN REJUVINATING CONVECTION.

ONCE FRONT CLEARS SOUTHERN TERMINALS...SKC-SCT CAN BE EXPECTED
THROUGH THE REMAINDER OF THE TAF VALID PERIOD WITH LIGHT NORTHEAST
WINDS BECOMING EASTERLY WEDNESDAY.

BARKER
&&

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

$$

000
FXUS63 KLOT 182218
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
518 PM CDT TUE JUN 18 2013

.DISCUSSION...
239 PM CDT

CONFIDENCE...HIGH.

WEDNESDAY THROUGH THURSDAY...

IT DOES APPEAR THAT ENOUGH DRY AIR WILL LINGER THRU THUR
AFTN/EVE...THUS HAVE HELD ONTO A DRY FORECAST IN THIS TIMEFRAME.
THIS PATTERN WILL BE CHANGING AS WE MIGRATE INTO THE EXTENDED
PERIODS.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN DRY WEATHER THROUGH THUR...MEDIUM/HIGH.

FRIDAY THROUGH MONDAY...
MINIMAL CHANGES FROM PREVIOUS FORECAST IN REGARDS TO THE EXTENDED
PERIODS. POSSIBLY THE FIRST STRETCH OF 90 DEG DAYS IS UPON US FOR
SUN/MON/TUE.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN PRECIP/CONVECTIVE FORECAST...MEDIUM/HIGH.

BEACHLER

.AVIATION...

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

* TIMING OF DIMINISHING GUSTS THIS EVENING.

LENNING

//DISCUSSION...UPDATED 18Z...

IFR/LIFR CIGS STILL PERSISTING SOUTH OF MDW FROM IGQ TO GYY EAST
ALONG THE INDIANA SHORELINE. CLEARING FROM THE EAST ALONG WITH
EROSION FROM THE SOUTHWEST SEEMS TO HAVE SLOWED IN THE PAST HR OR
SO. WHILE VFR CONDITIONS ARE NOW EXPECTED AT ORD/MDW...WILL NEED
TO MONITOR TRENDS FOR GYY THROUGH THE AFTERNOON. SOME CU ALONG
WITH MID CLOUDS POSSIBLE THROUGH EARLY EVENING...THEN SKC EXPECTED
FOR THE REMAINDER OF THE PERIOD.

NORTHEAST WINDS WILL REMAIN IN THE 10-15KT RANGE WITH GUSTS IN THE
16-20KT RANGE INTO THIS EVENING WITH WINDS DIMINISHING UNDER 10KTS
BY MID/LATE EVENING THEN TURNING MORE EASTERLY WEDNESDAY MORNING.

AS A WEAK WAVE MOVES SOUTH OF THE TERMINALS THIS AFTERNOON...THERE
COULD BE SOME SHOWERS AND POSSIBLY AN ISOLATED TSRA BUT ANY
ACTIVITY THAT DEVELOPS IS EXPECTED TO REMAIN SOUTH OF ALL THE
TERMINALS. CMS

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

* MEDIUM TO HIGH CONFIDENCE ON WIND TRENDS.

LENNING

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

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE VFR.

BMD

.MARINE...
137 PM CDT

KJB

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM TUESDAY.

SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 4 AM
WEDNESDAY.

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

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


000
FXUS63 KLOT 181950
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
250 PM CDT TUE JUN 18 2013

.DISCUSSION...
239 PM CDT

STRATUS LAYER THAT WAS ANCHORED OVER FAR NORTHEAST IL/NORTHWEST IN
THIS MORNING HAS ERODED WITH THE WARM AIR HEATING THE SFC. VISIBLE
IMAGERY INDICATES A FEW AREAS OF CUMULUS CLOUDS THAT HAVE DEVELOPED
THIS AFTERNOON ACROSS NORTHERN IL. IN ADDITION SOME BUILDING CUMULUS
CLOUDS WERE NOTED ALONG A PONTIAC TO KANKAKEE LINE...IN AN AREA OF A
STRONGER THERMAL DIFFERENTIAL. HOWEVER THE LIFT MECHANISM IN THIS
AREA IS MINIMAL...AND SO A FEW ISOLATED SHOWERS/THUNDERSTORMS MAY
DEVELOP BUT QUICKLY DISSIPATE. ALL PRECIPITATION OVER THE CWFA WILL
BE DIURNALLY DRIVEN...THUS BY SUNSET OR IMMEDIATELY AFTER SUNSET
PRECIP WILL COME TO AN END. FURTHER SOUTH STRONGER INSTABILITY WAS
POSITIONED ACROSS CENTRAL IL STRETCHING WEST THROUGH NORTHERN
MISSOURI. MID-LVL WAVE CONTINUES TO PIVOT EAST ACROSS FAR NORTHWEST
IL THIS AFTERNOON...AND WILL MAINTAIN THE NORTHEAST FLOW ACROSS MUCH
OF THE CWFA. AS A RESULT COOL TEMPS WILL PERSIST THIS EVENING...WITH
MINIMAL CLOUD COVER FROM THE DIFFLUENT FLOW ALOFT. SKIES WILL BECOME
MOSTLY CLEAR TONIGHT...WITH THE LLVL FLOW WEAKENING. THIS SHOULD
PROVIDE DECENT RADIATIONAL COOLING WITH TEMPS OVERNIGHT EXPECTED TO
BE IN THE MID 50S SOUTH OF I-80. FURTHER NORTH TEMPS WILL BE MUCH
COOLER TO ARND 50...POSSIBLY THE UPR 40S FOR AREAS ALONG AND NORTH
OF A ROCKFORD...AURORA...WAUKEGAN LINE.

CONFIDENCE...HIGH.

WEDNESDAY THROUGH THURSDAY...

500MB TROUGH AXIS SLOWLY PIVOTS TO THE EASTERN GREAT LAKES WED...AND
WILL CONTINUE TO PUSH EAST THUR. THE SFC RIDGE WILL ALSO BEGIN TO
PUSH EAST...HOWEVER AN ONSHORE OR NORTHEAST TO EAST FLOW WILL
PERSIST INTO WED FOR MUCH OF NORTHERN IL. THE DIFFERENCE FOR WED
WILL BE THAT THE 850MB THERMAL TROUGH WILL LINGER OVERHEAD. WITH
ABUNDANT SUNSHINE AND SFC HEATING...TEMPS SHUD WARM INTO THE MID/UPR
70S OR POSSIBLY THE LOW 80S FROM LASALLE TO IROQUOIS COUNTY.

FOR THUR 500MB HEIGHTS WILL BEGIN TO RISE WITH FLOW BEGINNING TO
TURN TO THE SOUTHEAST IN THE LLVLS. A WEAK LAKE BREEZE MAY DEVELOP
AND PUSH INTO LAKE COUNTY IL...WHICH WOULD MOST LIKELY PROVIDE A
COOLING TREND IN THE AFTN HOURS. 850MB TEMPS WILL STEADILY WARM FOR
THUR TO ARND 14 TO 16 DEG C...WITH CONTINUED THIN CLOUD COVER. THIS
WILL ALLOW TEMPS TO WARM INTO THE LOW/MID 80S. THE CAVEAT WILL BE
AREAS OF LAKE COUNTY IL POST FRONTAL PASSAGE THAT WILL ALLOW TEMPS
TO FALL INTO THE 60S IN THE AFTN.

IT DOES APPEAR THAT ENOUGH DRY AIR WILL LINGER THRU THUR
AFTN/EVE...THUS HAVE HELD ONTO A DRY FORECAST IN THIS TIMEFRAME.
THIS PATTERN WILL BE CHANGING AS WE MIGRATE INTO THE EXTENDED
PERIODS.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN DRY WEATHER THROUGH THUR...MEDIUM/HIGH.

FRIDAY THROUGH MONDAY...
MINIMAL CHANGES FROM PREVIOUS FORECAST IN REGARDS TO THE EXTENDED
PERIODS. POSSIBLY THE FIRST STRETCH OF 90 DEG DAYS IS UPON US FOR
SUN/MON/TUE.

GUIDANCE HAS A WARM FRONTAL BOUNDARY LIFTING OVERHEAD FRI WITH
SOUTHERLY FLOW USHERING IN ADDTL LLVL MOISTURE. IT DOES APPEAR A
WAVE WILL ALSO PUSH OVER THE CWFA FRI...WITH POTENTIAL FOR
SHOWERS/THUNDERSTORMS. TEMPS WILL BE SLIGHTLY WARM FOR FRI INTO THE
UPR 80S...WITH A FEW 90 DEGREE POINTS ACROSS THE CWFA.

ENSEMBLES FOR SEVERAL DAYS HAVE CONTINUED TO INDICATE THAT A 500MB
RIDGE ACROSS THE CENTRAL CONUS WILL ADVECT EAST AND BECOME ANCHORED
ACROSS THE EASTERN HALF OF THE CONUS BY THE WEEKEND AND POSSIBLY
PERSIST THROUGH EARLY NEXT WEEK. ADDITIONALLY...GUIDANCE HAS PROGGED
850MB TEMPS TO RISE TO ARND 20-22 DEG C FOR THE WEEKEND THRU EARLY
NEXT WEEK. CONSISTENCY FROM PREVIOUS RUNS SUGGESTS HIGH CONFIDENCE
IN THIS WARM STRETCH ARRIVING. THEN SUN/MON/TUE APPEAR TO BE NEAR
CARBON COPIES WITH TEMPS EASILY WARMING TO 90 DEGREES...POSSIBLY THE
LOW 90S. CLIMATOLOGY BASED ON THE 850MB TEMPS PROGGED AND TIME OF
YEAR WOULD SUGGEST TEMPS TO BE WARMER AS FORECASTED. A COUPLE
LIMITING FACTORS MIGHT BE THE POTENTIAL FOR A SERIES OF WAVES
BRINGING INSTABILITY AND THUNDERSTORM POTENTIAL EACH DAY OF THE
EXTENDED...ALONG WITH DEW PTS PROGGED TO BE ARND 70 DEG.
THIS COULD POTENTIALLY KEEP TEMPS IN CHECK IN THE MID/UPR 80S.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN PRECIP/CONVECTIVE FORECAST...MEDIUM/HIGH.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY NORTHEAST WINDS INTO THIS EVENING. CMS

//DISCUSSION...UPDATED 18Z...

IFR/LIFR CIGS STILL PERSISTING SOUTH OF MDW FROM IGQ TO GYY EAST
ALONG THE INDIANA SHORELINE. CLEARING FROM THE EAST ALONG WITH
EROSION FROM THE SOUTHWEST SEEMS TO HAVE SLOWED IN THE PAST HR OR
SO. WHILE VFR CONDITIONS ARE NOW EXPECTED AT ORD/MDW...WILL NEED
TO MONITOR TRENDS FOR GYY THROUGH THE AFTERNOON. SOME CU ALONG
WITH MID CLOUDS POSSIBLE THROUGH EARLY EVENING...THEN SKC EXPECTED
FOR THE REMAINDER OF THE PERIOD.

NORTHEAST WINDS WILL REMAIN IN THE 10-15KT RANGE WITH GUSTS IN THE
16-20KT RANGE INTO THIS EVENING WITH WINDS DIMINISHING UNDER 10KTS
BY MID/LATE EVENING THEN TURNING MORE EASTERLY WEDNESDAY MORNING.

AS A WEAK WAVE MOVES SOUTH OF THE TERMINALS THIS AFTERNOON...THERE
COULD BE SOME SHOWERS AND POSSIBLY AN ISOLATED TSRA BUT ANY
ACTIVITY THAT DEVELOPS IS EXPECTED TO REMAIN SOUTH OF ALL THE
TERMINALS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS THROUGH THE
  PERIOD. CMS

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

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE VFR.

BMD

&&

.MARINE...
137 PM CDT

A SURFACE RIDGE OF HIGH PRESSURE ACROSS THE UPPER GREAT LAKES
REGION...WILL SHIFT EASTWARD TOWARDS NEW ENGLAND BY WEDNESDAY
EVENING. MEANWHILE...LOW PRESSURE IS EXPECTED TO TAKE SHAPE ACROSS
THE PLAINS STATES. THIS PRESSURE PATTERN WILL REMAIN IN PLACE FOR A
FEW DAYS INTO THE WEEKEND. OVERALL...THIS WILL RESULT IN A PROLONGED
PERIOD OF SOUTHERLY WINDS ACROSS THE LAKE. WIND MAGNITUDES GENERALLY
LOOK TO BE IN THE 10 TO 20 KT RANGE...WITH A FEW PERIODS OF 15 TO 25
KT SOUTHERLY WINDS...ESPECIALLY LATER IN THE PERIOD.

THERE WILL ALSO BE INCREASING CHANCES FOR A FEW PERIODS OF
THUNDERSTORM ACTIVITY FRIDAY AND INTO THE WEEKEND OVER THE LAKE. A
FAIRLY ACTIVE WEATHER PATTERN LOOKS TO SETUP UP ACROSS THE GREAT
THE NORTHERN CONUS AND GREAT LAKES REGION.

IN THE SHORTER TERM...I HAVE EXTENDED THE SMALL CRAFT ADVISORY INTO
THIS EVENING FOR THE ILLINOIS SHORES AND MAINTAINED THE ADVISORY
THROUGH LATE TONIGHT FOR THE INDIANA SHORES. LOCAL BUOY OBS INDICATE
WAVES AROUND 4 FT...AND WITH THE ONSHORE FLOW CONTINUING TO BE IN THE
15 TO 20 KT RANGE AHEAD OF THE SURFACE HIGH...I DO NOT SEE ANY
IMPROVEMENT IN THE WAVE CONDITIONS FOR SEVERAL MORE HOURS.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
     IS UNTIL 10 PM TUESDAY.

     SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY
     IN UNTIL 4 AM WEDNESDAY.

&&

$$

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

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

000
FXUS63 KLOT 181940
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
240 PM CDT TUE JUN 18 2013

.DISCUSSION...
239 PM CDT

CONFIDENCE...HIGH.

WEDNESDAY THROUGH THURSDAY...

IT DOES APPEAR THAT ENOUGH DRY AIR WILL LINGER THRU THUR
AFTN/EVE...THUS HAVE HELD ONTO A DRY FORECAST IN THIS TIMEFRAME.
THIS PATTERN WILL BE CHANGING AS WE MIGRATE INTO THE EXTENDED
PERIODS.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN DRY WEATHER THROUGH THUR...MEDIUM/HIGH.

FRIDAY THROUGH MONDAY...
MINIMAL CHANGES FROM PREVIOUS FORECAST IN REGARDS TO THE EXTENDED
PERIODS. POSSIBLY THE FIRST STRETCH OF 90 DEG DAYS IS UPON US FOR
SUN/MON/TUE.

CONFIDENCE IN TEMPERATURE FORECAST...HIGH.
CONFIDENCE IN PRECIP/CONVECTIVE FORECAST...MEDIUM/HIGH.

BEACHLER

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* GUSTY NORTHEAST WINDS INTO THIS EVENING. CMS

//DISCUSSION...UPDATED 18Z...

NORTHEAST WINDS WILL REMAIN IN THE 10-15KT RANGE WITH GUSTS IN THE
16-20KT RANGE INTO THIS EVENING WITH WINDS DIMINISHING UNDER 10KTS
BY MID/LATE EVENING THEN TURNING MORE EASTERLY WEDNESDAY MORNING.

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS THROUGH THE
PERIOD. CMS

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

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE VFR.

BMD

.MARINE...
137 PM CDT

KJB

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM TUESDAY.

SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 4 AM
WEDNESDAY.

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

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

000
FXUS63 KLOT 181837
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
137 PM CDT TUE JUN 18 2013

.DISCUSSION...
330 AM CDT

PRIMARY FORECAST CHALLENGE THIS MORNING IS WITH PRECIP CHANCES
TODAY AND INTO THE WEEKEND...ALONG WITH POTENTIAL BIG WEEKEND WARM
UP.

SOMEWHAT DIFFUSE COLD FRONT...AIDED BY SOME LAKE ENHANCEMENT...HAS
PUSHED SOUTH OF THE CWA THIS MORNING WITH NORTH TO NORTHEAST WINDS
ADVECTING IN COOLER AND DRIER AIR MASS. HOWEVER...VIGOROUS SHORTWAVE
TROUGH OVER MN THIS MORNING IS PROGGED TO DROP SOUTHEAST TOWARD THE
AREA RESULTING IN A STEEPENING UP OF THE LOW AND ESPECIALLY MID
LEVEL LAPSE RATES RESULTING IN SOME INSTABILITY DEVELOPING.
INSTABILITY WILL BE MOST PRONOUNCED...ALBEIT LIKELY WEAK
STILL...WELL WEST AND SOUTH OF THE LAKE AS STABLE MARINE BOUNDARY
LAYER WILL BLEED WELL INLAND. NO REAL CHANGES MADE TO POPS TODAY
WITH EXPECTATION THAT THE GREATEST CHANCES OF CONVECTION WILL BE
FROM NC IL SE INTO SOUTHERN PORTIONS OF THE CWA. GIVEN THE STEEP
LAPSE RATES CAN NOT RULE OUT SOME SPRINKLES FALLING FROM SOME
ACCAS/MID DECK OVER CHICAGO AREA...BUT CHANCES LOOK TOO SLIM TO ADD
TO FORECAST.

A COUPLE OF TRULY SPECTACULAR WEATHER DAYS EXPECTED WEDNESDAY
AND PROBABLY INTO THURSDAY AS WELL. WEDNESDAY SHOULD FEATURE FULL
SUNSHINE AND BELOW AVERAGE TEMPERATURES WITH 70S INLAND AND 60S
LAKESIDE. TEMPS WILL WARM A COUPLE DEGREES ON THURSDAY...BUT
EXPECT SOME INCREASE IN MID-HIGH LEVEL CLOUDINESS IN THE AFTERNOON
AS REMNANTS OF DECAYING MCS POTENTIALLY MOVE INTO THE AREA. SOME
MODELS ARE SUGGESTING SOME PRECIP COULD MAKE IT INTO THE CWA
THURSDAY...ESPECIALLY WEST...BUT THINKING THAT CONVECTIVE ACTIVITY
SHOULD DRY UP PRETTY QUICKLY AS IT TRIES TO PENETRATE EASTWARD
INTO DRY CANADIAN AIR MASS OVER THE AREA.

FRIDAY THROUGH THE WEEKEND INTO EARLY NEXT WEEK LOOK PRETTY SUMMER
LIKE ON THE WHOLE. UPPER RIDGE IS PROGGED TO SPREAD EAST INTO THE
CENTRAL AND EVENTUALLY EASTERN CONUS...WITH OUR CWA LIKELY TO BE ON
THE NORTHERN FRINGES OF THIS RIDGE. THIS CERTAINLY COMPLICATES THE
FORECAST WITH RING OF FIRE PATTERN LIKELY TO SET UP ON THE PERIPHERY
OF THE RIDGE AND WITH OUR CWA LYING PRECARIOUSLY CLOSE TO THE EDGE
OF THE RIDGE AND STRONGER BELT OF WESTERLIES THE FORECAST IS A LOW
CONFIDENCE ONE. SYNOPTICALLY...IT WOULD APPEAR THE FRONT SHOULD LIE
NORTH OF THE CWA PUTTING US IN THE HOT AND HUMID AIR MASS WITH HIGHS
AROUND IF NOT INTO THE LOWER 90S. HOWEVER...SHOULD PARADE OF MCS
ACTIVITY NUDGE THE FRONT SOUTHWARD INTO THE AREA THEN TEMPS WOULD BE
COOLER WITH CLOUDS AND THUNDER POTENTIAL. UNFORTUNATELY AM LEFT WITH
LITTLE CHOICE OTHER THAN TO PAINT DAY AFTER DAY WITH CHANCES OF
SHOWERS AND THUNDERSTORMS...WHEN IN REALITY THE MAJORITY OF THE FRI
THROUGH MON PERIOD WILL BE DRY WITH A WORST CASE SCENARIO LIKELY
BEING ONE OR TWO ROUNDS OF THUNDERSTORMS.

IZZI

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* GUSTY NORTHEAST WINDS INTO THIS EVENING. CMS

//DISCUSSION...UPDATED 18Z...

NORTHEAST WINDS WILL REMAIN IN THE 10-15KT RANGE WITH GUSTS IN THE
16-20KT RANGE INTO THIS EVENING WITH WINDS DIMINISHING UNDER 10KTS
BY MID/LATE EVENING THEN TURNING MORE EASTERLY WEDNESDAY MORNING.

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS THROUGH THE
PERIOD. CMS

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

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE VFR.

BMD

.MARINE...
137 PM CDT

KJB

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM TUESDAY.

SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 4 AM
WEDNESDAY.

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

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


000
FXUS63 KILX 181834
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
134 PM CDT TUE JUN 18 2013

.DISCUSSION...
ISSUED 133 PM CDT TUE JUN 18 2013

LATEST MODEL SUITE IN REASONABLE AGREEMENT THROUGH THE FORECAST
PERIOD AS HEIGHTS BUILD AND SUMMER MOVES INTO FULL SWING.

SHORT TERM...TONIGHT THROUGH WEDNESDAY

COLD FRONT AT 18Z EXTENDS FROM NEAR MACOMB...ACROSS DECATUR...TO
NEAR TERRE HAUTE. INSTABILITY ALONG THE FRONT WILL LIKELY BE SUFFICIENT
FOR CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON AND EARLY EVENING ALONG
THE BOUNDARY WHERE CONVERGENCE AND POOLING DEW POINTS ARE
OCCURRING. HIGH PRESSURE CENTERED OVER THE UPPER GREAT LAKES IS
EXPECTED TO CONTINUE TO PUSH THE BOUNDARY SOUTHWARD THROUGH
TONIGHT. DIURNAL STABILITY COMBINED WITH DRIER AIR BEING ADVECTED
INTO ILLINOIS SHOULD END RAIN CHANCES BY MIDNIGHT.

WEDNESDAY SHOULD BE DRY AS HIGH PRESSURE DOMINATES. TEMPERATURES
SHOULD BE COOLER THAN NORMAL.  THAT WILL CHANGE AS THE WEEK GOES ON.

LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

STRONG UPPER LOW IN THE NORTHEAST PACIFIC IS EXPECTED TO MAKE
LANDFALL ACROSS THE NORTHWEST IN THE NEXT 24 HOURS. AS THIS
FEATURE PUSHES EAST...RIDGE SHOULD BUILD AHEAD OF IT. MODELS ARE
CONSISTENT IN DEVELOPING RISING HEIGHTS ACROSS THE MISSISSIPPI
VALLEY WITH RISES OF 160 METERS AT 500MB BETWEEN NOW AND FRIDAY
EVENING. TEMPERATURES SHOULD RESPOND BY MOVING ABOVE NORMAL FOR
THE LATE JUNE. LOW-LEVEL FLOW SHOULD ALSO COME AROUND TO SOUTH-
SOUTHWEST BY FRIDAY ALLOWING DEW POINTS TO CLIMB. COMBINATION OF
HUMIDITY AND TEMPS SHOULD BRING HEAT INDEX VALUES BETWEEN 95 AND
102 ACROSS THE AREA FOR THE WEEKEND AND INTO EARLY NEXT WEEK.

BIGGEST DIFFERENCE BETWEEN THE MAJOR MODELS IS WHETHER RIDGING
WILL BE SUFFICIENT TO KEEP PRECIP TO OUR NORTH. 00Z ECMWF/12Z NAM
ARE WEAKEST AND DEVELOP A PATTERN THAT IS MOST CONDUCIVE TO
DIURNAL CONVECTION. 12Z GFS/GEM IS STRONGER WITH RIDGE AND SUGGEST
THAT ANY ACTIVITY SHOULD REMAIN ISOLATED AT LEAST THROUGH THE WEEKEND.

MODELS IN GOOD AGREEMENT IN REDEVELOPING THE UPPER RIDGE BACK OVER
THE SOUTHERN ROCKIES BY NEXT TUESDAY WHICH WILL DEVELOP A LITTLE
MORE IN THE WAY OF FLOW ACROSS ILLINOIS AND HIGHER RAIN CHANCES.
THIS TRANSITION MAY BE A LITTLE FAST AND WILL KEEP TUESDAY DOWN TO
SLIGHT CHC FOR NOW BUT LATER SHIFTS WILL HAVE TO WATCH CAREFULLY
FOR MODEL TRENDS.

BARKER
&&

.AVIATION...
ISSUED 1218 PM CDT TUE JUN 18 2013

MAIN CONCERN FOR THIS TAF SET IS TIMING OF CONVECTION THIS
AFTERNOON. SEVERAL HIGH-RESOLUTION MODELS POINTING TO SCATTERED
STORM DEVELOPMENT IN CENTRAL ILLINOIS BEGINNING AROUND 19-20Z AND
MOST NUMEROUS DURING THE MID TO LATE AFTERNOON HOURS. HAVE KEPT
VCTS WORDING AT ALL TAF SITES FOR THIS AFTERNOON...BUT HAVE
FOCUSED ON THE KSPI-KDEC-KCMI CORRIDOR BY ADDING TEMPO PERIODS OF
TSRA AND VARIABLE/GUSTY WINDS WITH THE STORMS...AS THIS AREA IS
NEAR A FRONTAL BOUNDARY. SHOULD SEE THE CONVECTION FADE OUT WITH
SUNSET. DRIER NORTHEAST FLOW WILL CLEAR OUT MUCH OF THE AREA
OVERNIGHT. HAVE HELD OFF ON ANY OVERNIGHT MVFR FOG CONDITIONS...
BUT ANY AREAS THAT GET EXCESSIVE RAINFALL DURING THE DAY MAY SEE
SOME DEVELOP ALTHOUGH CONFIDENCE IS NOT HIGH AT THE MOMENT.

GEELHART
&&

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

$$


000
FXUS63 KLOT 181741
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1241 PM CDT TUE JUN 18 2013

.DISCUSSION...
330 AM CDT

PRIMARY FORECAST CHALLENGE THIS MORNING IS WITH PRECIP CHANCES
TODAY AND INTO THE WEEKEND...ALONG WITH POTENTIAL BIG WEEKEND WARM
UP.

SOMEWHAT DIFFUSE COLD FRONT...AIDED BY SOME LAKE ENHANCEMENT...HAS
PUSHED SOUTH OF THE CWA THIS MORNING WITH NORTH TO NORTHEAST WINDS
ADVECTING IN COOLER AND DRIER AIR MASS. HOWEVER...VIGOROUS SHORTWAVE
TROUGH OVER MN THIS MORNING IS PROGGED TO DROP SOUTHEAST TOWARD THE
AREA RESULTING IN A STEEPENING UP OF THE LOW AND ESPECIALLY MID
LEVEL LAPSE RATES RESULTING IN SOME INSTABILITY DEVELOPING.
INSTABILITY WILL BE MOST PRONOUNCED...ALBEIT LIKELY WEAK
STILL...WELL WEST AND SOUTH OF THE LAKE AS STABLE MARINE BOUNDARY
LAYER WILL BLEED WELL INLAND. NO REAL CHANGES MADE TO POPS TODAY
WITH EXPECTATION THAT THE GREATEST CHANCES OF CONVECTION WILL BE
FROM NC IL SE INTO SOUTHERN PORTIONS OF THE CWA. GIVEN THE STEEP
LAPSE RATES CAN NOT RULE OUT SOME SPRINKLES FALLING FROM SOME
ACCAS/MID DECK OVER CHICAGO AREA...BUT CHANCES LOOK TOO SLIM TO ADD
TO FORECAST.

A COUPLE OF TRULY SPECTACULAR WEATHER DAYS EXPECTED WEDNESDAY
AND PROBABLY INTO THURSDAY AS WELL. WEDNESDAY SHOULD FEATURE FULL
SUNSHINE AND BELOW AVERAGE TEMPERATURES WITH 70S INLAND AND 60S
LAKESIDE. TEMPS WILL WARM A COUPLE DEGREES ON THURSDAY...BUT
EXPECT SOME INCREASE IN MID-HIGH LEVEL CLOUDINESS IN THE AFTERNOON
AS REMNANTS OF DECAYING MCS POTENTIALLY MOVE INTO THE AREA. SOME
MODELS ARE SUGGESTING SOME PRECIP COULD MAKE IT INTO THE CWA
THURSDAY...ESPECIALLY WEST...BUT THINKING THAT CONVECTIVE ACTIVITY
SHOULD DRY UP PRETTY QUICKLY AS IT TRIES TO PENETRATE EASTWARD
INTO DRY CANADIAN AIR MASS OVER THE AREA.

FRIDAY THROUGH THE WEEKEND INTO EARLY NEXT WEEK LOOK PRETTY SUMMER
LIKE ON THE WHOLE. UPPER RIDGE IS PROGGED TO SPREAD EAST INTO THE
CENTRAL AND EVENTUALLY EASTERN CONUS...WITH OUR CWA LIKELY TO BE ON
THE NORTHERN FRINGES OF THIS RIDGE. THIS CERTAINLY COMPLICATES THE
FORECAST WITH RING OF FIRE PATTERN LIKELY TO SET UP ON THE PERIPHERY
OF THE RIDGE AND WITH OUR CWA LYING PRECARIOUSLY CLOSE TO THE EDGE
OF THE RIDGE AND STRONGER BELT OF WESTERLIES THE FORECAST IS A LOW
CONFIDENCE ONE. SYNOPTICALLY...IT WOULD APPEAR THE FRONT SHOULD LIE
NORTH OF THE CWA PUTTING US IN THE HOT AND HUMID AIR MASS WITH HIGHS
AROUND IF NOT INTO THE LOWER 90S. HOWEVER...SHOULD PARADE OF MCS
ACTIVITY NUDGE THE FRONT SOUTHWARD INTO THE AREA THEN TEMPS WOULD BE
COOLER WITH CLOUDS AND THUNDER POTENTIAL. UNFORTUNATELY AM LEFT WITH
LITTLE CHOICE OTHER THAN TO PAINT DAY AFTER DAY WITH CHANCES OF
SHOWERS AND THUNDERSTORMS...WHEN IN REALITY THE MAJORITY OF THE FRI
THROUGH MON PERIOD WILL BE DRY WITH A WORST CASE SCENARIO LIKELY
BEING ONE OR TWO ROUNDS OF THUNDERSTORMS.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* GUSTY NORTHEAST WINDS INTO THIS EVENING. CMS

//DISCUSSION...UPDATED 18Z...

IFR/LIFR CIGS STILL PERSISTING SOUTH OF MDW FROM IGQ TO GYY EAST
ALONG THE INDIANA SHORELINE. CLEARING FROM THE EAST ALONG WITH
EROSION FROM THE SOUTHWEST SEEMS TO HAVE SLOWED IN THE PAST HR OR
SO. WHILE VFR CONDITIONS ARE NOW EXPECTED AT ORD/MDW...WILL NEED
TO MONITOR TRENDS FOR GYY THROUGH THE AFTERNOON. SOME CU ALONG
WITH MID CLOUDS POSSIBLE THROUGH EARLY EVENING...THEN SKC EXPECTED
FOR THE REMAINDER OF THE PERIOD.

NORTHEAST WINDS WILL REMAIN IN THE 10-15KT RANGE WITH GUSTS IN THE
16-20KT RANGE INTO THIS EVENING WITH WINDS DIMINISHING UNDER 10KTS
BY MID/LATE EVENING THEN TURNING MORE EASTERLY WEDNESDAY MORNING.

AS A WEAK WAVE MOVES SOUTH OF THE TERMINALS THIS AFTERNOON...THERE
COULD BE SOME SHOWERS AND POSSIBLY AN ISOLATED TSRA BUT ANY
ACTIVITY THAT DEVELOPS IS EXPECTED TO REMAIN SOUTH OF ALL THE
TERMINALS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS THROUGH THE
  PERIOD. CMS

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

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE VFR.

BMD

&&

.MARINE...
300 AM CDT

A COLD FRONT HAS PUSHED SOUTH OF LAKE MICHIGAN AND HIGH PRESSURE
OVER THE NORTHERN LAKES REGION THIS MORNING WILL GRADUALLY SETTLE
SOUTHEAST OVER LAKE MICHIGAN TONIGHT AND WEDNESDAY. FRESH NORTHERLY
WINDS THIS MORNING WILL CONTINUE THROUGH TODAY AND THE PERSISTENT
AND LONG FETCH IS EXPECTED TO ALLOW WAVES TO BUILD ACROSS THE FAR
SOUTH PORTIONS OF THE LAKE AND NEARSHORE WATERS TO OR ABOVE 5
FT...THUS WILL ISSUE A SMALL CRAFT ADVISORY FOR THE INDIANA AND
EASTERN MOST ILLINOIS NEARSHORE ZONES. AS THE HIGH BUILDS SOUTH
OVERNIGHT WINDS AND WAVES SHOULD BEGIN TO DIMINISH. EXPECT LAKE
BREEZES TO DOMINATE THE WIND PATTERN WEDNESDAY AFTERNOON/EVENING.
LOW PRESSURE WILL BEGIN TO TAKE SHAPE OVER THE PLAINS AND THE
DEPARTING HIGH WILL ALLOW SOUTHERLY WINDS TO OVERTAKE THE LAKE
THURSDAY THROUGH THE WEEKEND. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
     IS UNTIL 4 PM TUESDAY.

     SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY
     IN UNTIL 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KILX 181719
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1219 PM CDT TUE JUN 18 2013

.DISCUSSION...
ISSUED 1010 AM CDT TUE JUN 18 2013

FRONTAL BOUNDARY HAS SETTLED SOUTHWARD TO AROUND THE I-74
CORRIDOR. VIGOROUS SHORTWAVE CURRENTLY IN NORTHEAST IOWA WILL
CONTINUE TO MOVE SOUTHEAST...AND WILL HELP TRIGGER SOME
THUNDERSTORMS OVER CENTRAL ILLINOIS BY MID AFTERNOON. CURRENTLY
HAVE A SLIGHT RISK OF SEVERE WEATHER FROM ABOUT PEORIA TO
WINCHESTER EASTWARD. LATEST RAP MODEL SHOWING ABOUT 40-50 KNOTS OF
0-6KM BULK SHEAR WITH THIS SHORTWAVE...WITH OVER 2000 J/KG OF
SBCAPE...SO THIS RISK AREA APPEARS WARRANTED. COULD SEE SOME
HEAVIER RAINS WITH THE STORMS...ALTHOUGH THE SOUTH HALF OF THE CWA
APPEARS MORE LIKELY FOR ANY SIGNIFICANT RAINS AS PWAT VALUES IN
THAT AREA ARE CLOSE TO 1.5 INCHES BY MID AFTERNOON.

HAVE SENT SOME MINOR ZONE/GRID UPDATES...MAINLY TO ADJUST THE
CLOUD AND WIND TRENDS. HIGH TEMPERATURES STILL APPEAR REASONABLE.

GEELHART


&&

.AVIATION...
ISSUED 1218 PM CDT TUE JUN 18 2013

MAIN CONCERN FOR THIS TAF SET IS TIMING OF CONVECTION THIS
AFTERNOON. SEVERAL HIGH-RESOLUTION MODELS POINTING TO SCATTERED
STORM DEVELOPMENT IN CENTRAL ILLINOIS BEGINNING AROUND 19-20Z AND
MOST NUMEROUS DURING THE MID TO LATE AFTERNOON HOURS. HAVE KEPT
VCTS WORDING AT ALL TAF SITES FOR THIS AFTERNOON...BUT HAVE
FOCUSED ON THE KSPI-KDEC-KCMI CORRIDOR BY ADDING TEMPO PERIODS OF
TSRA AND VARIABLE/GUSTY WINDS WITH THE STORMS...AS THIS AREA IS
NEAR A FRONTAL BOUNDARY. SHOULD SEE THE CONVECTION FADE OUT WITH
SUNSET. DRIER NORTHEAST FLOW WILL CLEAR OUT MUCH OF THE AREA
OVERNIGHT. HAVE HELD OFF ON ANY OVERNIGHT MVFR FOG CONDITIONS...
BUT ANY AREAS THAT GET EXCESSIVE RAINFALL DURING THE DAY MAY SEE
SOME DEVELOP ALTHOUGH CONFIDENCE IS NOT HIGH AT THE MOMENT.

GEELHART

&&

.PREV DISCUSSION...
ISSUED 254 AM CDT TUE JUN 18 2013

SHORT TERM...TODAY THROUGH THURSDAY

07Z/2AM SURFACE ANALYSIS SHOWS A WEAK COLD FRONT EXTENDING FROM
NORTHEAST IOWA E/SE ACROSS NORTH-CENTRAL ILLINOIS. THIS BOUNDARY
WILL BE THE PRIMARY FOCUSING MECHANISM FOR WIDELY SCATTERED
CONVECTION AS IT SAGS SLOWLY SOUTHWARD LATER TODAY. VIGOROUS
SHORT-WAVE TROUGH CURRENTLY NOTED ON WATER VAPOR IMAGERY OVER
SOUTHERN MINNESOTA WILL TRACK SOUTHEASTWARD AS WELL...PROVIDING
ENHANCED LIFT ACROSS THE AREA DURING PEAK HEATING. WITH SURFACE
DEWPOINTS ALONG/SOUTH OF THE BOUNDARY IN THE MIDDLE TO UPPER
60S...CAPE VALUES WILL REACH THE 1500 TO 2500J/KG RANGE. IN
ADDITION...0-6KM SHEAR WILL INCREASE TO AROUND 40KT ON THE SOUTHERN
PERIPHERY OF THE APPROACHING WAVE. ALL THESE INGREDIENTS WILL COME
TOGETHER TO PRODUCE SCATTERED THUNDERSTORMS THIS AFTERNOON...A FEW
OF WHICH COULD PRODUCE GUSTY WINDS AND HAIL. WILL CARRY 30-40 POPS
ACROSS THE ENTIRE AREA ACCORDINGLY. AS DAYTIME INSTABILITY IS
LOST...CONVECTION WILL DISSIPATE AFTER SUNSET. WILL LINGER A
SLIGHT CHANCE POP ACROSS THE S/SW KILX CWA THIS EVENING...THEN
WILL GO DRY ACROSS THE BOARD OVERNIGHT.

SURFACE HIGH PRESSURE BUILDING INTO THE REGION BEHIND THE
DEPARTING FRONT WILL PROVIDE WARM/DRY WEATHER ON WEDNESDAY...WITH
AFTERNOON HIGHS IN THE LOWER 80S AND OVERNIGHT LOWS IN THE LOWER
60S. NEXT APPROACHING UPPER WAVE WILL COME INTO THE PICTURE ON
THURSDAY...AS A PIECE OF ENERGY EJECTS EASTWARD FROM DEEP UPPER
LOW SPINNING OFF THE COAST OF THE PACIFIC NORTHWEST. THIS WAVE IS
PROGGED TO TRACK ACROSS CENTRAL ILLINOIS ON THURSDAY. DESPITE
SYNOPTIC LIFT ASSOCIATED WITH THIS FEATURE...AIR MASS WILL BE
RATHER DRY...SO AM NOT EXPECTING MUCH IN THE WAY OF PRECIP. HAVE
GONE WITH A PARTLY SUNNY FORECAST...WITH JUST A SLIM CHANCE FOR
SHOWERS/THUNDER WEST OF I-55 THURSDAY AFTERNOON.

LONG TERM...FRIDAY THROUGH MONDAY

UPPER RIDGE IS EXPECTED TO BUILD ACROSS THE MIDWEST BY THE END OF
THE WEEK...LEADING TO A HOT AND LARGELY DRY EXTENDED FORECAST.
STILL SOME QUESTION AS TO HOW QUICKLY THE RIDGE WILL BUILD AND
WHETHER ANY NOCTURNAL MCS ACTIVITY WILL IMPACT PARTS OF THE AREA
FRIDAY/SATURDAY...HOWEVER MODEL CONSENSUS CONTINUES TO SUGGEST
MOST OF THIS PRECIP WILL BE FOCUSED FURTHER NORTH ACROSS THE UPPER
MIDWEST INTO THE GREAT LAKES. WILL THEREFORE CONTINUE WITH A
MAINLY DRY FORECAST ACROSS CENTRAL ILLINOIS...WITH JUST SLIGHT
CHANCE POPS ACROSS THE FAR NORTH. MAIN STORY WILL BE THE HEAT...AS
HIGH TEMPS REACH THE 90S OVER THE WEEKEND. NEXT BIG QUESTION WILL
BE HOW QUICKLY THE RIDGE WILL FLATTEN EARLY NEXT WEEK. 00Z JUN 18
GFS/ECMWF ARE IN GOOD AGREEMENT THROUGH 168HR/00Z TUE...THEN
SOLUTIONS DIVERGE BY THE MIDDLE OF NEXT WEEK AS GFS HOLDS ONTO
RIDGING ACROSS THE MIDWEST...WHILE THE ECMWF SHIFTS THE RIDGE
FURTHER WEST INTO THE ROCKIES. BASED ON THE PATTERN WE HAVE BEEN
IN FOR MUCH OF THE SPRING...THINK ECMWF HAS A MORE REALISTIC
ANSWER. WILL THEREFORE GRADUALLY INTRODUCE SHOWERS/THUNDERSTORMS
INTO THE FORECAST ACROSS THE NORTHERN HALF OF THE CWA BY
MONDAY/MONDAY NIGHT...THEN EVERYWHERE TUESDAY AS THE RIDGE WEAKENS
AND A FRONTAL BOUNDARY SAGS SOUTHWARD INTO THE REGION.

BARNES


&&

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

$$


000
FXUS63 KLOT 181605
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1105 AM CDT TUE JUN 18 2013

.DISCUSSION...
330 AM CDT

PRIMARY FORECAST CHALLENGE THIS MORNING IS WITH PRECIP CHANCES
TODAY AND INTO THE WEEKEND...ALONG WITH POTENTIAL BIG WEEKEND WARM
UP.

SOMEWHAT DIFFUSE COLD FRONT...AIDED BY SOME LAKE ENHANCEMENT...HAS
PUSHED SOUTH OF THE CWA THIS MORNING WITH NORTH TO NORTHEAST WINDS
ADVECTING IN COOLER AND DRIER AIR MASS. HOWEVER...VIGOROUS SHORTWAVE
TROUGH OVER MN THIS MORNING IS PROGGED TO DROP SOUTHEAST TOWARD THE
AREA RESULTING IN A STEEPENING UP OF THE LOW AND ESPECIALLY MID
LEVEL LAPSE RATES RESULTING IN SOME INSTABILITY DEVELOPING.
INSTABILITY WILL BE MOST PRONOUNCED...ALBEIT LIKELY WEAK
STILL...WELL WEST AND SOUTH OF THE LAKE AS STABLE MARINE BOUNDARY
LAYER WILL BLEED WELL INLAND. NO REAL CHANGES MADE TO POPS TODAY
WITH EXPECTATION THAT THE GREATEST CHANCES OF CONVECTION WILL BE
FROM NC IL SE INTO SOUTHERN PORTIONS OF THE CWA. GIVEN THE STEEP
LAPSE RATES CAN NOT RULE OUT SOME SPRINKLES FALLING FROM SOME
ACCAS/MID DECK OVER CHICAGO AREA...BUT CHANCES LOOK TOO SLIM TO ADD
TO FORECAST.

A COUPLE OF TRULY SPECTACULAR WEATHER DAYS EXPECTED WEDNESDAY
AND PROBABLY INTO THURSDAY AS WELL. WEDNESDAY SHOULD FEATURE FULL
SUNSHINE AND BELOW AVERAGE TEMPERATURES WITH 70S INLAND AND 60S
LAKESIDE. TEMPS WILL WARM A COUPLE DEGREES ON THURSDAY...BUT
EXPECT SOME INCREASE IN MID-HIGH LEVEL CLOUDINESS IN THE AFTERNOON
AS REMNANTS OF DECAYING MCS POTENTIALLY MOVE INTO THE AREA. SOME
MODELS ARE SUGGESTING SOME PRECIP COULD MAKE IT INTO THE CWA
THURSDAY...ESPECIALLY WEST...BUT THINKING THAT CONVECTIVE ACTIVITY
SHOULD DRY UP PRETTY QUICKLY AS IT TRIES TO PENETRATE EASTWARD
INTO DRY CANADIAN AIR MASS OVER THE AREA.

FRIDAY THROUGH THE WEEKEND INTO EARLY NEXT WEEK LOOK PRETTY SUMMER
LIKE ON THE WHOLE. UPPER RIDGE IS PROGGED TO SPREAD EAST INTO THE
CENTRAL AND EVENTUALLY EASTERN CONUS...WITH OUR CWA LIKELY TO BE ON
THE NORTHERN FRINGES OF THIS RIDGE. THIS CERTAINLY COMPLICATES THE
FORECAST WITH RING OF FIRE PATTERN LIKELY TO SET UP ON THE PERIPHERY
OF THE RIDGE AND WITH OUR CWA LYING PRECARIOUSLY CLOSE TO THE EDGE
OF THE RIDGE AND STRONGER BELT OF WESTERLIES THE FORECAST IS A LOW
CONFIDENCE ONE. SYNOPTICALLY...IT WOULD APPEAR THE FRONT SHOULD LIE
NORTH OF THE CWA PUTTING US IN THE HOT AND HUMID AIR MASS WITH HIGHS
AROUND IF NOT INTO THE LOWER 90S. HOWEVER...SHOULD PARADE OF MCS
ACTIVITY NUDGE THE FRONT SOUTHWARD INTO THE AREA THEN TEMPS WOULD BE
COOLER WITH CLOUDS AND THUNDER POTENTIAL. UNFORTUNATELY AM LEFT WITH
LITTLE CHOICE OTHER THAN TO PAINT DAY AFTER DAY WITH CHANCES OF
SHOWERS AND THUNDERSTORMS...WHEN IN REALITY THE MAJORITY OF THE FRI
THROUGH MON PERIOD WILL BE DRY WITH A WORST CASE SCENARIO LIKELY
BEING ONE OR TWO ROUNDS OF THUNDERSTORMS.

IZZI

&&

.AVIATION...

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

* IFR CIGS THROUGH 17Z THEN POSSIBLE MVFR CIGS THROUGH 18Z-19Z.
* GUSTY NORTHEAST WINDS THROUGH THIS EVENING. CMS

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

LOW CIGS DEVELOPED OVER LAKE MICHIGAN OVERNIGHT AND MOVED ONSHORE
EARLY THIS MORNING. NAM/RAP GUIDANCE WHICH HAD GOOD HANDLE ON THE
DEVELOPMENT OF THE LOW CIGS INDICATE IT WILL LINGER THROUGH 15Z TO
17Z BEFORE SCATTERING WITH DAYTIME HEATING AND MIXING.
THEREAFTER...EXPECT NORTHEASTERLY WINDS TO INCREASE WITH MIXING WITH
GUSTS INTO THE HIGH TEENS POSSIBLE THROUGH THE AFTERNOON AND
EVENING. VFR CONDITIONS WILL PREVAIL THE REMAINDER OF THE FORECAST
PERIOD AS INCREASINGLY DRIER AIRMASS TAKES HOLD OVER THE AREA. WINDS
SHOULD DECOUPLE AND DIMINISH LESS THAN 10 KTS OVERNIGHT. WINDS
SHOULD THEN VEER TO THE EAST WEDNESDAY AS THE HIGH SHIFTS SOUTHEAST
FROM THE NORTHERN GREAT LAKES REGION INTO MICHIGAN.

BMD

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

* MEDIUM IFR CIGS WILL SCATTER OUT BY 17Z...LOW MVFR CIGS COULD
  CONTINUE THROUGH 18Z-19Z.
* MEDIUM FOR WIND SPEEDS/GUSTS THROUGH THE PERIOD. CMS

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

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE VFR.

BMD

&&

.MARINE...
300 AM CDT

A COLD FRONT HAS PUSHED SOUTH OF LAKE MICHIGAN AND HIGH PRESSURE
OVER THE NORTHERN LAKES REGION THIS MORNING WILL GRADUALLY SETTLE
SOUTHEAST OVER LAKE MICHIGAN TONIGHT AND WEDNESDAY. FRESH NORTHERLY
WINDS THIS MORNING WILL CONTINUE THROUGH TODAY AND THE PERSISTENT
AND LONG FETCH IS EXPECTED TO ALLOW WAVES TO BUILD ACROSS THE FAR
SOUTH PORTIONS OF THE LAKE AND NEARSHORE WATERS TO OR ABOVE 5
FT...THUS WILL ISSUE A SMALL CRAFT ADVISORY FOR THE INDIANA AND
EASTERN MOST ILLINOIS NEARSHORE ZONES. AS THE HIGH BUILDS SOUTH
OVERNIGHT WINDS AND WAVES SHOULD BEGIN TO DIMINISH. EXPECT LAKE
BREEZES TO DOMINATE THE WIND PATTERN WEDNESDAY AFTERNOON/EVENING.
LOW PRESSURE WILL BEGIN TO TAKE SHAPE OVER THE PLAINS AND THE
DEPARTING HIGH WILL ALLOW SOUTHERLY WINDS TO OVERTAKE THE LAKE
THURSDAY THROUGH THE WEEKEND. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
     IS UNTIL 4 PM TUESDAY.

     SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY
     IN UNTIL 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KILX 181511
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1011 AM CDT TUE JUN 18 2013

.DISCUSSION...
ISSUED 1010 AM CDT TUE JUN 18 2013

FRONTAL BOUNDARY HAS SETTLED SOUTHWARD TO AROUND THE I-74
CORRIDOR. VIGOROUS SHORTWAVE CURRENTLY IN NORTHEAST IOWA WILL
CONTINUE TO MOVE SOUTHEAST...AND WILL HELP TRIGGER SOME
THUNDERSTORMS OVER CENTRAL ILLINOIS BY MID AFTERNOON. CURRENTLY
HAVE A SLIGHT RISK OF SEVERE WEATHER FROM ABOUT PEORIA TO
WINCHESTER EASTWARD. LATEST RAP MODEL SHOWING ABOUT 40-50 KNOTS OF
0-6KM BULK SHEAR WITH THIS SHORTWAVE...WITH OVER 2000 J/KG OF
SBCAPE...SO THIS RISK AREA APPEARS WARRANTED. COULD SEE SOME
HEAVIER RAINS WITH THE STORMS...ALTHOUGH THE SOUTH HALF OF THE CWA
APPEARS MORE LIKELY FOR ANY SIGNIFICANT RAINS AS PWAT VALUES IN
THAT AREA ARE CLOSE TO 1.5 INCHES BY MID AFTERNOON.

HAVE SENT SOME MINOR ZONE/GRID UPDATES...MAINLY TO ADJUST THE
CLOUD AND WIND TRENDS. HIGH TEMPERATURES STILL APPEAR REASONABLE.

GEELHART

&&

.AVIATION...
ISSUED 650 AM CDT TUE JUN 18 2013

LIGHT FOG WITH MVFR VSBYS POSSIBLE OVER CENTRAL IL TAF SITES NEXT
HOUR OR TWO ESPECIALLY AT BMI AND CMI ALONG WITH 500 FOOT BROKEN
CEILINGS BRIEFLY POSSIBLE. OTHERWISE A FRONTAL BOUNDARY PUSHING
SOUTHWARD TOWARD I-74 EARLY THIS MORNING WILL BE THE FOCUS FOR
ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AS IT PUSHES
SOUTHWARD ACROSS THE CENTRAL IL TERMINAL AIRPORTS. ALSO A VIGOROUS
SHORT WAVE (572 DM 500 MB LOW) NEAR THE MN/IA BORDER WILL TRACK SE
ACROSS CENTRAL IL THIS AFTERNOON AND PROVIDE ADDITIONAL LIFT WITH
UNSTABLE AIR MASS WITH CAPES OF 1500-2500 J/KG. HI-RES MODELS SHOW
I-74 TAF SITES MAY BE ON NORTHERN EDGE OF THIS CONVECTION DEVELOP
THIS AFTERNOON. HAVE VFR BROKEN CEILINGS AROUND 5K FT THIS
AFTERNOON...THEN SCATTERED OUT EARLY EVENING AND CLEAR BETWEEN
02-04Z THIS EVENING. WSW WINDS AROUND 5 KTS WILL TURN NE AND
INCREASE TO 7-11 KTS DURING THIS MORNING AND HAVE RECENTLY DONE SO
AT BMI AS FRONTAL BOUNDARY EASES SOUTHWARD FROM I-74. NE WINDS TO
DIMINISH LIGHT AFTER SUNSET TONIGHT.

07

&&

.PREV DISCUSSION...
ISSUED 254 AM CDT TUE JUN 18 2013

SHORT TERM...TODAY THROUGH THURSDAY

07Z/2AM SURFACE ANALYSIS SHOWS A WEAK COLD FRONT EXTENDING FROM
NORTHEAST IOWA E/SE ACROSS NORTH-CENTRAL ILLINOIS. THIS BOUNDARY
WILL BE THE PRIMARY FOCUSING MECHANISM FOR WIDELY SCATTERED
CONVECTION AS IT SAGS SLOWLY SOUTHWARD LATER TODAY. VIGOROUS
SHORT-WAVE TROUGH CURRENTLY NOTED ON WATER VAPOR IMAGERY OVER
SOUTHERN MINNESOTA WILL TRACK SOUTHEASTWARD AS WELL...PROVIDING
ENHANCED LIFT ACROSS THE AREA DURING PEAK HEATING. WITH SURFACE
DEWPOINTS ALONG/SOUTH OF THE BOUNDARY IN THE MIDDLE TO UPPER
60S...CAPE VALUES WILL REACH THE 1500 TO 2500J/KG RANGE. IN
ADDITION...0-6KM SHEAR WILL INCREASE TO AROUND 40KT ON THE SOUTHERN
PERIPHERY OF THE APPROACHING WAVE. ALL THESE INGREDIENTS WILL COME
TOGETHER TO PRODUCE SCATTERED THUNDERSTORMS THIS AFTERNOON...A FEW
OF WHICH COULD PRODUCE GUSTY WINDS AND HAIL. WILL CARRY 30-40 POPS
ACROSS THE ENTIRE AREA ACCORDINGLY. AS DAYTIME INSTABILITY IS
LOST...CONVECTION WILL DISSIPATE AFTER SUNSET. WILL LINGER A
SLIGHT CHANCE POP ACROSS THE S/SW KILX CWA THIS EVENING...THEN
WILL GO DRY ACROSS THE BOARD OVERNIGHT.

SURFACE HIGH PRESSURE BUILDING INTO THE REGION BEHIND THE
DEPARTING FRONT WILL PROVIDE WARM/DRY WEATHER ON WEDNESDAY...WITH
AFTERNOON HIGHS IN THE LOWER 80S AND OVERNIGHT LOWS IN THE LOWER
60S. NEXT APPROACHING UPPER WAVE WILL COME INTO THE PICTURE ON
THURSDAY...AS A PIECE OF ENERGY EJECTS EASTWARD FROM DEEP UPPER
LOW SPINNING OFF THE COAST OF THE PACIFIC NORTHWEST. THIS WAVE IS
PROGGED TO TRACK ACROSS CENTRAL ILLINOIS ON THURSDAY. DESPITE
SYNOPTIC LIFT ASSOCIATED WITH THIS FEATURE...AIR MASS WILL BE
RATHER DRY...SO AM NOT EXPECTING MUCH IN THE WAY OF PRECIP. HAVE
GONE WITH A PARTLY SUNNY FORECAST...WITH JUST A SLIM CHANCE FOR
SHOWERS/THUNDER WEST OF I-55 THURSDAY AFTERNOON.

LONG TERM...FRIDAY THROUGH MONDAY

UPPER RIDGE IS EXPECTED TO BUILD ACROSS THE MIDWEST BY THE END OF
THE WEEK...LEADING TO A HOT AND LARGELY DRY EXTENDED FORECAST.
STILL SOME QUESTION AS TO HOW QUICKLY THE RIDGE WILL BUILD AND
WHETHER ANY NOCTURNAL MCS ACTIVITY WILL IMPACT PARTS OF THE AREA
FRIDAY/SATURDAY...HOWEVER MODEL CONSENSUS CONTINUES TO SUGGEST
MOST OF THIS PRECIP WILL BE FOCUSED FURTHER NORTH ACROSS THE UPPER
MIDWEST INTO THE GREAT LAKES. WILL THEREFORE CONTINUE WITH A
MAINLY DRY FORECAST ACROSS CENTRAL ILLINOIS...WITH JUST SLIGHT
CHANCE POPS ACROSS THE FAR NORTH. MAIN STORY WILL BE THE HEAT...AS
HIGH TEMPS REACH THE 90S OVER THE WEEKEND. NEXT BIG QUESTION WILL
BE HOW QUICKLY THE RIDGE WILL FLATTEN EARLY NEXT WEEK. 00Z JUN 18
GFS/ECMWF ARE IN GOOD AGREEMENT THROUGH 168HR/00Z TUE...THEN
SOLUTIONS DIVERGE BY THE MIDDLE OF NEXT WEEK AS GFS HOLDS ONTO
RIDGING ACROSS THE MIDWEST...WHILE THE ECMWF SHIFTS THE RIDGE
FURTHER WEST INTO THE ROCKIES. BASED ON THE PATTERN WE HAVE BEEN
IN FOR MUCH OF THE SPRING...THINK ECMWF HAS A MORE REALISTIC
ANSWER. WILL THEREFORE GRADUALLY INTRODUCE SHOWERS/THUNDERSTORMS
INTO THE FORECAST ACROSS THE NORTHERN HALF OF THE CWA BY
MONDAY/MONDAY NIGHT...THEN EVERYWHERE TUESDAY AS THE RIDGE WEAKENS
AND A FRONTAL BOUNDARY SAGS SOUTHWARD INTO THE REGION.

BARNES

&&

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

$$


000
FXUS63 KLOT 181402
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
902 AM CDT TUE JUN 18 2013

.DISCUSSION...
330 AM CDT

PRIMARY FORECAST CHALLENGE THIS MORNING IS WITH PRECIP CHANCES
TODAY AND INTO THE WEEKEND...ALONG WITH POTENTIAL BIG WEEKEND WARM
UP.

SOMEWHAT DIFFUSE COLD FRONT...AIDED BY SOME LAKE ENHANCEMENT...HAS
PUSHED SOUTH OF THE CWA THIS MORNING WITH NORTH TO NORTHEAST WINDS
ADVECTING IN COOLER AND DRIER AIR MASS. HOWEVER...VIGOROUS SHORTWAVE
TROUGH OVER MN THIS MORNING IS PROGGED TO DROP SOUTHEAST TOWARD THE
AREA RESULTING IN A STEEPENING UP OF THE LOW AND ESPECIALLY MID
LEVEL LAPSE RATES RESULTING IN SOME INSTABILITY DEVELOPING.
INSTABILITY WILL BE MOST PRONOUNCED...ALBEIT LIKELY WEAK
STILL...WELL WEST AND SOUTH OF THE LAKE AS STABLE MARINE BOUNDARY
LAYER WILL BLEED WELL INLAND. NO REAL CHANGES MADE TO POPS TODAY
WITH EXPECTATION THAT THE GREATEST CHANCES OF CONVECTION WILL BE
FROM NC IL SE INTO SOUTHERN PORTIONS OF THE CWA. GIVEN THE STEEP
LAPSE RATES CAN NOT RULE OUT SOME SPRINKLES FALLING FROM SOME
ACCAS/MID DECK OVER CHICAGO AREA...BUT CHANCES LOOK TOO SLIM TO ADD
TO FORECAST.

A COUPLE OF TRULY SPECTACULAR WEATHER DAYS EXPECTED WEDNESDAY
AND PROBABLY INTO THURSDAY AS WELL. WEDNESDAY SHOULD FEATURE FULL
SUNSHINE AND BELOW AVERAGE TEMPERATURES WITH 70S INLAND AND 60S
LAKESIDE. TEMPS WILL WARM A COUPLE DEGREES ON THURSDAY...BUT
EXPECT SOME INCREASE IN MID-HIGH LEVEL CLOUDINESS IN THE AFTERNOON
AS REMNANTS OF DECAYING MCS POTENTIALLY MOVE INTO THE AREA. SOME
MODELS ARE SUGGESTING SOME PRECIP COULD MAKE IT INTO THE CWA
THURSDAY...ESPECIALLY WEST...BUT THINKING THAT CONVECTIVE ACTIVITY
SHOULD DRY UP PRETTY QUICKLY AS IT TRIES TO PENETRATE EASTWARD
INTO DRY CANADIAN AIR MASS OVER THE AREA.

FRIDAY THROUGH THE WEEKEND INTO EARLY NEXT WEEK LOOK PRETTY SUMMER
LIKE ON THE WHOLE. UPPER RIDGE IS PROGGED TO SPREAD EAST INTO THE
CENTRAL AND EVENTUALLY EASTERN CONUS...WITH OUR CWA LIKELY TO BE ON
THE NORTHERN FRINGES OF THIS RIDGE. THIS CERTAINLY COMPLICATES THE
FORECAST WITH RING OF FIRE PATTERN LIKELY TO SET UP ON THE PERIPHERY
OF THE RIDGE AND WITH OUR CWA LYING PRECARIOUSLY CLOSE TO THE EDGE
OF THE RIDGE AND STRONGER BELT OF WESTERLIES THE FORECAST IS A LOW
CONFIDENCE ONE. SYNOPTICALLY...IT WOULD APPEAR THE FRONT SHOULD LIE
NORTH OF THE CWA PUTTING US IN THE HOT AND HUMID AIR MASS WITH HIGHS
AROUND IF NOT INTO THE LOWER 90S. HOWEVER...SHOULD PARADE OF MCS
ACTIVITY NUDGE THE FRONT SOUTHWARD INTO THE AREA THEN TEMPS WOULD BE
COOLER WITH CLOUDS AND THUNDER POTENTIAL. UNFORTUNATELY AM LEFT WITH
LITTLE CHOICE OTHER THAN TO PAINT DAY AFTER DAY WITH CHANCES OF
SHOWERS AND THUNDERSTORMS...WHEN IN REALITY THE MAJORITY OF THE FRI
THROUGH MON PERIOD WILL BE DRY WITH A WORST CASE SCENARIO LIKELY
BEING ONE OR TWO ROUNDS OF THUNDERSTORMS.

IZZI

&&

.AVIATION...

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

* LIFR/IFR CIGS THROUGH 16Z THEN POSSIBLE MVFR CIGS THROUGH 18Z-19Z.
* GUSTY NORTHEAST WINDS THROUGH THIS EVENING. CMS

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

LOW CIGS DEVELOPED OVER LAKE MICHIGAN OVERNIGHT AND MOVED ONSHORE
EARLY THIS MORNING. NAM/RAP GUIDANCE WHICH HAD GOOD HANDLE ON THE
DEVELOPMENT OF THE LOW CIGS INDICATE IT WILL LINGER THROUGH 15Z TO
17Z BEFORE SCATTERING WITH DAYTIME HEATING AND MIXING.
THEREAFTER...EXPECT NORTHEASTERLY WINDS TO INCREASE WITH MIXING WITH
GUSTS INTO THE HIGH TEENS POSSIBLE THROUGH THE AFTERNOON AND
EVENING. VFR CONDITIONS WILL PREVAIL THE REMAINDER OF THE FORECAST
PERIOD AS INCREASINGLY DRIER AIRMASS TAKES HOLD OVER THE AREA. WINDS
SHOULD DECOUPLE AND DIMINISH LESS THAN 10 KTS OVERNIGHT. WINDS
SHOULD THEN VEER TO THE EAST WEDNESDAY AS THE HIGH SHIFTS SOUTHEAST
FROM THE NORTHERN GREAT LAKES REGION INTO MICHIGAN.

BMD

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

* MEDIUM IFR CIGS WILL SCATTER OUT BY 16Z...LOW MVFR CIGS COULD
  CONTINUE INTO EARLY AFTERNOON.
* MEDIUM FOR WIND SPEEDS/GUSTS THROUGH THE PERIOD. CMS

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

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE VFR.

BMD

&&

.MARINE...
300 AM CDT

A COLD FRONT HAS PUSHED SOUTH OF LAKE MICHIGAN AND HIGH PRESSURE
OVER THE NORTHERN LAKES REGION THIS MORNING WILL GRADUALLY SETTLE
SOUTHEAST OVER LAKE MICHIGAN TONIGHT AND WEDNESDAY. FRESH NORTHERLY
WINDS THIS MORNING WILL CONTINUE THROUGH TODAY AND THE PERSISTENT
AND LONG FETCH IS EXPECTED TO ALLOW WAVES TO BUILD ACROSS THE FAR
SOUTH PORTIONS OF THE LAKE AND NEARSHORE WATERS TO OR ABOVE 5
FT...THUS WILL ISSUE A SMALL CRAFT ADVISORY FOR THE INDIANA AND
EASTERN MOST ILLINOIS NEARSHORE ZONES. AS THE HIGH BUILDS SOUTH
OVERNIGHT WINDS AND WAVES SHOULD BEGIN TO DIMINISH. EXPECT LAKE
BREEZES TO DOMINATE THE WIND PATTERN WEDNESDAY AFTERNOON/EVENING.
LOW PRESSURE WILL BEGIN TO TAKE SHAPE OVER THE PLAINS AND THE
DEPARTING HIGH WILL ALLOW SOUTHERLY WINDS TO OVERTAKE THE LAKE
THURSDAY THROUGH THE WEEKEND. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
     IS UNTIL NOON TUESDAY.

     SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...1 PM
     TUESDAY TO 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KILX 181151
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
651 AM CDT TUE JUN 18 2013

.DISCUSSION...
ISSUED 254 AM CDT TUE JUN 18 2013

SHORT TERM...TODAY THROUGH THURSDAY

07Z/2AM SURFACE ANALYSIS SHOWS A WEAK COLD FRONT EXTENDING FROM
NORTHEAST IOWA E/SE ACROSS NORTH-CENTRAL ILLINOIS. THIS BOUNDARY
WILL BE THE PRIMARY FOCUSING MECHANISM FOR WIDELY SCATTERED
CONVECTION AS IT SAGS SLOWLY SOUTHWARD LATER TODAY. VIGOROUS
SHORT-WAVE TROUGH CURRENTLY NOTED ON WATER VAPOR IMAGERY OVER
SOUTHERN MINNESOTA WILL TRACK SOUTHEASTWARD AS WELL...PROVIDING
ENHANCED LIFT ACROSS THE AREA DURING PEAK HEATING. WITH SURFACE
DEWPOINTS ALONG/SOUTH OF THE BOUNDARY IN THE MIDDLE TO UPPER
60S...CAPE VALUES WILL REACH THE 1500 TO 2500J/KG RANGE. IN
ADDITION...0-6KM SHEAR WILL INCREASE TO AROUND 40KT ON THE SOUTHERN
PERIPHERY OF THE APPROACHING WAVE. ALL THESE INGREDIENTS WILL COME
TOGETHER TO PRODUCE SCATTERED THUNDERSTORMS THIS AFTERNOON...A FEW
OF WHICH COULD PRODUCE GUSTY WINDS AND HAIL. WILL CARRY 30-40 POPS
ACROSS THE ENTIRE AREA ACCORDINGLY. AS DAYTIME INSTABILITY IS
LOST...CONVECTION WILL DISSIPATE AFTER SUNSET. WILL LINGER A
SLIGHT CHANCE POP ACROSS THE S/SW KILX CWA THIS EVENING...THEN
WILL GO DRY ACROSS THE BOARD OVERNIGHT.

SURFACE HIGH PRESSURE BUILDING INTO THE REGION BEHIND THE
DEPARTING FRONT WILL PROVIDE WARM/DRY WEATHER ON WEDNESDAY...WITH
AFTERNOON HIGHS IN THE LOWER 80S AND OVERNIGHT LOWS IN THE LOWER
60S. NEXT APPROACHING UPPER WAVE WILL COME INTO THE PICTURE ON
THURSDAY...AS A PIECE OF ENERGY EJECTS EASTWARD FROM DEEP UPPER
LOW SPINNING OFF THE COAST OF THE PACIFIC NORTHWEST. THIS WAVE IS
PROGGED TO TRACK ACROSS CENTRAL ILLINOIS ON THURSDAY. DESPITE
SYNOPTIC LIFT ASSOCIATED WITH THIS FEATURE...AIRMASS WILL BE
RATHER DRY...SO AM NOT EXPECTING MUCH IN THE WAY OF PRECIP. HAVE
GONE WITH A PARTLY SUNNY FORECAST...WITH JUST A SLIM CHANCE FOR
SHOWERS/THUNDER WEST OF I-55 THURSDAY AFTERNOON.

LONG TERM...FRIDAY THROUGH MONDAY

UPPER RIDGE IS EXPECTED TO BUILD ACROSS THE MIDWEST BY THE END OF
THE WEEK...LEADING TO A HOT AND LARGELY DRY EXTENDED FORECAST.
STILL SOME QUESTION AS TO HOW QUICKLY THE RIDGE WILL BUILD AND
WHETHER ANY NOCTURNAL MCS ACTIVITY WILL IMPACT PARTS OF THE AREA
FRIDAY/SATURDAY...HOWEVER MODEL CONSENSUS CONTINUES TO SUGGEST
MOST OF THIS PRECIP WILL BE FOCUSED FURTHER NORTH ACROSS THE UPPER
MIDWEST INTO THE GREAT LAKES. WILL THEREFORE CONTINUE WITH A
MAINLY DRY FORECAST ACROSS CENTRAL ILLINOIS...WITH JUST SLIGHT
CHANCE POPS ACROSS THE FAR NORTH. MAIN STORY WILL BE THE HEAT...AS
HIGH TEMPS REACH THE 90S OVER THE WEEKEND. NEXT BIG QUESTION WILL
BE HOW QUICKLY THE RIDGE WILL FLATTEN EARLY NEXT WEEK. 00Z JUN 18
GFS/ECMWF ARE IN GOOD AGREEMENT THROUGH 168HR/00Z TUE...THEN
SOLUTIONS DIVERGE BY THE MIDDLE OF NEXT WEEK AS GFS HOLDS ONTO
RIDGING ACROSS THE MIDWEST...WHILE THE ECMWF SHIFTS THE RIDGE
FURTHER WEST INTO THE ROCKIES. BASED ON THE PATTERN WE HAVE BEEN
IN FOR MUCH OF THE SPRING...THINK ECMWF HAS A MORE REALISTIC
ANSWER. WILL THEREFORE GRADUALLY INTRODUCE SHOWERS/THUNDERSTORMS
INTO THE FORECAST ACROSS THE NORTHERN HALF OF THE CWA BY
MONDAY/MONDAY NIGHT...THEN EVERYWHERE TUESDAY AS THE RIDGE WEAKENS
AND A FRONTAL BOUNDARY SAGS SOUTHWARD INTO THE REGION.

&&

.AVIATION...
ISSUED 650 AM CDT TUE JUN 18 2013

LIGHT FOG WITH MVFR VSBYS POSSIBLE OVER CENTRAL IL TAF SITES NEXT
HOUR OR TWO ESPECIALLY AT BMI AND CMI ALONG WITH 500 FOOT BROKEN
CEILINGS BRIEFLY POSSIBLE. OTHERWISE A FRONTAL BOUNDARY PUSHING
SOUTHWARD TOWARD I-74 EARLY THIS MORNING WILL BE THE FOCUS FOR
ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AS IT PUSHES
SOUTHWARD ACROSS THE CENTRAL IL TERMINAL AIRPORTS. ALSO A VIGOROUS
SHORT WAVE (572 DM 500 MB LOW) NEAR THE MN/IA BORDER WILL TRACK SE
ACROSS CENTRAL IL THIS AFTERNOON AND PROVIDE ADDITIONAL LIFT WITH
UNSTABLE AIR MASS WITH CAPES OF 1500-2500 J/KG. HI-RES MODELS SHOW
I-74 TAF SITES MAY BE ON NORTHERN EDGE OF THIS CONVECTION DEVELOP
THIS AFTERNOON. HAVE VFR BROKEN CEILINGS AROUND 5K FT THIS
AFTERNOON...THEN SCATTERED OUT EARLY EVENING AND CLEAR BETWEEN
02-04Z THIS EVENING. WSW WINDS AROUND 5 KTS WILL TURN NE AND
INCREASE TO 7-11 KTS DURING THIS MORNING AND HAVE RECENLY DONE SO
AT BMI AS FRONTAL BOUNARY EASES SOUTHWARD FROM I-74. NE WINDS TO
DIMINISH LIGHT AFTER SUNSET TONIGHT.

07

&&

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

&&

$$


000
FXUS63 KLOT 181143
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
643 AM CDT TUE JUN 18 2013

.DISCUSSION...
330 AM CDT

PRIMARY FORECAST CHALLENGE THIS MORNING IS WITH PRECIP CHANCES
TODAY AND INTO THE WEEKEND...ALONG WITH POTENTIAL BIG WEEKEND WARM
UP.

SOMEWHAT DIFFUSE COLD FRONT...AIDED BY SOME LAKE ENHANCEMENT...HAS
PUSHED SOUTH OF THE CWA THIS MORNING WITH NORTH TO NORTHEAST WINDS
ADVECTING IN COOLER AND DRIER AIR MASS. HOWEVER...VIGOROUS SHORTWAVE
TROUGH OVER MN THIS MORNING IS PROGGED TO DROP SOUTHEAST TOWARD THE
AREA RESULTING IN A STEEPENING UP OF THE LOW AND ESPECIALLY MID
LEVEL LAPSE RATES RESULTING IN SOME INSTABILITY DEVELOPING.
INSTABILITY WILL BE MOST PRONOUNCED...ALBEIT LIKELY WEAK
STILL...WELL WEST AND SOUTH OF THE LAKE AS STABLE MARINE BOUNDARY
LAYER WILL BLEED WELL INLAND. NO REAL CHANGES MADE TO POPS TODAY
WITH EXPECTATION THAT THE GREATEST CHANCES OF CONVECTION WILL BE
FROM NC IL SE INTO SOUTHERN PORTIONS OF THE CWA. GIVEN THE STEEP
LAPSE RATES CAN NOT RULE OUT SOME SPRINKLES FALLING FROM SOME
ACCAS/MID DECK OVER CHICAGO AREA...BUT CHANCES LOOK TOO SLIM TO ADD
TO FORECAST.

A COUPLE OF TRULY SPECTACULAR WEATHER DAYS EXPECTED WEDNESDAY
AND PROBABLY INTO THURSDAY AS WELL. WEDNESDAY SHOULD FEATURE FULL
SUNSHINE AND BELOW AVERAGE TEMPERATURES WITH 70S INLAND AND 60S
LAKESIDE. TEMPS WILL WARM A COUPLE DEGREES ON THURSDAY...BUT
EXPECT SOME INCREASE IN MID-HIGH LEVEL CLOUDINESS IN THE AFTERNOON
AS REMNANTS OF DECAYING MCS POTENTIALLY MOVE INTO THE AREA. SOME
MODELS ARE SUGGESTING SOME PRECIP COULD MAKE IT INTO THE CWA
THURSDAY...ESPECIALLY WEST...BUT THINKING THAT CONVECTIVE ACTIVITY
SHOULD DRY UP PRETTY QUICKLY AS IT TRIES TO PENETRATE EASTWARD
INTO DRY CANADIAN AIR MASS OVER THE AREA.

FRIDAY THROUGH THE WEEKEND INTO EARLY NEXT WEEK LOOK PRETTY SUMMER
LIKE ON THE WHOLE. UPPER RIDGE IS PROGGED TO SPREAD EAST INTO THE
CENTRAL AND EVENTUALLY EASTERN CONUS...WITH OUR CWA LIKELY TO BE ON
THE NORTHERN FRINGES OF THIS RIDGE. THIS CERTAINLY COMPLICATES THE
FORECAST WITH RING OF FIRE PATTERN LIKELY TO SET UP ON THE PERIPHERY
OF THE RIDGE AND WITH OUR CWA LYING PRECARIOUSLY CLOSE TO THE EDGE
OF THE RIDGE AND STRONGER BELT OF WESTERLIES THE FORECAST IS A LOW
CONFIDENCE ONE. SYNOPTICALLY...IT WOULD APPEAR THE FRONT SHOULD LIE
NORTH OF THE CWA PUTTING US IN THE HOT AND HUMID AIR MASS WITH HIGHS
AROUND IF NOT INTO THE LOWER 90S. HOWEVER...SHOULD PARADE OF MCS
ACTIVITY NUDGE THE FRONT SOUTHWARD INTO THE AREA THEN TEMPS WOULD BE
COOLER WITH CLOUDS AND THUNDER POTENTIAL. UNFORTUNATELY AM LEFT WITH
LITTLE CHOICE OTHER THAN TO PAINT DAY AFTER DAY WITH CHANCES OF
SHOWERS AND THUNDERSTORMS...WHEN IN REALITY THE MAJORITY OF THE FRI
THROUGH MON PERIOD WILL BE DRY WITH A WORST CASE SCENARIO LIKELY
BEING ONE OR TWO ROUNDS OF THUNDERSTORMS.

IZZI

&&

.AVIATION...

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

* TIMING IMPROVEMENT OF LOW STRATUS/FOG THIS MORNING.

BMD

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

LOW CIGS DEVELOPED OVER LAKE MICHIGAN OVERNIGHT AND MOVED ONSHORE
EARLY THIS MORNING. NAM/RAP GUIDANCE WHICH HAD GOOD HANDLE ON THE
DEVELOPMENT OF THE LOW CIGS INDICATE IT WILL LINGER THROUGH 15Z TO
17Z BEFORE SCATTERING WITH DAYTIME HEATING AND MIXING.
THEREAFTER...EXPECT NORTHEASTERLY WINDS TO INCREASE WITH MIXING WITH
GUSTS INTO THE HIGH TEENS POSSIBLE THROUGH THE AFTERNOON AND
EVENING. VFR CONDITIONS WILL PREVAIL THE REMAINDER OF THE FORECAST
PERIOD AS INCREASINGLY DRIER AIRMASS TAKES HOLD OVER THE AREA. WINDS
SHOULD DECOUPLE AND DIMINISH LESS THAN 10 KTS OVERNIGHT. WINDS
SHOULD THEN VEER TO THE EAST WEDNESDAY AS THE HIGH SHIFTS SOUTHEAST
FROM THE NORTHERN GREAT LAKES REGION INTO MICHIGAN.

BMD


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

* MEDIUM CONFIDENCE IN TIMING RETURN TO VFR CONDITIONS.
* HIGH CONFIDENCE IN OTHER FORECAST ELEMENTS.

BMD

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

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY THROUGH MONDAY...PERIODIC CHANCES FOR THUNDERSTORMS...ELSE VFR.

BMD

&&

.MARINE...
300 AM CDT

A COLD FRONT HAS PUSHED SOUTH OF LAKE MICHIGAN AND HIGH PRESSURE
OVER THE NORTHERN LAKES REGION THIS MORNING WILL GRADUALLY SETTLE
SOUTHEAST OVER LAKE MICHIGAN TONIGHT AND WEDNESDAY. FRESH NORTHERLY
WINDS THIS MORNING WILL CONTINUE THROUGH TODAY AND THE PERSISTENT
AND LONG FETCH IS EXPECTED TO ALLOW WAVES TO BUILD ACROSS THE FAR
SOUTH PORTIONS OF THE LAKE AND NEARSHORE WATERS TO OR ABOVE 5
FT...THUS WILL ISSUE A SMALL CRAFT ADVISORY FOR THE INDIANA AND
EASTERN MOST ILLINOIS NEARSHORE ZONES. AS THE HIGH BUILDS SOUTH
OVERNIGHT WINDS AND WAVES SHOULD BEGIN TO DIMINISH. EXPECT LAKE
BREEZES TO DOMINATE THE WIND PATTERN WEDNESDAY AFTERNOON/EVENING.
LOW PRESSURE WILL BEGIN TO TAKE SHAPE OVER THE PLAINS AND THE
DEPARTING HIGH WILL ALLOW SOUTHERLY WINDS TO OVERTAKE THE LAKE
THURSDAY THROUGH THE WEEKEND. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL NOON TUESDAY.

     SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...1 PM
     TUESDAY TO 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KLOT 180916
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
416 AM CDT TUE JUN 18 2013

.DISCUSSION...
330 AM CDT

PRIMARY FORECAST CHALLENGE THIS MORNING IS WITH PRECIP CHANCES
TODAY AND INTO THE WEEKEND...ALONG WITH POTENTIAL BIG WEEKEND WARM
UP.

SOMEWHAT DIFFUSE COLD FRONT...AIDED BY SOME LAKE ENHANCEMENT...HAS
PUSHED SOUTH OF THE CWA THIS MORNING WITH NORTH TO NORTHEAST WINDS
ADVECTING IN COOLER AND DRIER AIR MASS. HOWEVER...VIGOROUS SHORTWAVE
TROUGH OVER MN THIS MORNING IS PROGGED TO DROP SOUTHEAST TOWARD THE
AREA RESULTING IN A STEEPENING UP OF THE LOW AND ESPECIALLY MID
LEVEL LAPSE RATES RESULTING IN SOME INSTABILITY DEVELOPING.
INSTABILITY WILL BE MOST PRONOUNCED...ALBEIT LIKELY WEAK
STILL...WELL WEST AND SOUTH OF THE LAKE AS STABLE MARINE BOUNDARY
LAYER WILL BLEED WELL INLAND. NO REAL CHANGES MADE TO POPS TODAY
WITH EXPECTATION THAT THE GREATEST CHANCES OF CONVECTION WILL BE
FROM NC IL SE INTO SOUTHERN PORTIONS OF THE CWA. GIVEN THE STEEP
LAPSE RATES CAN NOT RULE OUT SOME SPRINKLES FALLING FROM SOME
ACCAS/MID DECK OVER CHICAGO AREA...BUT CHANCES LOOK TOO SLIM TO ADD
TO FORECAST.

A COUPLE OF TRULY SPECTACULAR WEATHER DAYS EXPECTED WEDNESDAY
AND PROBABLY INTO THURSDAY AS WELL. WEDNESDAY SHOULD FEATURE FULL
SUNSHINE AND BELOW AVERAGE TEMPERATURES WITH 70S INLAND AND 60S
LAKESIDE. TEMPS WILL WARM A COUPLE DEGREES ON THURSDAY...BUT
EXPECT SOME INCREASE IN MID-HIGH LEVEL CLOUDINESS IN THE AFTERNOON
AS REMNANTS OF DECAYING MCS POTENTIALLY MOVE INTO THE AREA. SOME
MODELS ARE SUGGESTING SOME PRECIP COULD MAKE IT INTO THE CWA
THURSDAY...ESPECIALLY WEST...BUT THINKING THAT CONVECTIVE ACTIVITY
SHOULD DRY UP PRETTY QUICKLY AS IT TRIES TO PENETRATE EASTWARD
INTO DRY CANADIAN AIR MASS OVER THE AREA.

FRIDAY THROUGH THE WEEKEND INTO EARLY NEXT WEEK LOOK PRETTY SUMMER
LIKE ON THE WHOLE. UPPER RIDGE IS PROGGED TO SPREAD EAST INTO THE
CENTRAL AND EVENTUALLY EASTERN CONUS...WITH OUR CWA LIKELY TO BE ON
THE NORTHERN FRINGES OF THIS RIDGE. THIS CERTAINLY COMPLICATES THE
FORECAST WITH RING OF FIRE PATTERN LIKELY TO SET UP ON THE PERIPHERY
OF THE RIDGE AND WITH OUR CWA LYING PRECARIOUSLY CLOSE TO THE EDGE
OF THE RIDGE AND STRONGER BELT OF WESTERLIES THE FORECAST IS A LOW
CONFIDENCE ONE. SYNOPTICALLY...IT WOULD APPEAR THE FRONT SHOULD LIE
NORTH OF THE CWA PUTTING US IN THE HOT AND HUMID AIR MASS WITH HIGHS
AROUND IF NOT INTO THE LOWER 90S. HOWEVER...SHOULD PARADE OF MCS
ACTIVITY NUDGE THE FRONT SOUTHWARD INTO THE AREA THEN TEMPS WOULD BE
COOLER WITH CLOUDS AND THUNDER POTENTIAL. UNFORTUNATELY AM LEFT WITH
LITTLE CHOICE OTHER THAN TO PAINT DAY AFTER DAY WITH CHANCES OF
SHOWERS AND THUNDERSTORMS...WHEN IN REALITY THE MAJORITY OF THE FRI
THROUGH MON PERIOD WILL BE DRY WITH A WORST CASE SCENARIO LIKELY
BEING ONE OR TWO ROUNDS OF THUNDERSTORMS.

IZZI

&&

.AVIATION...

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

* POTENTIAL FOR LOW CIGS OVERNIGHT.

BMD

//DISCUSSION...UPDATED 09Z...
BLOSSOMING AREA OF STRATUS IS MOVING ONSHORE FROM LAKE MICHIGAN THIS
HOUR AND MAY IMPACT THE CHICAGO TERMINALS IN THE NEXT HOUR OR SO.
SOME OF THE NEAR-SHORE OBSERVING PLAFORMS ARE INDICATING 007-012
CIGS. RAP/NAM WHICH SEEM TO HAVE HANDLED THE DEVELOPMENT WELL SHOW
CIGS SCATTERING OUT SOMEWHERE BETWEEN 14Z AND 16Z.

PREVIOUS DISCUSSION...06Z...
A COLD FRONT HAS DROPPED SOUTH ACROSS THE
TERMINALS LEAVING NORTHEAST FLOW OVER NORTHERN ILLINOIS AS HIGH
PRESSURE BUILDS ACROSS THE PLAINS AND NORTHERN LAKES REGION. THE
HIGH IS EXPECTED TO VERY GRADUALLY CONSOLIDATE AND SINK SOUTH
TOWARDS NORTHERN LAKE MICHIGAN THROUGH THE DAY TUESDAY LEADING TO
VERY LITTLE CHANCE IN THE WEATHER THROUGH THE FORECAST PERIOD.
WINDS WILL PICK UP WITH ONSET OF MIXING DURING THE DAY
TUESDAY...THEN SHOULD DIMINISH AFTER SUNSET. VFR CLOUDS EXPECTED
THROUGH THE PERIOD...BUT CONTINUE TO MONITOR CLOSELY THE CHANCE
FOR LOWER CIGS DEVELOPING OVERNIGHT INTO THE EARLY MORNING HOURS.
NAM/RAP SOUNDINGS CONTINUE TO ADVERTISE THE POTENTIAL FOR IFR CIGS
TO DEVELOP AS THE COLUMN COOLS...BUT SEE NO SIGN OF THIS YET
UPSTREAM AND OTHER MODELS AS LESS BULLISH ON THE DEVELOPMENT. NAM
HAS A TENDENCY TO OVERDO LOW LEVEL MOISTURE SO FOR NOW WILL
MONITOR CLOSELY. IF LOW CIGS DO DEVELOP THE BEST TIME FRAME WOULD
BE ROUGHLY 09-14Z.

BMD

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

* HIGH CONFIDENCE IN LOW CIGS DEVELOPING.
* HIGH CONFIDENCE IN OTHER FORECAST ELEMENTS.

BMD

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

WEDNESDAY...VFR.

THURSDAY...VFR.

FRIDAY...VFR EARLY...CHANCE OF TSRA OVERNIGHT.

SATURDAY AND SUNDAY...PERIODIC CHANCES FOR TSRA.

LENNING

&&

.MARINE...
300 AM CDT

A COLD FRONT HAS PUSHED SOUTH OF LAKE MICHIGAN AND HIGH PRESSURE
OVER THE NORTHERN LAKES REGION THIS MORNING WILL GRADUALLY SETTLE
SOUTHEAST OVER LAKE MICHIGAN TONIGHT AND WEDNESDAY. FRESH NORTHERLY
WINDS THIS MORNING WILL CONTINUE THROUGH TODAY AND THE PERSISTENT
AND LONG FETCH IS EXPECTED TO ALLOW WAVES TO BUILD ACROSS THE FAR
SOUTH PORTIONS OF THE LAKE AND NEARSHORE WATERS TO OR ABOVE 5
FT...THUS WILL ISSUE A SMALL CRAFT ADVISORY FOR THE INDIANA AND
EASTERN MOST ILLINOIS NEARSHORE ZONES. AS THE HIGH BUILDS SOUTH
OVERNIGHT WINDS AND WAVES SHOULD BEGIN TO DIMINISH. EXPECT LAKE
BREEZES TO DOMINATE THE WIND PATTERN WEDNESDAY AFTERNOON/EVENING.
LOW PRESSURE WILL BEGIN TO TAKE SHAPE OVER THE PLAINS AND THE
DEPARTING HIGH WILL ALLOW SOUTHERLY WINDS TO OVERTAKE THE LAKE
THURSDAY THROUGH THE WEEKEND. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...1 PM
     TUESDAY TO 4 AM WEDNESDAY.

&&

$$

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

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


000
FXUS63 KLOT 180830
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 AM CDT TUE JUN 18 2013

.DISCUSSION...
330 AM CDT

PRIMARY FORECAST CHALLENGE THIS MORNING IS WITH PRECIP CHANCES
TODAY AND INTO THE WEEKEND...ALONG WITH POTENTIAL BIG WEEKEND WARM
UP.

SOMEWHAT DIFFUSE COLD FRONT...AIDED BY SOME LAKE ENHANCEMENT...HAS
PUSHED SOUTH OF THE CWA THIS MORNING WITH NORTH TO NORTHEAST WINDS
ADVECTING IN COOLER AND DRIER AIR MASS. HOWEVER...VIGOROUS SHORTWAVE
TROUGH OVER MN THIS MORNING IS PROGGED TO DROP SOUTHEAST TOWARD THE
AREA RESULTING IN A STEEPENING UP OF THE LOW AND ESPECIALLY MID
LEVEL LAPSE RATES RESULTING IN SOME INSTABILITY DEVELOPING.
INSTABILITY WILL BE MOST PRONOUNCED...ALBEIT LIKELY WEAK
STILL...WELL WEST AND SOUTH OF THE LAKE AS STABLE MARINE BOUNDARY
LAYER WILL BLEED WELL INLAND. NO REAL CHANGES MADE TO POPS TODAY
WITH EXPECTATION THAT THE GREATEST CHANCES OF CONVECTION WILL BE
FROM NC IL SE INTO SOUTHERN PORTIONS OF THE CWA. GIVEN THE STEEP
LAPSE RATES CAN NOT RULE OUT SOME SPRINKLES FALLING FROM SOME
ACCAS/MID DECK OVER CHICAGO AREA...BUT CHANCES LOOK TOO SLIM TO ADD
TO FORECAST.

A COUPLE OF TRUELY SPECTACULAR WEATHER DAYS EXPECTED WEDNESDAY AND
PROBABLY INTO THURSDAY AS WELL. WEDNESDAY SHOULD FEATURE FULL
SUNSHINE AND BELOW AVERAGE TEMPERATURES WITH 70S INLAND AND 60S
LAKESIDE. TEMPS WILL WARM A COUPLE DEGREES ON THURSDAY...BUT EXPECT
SOME INCREASE IN MID-HIGH LEVEL CLOUDINESS IN THE AFTERNOON AS
REMNANTS OF DECAYING MCS POTENTIALLY MOVE INTO THE AREA. SOME
MODELS ARE SUGGESTING SOME PRECIP COULD MAKE IT INTO THE CWA
THURSDAY...ESPECIALLY WEST...BUT THINKING THAT CONVECTIVE ACTIVITY
SHOULD DRY UP PRETTY QUICKLY AS IT TRIES TO PENETRATE EASTWARD INTO
DRY CANADIAN AIR MASS OVER THE AREA.

FRIDAY THROUGH THE WEEKEND INTO EARLY NEXT WEEK LOOK PRETTY SUMMER
LIKE ON THE WHOLE. UPPER RIDGE IS PROGGED TO SPREAD EAST INTO THE
CENTRAL AND EVENTUALLY EASTERN CONUS...WITH OUR CWA LIKELY TO BE ON
THE NORTHERN FRINGES OF THIS RIDGE. THIS CERTAINLY COMPLICATES THE
FORECAST WITH RING OF FIRE PATTERN LIKELY TO SET UP ON THE PERIPHERY
OF THE RIDGE AND WITH OUT CWA LYING PRECARIOUSLY CLOSE TO THE EDGE
OF THE RIDGE AND STRONGER BELT OF WESTERLIES THE FORECAST IS A LOW
CONFIDENCE ONE. SYNOPTICALLY...IT WOULD APPEAR THE FRONT SHOULD LIE
NORTH OF THE CWA PUTTING US IN THE HOT AND HUMID AIR MASS WITH HIGHS
AROUND IF NOT INTO THE LOWER 90S. HOWEVER...SHOULD PARADE OF MCS
ACTIVITY NUDGE THE FRONT SOUTHWARD INTO THE AREA THEN TEMPS WOULD BE
COOLER WITH CLOUDS AND THUNDER POTENTIAL. UNFORTUNATELY AM LEFT WITH
LITTLE CHOICE OTHER THAN TO PAINT DAY AFTER DAY WITH CHANCES OF
SHOWERS AND THUNDERSTORMS...WHEN IN REALITY THE MAJORITY OF THE FRI
THROUGH MON PERIOD WILL BE DRY WITH A WORST CASE SCENARIO LIKELY
BEING ONE OR TWO ROUNDS OF THUNDERSTORMS.

IZZI

&&

.AVIATION...

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

* POTENTIAL FOR LOW CIGS OVERNIGHT.

BMD

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

A COLD FRONT HAS DROPPED SOUTH ACROSS THE TERMINALS LEAVING
NORTHEAST FLOW OVER NORTHERN ILLINOIS AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS AND NORTHERN LAKES REGION. THE HIGH IS EXPECTED TO VERY
GRADUALLY CONSOLIDATE AND SINK SOUTH TOWARDS NORTHERN LAKE MICHIGAN
THROUGH THE DAY TUESDAY LEADING TO VERY LITTLE CHANCE IN THE WEATHER
THROUGH THE FORECAST PERIOD. WINDS WILL PICK UP WITH ONSET OF MIXING
DURING THE DAY TUESDAY...THEN SHOULD DIMINISH AFTER SUNSET. VFR
CLOUDS EXPECTED THROUGH THE PERIOD...BUT CONTINUE TO MONITOR CLOSELY
THE CHANCE FOR LOWER CIGS DEVELOPING OVERNIGHT INTO THE EARLY
MORNING HOURS. NAM/RAP SOUNDINGS CONTINUE TO ADVERTISE THE POTENTIAL
FOR IFR CIGS TO DEVELOP AS THE COLUMN COOLS...BUT SEE NO SIGN OF
THIS YET UPSTREAM AND OTHER MODELS AS LESS BULLISH ON THE
DEVELOPMENT. NAM HAS A TENDENCY TO OVERDO LOW LEVEL MOISTURE SO FOR
NOW WILL MONITOR CLOSELY. IF LOW CIGS DO DEVELOP THE BEST TIME FRAME
WOULD BE ROUGHLY 09-14Z.

BMD

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

* LOW CONFIDENCE IN LOW CIGS DEVELOPING.
* HIGH CONFIDENCE IN OTHER FORECAST ELEMENTS.

BMD

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

WEDNESDAY...VFR.

THURSDAY...VFR.

FRIDAY...VFR EARLY...CHANCE OF TSRA OVERNIGHT.

SATURDAY AND SUNDAY...PERIODIC CHANCES FOR TSRA.

LENNING

&&

.MARINE...
300 AM CDT

A COLD FRONT HAS PUSHED SOUTH OF LAKE MICHIGAN AND HIGH PRESSURE
OVER THE NORTHERN LAKES REGION THIS MORNING WILL GRADUALLY SETTLE
SOUTHEAST OVER LAKE MICHIGAN TONIGHT AND WEDNESDAY. FRESH NORTHERLY
WINDS THIS MORNING WILL CONTINUE THROUGH TODAY AND THE PERSISTENT
AND LONG FETCH IS EXPECTED TO ALLOW WAVES TO BUILD ACROSS THE FAR
SOUTH PORTIONS OF THE LAKE AND NEARSHORE WATERS TO OR ABOVE 5
FT...THUS WILL ISSUE A SMALL CRAFT ADVISORY FOR THE INDIANA AND
EASTERN MOST ILLINOIS NEARSHORE ZONES. AS THE HIGH BUILDS SOUTH
OVERNIGHT WINDS AND WAVES SHOULD BEGIN TO DIMINISH. EXPECT LAKE
BREEZES TO DOMINATE THE WIND PATTERN WEDNESDAY AFTERNOON/EVENING.
LOW PRESSURE WILL BEGIN TO TAKE SHAPE OVER THE PLAINS AND THE
DEPARTING HIGH WILL ALLOW SOUTHERLY WINDS TO OVERTAKE THE LAKE
THURSDAY THROUGH THE WEEKEND. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...NONE.
&&

$$

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

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


000
FXUS63 KLOT 180800
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
300 AM CDT TUE JUN 18 2013

.DISCUSSION...
929 PM CDT

A SCATTERING OF SHOWERS WITH A FEW STORMS HAVE SEEN AN OVERALL
DIMINISHING IN COVERAGE SINCE 8 PM. ALMOST ALL NEW DEVELOPMENT IN
THAT TIME HAS BEEN ON OUTFLOW FROM PRECEDING SHOWERS/STORMS...WITH
THE 00Z DVN RAOB INDICATING INSTABILITY PRESENT FROM THE AFTERNOON
MIXED LAYER. SOME FESTERING ON OUTFLOWS IS LIKELY TO CONTINUE
ALTHOUGH EACH SUCCESSIVE REDEVELOPMENT SHOULD BE WEAKER. THE AREA
WILL REMAIN UNDER A FAVORABLE MID-LEVEL JET REGION INTO
OVERNIGHT...BUT THERE APPEARS TO BE A BREAK IN SHORT WAVES LET
ALONE THE DIMINISHING OF THE INSTABILITY WITH THE TIME OF DAY. SO
CONTINUE WITH NO SHOWERS FORECAST BY 1 AM.

OUTFLOWS BROUGHT RAIN-COOLED AIR ALONG WITH THE MARINE LAYER INTO
FAR NORTHEAST IL THAT CREATED A QUICK TEMPERATURE DROP. LOWS
STILL LOOK ON TRACK FOR MOST AREAS...ALTHOUGH DID BRING DOWN THE
FAR NORTHERN TWO TIERS OF COUNTIES A COUPLE DEGREES BASED ON THIS
LOWER STARTING POINT GOING INTO THE NIGHT. IF WINDS WERE LIGHTER
FOG MAY BE A CONCERN IN THOSE AREAS THAT SAW SHOWERS...BUT SPEEDS
WILL STAY UP TONIGHT AS THE SYNOPTIC COLD FRONT WORKS THROUGH THE
REGION.

THE GOES WV LOOP SHOWS THE NEXT SHORT WAVE BEING WELL-DEFINED IN
SOUTHEAST ND. THIS SMALL "BOWLING BALL" IN THE MID-LEVEL FLOW
LOOKS TO TRACK ACROSS THE SOUTHWEST FORECAST AREA DURING TUE
AFTERNOON. THE AMOUNT OF INSTABILITY ON GUIDANCE IS STRONGLY
CORRELATED TO THE SURFACE DEW POINT FORECAST...WHICH COULD BE HIGH
ON BOTH THE NAM AND GFS PER OBSERVATIONAL TRENDS AND INITIALIZATION
/AT LEAST ON THE 18Z RUNS/. STILL ENOUGH TO WARRANT A SLIGHT
CHANCE THOUGH...AS THERE CURRENTLY ARE STORMS WITH THE FEATURE IN
THE DAKOTAS AT THIS HOUR.

MTF

//PREV DISCUSSION...
251 PM CDT

TONIGHT...
VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CIRRUS SHIELD FROM
SOUTHEAST IOWA STRETCHING NORTHEAST ALONG I-80 IN ILLINOIS INTO
NORTHCENTRAL INDIANA. WATER VAPOR IMAGERY ALSO INDICATED AN
ABUNDANCE OF UPR LEVEL MOISTURE ASSOCIATED WITH THE CLOUDS...HOWEVER
SOME SUBSIDENCE WAS OCCURRING LATE THIS MORNING INTO THE AFTERNOON
HOURS AS DEW POINTS AT THE SFC WERE DROPPING INTO THE MID/UPR 50S
ACROSS THE CWFA. LLVL FLOW UNDER THE CLOUD SHIELD WAS GENERALLY
SOUTHWESTERLY...WHILE FURTHER NORTH WINDS WERE WESTERLY. IT APPEARS
THAT WHERE SKIES ARE MOSTLY SUNNY SLIGHTLY BETTER MIXING WAS
OCCURRING...WHICH WAS ALSO AIDING IN THE SUBSIDENCE AT THE SFC.

THE FOCUS FOR LATER THIS AFTERNOON/EVENING IS ON THE APPROACHING
FRONTAL BOUNDARY AND POTENTIAL FOR ISOLATED SHOWERS/THUNDERSTORMS
ALONG/JUST AHEAD OF THIS BOUNDARY. VISIBLE IMAGERY DOES SHOW A
NARROW CHANNEL OF A CUMULUS FIELD DEVELOPING ACROSS CENTRAL WISC
THIS AFTERNOON...STRETCHING NORTHWEST THROUGH MINN. A WEAK MID-LVL
WAVE WAS SLIDING SOUTHEAST THE UPPER MIDWEST...WHICH WILL BE THE
DRIVER FOR SOME ADDED LIFT INTO THIS CUMULUS FIELD. AS EXPECTED
ISOLATED SHOWERS/THUNDERSTORMS WERE DEVELOPING UNDER THIS CHANNEL OF
CUMULUS ACROSS CENTRAL WISC/EASTERN MINN. MID-LVLS ARE MUCH
COOLER...WITH STEEP LAPSE RATES TO THE NORTH ACROSS WISC. THIS
SUGGESTS THAT A FEW THUNDERSTORMS COULD EASILY GROW VERTICALLY AND
POSSIBLY PRODUCE SOME HAIL. FEEL THAT MOST OF THE LATE AFTN/EARLY
EVENING WILL END UP BEING DRY FOR THE CWFA. GUIDANCE CONTINUES TO
SUGGEST THAT THE BEST CHC FOR ANY PRECIP WILL LIKELY OCCUR AFT 00Z.
WITH MUCH OF THE CONVECTIVE POTENTIAL BEING DIURNALLY
DRIVEN...EXPECT THAT ARND 2-3Z THE INSTABILITY TO GREATLY DIMINISH.
AT THIS TIME WILL HOLD ONTO THE SLIGHT CHC OF TSRA WORDING THRU 3Z.
ACROSS THE NORTH...THEN LINGER THE TSRA WORDING THRU 06Z FOR THE
SOUTHEAST CWFA.

EARLIER THINKING WAS THAT THIS BOUNDARY WOULD END UP BEING A BACK
DOOR COLD FRONT...AND THIS APPEARS TO BE THE CASE BASED ON CURRENT
CONDS TO THE NORTH. CLOUD COVER SHUD BE SLOWLY THINNING OVERNIGHT TO
A P-CLOUDY SKY...WITH WINDS TURNING NORTHERLY POST FRONTAL PASSAGE.
THIS WILL USHER IN MUCH COOLER AIR AND ALLOW TEMPS TO EASILY RADIATE
INTO THE MID/UPR 50S.

CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...LOW/MEDIUM.

TUESDAY THROUGH WEDNESDAY...
INITIAL GLANCE IS THAT TUE WOULD BE DRY...HOWEVER THE CONCERN IS ON
THE SOUTHEAST DIVING 500MB VORT THAT WILL BE ARRIVING ACROSS THE
WESTERN CWFA MID/LATE MORNING AND PIVOTING EAST BY THE MID-AFTERNOON
HOURS. THIS MAY PROVIDE ENOUGH LIFT...COUPLED WITH DIURNAL CUMULUS
TUE...AND SOME MOISTURE FROM THE BOUNDARY TO ALLOW A FEW
THUNDERSTORMS TO DEVELOP. WITH TEMPS ALOFT STEADILY COOLING ACROSS
THE CWFA...LAPSE RATES WILL STEEPEN AND A FEW STRONGER STORMS COULD
EASILY PRODUCE SOME PEA SIZE HAIL...BRIEF WIND GUSTS AND HEAVY
DOWNPOURS. THE FOCUS APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO
BENTON COUNTY LINE.

OTHERWISE ANTI-CYCLONIC FLOW WILL CONTINUE TO SETTLE INTO THE GREAT
LAKES REGION...AND KEEP A NORTHEAST FLOW AT THE SFC. THIS WILL
EASILY AID IN THE MUCH COOLER MARINE ENVIRONMENT ADVECTING INLAND
ACROSS THE CWFA AND KEEP SFC TEMPS IN THE LOW/MID 70S...EXCEPT THE
FAR SOUTH/SOUTHWEST WHERE TEMPS MAY STILL TOUCH 80 DEG IN THE AFTN.
LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN MAY HAVE TEMPS
REMAIN IN THE MID 60S TUE.

OVERNIGHT TEMPS WILL BE MUCH COOLER IN THE LOW/MID 50S. A FEW
LOCATIONS ALONG AND NORTH OF A ROCKFORD...AURORA...WAUKEGAN LINE MAY
HAVE TEMPS IN THE UPR 40S EARLY WED MORNING. THEN HIGH PRESSURE
BEGINS TO DRIFT EAST. WHILE WINDS WILL BE MORE EASTERLY OFF OF THE
LAKE...TEMPS WILL BE SLIGHTLY WARMER WED AFTN IN THE UPR 70S TO LOW
80S. THE EXCEPTION WILL BE AREAS ADJACENT TO LAKE MICHIGAN...WHERE
TEMPS WILL LIKELY REMAIN IN THE 60S TO LOW 70S.

CONFIDENCE...HIGH.

THURSDAY THROUGH SUNDAY...
ENSEMBLES CONTINUES TO POINT TOWARDS A PATTERN CHANGE FOR THE END OF
THE WEEK INTO THE WEEKEND. MANY GUIDANCE MEMBERS ARE IN AGREEMENT
THAT THE 500MB TROUGH OVER THE GREAT LAKES REGION WILL PIVOT EAST
THUR...WITH A STRENGTHENING MID-LVL RIDGE ACROSS THE CENTRAL PLAINS
REPLACING THE DEPARTING TROUGH FRI. THE RIDGE DOES APPEAR TO FLATTEN
SLIGHTLY...WHICH MAY BE AN INDICATION THAT A SLIGHTLY ACTIVE PERIOD
MAY ACCOMPANY THE STEADY WARMING TREND. 850MB THERMAL RIDGE
CONTINUES TO BE RATHER WARM FOR THE WEEKEND...WITH TEMPS GENERALLY
AROUND 20-22 DEG C. THE EC/GEM HAVE TAKEN A SLIGHTLY COOLER APPROACH
WITH 18-20 DEG C...HOWEVER THE OVERALL THEME IS THAT TEMPS WILL BE
STEADILY WARMING. THE WILDCARD FOR MAX TEMPS SAT/SUN/MON...WILL BE
LLVL MOISTURE AND CLOUD COVER. GUIDANCE CONTINUES TO SUGGEST DEW
POINTS WILL GENERALLY BE AROUND 70 DEG. THIS MAY SLOW THE DIURNAL
CURVE FOR THE WEEKEND...HOWEVER TEMPS SHUD EASILY STILL WARM INTO
THE UPR 80S TO POSSIBLY LOWER 90S. AS A RESULT HAVE NUDGED TEMPS
WARMER THAN GUIDANCE FOR THE UPCOMING WEEKEND.

CONFIDENCE IN TEMPERATURES...MEDIUM/HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...MEDIUM.

BEACHLER

&&

.AVIATION...

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

* POTENTIAL FOR LOW CIGS OVERNIGHT.

BMD

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

A COLD FRONT HAS DROPPED SOUTH ACROSS THE TERMINALS LEAVING
NORTHEAST FLOW OVER NORTHERN ILLINOIS AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS AND NORTHERN LAKES REGION. THE HIGH IS EXPECTED TO VERY
GRADUALLY CONSOLIDATE AND SINK SOUTH TOWARDS NORTHERN LAKE MICHIGAN
THROUGH THE DAY TUESDAY LEADING TO VERY LITTLE CHANCE IN THE WEATHER
THROUGH THE FORECAST PERIOD. WINDS WILL PICK UP WITH ONSET OF MIXING
DURING THE DAY TUESDAY...THEN SHOULD DIMINISH AFTER SUNSET. VFR
CLOUDS EXPECTED THROUGH THE PERIOD...BUT CONTINUE TO MONITOR CLOSELY
THE CHANCE FOR LOWER CIGS DEVELOPING OVERNIGHT INTO THE EARLY
MORNING HOURS. NAM/RAP SOUNDINGS CONTINUE TO ADVERTISE THE POTENTIAL
FOR IFR CIGS TO DEVELOP AS THE COLUMN COOLS...BUT SEE NO SIGN OF
THIS YET UPSTREAM AND OTHER MODELS AS LESS BULLISH ON THE
DEVELOPMENT. NAM HAS A TENDENCY TO OVERDO LOW LEVEL MOISTURE SO FOR
NOW WILL MONITOR CLOSELY. IF LOW CIGS DO DEVELOP THE BEST TIME FRAME
WOULD BE ROUGHLY 09-14Z.

BMD

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

* LOW CONFIDENCE IN LOW CIGS DEVELOPING.
* HIGH CONFIDENCE IN OTHER FORECAST ELEMENTS.

BMD

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

WEDNESDAY...VFR.

THURSDAY...VFR.

FRIDAY...VFR EARLY...CHANCE OF TSRA OVERNIGHT.

SATURDAY AND SUNDAY...PERIODIC CHANCES FOR TSRA.

LENNING

&&

.MARINE...
300 AM CDT

A COLD FRONT HAS PUSHED SOUTH OF LAKE MICHIGAN AND HIGH PRESSURE
OVER THE NORTHERN LAKES REGION THIS MORNING WILL GRADUALLY SETTLE
SOUTHEAST OVER LAKE MICHIGAN TONIGHT AND WEDNESDAY. FRESH NORTHERLY
WINDS THIS MORNING WILL CONTINUE THROUGH TODAY AND THE PERSISTENT
AND LONG FETCH IS EXPECTED TO ALLOW WAVES TO BUILD ACROSS THE FAR
SOUTH PORTIONS OF THE LAKE AND NEARSHORE WATERS TO OR ABOVE 5
FT...THUS WILL ISSUE A SMALL CRAFT ADVISORY FOR THE INDIANA AND
EASTERN MOST ILLINOIS NEARSHORE ZONES. AS THE HIGH BUILDS SOUTH
OVERNIGHT WINDS AND WAVES SHOULD BEGIN TO DIMINISH. EXPECT LAKE
BREEZES TO DOMINATE THE WIND PATTERN WEDNESDAY AFTERNOON/EVENING.
LOW PRESSURE WILL BEGIN TO TAKE SHAPE OVER THE PLAINS AND THE
DEPARTING HIGH WILL ALLOW SOUTHERLY WINDS TO OVERTAKE THE LAKE
THURSDAY THROUGH THE WEEKEND. BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...4 PM
     TUESDAY TO 4 AM WEDNESDAY.

&&

$$

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000
FXUS63 KILX 180754
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
254 AM CDT TUE JUN 18 2013

.DISCUSSION...
ISSUED 254 AM CDT TUE JUN 18 2013

SHORT TERM...TODAY THROUGH THURSDAY

07Z/2AM SURFACE ANALYSIS SHOWS A WEAK COLD FRONT EXTENDING FROM
NORTHEAST IOWA E/SE ACROSS NORTH-CENTRAL ILLINOIS. THIS BOUNDARY
WILL BE THE PRIMARY FOCUSING MECHANISM FOR WIDELY SCATTERED
CONVECTION AS IT SAGS SLOWLY SOUTHWARD LATER TODAY. VIGOROUS
SHORT-WAVE TROUGH CURRENTLY NOTED ON WATER VAPOR IMAGERY OVER
SOUTHERN MINNESOTA WILL TRACK SOUTHEASTWARD AS WELL...PROVIDING
ENHANCED LIFT ACROSS THE AREA DURING PEAK HEATING. WITH SURFACE
DEWPOINTS ALONG/SOUTH OF THE BOUNDARY IN THE MIDDLE TO UPPER
60S...CAPE VALUES WILL REACH THE 1500 TO 2500J/KG RANGE. IN
ADDITION...0-6KM SHEAR WILL INCREASE TO AROUND 40KT ON THE SOUTHERN
PERIPHERY OF THE APPROACHING WAVE. ALL THESE INGREDIENTS WILL COME
TOGETHER TO PRODUCE SCATTERED THUNDERSTORMS THIS AFTERNOON...A FEW
OF WHICH COULD PRODUCE GUSTY WINDS AND HAIL. WILL CARRY 30-40 POPS
ACROSS THE ENTIRE AREA ACCORDINGLY. AS DAYTIME INSTABILITY IS
LOST...CONVECTION WILL DISSIPATE AFTER SUNSET. WILL LINGER A
SLIGHT CHANCE POP ACROSS THE S/SW KILX CWA THIS EVENING...THEN
WILL GO DRY ACROSS THE BOARD OVERNIGHT.

SURFACE HIGH PRESSURE BUILDING INTO THE REGION BEHIND THE
DEPARTING FRONT WILL PROVIDE WARM/DRY WEATHER ON WEDNESDAY...WITH
AFTERNOON HIGHS IN THE LOWER 80S AND OVERNIGHT LOWS IN THE LOWER
60S. NEXT APPROACHING UPPER WAVE WILL COME INTO THE PICTURE ON
THURSDAY...AS A PIECE OF ENERGY EJECTS EASTWARD FROM DEEP UPPER
LOW SPINNING OFF THE COAST OF THE PACIFIC NORTHWEST. THIS WAVE IS
PROGGED TO TRACK ACROSS CENTRAL ILLINOIS ON THURSDAY. DESPITE
SYNOPTIC LIFT ASSOCIATED WITH THIS FEATURE...AIRMASS WILL BE
RATHER DRY...SO AM NOT EXPECTING MUCH IN THE WAY OF PRECIP. HAVE
GONE WITH A PARTLY SUNNY FORECAST...WITH JUST A SLIM CHANCE FOR
SHOWERS/THUNDER WEST OF I-55 THURSDAY AFTERNOON.

LONG TERM...FRIDAY THROUGH MONDAY

UPPER RIDGE IS EXPECTED TO BUILD ACROSS THE MIDWEST BY THE END OF
THE WEEK...LEADING TO A HOT AND LARGELY DRY EXTENDED FORECAST.
STILL SOME QUESTION AS TO HOW QUICKLY THE RIDGE WILL BUILD AND
WHETHER ANY NOCTURNAL MCS ACTIVITY WILL IMPACT PARTS OF THE AREA
FRIDAY/SATURDAY...HOWEVER MODEL CONSENSUS CONTINUES TO SUGGEST
MOST OF THIS PRECIP WILL BE FOCUSED FURTHER NORTH ACROSS THE UPPER
MIDWEST INTO THE GREAT LAKES. WILL THEREFORE CONTINUE WITH A
MAINLY DRY FORECAST ACROSS CENTRAL ILLINOIS...WITH JUST SLIGHT
CHANCE POPS ACROSS THE FAR NORTH. MAIN STORY WILL BE THE HEAT...AS
HIGH TEMPS REACH THE 90S OVER THE WEEKEND. NEXT BIG QUESTION WILL
BE HOW QUICKLY THE RIDGE WILL FLATTEN EARLY NEXT WEEK. 00Z JUN 18
GFS/ECMWF ARE IN GOOD AGREEMENT THROUGH 168HR/00Z TUE...THEN
SOLUTIONS DIVERGE BY THE MIDDLE OF NEXT WEEK AS GFS HOLDS ONTO
RIDGING ACROSS THE MIDWEST...WHILE THE ECMWF SHIFTS THE RIDGE
FURTHER WEST INTO THE ROCKIES. BASED ON THE PATTERN WE HAVE BEEN
IN FOR MUCH OF THE SPRING...THINK ECMWF HAS A MORE REALISTIC
ANSWER. WILL THEREFORE GRADUALLY INTRODUCE SHOWERS/THUNDERSTORMS
INTO THE FORECAST ACROSS THE NORTHERN HALF OF THE CWA BY
MONDAY/MONDAY NIGHT...THEN EVERYWHERE TUESDAY AS THE RIDGE WEAKENS
AND A FRONTAL BOUNDARY SAGS SOUTHWARD INTO THE REGION.

BARNES
&&

.AVIATION...
ISSUED 1153 PM CDT MON JUN 17 2013

SCATTERED HIGH CIRRUS WILL SLOWLY MOVE ACROSS AND OUT OF THE AREA
OVERNIGHT AT ALL SITES. THEN EXPECTING LIGHT FOG TO
REDEVELOP...BUT NOT AS BAD AS LAST NIGHT AND NOT AS SOON. SO LIGHT
FOG WILL BE IN MVFR CATEGORY TOWARD MORNING AND LIKELY DISSIPATE
QUICKLY AFTER SUNRISE. THEN EXPECTING SOME SCATTERED CU DURING THE
MORNING HOURS AHEAD OF THE NEXT SYSTEM COMING DOWN FROM THE
NORTHWEST. MODELS SUGGEST A POSSIBILITY OF SCATTERED THUNDERSTORMS
ACROSS PARTS OF CENTRAL ILLINOIS DURING THE AFTERNOON
HOURS...MAINLY ALONG THE I-74 CORRIDOR. SO WILL HAVE VCTS AT
PIA...BMI...CMI FOR THE AFTERNOON. HAVE DECIDED TO INCLUDE SPI AND
DEC AS WELL GIVEN THEY WILL BE CLOSE TO THE BOUNDARY AS WELL AND
OUTFLOW BOUNDARIES FROM EXISTING STORMS COULD PRODUCE ADDITIONAL
STORMS TO THE WEST OF THE BOUNDARY. THEN AROUND SUNSET EXPECTING
PCPN TO END AND ALSO PUSH TO THE EAST AND SOUTHEAST. SKIES SHOULD
BECOME SCATTERED AGAIN FOR THE EVENING. DO NOT SE FOG POTENTIAL
TOMORROW NIGHT AS DRIER AIR SHOULD ADVECT INTO THE REGION. WINDS
WILL BE LIGHT AND VARIABLE OVERNIGHT AND THEN BECOME NORTHERLY
ALONG THE FRONT AND TOMORROW EVENING.

AUTEN
&&

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

$$


000
FXUS63 KLOT 180537
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1237 AM CDT TUE JUN 18 2013

.DISCUSSION...
929 PM CDT

A SCATTERING OF SHOWERS WITH A FEW STORMS HAVE SEEN AN OVERALL
DIMINISHING IN COVERAGE SINCE 8 PM. ALMOST ALL NEW DEVELOPMENT IN
THAT TIME HAS BEEN ON OUTFLOW FROM PRECEDING SHOWERS/STORMS...WITH
THE 00Z DVN RAOB INDICATING INSTABILITY PRESENT FROM THE AFTERNOON
MIXED LAYER. SOME FESTERING ON OUTFLOWS IS LIKELY TO CONTINUE
ALTHOUGH EACH SUCCESSIVE REDEVELOPMENT SHOULD BE WEAKER. THE AREA
WILL REMAIN UNDER A FAVORABLE MID-LEVEL JET REGION INTO
OVERNIGHT...BUT THERE APPEARS TO BE A BREAK IN SHORT WAVES LET
ALONE THE DIMINISHING OF THE INSTABILITY WITH THE TIME OF DAY. SO
CONTINUE WITH NO SHOWERS FORECAST BY 1 AM.

OUTFLOWS BROUGHT RAIN-COOLED AIR ALONG WITH THE MARINE LAYER INTO
FAR NORTHEAST IL THAT CREATED A QUICK TEMPERATURE DROP. LOWS
STILL LOOK ON TRACK FOR MOST AREAS...ALTHOUGH DID BRING DOWN THE
FAR NORTHERN TWO TIERS OF COUNTIES A COUPLE DEGREES BASED ON THIS
LOWER STARTING POINT GOING INTO THE NIGHT. IF WINDS WERE LIGHTER
FOG MAY BE A CONCERN IN THOSE AREAS THAT SAW SHOWERS...BUT SPEEDS
WILL STAY UP TONIGHT AS THE SYNOPTIC COLD FRONT WORKS THROUGH THE
REGION.

THE GOES WV LOOP SHOWS THE NEXT SHORT WAVE BEING WELL-DEFINED IN
SOUTHEAST ND. THIS SMALL "BOWLING BALL" IN THE MID-LEVEL FLOW
LOOKS TO TRACK ACROSS THE SOUTHWEST FORECAST AREA DURING TUE
AFTERNOON. THE AMOUNT OF INSTABILITY ON GUIDANCE IS STRONGLY
CORRELATED TO THE SURFACE DEW POINT FORECAST...WHICH COULD BE HIGH
ON BOTH THE NAM AND GFS PER OBSERVATIONAL TRENDS AND INITIALIZATION
/AT LEAST ON THE 18Z RUNS/. STILL ENOUGH TO WARRANT A SLIGHT
CHANCE THOUGH...AS THERE CURRENTLY ARE STORMS WITH THE FEATURE IN
THE DAKOTAS AT THIS HOUR.

MTF

//PREV DISCUSSION...
251 PM CDT

TONIGHT...
VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CIRRUS SHIELD FROM
SOUTHEAST IOWA STRETCHING NORTHEAST ALONG I-80 IN ILLINOIS INTO
NORTHCENTRAL INDIANA. WATER VAPOR IMAGERY ALSO INDICATED AN
ABUNDANCE OF UPR LEVEL MOISTURE ASSOCIATED WITH THE CLOUDS...HOWEVER
SOME SUBSIDENCE WAS OCCURRING LATE THIS MORNING INTO THE AFTERNOON
HOURS AS DEW POINTS AT THE SFC WERE DROPPING INTO THE MID/UPR 50S
ACROSS THE CWFA. LLVL FLOW UNDER THE CLOUD SHIELD WAS GENERALLY
SOUTHWESTERLY...WHILE FURTHER NORTH WINDS WERE WESTERLY. IT APPEARS
THAT WHERE SKIES ARE MOSTLY SUNNY SLIGHTLY BETTER MIXING WAS
OCCURRING...WHICH WAS ALSO AIDING IN THE SUBSIDENCE AT THE SFC.

THE FOCUS FOR LATER THIS AFTERNOON/EVENING IS ON THE APPROACHING
FRONTAL BOUNDARY AND POTENTIAL FOR ISOLATED SHOWERS/THUNDERSTORMS
ALONG/JUST AHEAD OF THIS BOUNDARY. VISIBLE IMAGERY DOES SHOW A
NARROW CHANNEL OF A CUMULUS FIELD DEVELOPING ACROSS CENTRAL WISC
THIS AFTERNOON...STRETCHING NORTHWEST THROUGH MINN. A WEAK MID-LVL
WAVE WAS SLIDING SOUTHEAST THE UPPER MIDWEST...WHICH WILL BE THE
DRIVER FOR SOME ADDED LIFT INTO THIS CUMULUS FIELD. AS EXPECTED
ISOLATED SHOWERS/THUNDERSTORMS WERE DEVELOPING UNDER THIS CHANNEL OF
CUMULUS ACROSS CENTRAL WISC/EASTERN MINN. MID-LVLS ARE MUCH
COOLER...WITH STEEP LAPSE RATES TO THE NORTH ACROSS WISC. THIS
SUGGESTS THAT A FEW THUNDERSTORMS COULD EASILY GROW VERTICALLY AND
POSSIBLY PRODUCE SOME HAIL. FEEL THAT MOST OF THE LATE AFTN/EARLY
EVENING WILL END UP BEING DRY FOR THE CWFA. GUIDANCE CONTINUES TO
SUGGEST THAT THE BEST CHC FOR ANY PRECIP WILL LIKELY OCCUR AFT 00Z.
WITH MUCH OF THE CONVECTIVE POTENTIAL BEING DIURNALLY
DRIVEN...EXPECT THAT ARND 2-3Z THE INSTABILITY TO GREATLY DIMINISH.
AT THIS TIME WILL HOLD ONTO THE SLIGHT CHC OF TSRA WORDING THRU 3Z.
ACROSS THE NORTH...THEN LINGER THE TSRA WORDING THRU 06Z FOR THE
SOUTHEAST CWFA.

EARLIER THINKING WAS THAT THIS BOUNDARY WOULD END UP BEING A BACK
DOOR COLD FRONT...AND THIS APPEARS TO BE THE CASE BASED ON CURRENT
CONDS TO THE NORTH. CLOUD COVER SHUD BE SLOWLY THINNING OVERNIGHT TO
A P-CLOUDY SKY...WITH WINDS TURNING NORTHERLY POST FRONTAL PASSAGE.
THIS WILL USHER IN MUCH COOLER AIR AND ALLOW TEMPS TO EASILY RADIATE
INTO THE MID/UPR 50S.

CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...LOW/MEDIUM.

TUESDAY THROUGH WEDNESDAY...
INITIAL GLANCE IS THAT TUE WOULD BE DRY...HOWEVER THE CONCERN IS ON
THE SOUTHEAST DIVING 500MB VORT THAT WILL BE ARRIVING ACROSS THE
WESTERN CWFA MID/LATE MORNING AND PIVOTING EAST BY THE MID-AFTERNOON
HOURS. THIS MAY PROVIDE ENOUGH LIFT...COUPLED WITH DIURNAL CUMULUS
TUE...AND SOME MOISTURE FROM THE BOUNDARY TO ALLOW A FEW
THUNDERSTORMS TO DEVELOP. WITH TEMPS ALOFT STEADILY COOLING ACROSS
THE CWFA...LAPSE RATES WILL STEEPEN AND A FEW STRONGER STORMS COULD
EASILY PRODUCE SOME PEA SIZE HAIL...BRIEF WIND GUSTS AND HEAVY
DOWNPOURS. THE FOCUS APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO
BENTON COUNTY LINE.

OTHERWISE ANTI-CYCLONIC FLOW WILL CONTINUE TO SETTLE INTO THE GREAT
LAKES REGION...AND KEEP A NORTHEAST FLOW AT THE SFC. THIS WILL
EASILY AID IN THE MUCH COOLER MARINE ENVIRONMENT ADVECTING INLAND
ACROSS THE CWFA AND KEEP SFC TEMPS IN THE LOW/MID 70S...EXCEPT THE
FAR SOUTH/SOUTHWEST WHERE TEMPS MAY STILL TOUCH 80 DEG IN THE AFTN.
LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN MAY HAVE TEMPS
REMAIN IN THE MID 60S TUE.

OVERNIGHT TEMPS WILL BE MUCH COOLER IN THE LOW/MID 50S. A FEW
LOCATIONS ALONG AND NORTH OF A ROCKFORD...AURORA...WAUKEGAN LINE MAY
HAVE TEMPS IN THE UPR 40S EARLY WED MORNING. THEN HIGH PRESSURE
BEGINS TO DRIFT EAST. WHILE WINDS WILL BE MORE EASTERLY OFF OF THE
LAKE...TEMPS WILL BE SLIGHTLY WARMER WED AFTN IN THE UPR 70S TO LOW
80S. THE EXCEPTION WILL BE AREAS ADJACENT TO LAKE MICHIGAN...WHERE
TEMPS WILL LIKELY REMAIN IN THE 60S TO LOW 70S.

CONFIDENCE...HIGH.

THURSDAY THROUGH SUNDAY...
ENSEMBLES CONTINUES TO POINT TOWARDS A PATTERN CHANGE FOR THE END OF
THE WEEK INTO THE WEEKEND. MANY GUIDANCE MEMBERS ARE IN AGREEMENT
THAT THE 500MB TROUGH OVER THE GREAT LAKES REGION WILL PIVOT EAST
THUR...WITH A STRENGTHENING MID-LVL RIDGE ACROSS THE CENTRAL PLAINS
REPLACING THE DEPARTING TROUGH FRI. THE RIDGE DOES APPEAR TO FLATTEN
SLIGHTLY...WHICH MAY BE AN INDICATION THAT A SLIGHTLY ACTIVE PERIOD
MAY ACCOMPANY THE STEADY WARMING TREND. 850MB THERMAL RIDGE
CONTINUES TO BE RATHER WARM FOR THE WEEKEND...WITH TEMPS GENERALLY
AROUND 20-22 DEG C. THE EC/GEM HAVE TAKEN A SLIGHTLY COOLER APPROACH
WITH 18-20 DEG C...HOWEVER THE OVERALL THEME IS THAT TEMPS WILL BE
STEADILY WARMING. THE WILDCARD FOR MAX TEMPS SAT/SUN/MON...WILL BE
LLVL MOISTURE AND CLOUD COVER. GUIDANCE CONTINUES TO SUGGEST DEW
POINTS WILL GENERALLY BE AROUND 70 DEG. THIS MAY SLOW THE DIURNAL
CURVE FOR THE WEEKEND...HOWEVER TEMPS SHUD EASILY STILL WARM INTO
THE UPR 80S TO POSSIBLY LOWER 90S. AS A RESULT HAVE NUDGED TEMPS
WARMER THAN GUIDANCE FOR THE UPCOMING WEEKEND.

CONFIDENCE IN TEMPERATURES...MEDIUM/HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...MEDIUM.

BEACHLER

&&

.AVIATION...

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

* POTENTIAL FOR LOW CIGS OVERNIGHT.

BMD

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

A COLD FRONT HAS DROPPED SOUTH ACROSS THE TERMINALS LEAVING
NORTHEAST FLOW OVER NORTHERN ILLINOIS AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS AND NORTHERN LAKES REGION. THE HIGH IS EXPECTED TO VERY
GRADUALLY CONSOLIDATE AND SINK SOUTH TOWARDS NORTHERN LAKE MICHIGAN
THROUGH THE DAY TUESDAY LEADING TO VERY LITTLE CHANCE IN THE WEATHER
THROUGH THE FORECAST PERIOD. WINDS WILL PICK UP WITH ONSET OF MIXING
DURING THE DAY TUESDAY...THEN SHOULD DIMINISH AFTER SUNSET. VFR
CLOUDS EXPECTED THROUGH THE PERIOD...BUT CONTINUE TO MONITOR CLOSELY
THE CHANCE FOR LOWER CIGS DEVELOPING OVERNIGHT INTO THE EARLY
MORNING HOURS. NAM/RAP SOUNDINGS CONTINUE TO ADVERTISE THE POTENTIAL
FOR IFR CIGS TO DEVELOP AS THE COLUMN COOLS...BUT SEE NO SIGN OF
THIS YET UPSTREAM AND OTHER MODELS AS LESS BULLISH ON THE
DEVELOPMENT. NAM HAS A TENDENCY TO OVERDO LOW LEVEL MOISTURE SO FOR
NOW WILL MONITOR CLOSELY. IF LOW CIGS DO DEVELOP THE BEST TIME FRAME
WOULD BE ROUGHLY 09-14Z.

BMD


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

* LOW CONFIDENCE IN LOW CIGS DEVELOPING.
* HIGH CONFIDENCE IN OTHER FORECAST ELEMENTS.

BMD

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

WEDNESDAY...VFR.

THURSDAY...VFR.

FRIDAY...VFR EARLY...CHANCE OF TSRA OVERNIGHT.

SATURDAY AND SUNDAY...PERIODIC CHANCES FOR TSRA.

LENNING

&&

.MARINE...
245 PM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. A TROUGH OF LOW
PRESSURE AND AN ASSOCIATED WEAK COLD FRONT...EXTEND FROM NORTHERN
MAINE WEST THROUGH CENTRAL LAKE MICHIGAN. AS THE LOW MOVES OFF TO
THE EAST...THE FRONT WILL CONTINUE TO MOVE SOUTH DOWN THE
LAKE...REACHING THE SOUTHERN TIP OF THE LAKE BY LATE THIS EVENING.
WINDS WILL SHIFT TO NORTHERLY BEHIND THE FRONT...WITH OCCASIONAL
GUSTS TO 25 KT TONIGHT. HIGH PRESSURE OVER THE NORTHERN PLAINS
WILL SPREAD EAST ACROSS THE GREAT LAKES LATE TONIGHT AND
TOMORROW...WITH HIGH PRESSURE REMAINING THE DOMINANT FEATURE OVER
THE LAKE THROUGH WEDNESDAY NIGHT WHEN THE HIGH WILL BEGIN TO SLIDE
OFF TO THE EAST. IN THE MEAN TIME...LOW PRESSURE DEVELOPING OVER
THE NORTHERN ROCKIES WEDNESDAY NIGHT AND WILL MOVE OVER THE
NORTHERN PLAINS BY FRIDAY MORNING. WITH THE HIGH PRESSURE TO THE
EAST AND THE DEVELOPING TROUGH TO THE WEST...WINDS WILL BECOME
SOUTHERLY BY WEDNESDAY OR WEDNESDAY NIGHT...THROUGH THE WEEKEND.

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...NONE.
&&

$$

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

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


000
FXUS63 KILX 180453
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1153 PM CDT MON JUN 17 2013

.DISCUSSION...
ISSUED 902 PM CDT MON JUN 17 2013

CURRENT FORECAST LOOKS OK BUT MAY NEED TO TWEAK THE ISOLATED
THUNDERSTORMS IN THE NORTH AND EXTENDED IT A FEW MORE HOURS...TIL
MIDNIGHT. THEN ISOLATED SHOWERS/THUNDERSTORMS WILL BE ACROSS THE
CENTRAL AND SOUTHEAST AFTER MIDNIGHT. REMAINDER OF THE FORECAST
LOOKS FINE WITH TEMPS FALLING INTO THE LOWER TO MIDDLE 60S BY
MORNING...WITH LIGHT WINDS AND MOSTLY CLEAR SKIES. SO WILL BE
MAKING SOME MINOR ADJUSTMENTS TO THE FORECAST. UPDATE WILL BE OUT
SHORTLY.

AUTEN
&&

.AVIATION...
ISSUED 1153 PM CDT MON JUN 17 2013

SCATTERED HIGH CIRRUS WILL SLOWLY MOVE ACROSS AND OUT OF THE AREA
OVERNIGHT AT ALL SITES. THEN EXPECTING LIGHT FOG TO
REDEVELOP...BUT NOT AS BAD AS LAST NIGHT AND NOT AS SOON. SO LIGHT
FOG WILL BE IN MVFR CATEGORY TOWARD MORNING AND LIKELY DISSIPATE
QUICKLY AFTER SUNRISE. THEN EXPECTING SOME SCATTERED CU DURING THE
MORNING HOURS AHEAD OF THE NEXT SYSTEM COMING DOWN FROM THE
NORTHWEST. MODELS SUGGEST A POSSIBILITY OF SCATTERED THUNDERSTORMS
ACROSS PARTS OF CENTRAL ILLINOIS DURING THE AFTERNOON
HOURS...MAINLY ALONG THE I-74 CORRIDOR. SO WILL HAVE VCTS AT
PIA...BMI...CMI FOR THE AFTERNOON. HAVE DECIDED TO INCLUDE SPI AND
DEC AS WELL GIVEN THEY WILL BE CLOSE TO THE BOUNDARY AS WELL AND
OUTFLOW BOUNDARIES FROM EXISTING STORMS COULD PRODUCE ADDITIONAL
STORMS TO THE WEST OF THE BOUNDARY. THEN AROUND SUNSET EXPECTING
PCPN TO END AND ALSO PUSH TO THE EAST AND SOUTHEAST. SKIES SHOULD
BECOME SCATTERED AGAIN FOR THE EVENING. DO NOT SE FOG POTENTIAL
TOMORROW NIGHT AS DRIER AIR SHOULD ADVECT INTO THE REGION. WINDS
WILL BE LIGHT AND VARIABLE OVERNIGHT AND THEN BECOME NORTHERLY
ALONG THE FRONT AND TOMORROW EVENING.

AUTEN
&&

.PREV DISCUSSION...
ISSUED 220 PM CDT MON JUN 17 2013

SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT

MAIN CONCERNS THIS PERIOD WILL BE WITH COVERAGE OF PRECIP ACRS OUR
SOUTHERN COUNTIES TONIGHT...ASSOCIATED WITH AN MCV OVER MISSOURI...
AND WITH A WEAK SURFACE BOUNDARY FORECAST TO EDGE INTO OUR AREA
TUESDAY AFTERNOON. AFTER THAT...SOMEWHAT COOLER AND LESS HUMID WEATHER
WILL FOLLOW INTO THURSDAY BEFORE HEAT BUILDS NORTHWARD INTO THE REGION
FOR THE END OF THE WEEK AND NEXT WEEKEND.

WATER VAPOR LOOP SHOWING THE CONVECTIVE COMPLEX FROM LAST NIGHT
PRODUCING A DISTINCT MCV OVER PARTS OF WESTERN MO WITH NEW CONVECTION
DEVELOPING TO ITS EAST INTO EAST CENTRAL AND SE MO AND TRYING TO
DEVELOP A BIT FURTHER NORTH INTO SOUTHERN ILLINOIS. LOOKING NORTH...
SEVERAL LOW AMPLITUDE SHORTWAVES TRACKING E-SE ACRS THE NORTHERN
PLAINS. ONCE SUCH WAVE PUSHING ACRS WISCONSIN WITH A WEAK SFC BOUNDARY
SHIFTING SOUTH DOWN LAKE MICHIGAN...WHICH SHORT TERM MODELS SUGGEST
WILL PUSH ACRS EXTREME SOUTHERN LAKE MICHIGAN LATER THIS EVENING.
THE AIR MASS AHEAD OF THIS FEATURE NOT PARTICULARLY CONDUCIVE TO
WIDESPREAD CONVECTION DEVELOPING AHEAD OF IT SO OTHER THAN SOME
SLIGHT CHANCE (ISOLATED WORDING) FOR THIS EVENING ACRS THE FAR
NORTH...IT STILL APPEARS THE BETTER PROBABILITIES FOR EVENING
CONVECTION WILL BE TIED TO THE MISSOURI MCV AS IT TRACKS ESE WELL
TO OUR SOUTH.

THE NORTHERN STREAM WAVE ACRS NORTH DAKOTA LOOKS A BIT MORE IMPRESSIVE
THAN WHAT MODELS WERE DEPICTING AT THIS TIME YESTERDAY. MODELS CONTINUE
TO BRING THIS WAVE ESE INTO THE LAKES REGION TUESDAY AFTERNOON WITH
A WEAK COLD FRONT EDGING SOUTH INTO OUR AREA. CONVERGENCE ALONG THE
BOUNDARY IS NOT VERY IMPRESSIVE AT ALL BUT WITH THE TIMING OF THE
BOUNDARY INTO OUR AREA DURING PEAK HEATING...IT STILL WARRANTS SLIGHT
CHANCE (ISOLATED COVERAGE) FOR TUESDAY AFTERNOON. SOMEWHAT COOLER AND
LESS HUMID AIR WILL FILTER SOUTH ACRS THE AREA IN THE WAKE OF THE
SHORTWAVE TUESDAY NIGHT INTO WEDNESDAY BRINGING QUIET AND PLEASANT
WEATHER FOR THE REMAINDER OF THE SHORT TERM PERIOD.

LONG TERM...FRIDAY THROUGH MONDAY

LONGER RANGE MODELS...AT LEAST THE GFS AND UK...WERE MUCH MORE
AGGRESSIVE WITH THE RETROGRESSION OF THE SUBTROPICAL RIDGE ACRS
THE CENTRAL U.S...TAKING THE STRONGER 500 MB FLOW FURTHER NORTH
AWAY FROM OUR AREA. THE 12Z ECMWF NOT NEARLY AS STRONG WITH THE
UPPER RIDGE AS IT TAKES A SERIES OF SHORTWAVES FROM THE LONGWAVE
TROF ACRS THE PACIFIC NW AND TEMPORARILY FLATTENS THE RIDGE AXIS
TO OUR WEST...KEEPING THE AMPLITUDE MUCH FLATTER OVER THE LOWER
48...WHICH GIVES OUR AREA A BETTER CHANCE FOR SEEING SCATTERED
CONVECTION...ESPECIALLY ACRS THE NORTH DURING THE WEEKEND. LOOKS
AS IF THE GFS SOLUTION MAY BE OVERDONE...COMPARED TO WHAT IT WAS
SHOWING THE PAST SEVERAL RUNS. SO FAR THIS SPRING...THE SHORTWAVES
EJECTING ENE FROM THE WESTERN U.S. TROFS AND THEIR ASSOCIATED
CONVECTION HAVE BEEN SUCCESSFUL IN KEEPING THE AMPLITUDE OF THE
RIDGE ACRS THE CENTRAL PORTION OF THE COUNTRY FLATTER. WILL TEND
TO SIDE MORE WITH THE ECMWF THIS PERIOD BUT IT WON`T MAKE MUCH OF
A DIFFERENCE IN THE EXTENDED PORTION OF THE FORECAST WITH HOT
WEATHER RETURNING FOR THE WEEKEND AND THE HIGHER RAIN CHANCES ACRS
THE NORTH.

SMITH


&&

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

$$


000
FXUS63 KLOT 180305
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1005 PM CDT MON JUN 17 2013

.DISCUSSION...
929 PM CDT

A SCATTERING OF SHOWERS WITH A FEW STORMS HAVE SEEN AN OVERALL
DIMINISHING IN COVERAGE SINCE 8 PM. ALMOST ALL NEW DEVELOPMENT IN
THAT TIME HAS BEEN ON OUTFLOW FROM PRECEDING SHOWERS/STORMS...WITH
THE 00Z DVN RAOB INDICATING INSTABILITY PRESENT FROM THE AFTERNOON
MIXED LAYER. SOME FESTERING ON OUTFLOWS IS LIKELY TO CONTINUE
ALTHOUGH EACH SUCCESSIVE REDEVELOPMENT SHOULD BE WEAKER. THE AREA
WILL REMAIN UNDER A FAVORABLE MID-LEVEL JET REGION INTO
OVERNIGHT...BUT THERE APPEARS TO BE A BREAK IN SHORT WAVES LET
ALONE THE DIMINISHING OF THE INSTABILITY WITH THE TIME OF DAY. SO
CONTINUE WITH NO SHOWERS FORECAST BY 1 AM.

OUTFLOWS BROUGHT RAIN-COOLED AIR ALONG WITH THE MARINE LAYER INTO
FAR NORTHEAST IL THAT CREATED A QUICK TEMPERATURE DROP. LOWS
STILL LOOK ON TRACK FOR MOST AREAS...ALTHOUGH DID BRING DOWN THE
FAR NORTHERN TWO TIERS OF COUNTIES A COUPLE DEGREES BASED ON THIS
LOWER STARTING POINT GOING INTO THE NIGHT. IF WINDS WERE LIGHTER
FOG MAY BE A CONCERN IN THOSE AREAS THAT SAW SHOWERS...BUT SPEEDS
WILL STAY UP TONIGHT AS THE SYNOPTIC COLD FRONT WORKS THROUGH THE
REGION.

THE GOES WV LOOP SHOWS THE NEXT SHORT WAVE BEING WELL-DEFINED IN
SOUTHEAST ND. THIS SMALL "BOWLING BALL" IN THE MID-LEVEL FLOW
LOOKS TO TRACK ACROSS THE SOUTHWEST FORECAST AREA DURING TUE
AFTERNOON. THE AMOUNT OF INSTABILITY ON GUIDANCE IS STRONGLY
CORRELATED TO THE SURFACE DEW POINT FORECAST...WHICH COULD BE HIGH
ON BOTH THE NAM AND GFS PER OBSERVATIONAL TRENDS AND INITIALIZATION
/AT LEAST ON THE 18Z RUNS/. STILL ENOUGH TO WARRANT A SLIGHT
CHANCE THOUGH...AS THERE CURRENTLY ARE STORMS WITH THE FEATURE IN
THE DAKOTAS AT THIS HOUR.

MTF

//PREV DISCUSSION...
251 PM CDT

TONIGHT...
VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CIRRUS SHIELD FROM
SOUTHEAST IOWA STRETCHING NORTHEAST ALONG I-80 IN ILLINOIS INTO
NORTHCENTRAL INDIANA. WATER VAPOR IMAGERY ALSO INDICATED AN
ABUNDANCE OF UPR LEVEL MOISTURE ASSOCIATED WITH THE CLOUDS...HOWEVER
SOME SUBSIDENCE WAS OCCURRING LATE THIS MORNING INTO THE AFTERNOON
HOURS AS DEW POINTS AT THE SFC WERE DROPPING INTO THE MID/UPR 50S
ACROSS THE CWFA. LLVL FLOW UNDER THE CLOUD SHIELD WAS GENERALLY
SOUTHWESTERLY...WHILE FURTHER NORTH WINDS WERE WESTERLY. IT APPEARS
THAT WHERE SKIES ARE MOSTLY SUNNY SLIGHTLY BETTER MIXING WAS
OCCURRING...WHICH WAS ALSO AIDING IN THE SUBSIDENCE AT THE SFC.

THE FOCUS FOR LATER THIS AFTERNOON/EVENING IS ON THE APPROACHING
FRONTAL BOUNDARY AND POTENTIAL FOR ISOLATED SHOWERS/THUNDERSTORMS
ALONG/JUST AHEAD OF THIS BOUNDARY. VISIBLE IMAGERY DOES SHOW A
NARROW CHANNEL OF A CUMULUS FIELD DEVELOPING ACROSS CENTRAL WISC
THIS AFTERNOON...STRETCHING NORTHWEST THROUGH MINN. A WEAK MID-LVL
WAVE WAS SLIDING SOUTHEAST THE UPPER MIDWEST...WHICH WILL BE THE
DRIVER FOR SOME ADDED LIFT INTO THIS CUMULUS FIELD. AS EXPECTED
ISOLATED SHOWERS/THUNDERSTORMS WERE DEVELOPING UNDER THIS CHANNEL OF
CUMULUS ACROSS CENTRAL WISC/EASTERN MINN. MID-LVLS ARE MUCH
COOLER...WITH STEEP LAPSE RATES TO THE NORTH ACROSS WISC. THIS
SUGGESTS THAT A FEW THUNDERSTORMS COULD EASILY GROW VERTICALLY AND
POSSIBLY PRODUCE SOME HAIL. FEEL THAT MOST OF THE LATE AFTN/EARLY
EVENING WILL END UP BEING DRY FOR THE CWFA. GUIDANCE CONTINUES TO
SUGGEST THAT THE BEST CHC FOR ANY PRECIP WILL LIKELY OCCUR AFT 00Z.
WITH MUCH OF THE CONVECTIVE POTENTIAL BEING DIURNALLY
DRIVEN...EXPECT THAT ARND 2-3Z THE INSTABILITY TO GREATLY DIMINISH.
AT THIS TIME WILL HOLD ONTO THE SLIGHT CHC OF TSRA WORDING THRU 3Z.
ACROSS THE NORTH...THEN LINGER THE TSRA WORDING THRU 06Z FOR THE
SOUTHEAST CWFA.

EARLIER THINKING WAS THAT THIS BOUNDARY WOULD END UP BEING A BACK
DOOR COLD FRONT...AND THIS APPEARS TO BE THE CASE BASED ON CURRENT
CONDS TO THE NORTH. CLOUD COVER SHUD BE SLOWLY THINNING OVERNIGHT TO
A P-CLOUDY SKY...WITH WINDS TURNING NORTHERLY POST FRONTAL PASSAGE.
THIS WILL USHER IN MUCH COOLER AIR AND ALLOW TEMPS TO EASILY RADIATE
INTO THE MID/UPR 50S.

CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...LOW/MEDIUM.

TUESDAY THROUGH WEDNESDAY...
INITIAL GLANCE IS THAT TUE WOULD BE DRY...HOWEVER THE CONCERN IS ON
THE SOUTHEAST DIVING 500MB VORT THAT WILL BE ARRIVING ACROSS THE
WESTERN CWFA MID/LATE MORNING AND PIVOTING EAST BY THE MID-AFTERNOON
HOURS. THIS MAY PROVIDE ENOUGH LIFT...COUPLED WITH DIURNAL CUMULUS
TUE...AND SOME MOISTURE FROM THE BOUNDARY TO ALLOW A FEW
THUNDERSTORMS TO DEVELOP. WITH TEMPS ALOFT STEADILY COOLING ACROSS
THE CWFA...LAPSE RATES WILL STEEPEN AND A FEW STRONGER STORMS COULD
EASILY PRODUCE SOME PEA SIZE HAIL...BRIEF WIND GUSTS AND HEAVY
DOWNPOURS. THE FOCUS APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO
BENTON COUNTY LINE.

OTHERWISE ANTI-CYCLONIC FLOW WILL CONTINUE TO SETTLE INTO THE GREAT
LAKES REGION...AND KEEP A NORTHEAST FLOW AT THE SFC. THIS WILL
EASILY AID IN THE MUCH COOLER MARINE ENVIRONMENT ADVECTING INLAND
ACROSS THE CWFA AND KEEP SFC TEMPS IN THE LOW/MID 70S...EXCEPT THE
FAR SOUTH/SOUTHWEST WHERE TEMPS MAY STILL TOUCH 80 DEG IN THE AFTN.
LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN MAY HAVE TEMPS
REMAIN IN THE MID 60S TUE.

OVERNIGHT TEMPS WILL BE MUCH COOLER IN THE LOW/MID 50S. A FEW
LOCATIONS ALONG AND NORTH OF A ROCKFORD...AURORA...WAUKEGAN LINE MAY
HAVE TEMPS IN THE UPR 40S EARLY WED MORNING. THEN HIGH PRESSURE
BEGINS TO DRIFT EAST. WHILE WINDS WILL BE MORE EASTERLY OFF OF THE
LAKE...TEMPS WILL BE SLIGHTLY WARMER WED AFTN IN THE UPR 70S TO LOW
80S. THE EXCEPTION WILL BE AREAS ADJACENT TO LAKE MICHIGAN...WHERE
TEMPS WILL LIKELY REMAIN IN THE 60S TO LOW 70S.

CONFIDENCE...HIGH.

THURSDAY THROUGH SUNDAY...
ENSEMBLES CONTINUES TO POINT TOWARDS A PATTERN CHANGE FOR THE END OF
THE WEEK INTO THE WEEKEND. MANY GUIDANCE MEMBERS ARE IN AGREEMENT
THAT THE 500MB TROUGH OVER THE GREAT LAKES REGION WILL PIVOT EAST
THUR...WITH A STRENGTHENING MID-LVL RIDGE ACROSS THE CENTRAL PLAINS
REPLACING THE DEPARTING TROUGH FRI. THE RIDGE DOES APPEAR TO FLATTEN
SLIGHTLY...WHICH MAY BE AN INDICATION THAT A SLIGHTLY ACTIVE PERIOD
MAY ACCOMPANY THE STEADY WARMING TREND. 850MB THERMAL RIDGE
CONTINUES TO BE RATHER WARM FOR THE WEEKEND...WITH TEMPS GENERALLY
AROUND 20-22 DEG C. THE EC/GEM HAVE TAKEN A SLIGHTLY COOLER APPROACH
WITH 18-20 DEG C...HOWEVER THE OVERALL THEME IS THAT TEMPS WILL BE
STEADILY WARMING. THE WILDCARD FOR MAX TEMPS SAT/SUN/MON...WILL BE
LLVL MOISTURE AND CLOUD COVER. GUIDANCE CONTINUES TO SUGGEST DEW
POINTS WILL GENERALLY BE AROUND 70 DEG. THIS MAY SLOW THE DIURNAL
CURVE FOR THE WEEKEND...HOWEVER TEMPS SHUD EASILY STILL WARM INTO
THE UPR 80S TO POSSIBLY LOWER 90S. AS A RESULT HAVE NUDGED TEMPS
WARMER THAN GUIDANCE FOR THE UPCOMING WEEKEND.

CONFIDENCE IN TEMPERATURES...MEDIUM/HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...MEDIUM.

BEACHLER

&&

.AVIATION...

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

* SOME UNCERTAINTY REGARDING GUSTS IN THE NEAR TERM...THINKING
  THEY WILL DIMINISH AS THE NIGHT GOES ALONG.

LENNING

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

SHOWERS PASSING NEAR THE TERMINALS AROUND 00Z ARE ANTICIPATED TO
BE SHORT LIVED AS AFTERNOON HEATING DIMINISHES. AS OF THIS
MOMENT...WINDS HAVE TURNED NORTH AT ORD BUT ARE STILL WSW AT
MDW...THOUGH EXPECTED TO FOLLOW THE ORD EXAMPLE SHORTLY. THIS WIND
DIRECTION IS BEING INFLUENCED BY THE LOCAL LAKE BREEZE AND OUTFLOW
FROM NEIGHBORHOOD SHOWERS...BUT THE OVERALL TREND IS TO REMAIN OUT
OF THE NORTH. IT IS POSSIBLE THAT A NORTHWEST DIRECTION COULD
RETURN BRIEFLY THIS EVENING...BUT ELECTED IN THE FCST TO STAY
WITH A NORTHERLY DIRECTION THROUGH THE NIGHT...GRADUALLY TURNING
NORTHEAST TOMORROW AS PER MODEL GUIDANCE AND WIND ROSES FOR THIS
TIME OF YEAR. NO MAJOR CONCERNS WITH THE WEATHER FOR TOMORROW.

LENNING

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

* MEDIUM TO HIGH CONFIDENCE THAT GUSTS WILL BE SHORT LIVED TONIGHT.

* HIGH CONFIDENCE IN PREVAILING NORTHEASTERLY WIND FOR MUCH OF THE
  FCST PERIOD.

LENNING

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

WEDNESDAY...VFR.

THURSDAY...VFR.

FRIDAY...VFR EARLY...CHANCE OF TSRA OVERNIGHT.

SATURDAY AND SUNDAY...PERIODIC CHANCES FOR TSRA.

LENNING

&&

.MARINE...
245 PM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. A TROUGH OF LOW
PRESSURE AND AN ASSOCIATED WEAK COLD FRONT...EXTEND FROM NORTHERN
MAINE WEST THROUGH CENTRAL LAKE MICHIGAN. AS THE LOW MOVES OFF TO
THE EAST...THE FRONT WILL CONTINUE TO MOVE SOUTH DOWN THE
LAKE...REACHING THE SOUTHERN TIP OF THE LAKE BY LATE THIS EVENING.
WINDS WILL SHIFT TO NORTHERLY BEHIND THE FRONT...WITH OCCASIONAL
GUSTS TO 25 KT TONIGHT. HIGH PRESSURE OVER THE NORTHERN PLAINS
WILL SPREAD EAST ACROSS THE GREAT LAKES LATE TONIGHT AND
TOMORROW...WITH HIGH PRESSURE REMAINING THE DOMINANT FEATURE OVER
THE LAKE THROUGH WEDNESDAY NIGHT WHEN THE HIGH WILL BEGIN TO SLIDE
OFF TO THE EAST. IN THE MEAN TIME...LOW PRESSURE DEVELOPING OVER
THE NORTHERN ROCKIES WEDNESDAY NIGHT AND WILL MOVE OVER THE
NORTHERN PLAINS BY FRIDAY MORNING. WITH THE HIGH PRESSURE TO THE
EAST AND THE DEVELOPING TROUGH TO THE WEST...WINDS WILL BECOME
SOUTHERLY BY WEDNESDAY OR WEDNESDAY NIGHT...THROUGH THE WEEKEND.

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...NONE.
&&

$$

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

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


000
FXUS63 KLOT 180229 AAA
AFDLOT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
929 PM CDT MON JUN 17 2013

.DISCUSSION...
929 PM CDT

A SCATTERING OF SHOWERS WITH A FEW STORMS HAVE SEEN AN OVERALL
DIMINISHING IN COVERAGE SINCE 8 PM. ALMOST ALL NEW DEVELOPMENT IN
THAT TIME HAS BEEN ON OUTFLOW FROM PRECEDING SHOWERS/STORMS...WITH
THE 00Z DVN RAOB INDICATING INSTABILITY PRESENT FROM THE AFTERNOON
MIXED LAYER. SOME FESTERING ON OUTFLOWS IS LIKELY TO CONTINUE
ALTHOUGH EACH SUCCESSIVE REDEVELOPMENT SHOULD BE WEAKER. THE AREA
WILL REMAIN UNDER A FAVORABLE MID-LEVEL JET REGION INTO
OVERNIGHT...BUT THERE APPEARS TO BE A BREAK IN SHORT WAVES LET
ALONE THE DIMINISHING OF THE INSTABILITY WITH THE TIME OF DAY. SO
CONTINUE WITH NO SHOWERS FORECAST BY 1 AM.

OUTFLOWS BROUGHT RAIN-COOLED AIR ALONG WITH THE MARINE LAYER INTO
FAR NORTHEAST IL THAT CREATED A QUICK TEMPERATURE DROP. LOWS
STILL LOOK ON TRACK FOR MOST AREAS...ALTHOUGH DID BRING DOWN THE
FAR NORTHERN TWO TIERS OF COUNTIES A COUPLE DEGREES BASED ON THIS
LOWER STARTING POINT GOING INTO THE NIGHT. IF WINDS WERE LIGHTER
FOG MAY BE A CONCERN IN THOSE AREAS THAT SAW SHOWERS...BUT SPEEDS
WILL STAY UP TONIGHT AS THE SYNOPTIC COLD FRONT WORKS THROUGH THE
REGION.

THE GOES WV LOOP SHOWS THE NEXT SHORT WAVE BEING WELL-DEFINED IN
SOUTHEAST ND. THIS SMALL "BOWLING BALL" IN THE MID-LEVEL FLOW
LOOKS TO TRACK ACROSS THE SOUTHWEST FORECAST AREA DURING TUE
AFTERNOON. THE AMOUNT OF INSTABILITY ON GUIDANCE IS STRONGLY
CORRELATED TO THE SURFACE DEW POINT FORECAST...WHICH COULD BE HIGH
ON BOTH THE NAM AND GFS PER OBSERVATIONAL TRENDS AND INITIALIZATION
/AT LEAST ON THE 18Z RUNS/. STILL ENOUGH TO WARRANT A SLIGHT
CHANCE THOUGH...AS THERE CURRENTLY ARE STORMS WITH THE FEATURE IN
THE DAKOTAS AT THIS HOUR.

MTF

&&

.PREV DISCUSSION...
251 PM CDT

TONIGHT...
VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CIRRUS SHIELD FROM
SOUTHEAST IOWA STRETCHING NORTHEAST ALONG I-80 IN ILLINOIS INTO
NORTHCENTRAL INDIANA. WATER VAPOR IMAGERY ALSO INDICATED AN
ABUNDANCE OF UPR LEVEL MOISTURE ASSOCIATED WITH THE CLOUDS...HOWEVER
SOME SUBSIDENCE WAS OCCURRING LATE THIS MORNING INTO THE AFTERNOON
HOURS AS DEW POINTS AT THE SFC WERE DROPPING INTO THE MID/UPR 50S
ACROSS THE CWFA. LLVL FLOW UNDER THE CLOUD SHIELD WAS GENERALLY
SOUTHWESTERLY...WHILE FURTHER NORTH WINDS WERE WESTERLY. IT APPEARS
THAT WHERE SKIES ARE MOSTLY SUNNY SLIGHTLY BETTER MIXING WAS
OCCURRING...WHICH WAS ALSO AIDING IN THE SUBSIDENCE AT THE SFC.

THE FOCUS FOR LATER THIS AFTERNOON/EVENING IS ON THE APPROACHING
FRONTAL BOUNDARY AND POTENTIAL FOR ISOLATED SHOWERS/THUNDERSTORMS
ALONG/JUST AHEAD OF THIS BOUNDARY. VISIBLE IMAGERY DOES SHOW A
NARROW CHANNEL OF A CUMULUS FIELD DEVELOPING ACROSS CENTRAL WISC
THIS AFTERNOON...STRETCHING NORTHWEST THROUGH MINN. A WEAK MID-LVL
WAVE WAS SLIDING SOUTHEAST THE UPPER MIDWEST...WHICH WILL BE THE
DRIVER FOR SOME ADDED LIFT INTO THIS CUMULUS FIELD. AS EXPECTED
ISOLATED SHOWERS/THUNDERSTORMS WERE DEVELOPING UNDER THIS CHANNEL OF
CUMULUS ACROSS CENTRAL WISC/EASTERN MINN. MID-LVLS ARE MUCH
COOLER...WITH STEEP LAPSE RATES TO THE NORTH ACROSS WISC. THIS
SUGGESTS THAT A FEW THUNDERSTORMS COULD EASILY GROW VERTICALLY AND
POSSIBLY PRODUCE SOME HAIL. FEEL THAT MOST OF THE LATE AFTN/EARLY
EVENING WILL END UP BEING DRY FOR THE CWFA. GUIDANCE CONTINUES TO
SUGGEST THAT THE BEST CHC FOR ANY PRECIP WILL LIKELY OCCUR AFT 00Z.
WITH MUCH OF THE CONVECTIVE POTENTIAL BEING DIURNALLY
DRIVEN...EXPECT THAT ARND 2-3Z THE INSTABILITY TO GREATLY DIMINISH.
AT THIS TIME WILL HOLD ONTO THE SLIGHT CHC OF TSRA WORDING THRU 3Z.
ACROSS THE NORTH...THEN LINGER THE TSRA WORDING THRU 06Z FOR THE
SOUTHEAST CWFA.

EARLIER THINKING WAS THAT THIS BOUNDARY WOULD END UP BEING A BACK
DOOR COLD FRONT...AND THIS APPEARS TO BE THE CASE BASED ON CURRENT
CONDS TO THE NORTH. CLOUD COVER SHUD BE SLOWLY THINNING OVERNIGHT TO
A P-CLOUDY SKY...WITH WINDS TURNING NORTHERLY POST FRONTAL PASSAGE.
THIS WILL USHER IN MUCH COOLER AIR AND ALLOW TEMPS TO EASILY RADIATE
INTO THE MID/UPR 50S.

CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...LOW/MEDIUM.

TUESDAY THROUGH WEDNESDAY...
INITIAL GLANCE IS THAT TUE WOULD BE DRY...HOWEVER THE CONCERN IS ON
THE SOUTHEAST DIVING 500MB VORT THAT WILL BE ARRIVING ACROSS THE
WESTERN CWFA MID/LATE MORNING AND PIVOTING EAST BY THE MID-AFTERNOON
HOURS. THIS MAY PROVIDE ENOUGH LIFT...COUPLED WITH DIURNAL CUMULUS
TUE...AND SOME MOISTURE FROM THE BOUNDARY TO ALLOW A FEW
THUNDERSTORMS TO DEVELOP. WITH TEMPS ALOFT STEADILY COOLING ACROSS
THE CWFA...LAPSE RATES WILL STEEPEN AND A FEW STRONGER STORMS COULD
EASILY PRODUCE SOME PEA SIZE HAIL...BRIEF WIND GUSTS AND HEAVY
DOWNPOURS. THE FOCUS APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO
BENTON COUNTY LINE.

OTHERWISE ANTI-CYCLONIC FLOW WILL CONTINUE TO SETTLE INTO THE GREAT
LAKES REGION...AND KEEP A NORTHEAST FLOW AT THE SFC. THIS WILL
EASILY AID IN THE MUCH COOLER MARINE ENVIRONMENT ADVECTING INLAND
ACROSS THE CWFA AND KEEP SFC TEMPS IN THE LOW/MID 70S...EXCEPT THE
FAR SOUTH/SOUTHWEST WHERE TEMPS MAY STILL TOUCH 80 DEG IN THE AFTN.
LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN MAY HAVE TEMPS
REMAIN IN THE MID 60S TUE.

OVERNIGHT TEMPS WILL BE MUCH COOLER IN THE LOW/MID 50S. A FEW
LOCATIONS ALONG AND NORTH OF A ROCKFORD...AURORA...WAUKEGAN LINE MAY
HAVE TEMPS IN THE UPR 40S EARLY WED MORNING. THEN HIGH PRESSURE
BEGINS TO DRIFT EAST. WHILE WINDS WILL BE MORE EASTERLY OFF OF THE
LAKE...TEMPS WILL BE SLIGHTLY WARMER WED AFTN IN THE UPR 70S TO LOW
80S. THE EXCEPTION WILL BE AREAS ADJACENT TO LAKE MICHIGAN...WHERE
TEMPS WILL LIKELY REMAIN IN THE 60S TO LOW 70S.

CONFIDENCE...HIGH.

THURSDAY THROUGH SUNDAY...
ENSEMBLES CONTINUES TO POINT TOWARDS A PATTERN CHANGE FOR THE END OF
THE WEEK INTO THE WEEKEND. MANY GUIDANCE MEMBERS ARE IN AGREEMENT
THAT THE 500MB TROUGH OVER THE GREAT LAKES REGION WILL PIVOT EAST
THUR...WITH A STRENGTHENING MID-LVL RIDGE ACROSS THE CENTRAL PLAINS
REPLACING THE DEPARTING TROUGH FRI. THE RIDGE DOES APPEAR TO FLATTEN
SLIGHTLY...WHICH MAY BE AN INDICATION THAT A SLIGHTLY ACTIVE PERIOD
MAY ACCOMPANY THE STEADY WARMING TREND. 850MB THERMAL RIDGE
CONTINUES TO BE RATHER WARM FOR THE WEEKEND...WITH TEMPS GENERALLY
AROUND 20-22 DEG C. THE EC/GEM HAVE TAKEN A SLIGHTLY COOLER APPROACH
WITH 18-20 DEG C...HOWEVER THE OVERALL THEME IS THAT TEMPS WILL BE
STEADILY WARMING. THE WILDCARD FOR MAX TEMPS SAT/SUN/MON...WILL BE
LLVL MOISTURE AND CLOUD COVER. GUIDANCE CONTINUES TO SUGGEST DEW
POINTS WILL GENERALLY BE AROUND 70 DEG. THIS MAY SLOW THE DIURNAL
CURVE FOR THE WEEKEND...HOWEVER TEMPS SHUD EASILY STILL WARM INTO
THE UPR 80S TO POSSIBLY LOWER 90S. AS A RESULT HAVE NUDGED TEMPS
WARMER THAN GUIDANCE FOR THE UPCOMING WEEKEND.

CONFIDENCE IN TEMPERATURES...MEDIUM/HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...MEDIUM.

BEACHLER

&&

.AVIATION...

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

* WIND SHIFT TO THE NORTH...JUST BEFORE 00Z AT ORD AND IMMINENT AT MDW.

* NEAR TERM GUSTINESS WITH THE NEW WIND DIRECTION.

* HIGH BASED SHRA IN THE AREA...BUT LITTLE IF ANY TSRA ANTICIPATED.

LENNING

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

SHOWERS PASSING NEAR THE TERMINALS AROUND 00Z ARE ANTICIPATED TO
BE SHORT LIVED AS AFTERNOON HEATING DIMINISHES. AS OF THIS
MOMENT...WINDS HAVE TURNED NORTH AT ORD BUT ARE STILL WSW AT
MDW...THOUGH EXPECTED TO FOLLOW THE ORD EXAMPLE SHORTLY. THIS WIND
DIRECTION IS BEING INFLUENCED BY THE LOCAL LAKE BREEZE AND OUTFLOW
FROM NEIGHBORHOOD SHOWERS...BUT THE OVERALL TREND IS TO REMAIN OUT
OF THE NORTH. IT IS POSSIBLE THAT A NORTHWEST DIRECTION COULD
RETURN BRIEFLY THIS EVENING...BUT ELECTED IN THE FCST TO STAY
WITH A NORTHERLY DIRECTION THROUGH THE NIGHT...GRADUALLY TURNING
NORTHEAST TOMORROW AS PER MODEL GUIDANCE AND WIND ROSES FOR THIS
TIME OF YEAR. NO MAJOR CONCERNS WITH THE WEATHER FOR TOMORROW.

LENNING

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

* MEDIUM TO HIGH CONFIDENCE OF WINDS REMAINING NORTH TO NORTHEAST
  THROUGH THE TAF PERIOD.

* HIGH CONFIDENCE THAT SHOWERS WILL DISSIPATE THIS EVENING.

LENNING

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

WEDNESDAY...VFR.

THURSDAY...VFR.

FRIDAY...VFR EARLY...CHANCE OF TSRA OVERNIGHT.

SATURDAY AND SUNDAY...PERIODIC CHANCES FOR TSRA.

LENNING

&&

.MARINE...
245 PM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. A TROUGH OF LOW
PRESSURE AND AN ASSOCIATED WEAK COLD FRONT...EXTEND FROM NORTHERN
MAINE WEST THROUGH CENTRAL LAKE MICHIGAN. AS THE LOW MOVES OFF TO
THE EAST...THE FRONT WILL CONTINUE TO MOVE SOUTH DOWN THE
LAKE...REACHING THE SOUTHERN TIP OF THE LAKE BY LATE THIS EVENING.
WINDS WILL SHIFT TO NORTHERLY BEHIND THE FRONT...WITH OCCASIONAL
GUSTS TO 25 KT TONIGHT. HIGH PRESSURE OVER THE NORTHERN PLAINS
WILL SPREAD EAST ACROSS THE GREAT LAKES LATE TONIGHT AND
TOMORROW...WITH HIGH PRESSURE REMAINING THE DOMINANT FEATURE OVER
THE LAKE THROUGH WEDNESDAY NIGHT WHEN THE HIGH WILL BEGIN TO SLIDE
OFF TO THE EAST. IN THE MEAN TIME...LOW PRESSURE DEVELOPING OVER
THE NORTHERN ROCKIES WEDNESDAY NIGHT AND WILL MOVE OVER THE
NORTHERN PLAINS BY FRIDAY MORNING. WITH THE HIGH PRESSURE TO THE
EAST AND THE DEVELOPING TROUGH TO THE WEST...WINDS WILL BECOME
SOUTHERLY BY WEDNESDAY OR WEDNESDAY NIGHT...THROUGH THE WEEKEND.

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...NONE.
&&

$$

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

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


000
FXUS63 KILX 180202
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
902 PM CDT MON JUN 17 2013

.DISCUSSION...
ISSUED 902 PM CDT MON JUN 17 2013

CURRENT FORECAST LOOKS OK BUT MAY NEED TO TWEAK THE ISOLATED
THUNDERSTORMS IN THE NORTH AND EXTENDED IT A FEW MORE HOURS...TIL
MIDNIGHT. THEN ISOLATED SHOWERS/THUNDERSTORMS WILL BE ACROSS THE
CENTRAL AND SOUTHEAST AFTER MIDNIGHT. REMAINDER OF THE FORECAST
LOOKS FINE WITH TEMPS FALLING INTO THE LOWER TO MIDDLE 60S BY
MORNING...WITH LIGHT WINDS AND MOSTLY CLEAR SKIES. SO WILL BE
MAKING SOME MINOR ADJUSTMENTS TO THE FORECAST. UPDATE WILL BE OUT
SHORTLY.

AUTEN
&&

.AVIATION...
ISSUED 634 PM CDT MON JUN 17 2013

ALL TAF SITES WILL START WITH HIGH CIRRUS THIS EVENING. AS THE
SYSTEM DOWN OVER SOUTHERN IL MOVES EAST THE CLOUDS WILL SCATTER
OUT LATER TONIGHT AND OVERNIGHT. HOWEVER...WITH MOSTLY CLEAR SKIES
AND LIGHT WINDS AGAIN...WILL PROBABLY SEE SOME LIGHT FOG AGAIN.
NOT EXPECTING VIS TO GO AS LOW AS IT DID LAST NIGHT. SO WILL KEEP
VIS AT LOWER MVFR LEVELS. THEN CONDITIONS WILL IMPROVE DURING THE
MORNING HOURS WITH SCATTERED CU EXPECTED. THEN ANOTHER SYSTEM WILL
DROP SOUTHEAST TOWARD THE AREA IN THE AFTERNOON. ALL MODELS HAVE
SOME LIGHT QPF ACROSS THE AREA TUE AFTERNOON SO WILL GO AHEAD AND
HAVE VCTS FOR ALL TAF SITES FOR AFTERNOON TIME FRAME. WINDS WILL
BE LIGHT AND VARIABLE OVERNIGHT AND EARLY TOMORROW...THEN BECOME
MORE NORTH TO NORTHEAST DURING THE DAY AND IN THE AFTERNOON.

AUTEN
&&

.PREV DISCUSSION...
ISSUED 220 PM CDT MON JUN 17 2013

SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT

MAIN CONCERNS THIS PERIOD WILL BE WITH COVERAGE OF PRECIP ACRS OUR
SOUTHERN COUNTIES TONIGHT...ASSOCIATED WITH AN MCV OVER MISSOURI...
AND WITH A WEAK SURFACE BOUNDARY FORECAST TO EDGE INTO OUR AREA
TUESDAY AFTERNOON. AFTER THAT...SOMEWHAT COOLER AND LESS HUMID WEATHER
WILL FOLLOW INTO THURSDAY BEFORE HEAT BUILDS NORTHWARD INTO THE REGION
FOR THE END OF THE WEEK AND NEXT WEEKEND.

WATER VAPOR LOOP SHOWING THE CONVECTIVE COMPLEX FROM LAST NIGHT
PRODUCING A DISTINCT MCV OVER PARTS OF WESTERN MO WITH NEW CONVECTION
DEVELOPING TO ITS EAST INTO EAST CENTRAL AND SE MO AND TRYING TO
DEVELOP A BIT FURTHER NORTH INTO SOUTHERN ILLINOIS. LOOKING NORTH...
SEVERAL LOW AMPLITUDE SHORTWAVES TRACKING E-SE ACRS THE NORTHERN
PLAINS. ONCE SUCH WAVE PUSHING ACRS WISCONSIN WITH A WEAK SFC BOUNDARY
SHIFTING SOUTH DOWN LAKE MICHIGAN...WHICH SHORT TERM MODELS SUGGEST
WILL PUSH ACRS EXTREME SOUTHERN LAKE MICHIGAN LATER THIS EVENING.
THE AIR MASS AHEAD OF THIS FEATURE NOT PARTICULARLY CONDUCIVE TO
WIDESPREAD CONVECTION DEVELOPING AHEAD OF IT SO OTHER THAN SOME
SLIGHT CHANCE (ISOLATED WORDING) FOR THIS EVENING ACRS THE FAR
NORTH...IT STILL APPEARS THE BETTER PROBABILITIES FOR EVENING
CONVECTION WILL BE TIED TO THE MISSOURI MCV AS IT TRACKS ESE WELL
TO OUR SOUTH.

THE NORTHERN STREAM WAVE ACRS NORTH DAKOTA LOOKS A BIT MORE IMPRESSIVE
THAN WHAT MODELS WERE DEPICTING AT THIS TIME YESTERDAY. MODELS CONTINUE
TO BRING THIS WAVE ESE INTO THE LAKES REGION TUESDAY AFTERNOON WITH
A WEAK COLD FRONT EDGING SOUTH INTO OUR AREA. CONVERGENCE ALONG THE
BOUNDARY IS NOT VERY IMPRESSIVE AT ALL BUT WITH THE TIMING OF THE
BOUNDARY INTO OUR AREA DURING PEAK HEATING...IT STILL WARRANTS SLIGHT
CHANCE (ISOLATED COVERAGE) FOR TUESDAY AFTERNOON. SOMEWHAT COOLER AND
LESS HUMID AIR WILL FILTER SOUTH ACRS THE AREA IN THE WAKE OF THE
SHORTWAVE TUESDAY NIGHT INTO WEDNESDAY BRINGING QUIET AND PLEASANT
WEATHER FOR THE REMAINDER OF THE SHORT TERM PERIOD.

LONG TERM...FRIDAY THROUGH MONDAY

LONGER RANGE MODELS...AT LEAST THE GFS AND UK...WERE MUCH MORE
AGGRESSIVE WITH THE RETROGRESSION OF THE SUBTROPICAL RIDGE ACRS
THE CENTRAL U.S...TAKING THE STRONGER 500 MB FLOW FURTHER NORTH
AWAY FROM OUR AREA. THE 12Z ECMWF NOT NEARLY AS STRONG WITH THE
UPPER RIDGE AS IT TAKES A SERIES OF SHORTWAVES FROM THE LONGWAVE
TROF ACRS THE PACIFIC NW AND TEMPORARILY FLATTENS THE RIDGE AXIS
TO OUR WEST...KEEPING THE AMPLITUDE MUCH FLATTER OVER THE LOWER
48...WHICH GIVES OUR AREA A BETTER CHANCE FOR SEEING SCATTERED
CONVECTION...ESPECIALLY ACRS THE NORTH DURING THE WEEKEND. LOOKS
AS IF THE GFS SOLUTION MAY BE OVERDONE...COMPARED TO WHAT IT WAS
SHOWING THE PAST SEVERAL RUNS. SO FAR THIS SPRING...THE SHORTWAVES
EJECTING ENE FROM THE WESTERN U.S. TROFS AND THEIR ASSOCIATED
CONVECTION HAVE BEEN SUCCESSFUL IN KEEPING THE AMPLITUDE OF THE
RIDGE ACRS THE CENTRAL PORTION OF THE COUNTRY FLATTER. WILL TEND
TO SIDE MORE WITH THE ECMWF THIS PERIOD BUT IT WON`T MAKE MUCH OF
A DIFFERENCE IN THE EXTENDED PORTION OF THE FORECAST WITH HOT
WEATHER RETURNING FOR THE WEEKEND AND THE HIGHER RAIN CHANCES ACRS
THE NORTH.

SMITH

&&

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

$$


000
FXUS63 KLOT 180003
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
703 PM CDT MON JUN 17 2013

.DISCUSSION...
251 PM CDT

TONIGHT...
VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CIRRUS SHIELD FROM
SOUTHEAST IOWA STRETCHING NORTHEAST ALONG I-80 IN ILLINOIS INTO
NORTHCENTRAL INDIANA. WATER VAPOR IMAGERY ALSO INDICATED AN
ABUNDANCE OF UPR LEVEL MOISTURE ASSOCIATED WITH THE CLOUDS...HOWEVER
SOME SUBSIDENCE WAS OCCURRING LATE THIS MORNING INTO THE AFTERNOON
HOURS AS DEW POINTS AT THE SFC WERE DROPPING INTO THE MID/UPR 50S
ACROSS THE CWFA. LLVL FLOW UNDER THE CLOUD SHIELD WAS GENERALLY
SOUTHWESTERLY...WHILE FURTHER NORTH WINDS WERE WESTERLY. IT APPEARS
THAT WHERE SKIES ARE MOSTLY SUNNY SLIGHTLY BETTER MIXING WAS
OCCURRING...WHICH WAS ALSO AIDING IN THE SUBSIDENCE AT THE SFC.

THE FOCUS FOR LATER THIS AFTERNOON/EVENING IS ON THE APPROACHING
FRONTAL BOUNDARY AND POTENTIAL FOR ISOLATED SHOWERS/THUNDERSTORMS
ALONG/JUST AHEAD OF THIS BOUNDARY. VISIBLE IMAGERY DOES SHOW A
NARROW CHANNEL OF A CUMULUS FIELD DEVELOPING ACROSS CENTRAL WISC
THIS AFTERNOON...STRETCHING NORTHWEST THROUGH MINN. A WEAK MID-LVL
WAVE WAS SLIDING SOUTHEAST THE UPPER MIDWEST...WHICH WILL BE THE
DRIVER FOR SOME ADDED LIFT INTO THIS CUMULUS FIELD. AS EXPECTED
ISOLATED SHOWERS/THUNDERSTORMS WERE DEVELOPING UNDER THIS CHANNEL OF
CUMULUS ACROSS CENTRAL WISC/EASTERN MINN. MID-LVLS ARE MUCH
COOLER...WITH STEEP LAPSE RATES TO THE NORTH ACROSS WISC. THIS
SUGGESTS THAT A FEW THUNDERSTORMS COULD EASILY GROW VERTICALLY AND
POSSIBLY PRODUCE SOME HAIL. FEEL THAT MOST OF THE LATE AFTN/EARLY
EVENING WILL END UP BEING DRY FOR THE CWFA. GUIDANCE CONTINUES TO
SUGGEST THAT THE BEST CHC FOR ANY PRECIP WILL LIKELY OCCUR AFT 00Z.
WITH MUCH OF THE CONVECTIVE POTENTIAL BEING DIURNALLY
DRIVEN...EXPECT THAT ARND 2-3Z THE INSTABILITY TO GREATLY DIMINISH.
AT THIS TIME WILL HOLD ONTO THE SLIGHT CHC OF TSRA WORDING THRU 3Z.
ACROSS THE NORTH...THEN LINGER THE TSRA WORDING THRU 06Z FOR THE
SOUTHEAST CWFA.

EARLIER THINKING WAS THAT THIS BOUNDARY WOULD END UP BEING A BACK
DOOR COLD FRONT...AND THIS APPEARS TO BE THE CASE BASED ON CURRENT
CONDS TO THE NORTH. CLOUD COVER SHUD BE SLOWLY THINNING OVERNIGHT TO
A P-CLOUDY SKY...WITH WINDS TURNING NORTHERLY POST FRONTAL PASSAGE.
THIS WILL USHER IN MUCH COOLER AIR AND ALLOW TEMPS TO EASILY RADIATE
INTO THE MID/UPR 50S.

CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...LOW/MEDIUM.

TUESDAY THROUGH WEDNESDAY...
INITIAL GLANCE IS THAT TUE WOULD BE DRY...HOWEVER THE CONCERN IS ON
THE SOUTHEAST DIVING 500MB VORT THAT WILL BE ARRIVING ACROSS THE
WESTERN CWFA MID/LATE MORNING AND PIVOTING EAST BY THE MID-AFTERNOON
HOURS. THIS MAY PROVIDE ENOUGH LIFT...COUPLED WITH DIURNAL CUMULUS
TUE...AND SOME MOISTURE FROM THE BOUNDARY TO ALLOW A FEW
THUNDERSTORMS TO DEVELOP. WITH TEMPS ALOFT STEADILY COOLING ACROSS
THE CWFA...LAPSE RATES WILL STEEPEN AND A FEW STRONGER STORMS COULD
EASILY PRODUCE SOME PEA SIZE HAIL...BRIEF WIND GUSTS AND HEAVY
DOWNPOURS. THE FOCUS APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO
BENTON COUNTY LINE.

OTHERWISE ANTI-CYCLONIC FLOW WILL CONTINUE TO SETTLE INTO THE GREAT
LAKES REGION...AND KEEP A NORTHEAST FLOW AT THE SFC. THIS WILL
EASILY AID IN THE MUCH COOLER MARINE ENVIRONMENT ADVECTING INLAND
ACROSS THE CWFA AND KEEP SFC TEMPS IN THE LOW/MID 70S...EXCEPT THE
FAR SOUTH/SOUTHWEST WHERE TEMPS MAY STILL TOUCH 80 DEG IN THE AFTN.
LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN MAY HAVE TEMPS
REMAIN IN THE MID 60S TUE.

OVERNIGHT TEMPS WILL BE MUCH COOLER IN THE LOW/MID 50S. A FEW
LOCATIONS ALONG AND NORTH OF A ROCKFORD...AURORA...WAUKEGAN LINE MAY
HAVE TEMPS IN THE UPR 40S EARLY WED MORNING. THEN HIGH PRESSURE
BEGINS TO DRIFT EAST. WHILE WINDS WILL BE MORE EASTERLY OFF OF THE
LAKE...TEMPS WILL BE SLIGHTLY WARMER WED AFTN IN THE UPR 70S TO LOW
80S. THE EXCEPTION WILL BE AREAS ADJACENT TO LAKE MICHIGAN...WHERE
TEMPS WILL LIKELY REMAIN IN THE 60S TO LOW 70S.

CONFIDENCE...HIGH.

THURSDAY THROUGH SUNDAY...
ENSEMBLES CONTINUES TO POINT TOWARDS A PATTERN CHANGE FOR THE END OF
THE WEEK INTO THE WEEKEND. MANY GUIDANCE MEMBERS ARE IN AGREEMENT
THAT THE 500MB TROUGH OVER THE GREAT LAKES REGION WILL PIVOT EAST
THUR...WITH A STRENGTHENING MID-LVL RIDGE ACROSS THE CENTRAL PLAINS
REPLACING THE DEPARTING TROUGH FRI. THE RIDGE DOES APPEAR TO FLATTEN
SLIGHTLY...WHICH MAY BE AN INDICATION THAT A SLIGHTLY ACTIVE PERIOD
MAY ACCOMPANY THE STEADY WARMING TREND. 850MB THERMAL RIDGE
CONTINUES TO BE RATHER WARM FOR THE WEEKEND...WITH TEMPS GENERALLY
AROUND 20-22 DEG C. THE EC/GEM HAVE TAKEN A SLIGHTLY COOLER APPROACH
WITH 18-20 DEG C...HOWEVER THE OVERALL THEME IS THAT TEMPS WILL BE
STEADILY WARMING. THE WILDCARD FOR MAX TEMPS SAT/SUN/MON...WILL BE
LLVL MOISTURE AND CLOUD COVER. GUIDANCE CONTINUES TO SUGGEST DEW
POINTS WILL GENERALLY BE AROUND 70 DEG. THIS MAY SLOW THE DIURNAL
CURVE FOR THE WEEKEND...HOWEVER TEMPS SHUD EASILY STILL WARM INTO
THE UPR 80S TO POSSIBLY LOWER 90S. AS A RESULT HAVE NUDGED TEMPS
WARMER THAN GUIDANCE FOR THE UPCOMING WEEKEND.

CONFIDENCE IN TEMPERATURES...MEDIUM/HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...MEDIUM.

BEACHLER

&&

.AVIATION...

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

* WIND SHIFT TO THE NORTH...JUST BEFORE 00Z AT ORD AND IMMINENT AT MDW.

* NEAR TERM GUSTINESS WITH THE NEW WIND DIRECTION.

* HIGH BASED SHRA IN THE AREA...BUT LITTLE IF ANY TSRA ANTICIPATED.

LENNING

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

SHOWERS PASSING NEAR THE TERMINALS AROUND 00Z ARE ANTICIPATED TO
BE SHORT LIVED AS AFTERNOON HEATING DIMINISHES. AS OF THIS
MOMENT...WINDS HAVE TURNED NORTH AT ORD BUT ARE STILL WSW AT
MDW...THOUGH EXPECTED TO FOLLOW THE ORD EXAMPLE SHORTLY. THIS WIND
DIRECTION IS BEING INFLUENCED BY THE LOCAL LAKE BREEZE AND OUTFLOW
FROM NEIGHBORHOOD SHOWERS...BUT THE OVERALL TREND IS TO REMAIN OUT
OF THE NORTH. IT IS POSSIBLE THAT A NORTHWEST DIRECTION COULD
RETURN BRIEFLY THIS EVENING...BUT ELECTED IN THE FCST TO STAY
WITH A NORTHERLY DIRECTION THROUGH THE NIGHT...GRADUALLY TURNING
NORTHEAST TOMORROW AS PER MODEL GUIDANCE AND WIND ROSES FOR THIS
TIME OF YEAR. NO MAJOR CONCERNS WITH THE WEATHER FOR TOMORROW.

LENNING


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

* MEDIUM TO HIGH CONFIDENCE OF WINDS REMAINING NORTH TO NORTHEAST
  THROUGH THE TAF PERIOD.

* HIGH CONFIDENCE THAT SHOWERS WILL DISSIPATE THIS EVENING.

LENNING

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

WEDNESDAY...VFR.

THURSDAY...VFR.

FRIDAY...VFR EARLY...CHANCE OF TSRA OVERNIGHT.

SATURDAY AND SUNDAY...PERIODIC CHANCES FOR TSRA.

LENNING

&&

.MARINE...
245 PM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. A TROUGH OF LOW
PRESSURE AND AN ASSOCIATED WEAK COLD FRONT...EXTEND FROM NORTHERN
MAINE WEST THROUGH CENTRAL LAKE MICHIGAN. AS THE LOW MOVES OFF TO
THE EAST...THE FRONT WILL CONTINUE TO MOVE SOUTH DOWN THE
LAKE...REACHING THE SOUTHERN TIP OF THE LAKE BY LATE THIS EVENING.
WINDS WILL SHIFT TO NORTHERLY BEHIND THE FRONT...WITH OCCASIONAL
GUSTS TO 25 KT TONIGHT. HIGH PRESSURE OVER THE NORTHERN PLAINS
WILL SPREAD EAST ACROSS THE GREAT LAKES LATE TONIGHT AND
TOMORROW...WITH HIGH PRESSURE REMAINING THE DOMINANT FEATURE OVER
THE LAKE THROUGH WEDNESDAY NIGHT WHEN THE HIGH WILL BEGIN TO SLIDE
OFF TO THE EAST. IN THE MEAN TIME...LOW PRESSURE DEVELOPING OVER
THE NORTHERN ROCKIES WEDNESDAY NIGHT AND WILL MOVE OVER THE
NORTHERN PLAINS BY FRIDAY MORNING. WITH THE HIGH PRESSURE TO THE
EAST AND THE DEVELOPING TROUGH TO THE WEST...WINDS WILL BECOME
SOUTHERLY BY WEDNESDAY OR WEDNESDAY NIGHT...THROUGH THE WEEKEND.

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...NONE.
&&

$$

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

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


000
FXUS63 KILX 172334
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
634 PM CDT MON JUN 17 2013

.DISCUSSION...
ISSUED 220 PM CDT MON JUN 17 2013

SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT

MAIN CONCERNS THIS PERIOD WILL BE WITH COVERAGE OF PRECIP ACRS OUR
SOUTHERN COUNTIES TONIGHT...ASSOCIATED WITH AN MCV OVER MISSOURI...
AND WITH A WEAK SURFACE BOUNDARY FORECAST TO EDGE INTO OUR AREA
TUESDAY AFTERNOON. AFTER THAT...SOMEWHAT COOLER AND LESS HUMID WEATHER
WILL FOLLOW INTO THURSDAY BEFORE HEAT BUILDS NORTHWARD INTO THE REGION
FOR THE END OF THE WEEK AND NEXT WEEKEND.

WATER VAPOR LOOP SHOWING THE CONVECTIVE COMPLEX FROM LAST NIGHT
PRODUCING A DISTINCT MCV OVER PARTS OF WESTERN MO WITH NEW CONVECTION
DEVELOPING TO ITS EAST INTO EAST CENTRAL AND SE MO AND TRYING TO
DEVELOP A BIT FURTHER NORTH INTO SOUTHERN ILLINOIS. LOOKING NORTH...
SEVERAL LOW AMPLITUDE SHORTWAVES TRACKING E-SE ACRS THE NORTHERN
PLAINS. ONCE SUCH WAVE PUSHING ACRS WISCONSIN WITH A WEAK SFC BOUNDARY
SHIFTING SOUTH DOWN LAKE MICHIGAN...WHICH SHORT TERM MODELS SUGGEST
WILL PUSH ACRS EXTREME SOUTHERN LAKE MICHIGAN LATER THIS EVENING.
THE AIR MASS AHEAD OF THIS FEATURE NOT PARTICULARLY CONDUCIVE TO
WIDESPREAD CONVECTION DEVELOPING AHEAD OF IT SO OTHER THAN SOME
SLIGHT CHANCE (ISOLATED WORDING) FOR THIS EVENING ACRS THE FAR
NORTH...IT STILL APPEARS THE BETTER PROBABILITIES FOR EVENING
CONVECTION WILL BE TIED TO THE MISSOURI MCV AS IT TRACKS ESE WELL
TO OUR SOUTH.

THE NORTHERN STREAM WAVE ACRS NORTH DAKOTA LOOKS A BIT MORE IMPRESSIVE
THAN WHAT MODELS WERE DEPICTING AT THIS TIME YESTERDAY. MODELS CONTINUE
TO BRING THIS WAVE ESE INTO THE LAKES REGION TUESDAY AFTERNOON WITH
A WEAK COLD FRONT EDGING SOUTH INTO OUR AREA. CONVERGENCE ALONG THE
BOUNDARY IS NOT VERY IMPRESSIVE AT ALL BUT WITH THE TIMING OF THE
BOUNDARY INTO OUR AREA DURING PEAK HEATING...IT STILL WARRANTS SLIGHT
CHANCE (ISOLATED COVERAGE) FOR TUESDAY AFTERNOON. SOMEWHAT COOLER AND
LESS HUMID AIR WILL FILTER SOUTH ACRS THE AREA IN THE WAKE OF THE
SHORTWAVE TUESDAY NIGHT INTO WEDNESDAY BRINGING QUIET AND PLEASANT
WEATHER FOR THE REMAINDER OF THE SHORT TERM PERIOD.

LONG TERM...FRIDAY THROUGH MONDAY

LONGER RANGE MODELS...AT LEAST THE GFS AND UK...WERE MUCH MORE
AGGRESSIVE WITH THE RETROGRESSION OF THE SUBTROPICAL RIDGE ACRS
THE CENTRAL U.S...TAKING THE STRONGER 500 MB FLOW FURTHER NORTH
AWAY FROM OUR AREA. THE 12Z ECMWF NOT NEARLY AS STRONG WITH THE
UPPER RIDGE AS IT TAKES A SERIES OF SHORTWAVES FROM THE LONGWAVE
TROF ACRS THE PACIFIC NW AND TEMPORARILY FLATTENS THE RIDGE AXIS
TO OUR WEST...KEEPING THE AMPLITUDE MUCH FLATTER OVER THE LOWER
48...WHICH GIVES OUR AREA A BETTER CHANCE FOR SEEING SCATTERED
CONVECTION...ESPECIALLY ACRS THE NORTH DURING THE WEEKEND. LOOKS
AS IF THE GFS SOLUTION MAY BE OVERDONE...COMPARED TO WHAT IT WAS
SHOWING THE PAST SEVERAL RUNS. SO FAR THIS SPRING...THE SHORTWAVES
EJECTING ENE FROM THE WESTERN U.S. TROFS AND THEIR ASSOCIATED
CONVECTION HAVE BEEN SUCCESSFUL IN KEEPING THE AMPLITUDE OF THE
RIDGE ACRS THE CENTRAL PORTION OF THE COUNTRY FLATTER. WILL TEND
TO SIDE MORE WITH THE ECMWF THIS PERIOD BUT IT WON`T MAKE MUCH OF
A DIFFERENCE IN THE EXTENDED PORTION OF THE FORECAST WITH HOT
WEATHER RETURNING FOR THE WEEKEND AND THE HIGHER RAIN CHANCES ACRS
THE NORTH.

SMITH
&&

.AVIATION...
ISSUED 634 PM CDT MON JUN 17 2013

ALL TAF SITES WILL START WITH HIGH CIRRUS THIS EVENING. AS THE
SYSTEM DOWN OVER SOUTHERN IL MOVES EAST THE CLOUDS WILL SCATTER
OUT LATER TONIGHT AND OVERNIGHT. HOWEVER...WITH MOSTLY CLEAR SKIES
AND LIGHT WINDS AGAIN...WILL PROBABLY SEE SOME LIGHT FOG AGAIN.
NOT EXPECTING VIS TO GO AS LOW AS IT DID LAST NIGHT. SO WILL KEEP
VIS AT LOWER MVFR LEVELS. THEN CONDITIONS WILL IMPROVE DURING THE
MORNING HOURS WITH SCATTERED CU EXPECTED. THEN ANOTHER SYSTEM WILL
DROP SOUTHEAST TOWARD THE AREA IN THE AFTERNOON. ALL MODELS HAVE
SOME LIGHT QPF ACROSS THE AREA TUE AFTERNOON SO WILL GO AHEAD AND
HAVE VCTS FOR ALL TAF SITES FOR AFTERNOON TIME FRAME. WINDS WILL
BE LIGHT AND VARIABLE OVERNIGHT AND EARLY TOMORROW...THEN BECOME
MORE NORTH TO NORTHEAST DURING THE DAY AND IN THE AFTERNOON.

AUTEN
&&

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

$$


000
FXUS63 KLOT 172232
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
532 PM CDT MON JUN 17 2013

.DISCUSSION...
251 PM CDT

TONIGHT...
VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CIRRUS SHIELD FROM
SOUTHEAST IOWA STRETCHING NORTHEAST ALONG I-80 IN ILLINOIS INTO
NORTHCENTRAL INDIANA. WATER VAPOR IMAGERY ALSO INDICATED AN
ABUNDANCE OF UPR LEVEL MOISTURE ASSOCIATED WITH THE CLOUDS...HOWEVER
SOME SUBSIDENCE WAS OCCURRING LATE THIS MORNING INTO THE AFTERNOON
HOURS AS DEW POINTS AT THE SFC WERE DROPPING INTO THE MID/UPR 50S
ACROSS THE CWFA. LLVL FLOW UNDER THE CLOUD SHIELD WAS GENERALLY
SOUTHWESTERLY...WHILE FURTHER NORTH WINDS WERE WESTERLY. IT APPEARS
THAT WHERE SKIES ARE MOSTLY SUNNY SLIGHTLY BETTER MIXING WAS
OCCURRING...WHICH WAS ALSO AIDING IN THE SUBSIDENCE AT THE SFC.

THE FOCUS FOR LATER THIS AFTERNOON/EVENING IS ON THE APPROACHING
FRONTAL BOUNDARY AND POTENTIAL FOR ISOLATED SHOWERS/THUNDERSTORMS
ALONG/JUST AHEAD OF THIS BOUNDARY. VISIBLE IMAGERY DOES SHOW A
NARROW CHANNEL OF A CUMULUS FIELD DEVELOPING ACROSS CENTRAL WISC
THIS AFTERNOON...STRETCHING NORTHWEST THROUGH MINN. A WEAK MID-LVL
WAVE WAS SLIDING SOUTHEAST THE UPPER MIDWEST...WHICH WILL BE THE
DRIVER FOR SOME ADDED LIFT INTO THIS CUMULUS FIELD. AS EXPECTED
ISOLATED SHOWERS/THUNDERSTORMS WERE DEVELOPING UNDER THIS CHANNEL OF
CUMULUS ACROSS CENTRAL WISC/EASTERN MINN. MID-LVLS ARE MUCH
COOLER...WITH STEEP LAPSE RATES TO THE NORTH ACROSS WISC. THIS
SUGGESTS THAT A FEW THUNDERSTORMS COULD EASILY GROW VERTICALLY AND
POSSIBLY PRODUCE SOME HAIL. FEEL THAT MOST OF THE LATE AFTN/EARLY
EVENING WILL END UP BEING DRY FOR THE CWFA. GUIDANCE CONTINUES TO
SUGGEST THAT THE BEST CHC FOR ANY PRECIP WILL LIKELY OCCUR AFT 00Z.
WITH MUCH OF THE CONVECTIVE POTENTIAL BEING DIURNALLY
DRIVEN...EXPECT THAT ARND 2-3Z THE INSTABILITY TO GREATLY DIMINISH.
AT THIS TIME WILL HOLD ONTO THE SLIGHT CHC OF TSRA WORDING THRU 3Z.
ACROSS THE NORTH...THEN LINGER THE TSRA WORDING THRU 06Z FOR THE
SOUTHEAST CWFA.

EARLIER THINKING WAS THAT THIS BOUNDARY WOULD END UP BEING A BACK
DOOR COLD FRONT...AND THIS APPEARS TO BE THE CASE BASED ON CURRENT
CONDS TO THE NORTH. CLOUD COVER SHUD BE SLOWLY THINNING OVERNIGHT TO
A P-CLOUDY SKY...WITH WINDS TURNING NORTHERLY POST FRONTAL PASSAGE.
THIS WILL USHER IN MUCH COOLER AIR AND ALLOW TEMPS TO EASILY RADIATE
INTO THE MID/UPR 50S.

CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...LOW/MEDIUM.

TUESDAY THROUGH WEDNESDAY...
INITIAL GLANCE IS THAT TUE WOULD BE DRY...HOWEVER THE CONCERN IS ON
THE SOUTHEAST DIVING 500MB VORT THAT WILL BE ARRIVING ACROSS THE
WESTERN CWFA MID/LATE MORNING AND PIVOTING EAST BY THE MID-AFTERNOON
HOURS. THIS MAY PROVIDE ENOUGH LIFT...COUPLED WITH DIURNAL CUMULUS
TUE...AND SOME MOISTURE FROM THE BOUNDARY TO ALLOW A FEW
THUNDERSTORMS TO DEVELOP. WITH TEMPS ALOFT STEADILY COOLING ACROSS
THE CWFA...LAPSE RATES WILL STEEPEN AND A FEW STRONGER STORMS COULD
EASILY PRODUCE SOME PEA SIZE HAIL...BRIEF WIND GUSTS AND HEAVY
DOWNPOURS. THE FOCUS APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO
BENTON COUNTY LINE.

OTHERWISE ANTI-CYCLONIC FLOW WILL CONTINUE TO SETTLE INTO THE GREAT
LAKES REGION...AND KEEP A NORTHEAST FLOW AT THE SFC. THIS WILL
EASILY AID IN THE MUCH COOLER MARINE ENVIRONMENT ADVECTING INLAND
ACROSS THE CWFA AND KEEP SFC TEMPS IN THE LOW/MID 70S...EXCEPT THE
FAR SOUTH/SOUTHWEST WHERE TEMPS MAY STILL TOUCH 80 DEG IN THE AFTN.
LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN MAY HAVE TEMPS
REMAIN IN THE MID 60S TUE.

OVERNIGHT TEMPS WILL BE MUCH COOLER IN THE LOW/MID 50S. A FEW
LOCATIONS ALONG AND NORTH OF A ROCKFORD...AURORA...WAUKEGAN LINE MAY
HAVE TEMPS IN THE UPR 40S EARLY WED MORNING. THEN HIGH PRESSURE
BEGINS TO DRIFT EAST. WHILE WINDS WILL BE MORE EASTERLY OFF OF THE
LAKE...TEMPS WILL BE SLIGHTLY WARMER WED AFTN IN THE UPR 70S TO LOW
80S. THE EXCEPTION WILL BE AREAS ADJACENT TO LAKE MICHIGAN...WHERE
TEMPS WILL LIKELY REMAIN IN THE 60S TO LOW 70S.

CONFIDENCE...HIGH.

THURSDAY THROUGH SUNDAY...
ENSEMBLES CONTINUES TO POINT TOWARDS A PATTERN CHANGE FOR THE END OF
THE WEEK INTO THE WEEKEND. MANY GUIDANCE MEMBERS ARE IN AGREEMENT
THAT THE 500MB TROUGH OVER THE GREAT LAKES REGION WILL PIVOT EAST
THUR...WITH A STRENGTHENING MID-LVL RIDGE ACROSS THE CENTRAL PLAINS
REPLACING THE DEPARTING TROUGH FRI. THE RIDGE DOES APPEAR TO FLATTEN
SLIGHTLY...WHICH MAY BE AN INDICATION THAT A SLIGHTLY ACTIVE PERIOD
MAY ACCOMPANY THE STEADY WARMING TREND. 850MB THERMAL RIDGE
CONTINUES TO BE RATHER WARM FOR THE WEEKEND...WITH TEMPS GENERALLY
AROUND 20-22 DEG C. THE EC/GEM HAVE TAKEN A SLIGHTLY COOLER APPROACH
WITH 18-20 DEG C...HOWEVER THE OVERALL THEME IS THAT TEMPS WILL BE
STEADILY WARMING. THE WILDCARD FOR MAX TEMPS SAT/SUN/MON...WILL BE
LLVL MOISTURE AND CLOUD COVER. GUIDANCE CONTINUES TO SUGGEST DEW
POINTS WILL GENERALLY BE AROUND 70 DEG. THIS MAY SLOW THE DIURNAL
CURVE FOR THE WEEKEND...HOWEVER TEMPS SHUD EASILY STILL WARM INTO
THE UPR 80S TO POSSIBLY LOWER 90S. AS A RESULT HAVE NUDGED TEMPS
WARMER THAN GUIDANCE FOR THE UPCOMING WEEKEND.

CONFIDENCE IN TEMPERATURES...MEDIUM/HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...MEDIUM.

BEACHLER

&&

.AVIATION...

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

* SHOWERS IN THE VICINITY...THUNDERSTORMS POSSIBLE...WITH VARIABLE
  BUT STILL PRIMARILY WESTERLY WINDS ASSOCIATED WITH THESE.

* TIMING OF WIND SHIFT TO NORTH OR NNE FROM LAKE BREEZE OR FRONTAL
  PASSAGE THIS EVENING.

LENNING

//DISCUSSION...UPDATED 18Z...

A COLD FRONT EXTENDING ACROSS NORTHERN WI AND NORTHERN LAKE
MICHIGAN WILL MOVE SOUTH THIS AFTERNOON ARRIVING INTO NORTHEAST IL
EARLY THIS EVENING. A LAKE BREEZE HAS ALREADY FORMED ACROSS THE
SOUTHEAST SHORE OF WISCONSIN AND THIS WILL NEED TO BE MONITORED
FOR A FASTER PUSH TO THE SOUTHWEST AS THE COLD FRONT CATCHES UP TO
THIS BOUNDARY. WESTERLY WINDS WILL SHIFT TO THE NORTHEAST ONCE THE
FRONT MOVES THROUGH THE TERMINALS EARLY THIS EVENING. NORTHEAST
WINDS WILL THEN PREVAIL THROUGH THE REST OF THE PERIOD. SOME GUSTS
ARE POSSIBLE THIS AFTERNOON BUT SHOULD REMAIN LESS THAN 20 KTS.

SHORT TERM/HI RES GUIDANCE CONTINUES TO SUGGEST RATHER SPARSE
COVERAGE FOR ANY SHRA OR TSRA ACTIVITY THIS AFTERNOON INTO THIS
EVENING. MOST AREAS WILL PROBABLY STAY DRY BUT WILL LEAVE VICINITY
MENTION IN THIS FORECAST. ANY ACTIVITY THAT DOES DEVELOP SHOULD
QUICKLY PUSH SOUTHEAST AND AWAY FROM THE TERMINALS BY MID EVENING.

CIGS EXPECTED TO REMAIN VFR THROUGH THE PERIOD. HOWEVER...THERE IS
A CHANCE OF LOWER CIGS...POSSIBLY IFR...LATE TONIGHT INTO TUESDAY
MORNING AS THE COLDER AIR RUNS INTO THE MORE MOIST LOW LEVELS. IN
ADDITION...AN AREA OF LOW CLOUDS/POSSIBLY FOG OVER NORTHERN LAKE
MICHIGAN MAY CONTINUE MOVING SOUTH ACROSS THE LAKE INTO TONIGHT.
APPEARS THE BEST CHANCE OF ANY LOWER CIGS WOULD BE NEAR THE LAKE
AND POSSIBLY AFFECTING GYY. CONFIDENCE TOO LOW FOR EVEN FEW/SCT
MENTION BUT WILL NEED TO MONITOR THIS WITH LATER FORECASTS. CMS

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

* LOW CONFIDENCE ON TIMING OF WIND SHIFT AND EVENTUAL DIRECTION
  THIS EVENING. MEDIUM CONFIDENCE THAT WESTERLY COMPONENT PREVAILS
  THROUGH THE PEAK EVENING PUSH...LIKE 01 OR 02 UTC.

* MEDIUM CONFIDENCE OF TSRA STAYING OUT OF THE TERMINALS...BUT
  LESS CONFIDENCE THAT SHRA WILL.

LENNING

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

TUESDAY NIGHT THROUGH FRIDAY...VFR.
FRIDAY NIGHT THROUGH SUNDAY...PERIODIC CHANCES FOR THUNDERSTORMS.

BMD

&&

.MARINE...
245 PM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. A TROUGH OF LOW
PRESSURE AND AN ASSOCIATED WEAK COLD FRONT...EXTEND FROM NORTHERN
MAINE WEST THROUGH CENTRAL LAKE MICHIGAN. AS THE LOW MOVES OFF TO
THE EAST...THE FRONT WILL CONTINUE TO MOVE SOUTH DOWN THE
LAKE...REACHING THE SOUTHERN TIP OF THE LAKE BY LATE THIS EVENING.
WINDS WILL SHIFT TO NORTHERLY BEHIND THE FRONT...WITH OCCASIONAL
GUSTS TO 25 KT TONIGHT. HIGH PRESSURE OVER THE NORTHERN PLAINS
WILL SPREAD EAST ACROSS THE GREAT LAKES LATE TONIGHT AND
TOMORROW...WITH HIGH PRESSURE REMAINING THE DOMINANT FEATURE OVER
THE LAKE THROUGH WEDNESDAY NIGHT WHEN THE HIGH WILL BEGIN TO SLIDE
OFF TO THE EAST. IN THE MEAN TIME...LOW PRESSURE DEVELOPING OVER
THE NORTHERN ROCKIES WEDNESDAY NIGHT AND WILL MOVE OVER THE
NORTHERN PLAINS BY FRIDAY MORNING. WITH THE HIGH PRESSURE TO THE
EAST AND THE DEVELOPING TROUGH TO THE WEST...WINDS WILL BECOME
SOUTHERLY BY WEDNESDAY OR WEDNESDAY NIGHT...THROUGH THE WEEKEND.

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM TUESDAY TO 4 AM
     WEDNESDAY.

LM...NONE.
&&

$$

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

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


000
FXUS63 KLOT 171957
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
257 PM CDT MON JUN 17 2013

.DISCUSSION...
251 PM CDT

TONIGHT...
VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CIRRUS SHIELD FROM
SOUTHEAST IOWA STRETCHING NORTHEAST ALONG I-80 IN ILLINOIS INTO
NORTHCENTRAL INDIANA. WATER VAPOR IMAGERY ALSO INDICATED AN
ABUNDANCE OF UPR LEVEL MOISTURE ASSOCIATED WITH THE CLOUDS...HOWEVER
SOME SUBSIDENCE WAS OCCURRING LATE THIS MORNING INTO THE AFTERNOON
HOURS AS DEW POINTS AT THE SFC WERE DROPPING INTO THE MID/UPR 50S
ACROSS THE CWFA. LLVL FLOW UNDER THE CLOUD SHIELD WAS GENERALLY
SOUTHWESTERLY...WHILE FURTHER NORTH WINDS WERE WESTERLY. IT APPEARS
THAT WHERE SKIES ARE MOSTLY SUNNY SLIGHTLY BETTER MIXING WAS
OCCURRING...WHICH WAS ALSO AIDING IN THE SUBSIDENCE AT THE SFC.

THE FOCUS FOR LATER THIS AFTERNOON/EVENING IS ON THE APPROACHING
FRONTAL BOUNDARY AND POTENTIAL FOR ISOLATED SHOWERS/THUNDERSTORMS
ALONG/JUST AHEAD OF THIS BOUNDARY. VISIBLE IMAGERY DOES SHOW A
NARROW CHANNEL OF A CUMULUS FIELD DEVELOPING ACROSS CENTRAL WISC
THIS AFTERNOON...STRETCHING NORTHWEST THROUGH MINN. A WEAK MID-LVL
WAVE WAS SLIDING SOUTHEAST THE UPPER MIDWEST...WHICH WILL BE THE
DRIVER FOR SOME ADDED LIFT INTO THIS CUMULUS FIELD. AS EXPECTED
ISOLATED SHOWERS/THUNDERSTORMS WERE DEVELOPING UNDER THIS CHANNEL OF
CUMULUS ACROSS CENTRAL WISC/EASTERN MINN. MID-LVLS ARE MUCH
COOLER...WITH STEEP LAPSE RATES TO THE NORTH ACROSS WISC. THIS
SUGGESTS THAT A FEW THUNDERSTORMS COULD EASILY GROW VERTICALLY AND
POSSIBLY PRODUCE SOME HAIL. FEEL THAT MOST OF THE LATE AFTN/EARLY
EVENING WILL END UP BEING DRY FOR THE CWFA. GUIDANCE CONTINUES TO
SUGGEST THAT THE BEST CHC FOR ANY PRECIP WILL LIKELY OCCUR AFT 00Z.
WITH MUCH OF THE CONVECTIVE POTENTIAL BEING DIURNALLY
DRIVEN...EXPECT THAT ARND 2-3Z THE INSTABILITY TO GREATLY DIMINISH.
AT THIS TIME WILL HOLD ONTO THE SLIGHT CHC OF TSRA WORDING THRU 3Z.
ACROSS THE NORTH...THEN LINGER THE TSRA WORDING THRU 06Z FOR THE
SOUTHEAST CWFA.

EARLIER THINKING WAS THAT THIS BOUNDARY WOULD END UP BEING A BACK
DOOR COLD FRONT...AND THIS APPEARS TO BE THE CASE BASED ON CURRENT
CONDS TO THE NORTH. CLOUD COVER SHUD BE SLOWLY THINNING OVERNIGHT TO
A P-CLOUDY SKY...WITH WINDS TURNING NORTHERLY POST FRONTAL PASSAGE.
THIS WILL USHER IN MUCH COOLER AIR AND ALLOW TEMPS TO EASILY RADIATE
INTO THE MID/UPR 50S.

CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...LOW/MEDIUM.

TUESDAY THROUGH WEDNESDAY...
INITIAL GLANCE IS THAT TUE WOULD BE DRY...HOWEVER THE CONCERN IS ON
THE SOUTHEAST DIVING 500MB VORT THAT WILL BE ARRIVING ACROSS THE
WESTERN CWFA MID/LATE MORNING AND PIVOTING EAST BY THE MID-AFTERNOON
HOURS. THIS MAY PROVIDE ENOUGH LIFT...COUPLED WITH DIURNAL CUMULUS
TUE...AND SOME MOISTURE FROM THE BOUNDARY TO ALLOW A FEW
THUNDERSTORMS TO DEVELOP. WITH TEMPS ALOFT STEADILY COOLING ACROSS
THE CWFA...LAPSE RATES WILL STEEPEN AND A FEW STRONGER STORMS COULD
EASILY PRODUCE SOME PEA SIZE HAIL...BRIEF WIND GUSTS AND HEAVY
DOWNPOURS. THE FOCUS APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO
BENTON COUNTY LINE.

OTHERWISE ANTI-CYCLONIC FLOW WILL CONTINUE TO SETTLE INTO THE GREAT
LAKES REGION...AND KEEP A NORTHEAST FLOW AT THE SFC. THIS WILL
EASILY AID IN THE MUCH COOLER MARINE ENVIRONMENT ADVECTING INLAND
ACROSS THE CWFA AND KEEP SFC TEMPS IN THE LOW/MID 70S...EXCEPT THE
FAR SOUTH/SOUTHWEST WHERE TEMPS MAY STILL TOUCH 80 DEG IN THE AFTN.
LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN MAY HAVE TEMPS
REMAIN IN THE MID 60S TUE.

OVERNIGHT TEMPS WILL BE MUCH COOLER IN THE LOW/MID 50S. A FEW
LOCATIONS ALONG AND NORTH OF A ROCKFORD...AURORA...WAUKEGAN LINE MAY
HAVE TEMPS IN THE UPR 40S EARLY WED MORNING. THEN HIGH PRESSURE
BEGINS TO DRIFT EAST. WHILE WINDS WILL BE MORE EASTERLY OFF OF THE
LAKE...TEMPS WILL BE SLIGHTLY WARMER WED AFTN IN THE UPR 70S TO LOW
80S. THE EXCEPTION WILL BE AREAS ADJACENT TO LAKE MICHIGAN...WHERE
TEMPS WILL LIKELY REMAIN IN THE 60S TO LOW 70S.

CONFIDENCE...HIGH.

THURSDAY THROUGH SUNDAY...
ENSEMBLES CONTINUES TO POINT TOWARDS A PATTERN CHANGE FOR THE END OF
THE WEEK INTO THE WEEKEND. MANY GUIDANCE MEMBERS ARE IN AGREEMENT
THAT THE 500MB TROUGH OVER THE GREAT LAKES REGION WILL PIVOT EAST
THUR...WITH A STRENGTHENING MID-LVL RIDGE ACROSS THE CENTRAL PLAINS
REPLACING THE DEPARTING TROUGH FRI. THE RIDGE DOES APPEAR TO FLATTEN
SLIGHTLY...WHICH MAY BE AN INDICATION THAT A SLIGHTLY ACTIVE PERIOD
MAY ACCOMPANY THE STEADY WARMING TREND. 850MB THERMAL RIDGE
CONTINUES TO BE RATHER WARM FOR THE WEEKEND...WITH TEMPS GENERALLY
AROUND 20-22 DEG C. THE EC/GEM HAVE TAKEN A SLIGHTLY COOLER APPROACH
WITH 18-20 DEG C...HOWEVER THE OVERALL THEME IS THAT TEMPS WILL BE
STEADILY WARMING. THE WILDCARD FOR MAX TEMPS SAT/SUN/MON...WILL BE
LLVL MOISTURE AND CLOUD COVER. GUIDANCE CONTINUES TO SUGGEST DEW
POINTS WILL GENERALLY BE AROUND 70 DEG. THIS MAY SLOW THE DIURNAL
CURVE FOR THE WEEKEND...HOWEVER TEMPS SHUD EASILY STILL WARM INTO
THE UPR 80S TO POSSIBLY LOWER 90S. AS A RESULT HAVE NUDGED TEMPS
WARMER THAN GUIDANCE FOR THE UPCOMING WEEKEND.

CONFIDENCE IN TEMPERATURES...MEDIUM/HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...MEDIUM.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WESTERLY WINDS THIS AFTERNOON.
* WIND SHIFT TO THE NORTHEAST EARLY EVENING.
* CHANCE OF SHRA...POSSIBLY AN ISOLATED TSRA...LATE THIS AFTERNOON
  OR EARLY THIS EVENING.
* POSSIBLE LOW CIGS EARLY TUESDAY. CMS

//DISCUSSION...UPDATED 18Z...

A COLD FRONT EXTENDING ACROSS NORTHERN WI AND NORTHERN LAKE
MICHIGAN WILL MOVE SOUTH THIS AFTERNOON ARRIVING INTO NORTHEAST IL
EARLY THIS EVENING. A LAKE BREEZE HAS ALREADY FORMED ACROSS THE
SOUTHEAST SHORE OF WISCONSIN AND THIS WILL NEED TO BE MONITORED
FOR A FASTER PUSH TO THE SOUTHWEST AS THE COLD FRONT CATCHES UP TO
THIS BOUNDARY. WESTERLY WINDS WILL SHIFT TO THE NORTHEAST ONCE THE
FRONT MOVES THROUGH THE TERMINALS EARLY THIS EVENING. NORTHEAST
WINDS WILL THEN PREVAIL THROUGH THE REST OF THE PERIOD. SOME GUSTS
ARE POSSIBLE THIS AFTERNOON BUT SHOULD REMAIN LESS THAN 20 KTS.

SHORT TERM/HI RES GUIDANCE CONTINUES TO SUGGEST RATHER SPARSE
COVERAGE FOR ANY SHRA OR TSRA ACTIVITY THIS AFTERNOON INTO THIS
EVENING. MOST AREAS WILL PROBABLY STAY DRY BUT WILL LEAVE VICINITY
MENTION IN THIS FORECAST. ANY ACTIVITY THAT DOES DEVELOP SHOULD
QUICKLY PUSH SOUTHEAST AND AWAY FROM THE TERMINALS BY MID EVENING.

CIGS EXPECTED TO REMAIN VFR THROUGH THE PERIOD. HOWEVER...THERE IS
A CHANCE OF LOWER CIGS...POSSIBLY IFR...LATE TONIGHT INTO TUESDAY
MORNING AS THE COLDER AIR RUNS INTO THE MORE MOIST LOW LEVELS. IN
ADDITION...AN AREA OF LOW CLOUDS/POSSIBLY FOG OVER NORTHERN LAKE
MICHIGAN MAY CONTINUE MOVING SOUTH ACROSS THE LAKE INTO TONIGHT.
APPEARS THE BEST CHANCE OF ANY LOWER CIGS WOULD BE NEAR THE LAKE
AND POSSIBLY AFFECTING GYY. CONFIDENCE TOO LOW FOR EVEN FEW/SCT
MENTION BUT WILL NEED TO MONITOR THIS WITH LATER FORECASTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH FOR A WIND SHIFT TO THE NORTHEAST...MEDIUM FOR TIMING AND
  SPECIFIC DIRECTION/SPEEDS.
* LOW FOR SHRA/TSRA.
* LOW FOR LOWER CIGS EARLY TUESDAY. CMS

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

TUESDAY NIGHT THROUGH FRIDAY...VFR.
FRIDAY NIGHT THROUGH SUNDAY...PERIODIC CHANCES FOR THUNDERSTORMS.

BMD

&&

.MARINE...
245 PM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. A TROUGH OF LOW
PRESSURE AND AN ASSOCIATED WEAK COLD FRONT...EXTEND FROM NORTHERN
MAINE WEST THROUGH CENTRAL LAKE MICHIGAN. AS THE LOW MOVES OFF TO
THE EAST...THE FRONT WILL CONTINUE TO MOVE SOUTH DOWN THE
LAKE...REACHING THE SOUTHERN TIP OF THE LAKE BY LATE THIS EVENING.
WINDS WILL SHIFT TO NORTHERLY BEHIND THE FRONT...WITH OCCASIONAL
GUSTS TO 25 KT TONIGHT. HIGH PRESSURE OVER THE NORTHERN PLAINS
WILL SPREAD EAST ACROSS THE GREAT LAKES LATE TONIGHT AND
TOMORROW...WITH HIGH PRESSURE REMAINING THE DOMINANT FEATURE OVER
THE LAKE THROUGH WEDNESDAY NIGHT WHEN THE HIGH WILL BEGIN TO SLIDE
OFF TO THE EAST. IN THE MEAN TIME...LOW PRESSURE DEVELOPING OVER
THE NORTHERN ROCKIES WEDNESDAY NIGHT AND WILL MOVE OVER THE
NORTHERN PLAINS BY FRIDAY MORNING. WITH THE HIGH PRESSURE TO THE
EAST AND THE DEVELOPING TROUGH TO THE WEST...WINDS WILL BECOME
SOUTHERLY BY WEDNESDAY OR WEDNESDAY NIGHT...THROUGH THE WEEKEND.

&&

.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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO


000
FXUS63 KLOT 171951
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
251 PM CDT MON JUN 17 2013

.DISCUSSION...
251 PM CDT

TONIGHT...
VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CIRRUS SHIELD FROM
SOUTHEAST IOWA STRETCHING NORTHEAST ALONG I-80 IN ILLINOIS INTO
NORTHCENTRAL INDIANA. WATER VAPOR IMAGERY ALSO INDICATED AN
ABUNDANCE OF UPR LEVEL MOISTURE ASSOCIATED WITH THE CLOUDS...HOWEVER
SOME SUBSIDENCE WAS OCCURRING LATE THIS MORNING INTO THE AFTERNOON
HOURS AS DEW POINTS AT THE SFC WERE DROPPING INTO THE MID/UPR 50S
ACROSS THE CWFA. LLVL FLOW UNDER THE CLOUD SHIELD WAS GENERALLY
SOUTHWESTERLY...WHILE FURTHER NORTH WINDS WERE WESTERLY. IT APPEARS
THAT WHERE SKIES ARE MOSTLY SUNNY SLIGHTLY BETTER MIXING WAS
OCCURRING...WHICH WAS ALSO AIDING IN THE SUBSIDENCE AT THE SFC.

THE FOCUS FOR LATER THIS AFTERNOON/EVENING IS ON THE APPROACHING
FRONTAL BOUNDARY AND POTENTIAL FOR ISOLATED SHOWERS/THUNDERSTORMS
ALONG/JUST AHEAD OF THIS BOUNDARY. VISIBLE IMAGERY DOES SHOW A
NARROW CHANNEL OF A CUMULUS FIELD DEVELOPING ACROSS CENTRAL WISC
THIS AFTERNOON...STRETCHING NORTHWEST THROUGH MINN. A WEAK MID-LVL
WAVE WAS SLIDING SOUTHEAST THE UPPER MIDWEST...WHICH WILL BE THE
DRIVER FOR SOME ADDED LIFT INTO THIS CUMULUS FIELD. AS EXPECTED
ISOLATED SHOWERS/THUNDERSTORMS WERE DEVELOPING UNDER THIS CHANNEL OF
CUMULUS ACROSS CENTRAL WISC/EASTERN MINN. MID-LVLS ARE MUCH
COOLER...WITH STEEP LAPSE RATES TO THE NORTH ACROSS WISC. THIS
SUGGESTS THAT A FEW THUNDERSTORMS COULD EASILY GROW VERTICALLY AND
POSSIBLY PRODUCE SOME HAIL. FEEL THAT MOST OF THE LATE AFTN/EARLY
EVENING WILL END UP BEING DRY FOR THE CWFA. GUIDANCE CONTINUES TO
SUGGEST THAT THE BEST CHC FOR ANY PRECIP WILL LIKELY OCCUR AFT 00Z.
WITH MUCH OF THE CONVECTIVE POTENTIAL BEING DIURNALLY
DRIVEN...EXPECT THAT ARND 2-3Z THE INSTABILITY TO GREATLY DIMINISH.
AT THIS TIME WILL HOLD ONTO THE SLIGHT CHC OF TSRA WORDING THRU 3Z.
ACROSS THE NORTH...THEN LINGER THE TSRA WORDING THRU 06Z FOR THE
SOUTHEAST CWFA.

EARLIER THINKING WAS THAT THIS BOUNDARY WOULD END UP BEING A BACK
DOOR COLD FRONT...AND THIS APPEARS TO BE THE CASE BASED ON CURRENT
CONDS TO THE NORTH. CLOUD COVER SHUD BE SLOWLY THINNING OVERNIGHT TO
A P-CLOUDY SKY...WITH WINDS TURNING NORTHERLY POST FRONTAL PASSAGE.
THIS WILL USHER IN MUCH COOLER AIR AND ALLOW TEMPS TO EASILY RADIATE
INTO THE MID/UPR 50S.

CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...LOW/MEDIUM.

TUESDAY THROUGH WEDNESDAY...
INITIAL GLANCE IS THAT TUE WOULD BE DRY...HOWEVER THE CONCERN IS ON
THE SOUTHEAST DIVING 500MB VORT THAT WILL BE ARRIVING ACROSS THE
WESTERN CWFA MID/LATE MORNING AND PIVOTING EAST BY THE MID-AFTERNOON
HOURS. THIS MAY PROVIDE ENOUGH LIFT...COUPLED WITH DIURNAL CUMULUS
TUE...AND SOME MOISTURE FROM THE BOUNDARY TO ALLOW A FEW
THUNDERSTORMS TO DEVELOP. WITH TEMPS ALOFT STEADILY COOLING ACROSS
THE CWFA...LAPSE RATES WILL STEEPEN AND A FEW STRONGER STORMS COULD
EASILY PRODUCE SOME PEA SIZE HAIL...BRIEF WIND GUSTS AND HEAVY
DOWNPOURS. THE FOCUS APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO
BENTON COUNTY LINE.

OTHERWISE ANTI-CYCLONIC FLOW WILL CONTINUE TO SETTLE INTO THE GREAT
LAKES REGION...AND KEEP A NORTHEAST FLOW AT THE SFC. THIS WILL
EASILY AID IN THE MUCH COOLER MARINE ENVIRONMENT ADVECTING INLAND
ACROSS THE CWFA AND KEEP SFC TEMPS IN THE LOW/MID 70S...EXCEPT THE
FAR SOUTH/SOUTHWEST WHERE TEMPS MAY STILL TOUCH 80 DEG IN THE AFTN.
LOCATIONS IMMEDIATELY ADJACENT TO LAKE MICHIGAN MAY HAVE TEMPS
REMAIN IN THE MID 60S TUE.

OVERNIGHT TEMPS WILL BE MUCH COOLER IN THE LOW/MID 50S. A FEW
LOCATIONS ALONG AND NORTH OF A ROCKFORD...AURORA...WAUKEGAN LINE MAY
HAVE TEMPS IN THE UPR 40S EARLY WED MORNING. THEN HIGH PRESSURE
BEGINS TO DRIFT EAST. WHILE WINDS WILL BE MORE EASTERLY OFF OF THE
LAKE...TEMPS WILL BE SLIGHTLY WARMER WED AFTN IN THE UPR 70S TO LOW
80S. THE EXCEPTION WILL BE AREAS ADJACENT TO LAKE MICHIGAN...WHERE
TEMPS WILL LIKELY REMAIN IN THE 60S TO LOW 70S.

CONFIDENCE...HIGH.

THURSDAY THROUGH SUNDAY...
ENSEMBLES CONTINUES TO POINT TOWARDS A PATTERN CHANGE FOR THE END OF
THE WEEK INTO THE WEEKEND. MANY GUIDANCE MEMBERS ARE IN AGREEMENT
THAT THE 500MB TROUGH OVER THE GREAT LAKES REGION WILL PIVOT EAST
THUR...WITH A STRENGTHENING MID-LVL RIDGE ACROSS THE CENTRAL PLAINS
REPLACING THE DEPARTING TROUGH FRI. THE RIDGE DOES APPEAR TO FLATTEN
SLIGHTLY...WHICH MAY BE AN INDICATION THAT A SLIGHTLY ACTIVE PERIOD
MAY ACCOMPANY THE STEADY WARMING TREND. 850MB THERMAL RIDGE
CONTINUES TO BE RATHER WARM FOR THE WEEKEND...WITH TEMPS GENERALLY
AROUND 20-22 DEG C. THE EC/GEM HAVE TAKEN A SLIGHTLY COOLER APPROACH
WITH 18-20 DEG C...HOWEVER THE OVERALL THEME IS THAT TEMPS WILL BE
STEADILY WARMING. THE WILDCARD FOR MAX TEMPS SAT/SUN/MON...WILL BE
LLVL MOISTURE AND CLOUD COVER. GUIDANCE CONTINUES TO SUGGEST DEW
POINTS WILL GENERALLY BE AROUND 70 DEG. THIS MAY SLOW THE DIURNAL
CURVE FOR THE WEEKEND...HOWEVER TEMPS SHUD EASILY STILL WARM INTO
THE UPR 80S TO POSSIBLY LOWER 90S. AS A RESULT HAVE NUDGED TEMPS
WARMER THAN GUIDANCE FOR THE UPCOMING WEEKEND.

CONFIDENCE IN TEMPERATURES...MEDIUM/HIGH.
CONFIDENCE IN PRECIPITATION/THUNDERSTORMS...MEDIUM.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* WIND SHIFT TO THE NORTHEAST EARLY EVENING.
* CHANCE OF SHRA...POSSIBLY AN ISOLATED TSRA...LATE THIS AFTERNOON
  OR EARLY THIS EVENING.
* POSSIBLE LOW CIGS EARLY TUESDAY. CMS

//DISCUSSION...UPDATED 18Z...

A COLD FRONT EXTENDING ACROSS NORTHERN WI AND NORTHERN LAKE
MICHIGAN WILL MOVE SOUTH THIS AFTERNOON ARRIVING INTO NORTHEAST IL
EARLY THIS EVENING. A LAKE BREEZE HAS ALREADY FORMED ACROSS THE
SOUTHEAST SHORE OF WISCONSIN AND THIS WILL NEED TO BE MONITORED
FOR A FASTER PUSH TO THE SOUTHWEST AS THE COLD FRONT CATCHES UP TO
THIS BOUNDARY. WESTERLY WINDS WILL SHIFT TO THE NORTHEAST ONCE THE
FRONT MOVES THROUGH THE TERMINALS EARLY THIS EVENING. NORTHEAST
WINDS WILL THEN PREVAIL THROUGH THE REST OF THE PERIOD. SOME GUSTS
ARE POSSIBLE THIS AFTERNOON BUT SHOULD REMAIN LESS THAN 20 KTS.

SHORT TERM/HI RES GUIDANCE CONTINUES TO SUGGEST RATHER SPARSE
COVERAGE FOR ANY SHRA OR TSRA ACTIVITY THIS AFTERNOON INTO THIS
EVENING. MOST AREAS WILL PROBABLY STAY DRY BUT WILL LEAVE VICINITY
MENTION IN THIS FORECAST. ANY ACTIVITY THAT DOES DEVELOP SHOULD
QUICKLY PUSH SOUTHEAST AND AWAY FROM THE TERMINALS BY MID EVENING.

CIGS EXPECTED TO REMAIN VFR THROUGH THE PERIOD. HOWEVER...THERE IS
A CHANCE OF LOWER CIGS...POSSIBLY IFR...LATE TONIGHT INTO TUESDAY
MORNING AS THE COLDER AIR RUNS INTO THE MORE MOIST LOW LEVELS. IN
ADDITION...AN AREA OF LOW CLOUDS/POSSIBLY FOG OVER NORTHERN LAKE
MICHIGAN MAY CONTINUE MOVING SOUTH ACROSS THE LAKE INTO TONIGHT.
APPEARS THE BEST CHANCE OF ANY LOWER CIGS WOULD BE NEAR THE LAKE
AND POSSIBLY AFFECTING GYY. CONFIDENCE TOO LOW FOR EVEN FEW/SCT
MENTION BUT WILL NEED TO MONITOR THIS WITH LATER FORECASTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH FOR A WIND SHIFT TO THE NORTHEAST...MEDIUM FOR TIMING AND
  SPECIFIC DIRECTION/SPEEDS.
* LOW FOR SHRA/TSRA.
* LOW FOR LOWER CIGS EARLY TUESDAY. CMS

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

TUESDAY NIGHT THROUGH FRIDAY...VFR.
FRIDAY NIGHT THROUGH SUNDAY...PERIODIC CHANCES FOR THUNDERSTORMS.

BMD

&&

.MARINE...
245 PM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. A TROUGH OF LOW
PRESSURE AND AN ASSOCIATED WEAK COLD FRONT...EXTEND FROM NORTHERN
MAINE WEST THROUGH CENTRAL LAKE MICHIGAN. AS THE LOW MOVES OFF TO
THE EAST...THE FRONT WILL CONTINUE TO MOVE SOUTH DOWN THE
LAKE...REACHING THE SOUTHERN TIP OF THE LAKE BY LATE THIS EVENING.
WINDS WILL SHIFT TO NORTHERLY BEHIND THE FRONT...WITH OCCASIONAL
GUSTS TO 25 KT TONIGHT. HIGH PRESSURE OVER THE NORTHERN PLAINS
WILL SPREAD EAST ACROSS THE GREAT LAKES LATE TONIGHT AND
TOMORROW...WITH HIGH PRESSURE REMAINING THE DOMINANT FEATURE OVER
THE LAKE THROUGH WEDNESDAY NIGHT WHEN THE HIGH WILL BEGIN TO SLIDE
OFF TO THE EAST. IN THE MEAN TIME...LOW PRESSURE DEVELOPING OVER
THE NORTHERN ROCKIES WEDNESDAY NIGHT AND WILL MOVE OVER THE
NORTHERN PLAINS BY FRIDAY MORNING. WITH THE HIGH PRESSURE TO THE
EAST AND THE DEVELOPING TROUGH TO THE WEST...WINDS WILL BECOME
SOUTHERLY BY WEDNESDAY OR WEDNESDAY NIGHT...THROUGH THE WEEKEND.

&&

.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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO


000
FXUS63 KLOT 171945
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
245 PM CDT MON JUN 17 2013

.DISCUSSION...
329 AM CDT

PRIMARY FORECAST CHALLENGE IS TEMPS AHEAD OF AND BEHIND BACK DOOR
FRONT COMING IN OFF THE LAKE THIS EVENING...THEN THUNDERSTORM
CHANCES LATE THIS AFTERNOON/EVENING AND AGAIN TUESDAY...FOLLOWED BY
LATE WEEK WARM UP.

STAGE APPEARS TO BE SET FOR A PRETTY SUMMER-LIKE DAY WITH A GOOD
DEAL OF SUNSHINE AND WARM TEMPERATURES. SECONDARY COLD FRONT OVER
THE NORTHERN LAKES WILL DROP SOUTH TODAY...ACCELERATING DOWN THE
LAKE AS IT GETS A BOOST FROM THE STILL CHILLY LAKE MICHIGAN WATERS.
AHEAD OF THE FRONT...H8 TEMPS IN THE MID-UPPER TEENS AND 925MB TEMPS
AOA 20C WITH WEST WINDS AND A GOOD DEAL OF SUNSHINE SHOULD ALLOW
HIGHS TO GET WELL INTO THE 80S AND MAYBE MAKE A RUN AT 90 IN A FEW
OF THE HOT SPOTS. LAKE ENHANCED COLD FRONT WILL MAKE ITS PRESENCE
WELL KNOWN EARLY THIS EVENING...ESPECIALLY ALONG THE IMMEDIATE LAKE
FRONT WHERE TEMPS COULD DROP 20F IN A MATTER OF MINUTES AS WINDS
SHIFT TO NE BEHIND THE FRONT. AM CONCERNED THAT FRONT MAY MOVE MORE
QUICKLY THAN RUC/HRRR ARE SUGGESTING...POSSIBLY ARRIVING IN THE
NORTH SHORE AREA LATE THIS AFTERNOON.

GUIDANCE HAS BACKED OFF ON THE STRENGTH OF THE PUSH OF COOLER
CANADIAN AIR INTO THE REGION BEHIND THE FRONT TUESDAY. IN FACT...NOW
LOOKS LIKE FRONT MAY BE LURKING NOT TOO FAR SOUTH AND WEST OF CWA
WITH MANY MODELS NOW SUGGESTING THAT SOME CONVECTION COULD DEVELOP
IN THE AFTERNOON TUESDAY AS NW FLOW SHORTWAVE DROPS INTO THE AREA.
NEAR AND DOWN WIND OF THE LAKE PRECIP CHANCES WILL BE LOWER AND
SHOULD BE DRY AND MUCH COOLER AS MARINE LAYER SEEPS INLAND.

LOOKS LIKE THE MIDDLE AND END OF THE UPCOMING WORK WEEK SHOULD BE
DRY WITH A WARMING TREND...THOUGH ONSHORE FLOW SHOULD KEEP LAKE SIDE
AREAS COOLER...PARTICULARLY WEDNESDAY AND THURSDAY. BY FRIDAY AND
INTO NEXT WEEKEND MEDIUM RANGE MODELS BRING STRONG UPPER LOW OFF THE
PAC NW COAST INLAND INTO THE NORTHERN ROCKIES WHICH SHOULD HELP POP
A RIDGE IN THE NATIONS MID SECTION AND LIKELY RESULT IN ANOTHER
TASTE OF SUMMER BY FRIDAY AND INTO NEXT WEEKEND. JUST HOW HOT IT
GETS WILL DEPEND ON WHERE RING OF FIRE SETS UP...IF THE CONVECTION
TRAIN REMAINS MAINLY TO OUR NORTH THEN MANY AREAS IN OUR CWA WILL
PROBABLY BREAK THE 90 DEGREE MARK. CONVERSELY...SHOULD CONVECTION
AND/OR ITS DEBRIS/OUTFLOW END UP FESTERING IN OUR AREA THAT TEMPS
MAY HOLD IN THE 80S. HAVE HEDGED TOWARD THE WARMER SOLUTION GIVEN
THE PROGGED STRENGTH OF THE H5 RIDGE...BUT OBVIOUSLY THIS WILL NEED
TO BE FINE TUNED AS WE GET CLOSER.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* WIND SHIFT TO THE NORTHEAST EARLY EVENING.
* CHANCE OF SHRA...POSSIBLY AN ISOLATED TSRA...LATE THIS AFTERNOON
  OR EARLY THIS EVENING.
* POSSIBLE LOW CIGS EARLY TUESDAY. CMS

//DISCUSSION...UPDATED 18Z...

A COLD FRONT EXTENDING ACROSS NORTHERN WI AND NORTHERN LAKE
MICHIGAN WILL MOVE SOUTH THIS AFTERNOON ARRIVING INTO NORTHEAST IL
EARLY THIS EVENING. A LAKE BREEZE HAS ALREADY FORMED ACROSS THE
SOUTHEAST SHORE OF WISCONSIN AND THIS WILL NEED TO BE MONITORED
FOR A FASTER PUSH TO THE SOUTHWEST AS THE COLD FRONT CATCHES UP TO
THIS BOUNDARY. WESTERLY WINDS WILL SHIFT TO THE NORTHEAST ONCE THE
FRONT MOVES THROUGH THE TERMINALS EARLY THIS EVENING. NORTHEAST
WINDS WILL THEN PREVAIL THROUGH THE REST OF THE PERIOD. SOME GUSTS
ARE POSSIBLE THIS AFTERNOON BUT SHOULD REMAIN LESS THAN 20 KTS.

SHORT TERM/HI RES GUIDANCE CONTINUES TO SUGGEST RATHER SPARSE
COVERAGE FOR ANY SHRA OR TSRA ACTIVITY THIS AFTERNOON INTO THIS
EVENING. MOST AREAS WILL PROBABLY STAY DRY BUT WILL LEAVE VICINITY
MENTION IN THIS FORECAST. ANY ACTIVITY THAT DOES DEVELOP SHOULD
QUICKLY PUSH SOUTHEAST AND AWAY FROM THE TERMINALS BY MID EVENING.

CIGS EXPECTED TO REMAIN VFR THROUGH THE PERIOD. HOWEVER...THERE IS
A CHANCE OF LOWER CIGS...POSSIBLY IFR...LATE TONIGHT INTO TUESDAY
MORNING AS THE COLDER AIR RUNS INTO THE MORE MOIST LOW LEVELS. IN
ADDITION...AN AREA OF LOW CLOUDS/POSSIBLY FOG OVER NORTHERN LAKE
MICHIGAN MAY CONTINUE MOVING SOUTH ACROSS THE LAKE INTO TONIGHT.
APPEARS THE BEST CHANCE OF ANY LOWER CIGS WOULD BE NEAR THE LAKE
AND POSSIBLY AFFECTING GYY. CONFIDENCE TOO LOW FOR EVEN FEW/SCT
MENTION BUT WILL NEED TO MONITOR THIS WITH LATER FORECASTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH FOR A WIND SHIFT TO THE NORTHEAST...MEDIUM FOR TIMING AND
  SPECIFIC DIRECTION/SPEEDS.
* LOW FOR SHRA/TSRA.
* LOW FOR LOWER CIGS EARLY TUESDAY. CMS

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

TUESDAY NIGHT THROUGH FRIDAY...VFR.
FRIDAY NIGHT THROUGH SUNDAY...PERIODIC CHANCES FOR THUNDERSTORMS.

BMD

&&

.MARINE...
245 PM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. A TROUGH OF LOW
PRESSURE AND AN ASSOCIATED WEAK COLD FRONT...EXTEND FROM NORTHERN
MAINE WEST THROUGH CENTRAL LAKE MICHIGAN. AS THE LOW MOVES OFF TO
THE EAST...THE FRONT WILL CONTINUE TO MOVE SOUTH DOWN THE
LAKE...REACHING THE SOUTHERN TIP OF THE LAKE BY LATE THIS EVENING.
WINDS WILL SHIFT TO NORTHERLY BEHIND THE FRONT...WITH OCCASIONAL
GUSTS TO 25 KT TONIGHT. HIGH PRESSURE OVER THE NORTHERN PLAINS
WILL SPREAD EAST ACROSS THE GREAT LAKES LATE TONIGHT AND
TOMORROW...WITH HIGH PRESSURE REMAINING THE DOMINANT FEATURE OVER
THE LAKE THROUGH WEDNESDAY NIGHT WHEN THE HIGH WILL BEGIN TO SLIDE
OFF TO THE EAST. IN THE MEAN TIME...LOW PRESSURE DEVELOPING OVER
THE NORTHERN ROCKIES WEDNESDAY NIGHT AND WILL MOVE OVER THE
NORTHERN PLAINS BY FRIDAY MORNING. WITH THE HIGH PRESSURE TO THE
EAST AND THE DEVELOPING TROUGH TO THE WEST...WINDS WILL BECOME
SOUTHERLY BY WEDNESDAY OR WEDNESDAY NIGHT...THROUGH THE WEEKEND.

&&

.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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO


000
FXUS63 KILX 171934
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
234 PM CDT MON JUN 17 2013

.DISCUSSION...
ISSUED 220 PM CDT MON JUN 17 2013

SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT

MAIN CONCERNS THIS PERIOD WILL BE WITH COVERAGE OF PRECIP ACRS OUR
SOUTHERN COUNTIES TONIGHT...ASSOCIATED WITH AN MCV OVER MISSOURI...
AND WITH A WEAK SURFACE BOUNDARY FORECAST TO EDGE INTO OUR AREA
TUESDAY AFTERNOON. AFTER THAT...SOMEWHAT COOLER AND LESS HUMID WEATHER
WILL FOLLOW INTO THURSDAY BEFORE HEAT BUILDS NORTHWARD INTO THE REGION
FOR THE END OF THE WEEK AND NEXT WEEKEND.

WATER VAPOR LOOP SHOWING THE CONVECTIVE COMPLEX FROM LAST NIGHT
PRODUCING A DISTINT MCV OVER PARTS OF WESTERN MO WITH NEW CONVECTION
DEVELOPING TO ITS EAST INTO EAST CENTRAL AND SE MO AND TRYING TO
DEVELOP A BIT FURTHER NORTH INTO SOUTHERN ILLINOIS. LOOKING NORTH...
SEVERAL LOW AMPLITUDE SHORTWAVES TRACKING E-SE ACRS THE NORTHERN
PLAINS. ONCE SUCH WAVE PUSHING ACRS WISCONSIN WITH A WEAK SFC BOUNDARY
SHIFTING SOUTH DOWN LAKE MICHIGAN...WHICH SHORT TERM MODELS SUGGEST
WILL PUSH ACRS EXTREME SOUTHERN LAKE MICHIGAN LATER THIS EVENING.
THE AIR MASS AHEAD OF THIS FEATURE NOT PARTICULARLY CONDUCIVE TO
WIDESPREAD CONVECTION DEVELOPING AHEAD OF IT SO OTHER THAN SOME
SLIGHT CHANCE (ISOLATED WORDING) FOR THIS EVENING ACRS THE FAR
NORTH...IT STILL APPEARS THE BETTER PROBABILTIES FOR EVENING
CONVECTION WILL BE TIED TO THE MISSOURI MCV AS IT TRACKS ESE WELL
TO OUR SOUTH.

THE NORTHERN STREAM WAVE ACRS NORTH DAKOTA LOOKS A BIT MORE IMPRESSIVE
THAN WHAT MODELS WERE DEPICTING AT THIS TIME YESTERDAY. MODELS CONTINUE
TO BRING THIS WAVE ESE INTO THE LAKES REGION TUESDAY AFTERNOON WITH
A WEAK COLD FRONT EDGING SOUTH INTO OUR AREA. CONVERGENCE ALONG THE
BOUNDARY IS NOT VERY IMPRESSIVE AT ALL BUT WITH THE TIMING OF THE
BOUNDARY INTO OUR AREA DURING PEAK HEATING...IT STILL WARRANTS SLIGHT
CHANCE (ISOLATED COVERAGE) FOR TUESDAY AFTERNOON. SOMEWHAT COOLER AND
LESS HUMID AIR WILL FILTER SOUTH ACRS THE AREA IN THE WAKE OF THE
SHORTWAVE TUESDAY NIGHT INTO WEDNESDAY BRINGING QUIET AND PLEASANT
WEATHER FOR THE REMAINDER OF THE SHORT TERM PERIOD.

LONG TERM...FRIDAY THROUGH MONDAY

LONGER RANGE MODELS...AT LEAST THE GFS AND UK...WERE MUCH MORE
AGGRESSIVE WITH THE RETROGRESSION OF THE SUBTROPICAL RIDGE ACRS
THE CENTRAL U.S...TAKING THE STRONGER 500 MB FLOW FURTHER NORTH
AWAY FROM OUR AREA. THE 12Z ECMWF NOT NEARLY AS STRONG WITH THE
UPPER RIDGE AS IT TAKES A SERIES OF SHORTWAVES FROM THE LONGWAVE
TROF ACRS THE PACIFIC NW AND TEMPORARILY FLATTENS THE RIDGE AXIS
TO OUR WEST...KEEPING THE AMPLITUDE MUCH FLATTER OVER THE LOWER
48...WHICH GIVES OUR AREA A BETTER CHANCE FOR SEEING SCATTERED
CONVECTION...ESPECIALLY ACRS THE NORTH DURING THE WEEKEND. LOOKS
AS IF THE GFS SOLUTION MAY BE OVERDONE...COMPARED TO WHAT IT WAS
SHOWING THE PAST SEVERAL RUNS. SO FAR THIS SPRING...THE SHORTWAVES
EJECTING ENE FROM THE WESTERN U.S. TROFS AND THEIR ASSOCIATED
CONVECTION HAVE BEEN SUCCESSFUL IN KEEPING THE AMPLITUDE OF THE
RIDGE ACRS THE CENTRAL PORTION OF THE COUNTRY FLATTER. WILL TEND
TO SIDE MORE WITH THE ECMWF THIS PERIOD BUT IT WON`T MAKE MUCH OF
A DIFFERENCE IN THE EXTENDED PORTION OF THE FORECAST WITH HOT
WEATHER RETURNING FOR THE WEEKEND AND THE HIGHER RAIN CHANCES ACRS
THE NORTH.

SMITH
&&

.AVIATION...
ISSUED 1204 PM CDT MON JUN 17 2013

MAIN CONCERN WITH 18Z TAF SET INVOLVES POTENTIAL FOR POP-UP
CONVECTION. MIDDAY SURFACE MAP SHOWS A COUPLE WEAK BOUNDARIES OVER
CENTRAL ILLINOIS AND LATEST VISIBLE SATELLITE SHOWING CUMULUS
STARTING TO DEVELOP ALONG THEM. THE BOUNDARIES SHOULD NOT MOVE
MUCH DURING THE AFTERNOON...BUT DRIER AIR IS SPREADING SOUTHWARD
TOWARD THEM. THUS...AM THINKING THAT ONLY KSPI/KDEC/KCMI MAY SEE A
THREAT OF THUNDER THIS AFTERNOON...AS THEY ARE CLOSEST TO THE
BOUNDARY. COVERAGE CURRENTLY NOT EXPECTED TO BE ENOUGH TO WARRANT
MORE THAN A VCTS MENTION AT THESE SITES. ANY THUNDER NEAR THE TAF
SITES SHOULD FADE WITH SUNSET. LATE IN THE PERIOD...MAY SEE SOME
MVFR CONDITIONS AT TIMES JUST BEFORE SUNRISE...BUT DO NOT THINK IT
WILL GET AS WIDESPREAD OR DENSE AS THIS MORNING...DUE TO HIGHER
RANGES BETWEEN TEMPERATURE AND DEW POINT.

GEELHART
&&

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

$$


000
FXUS63 KLOT 171737
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1237 PM CDT MON JUN 17 2013

.DISCUSSION...
329 AM CDT

PRIMARY FORECAST CHALLENGE IS TEMPS AHEAD OF AND BEHIND BACK DOOR
FRONT COMING IN OFF THE LAKE THIS EVENING...THEN THUNDERSTORM
CHANCES LATE THIS AFTERNOON/EVENING AND AGAIN TUESDAY...FOLLOWED BY
LATE WEEK WARM UP.

STAGE APPEARS TO BE SET FOR A PRETTY SUMMER-LIKE DAY WITH A GOOD
DEAL OF SUNSHINE AND WARM TEMPERATURES. SECONDARY COLD FRONT OVER
THE NORTHERN LAKES WILL DROP SOUTH TODAY...ACCELERATING DOWN THE
LAKE AS IT GETS A BOOST FROM THE STILL CHILLY LAKE MICHIGAN WATERS.
AHEAD OF THE FRONT...H8 TEMPS IN THE MID-UPPER TEENS AND 925MB TEMPS
AOA 20C WITH WEST WINDS AND A GOOD DEAL OF SUNSHINE SHOULD ALLOW
HIGHS TO GET WELL INTO THE 80S AND MAYBE MAKE A RUN AT 90 IN A FEW
OF THE HOT SPOTS. LAKE ENHANCED COLD FRONT WILL MAKE ITS PRESENCE
WELL KNOWN EARLY THIS EVENING...ESPECIALLY ALONG THE IMMEDIATE LAKE
FRONT WHERE TEMPS COULD DROP 20F IN A MATTER OF MINUTES AS WINDS
SHIFT TO NE BEHIND THE FRONT. AM CONCERNED THAT FRONT MAY MOVE MORE
QUICKLY THAN RUC/HRRR ARE SUGGESTING...POSSIBLY ARRIVING IN THE
NORTH SHORE AREA LATE THIS AFTERNOON.

GUIDANCE HAS BACKED OFF ON THE STRENGTH OF THE PUSH OF COOLER
CANADIAN AIR INTO THE REGION BEHIND THE FRONT TUESDAY. IN FACT...NOW
LOOKS LIKE FRONT MAY BE LURKING NOT TOO FAR SOUTH AND WEST OF CWA
WITH MANY MODELS NOW SUGGESTING THAT SOME CONVECTION COULD DEVELOP
IN THE AFTERNOON TUESDAY AS NW FLOW SHORTWAVE DROPS INTO THE AREA.
NEAR AND DOWN WIND OF THE LAKE PRECIP CHANCES WILL BE LOWER AND
SHOULD BE DRY AND MUCH COOLER AS MARINE LAYER SEEPS INLAND.

LOOKS LIKE THE MIDDLE AND END OF THE UPCOMING WORK WEEK SHOULD BE
DRY WITH A WARMING TREND...THOUGH ONSHORE FLOW SHOULD KEEP LAKE SIDE
AREAS COOLER...PARTICULARLY WEDNESDAY AND THURSDAY. BY FRIDAY AND
INTO NEXT WEEKEND MEDIUM RANGE MODELS BRING STRONG UPPER LOW OFF THE
PAC NW COAST INLAND INTO THE NORTHERN ROCKIES WHICH SHOULD HELP POP
A RIDGE IN THE NATIONS MID SECTION AND LIKELY RESULT IN ANOTHER
TASTE OF SUMMER BY FRIDAY AND INTO NEXT WEEKEND. JUST HOW HOT IT
GETS WILL DEPEND ON WHERE RING OF FIRE SETS UP...IF THE CONVECTION
TRAIN REMAINS MAINLY TO OUR NORTH THEN MANY AREAS IN OUR CWA WILL
PROBABLY BREAK THE 90 DEGREE MARK. CONVERSELY...SHOULD CONVECTION
AND/OR ITS DEBRIS/OUTFLOW END UP FESTERING IN OUR AREA THAT TEMPS
MAY HOLD IN THE 80S. HAVE HEDGED TOWARD THE WARMER SOLUTION GIVEN
THE PROGGED STRENGTH OF THE H5 RIDGE...BUT OBVIOUSLY THIS WILL NEED
TO BE FINE TUNED AS WE GET CLOSER.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* WIND SHIFT TO THE NORTHEAST EARLY EVENING.
* CHANCE OF SHRA...POSSIBLY AN ISOLATED TSRA...LATE THIS AFTERNOON
  OR EARLY THIS EVENING.
* POSSIBLE LOW CIGS EARLY TUESDAY. CMS

//DISCUSSION...UPDATED 18Z...

A COLD FRONT EXTENDING ACROSS NORTHERN WI AND NORTHERN LAKE
MICHIGAN WILL MOVE SOUTH THIS AFTERNOON ARRIVING INTO NORTHEAST IL
EARLY THIS EVENING. A LAKE BREEZE HAS ALREADY FORMED ACROSS THE
SOUTHEAST SHORE OF WISCONSIN AND THIS WILL NEED TO BE MONITORED
FOR A FASTER PUSH TO THE SOUTHWEST AS THE COLD FRONT CATCHES UP TO
THIS BOUNDARY. WESTERLY WINDS WILL SHIFT TO THE NORTHEAST ONCE THE
FRONT MOVES THROUGH THE TERMINALS EARLY THIS EVENING. NORTHEAST
WINDS WILL THEN PREVAIL THROUGH THE REST OF THE PERIOD. SOME GUSTS
ARE POSSIBLE THIS AFTERNOON BUT SHOULD REMAIN LESS THAN 20 KTS.

SHORT TERM/HI RES GUIDANCE CONTINUES TO SUGGEST RATHER SPARSE
COVERAGE FOR ANY SHRA OR TSRA ACTIVITY THIS AFTERNOON INTO THIS
EVENING. MOST AREAS WILL PROBABLY STAY DRY BUT WILL LEAVE VICINITY
MENTION IN THIS FORECAST. ANY ACTIVITY THAT DOES DEVELOP SHOULD
QUICKLY PUSH SOUTHEAST AND AWAY FROM THE TERMINALS BY MID EVENING.

CIGS EXPECTED TO REMAIN VFR THROUGH THE PERIOD. HOWEVER...THERE IS
A CHANCE OF LOWER CIGS...POSSIBLY IFR...LATE TONIGHT INTO TUESDAY
MORNING AS THE COLDER AIR RUNS INTO THE MORE MOIST LOW LEVELS. IN
ADDITION...AN AREA OF LOW CLOUDS/POSSIBLY FOG OVER NORTHERN LAKE
MICHIGAN MAY CONTINUE MOVING SOUTH ACROSS THE LAKE INTO TONIGHT.
APPEARS THE BEST CHANCE OF ANY LOWER CIGS WOULD BE NEAR THE LAKE
AND POSSIBLY AFFECTING GYY. CONFIDENCE TOO LOW FOR EVEN FEW/SCT
MENTION BUT WILL NEED TO MONITOR THIS WITH LATER FORECASTS. CMS

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH FOR A WIND SHIFT TO THE NORTHEAST...MEDIUM FOR TIMING AND
  SPECIFIC DIRECTION/SPEEDS.
* LOW FOR SHRA/TSRA.
* LOW FOR LOWER CIGS EARLY TUESDAY. CMS

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

TUESDAY NIGHT THROUGH FRIDAY...VFR.
FRIDAY NIGHT THROUGH SUNDAY...PERIODIC CHANCES FOR THUNDERSTORMS.

BMD

&&

.MARINE...
232 AM CDT

A STRETCH OF RELATIVELY QUIET WEATHER IS STILL IN THE FORECAST
FOR LAKE MICHIGAN OVER MUCH OF THE UPCOMING WEAK. THE PRESSURE
GRADIENT REMAINS WEAK AS A BROAD FRONTAL TROUGH SLOWLY SAGS SOUTH
ACROSS LAKE MICHIGAN TODAY TURNING WINDS TO NORTHERLY. WHILE THERE
MAY BE A PERIOD OF 10 TO 20 KT WINDS BEHIND THE FRONT THROUGH
TUESDAY...WINDS WILL DIMINISH MID WEEK AS HIGH PRESSURE BUILDS
OVER THE LAKES. WINDS SHOULD THEN REMAIN LIGHT THROUGH
FRIDAY...WHEN WINDS FRESHEN UP SLIGHTLY AS LOW PRESSURE LIFTS
NORTHEAST FROM THE PLAINS INTO THE WESTERN LAKES REGION THIS
WEEKEND. BMD

&&

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

$$

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000
FXUS63 KILX 171708
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1208 PM CDT MON JUN 17 2013

.DISCUSSION...
ISSUED 1010 AM CDT MON JUN 17 2013

EARLY MORNING FOG HAS LARGELY LIFTED...WITH JUST A BIT OF HAZE
LINGERING NEAR THE INDIANA BORDER. LARGE CIRRUS SHIELD SPREADING
OVER MOST OF THE FORECAST AREA...ALTHOUGH A BAND OF ALTOCUMULUS IS
ALONG THE I-70 CORRIDOR. THIS IS IN THE SAME GENERAL AREA AS A
WEAK SURFACE BOUNDARY...AND IS THE MOST LIKELY LOCATION FOR ANY
CONVECTION TO DEVELOP...MAINLY DURING THE AFTERNOON HOURS. WITH A
BROAD POOL OF DEW POINTS NEAR 70 ALONG THE I-72 CORRIDOR...
SCATTERED STORMS ARE ALSO POSSIBLE THERE WITH THE BOUNDARY NOT TOO
FAR AWAY...BUT THEY SHOULD NOT BE THAT ORGANIZED. ANOTHER BOUNDARY
DROPPING INTO THE NORTHWEST PART OF THE FORECAST AREA MAY ALSO
TRIGGER A COUPLE SHOWERS/STORMS THIS AFTERNOON AS WELL IN THAT
AREA.

HAVE SENT SOME UPDATED ZONES/GRIDS...MAINLY TO UPDATE THE
PRECIPITATION TRENDS.

GEELHART


&&

.AVIATION...
ISSUED 1204 PM CDT MON JUN 17 2013

MAIN CONCERN WITH 18Z TAF SET INVOLVES POTENTIAL FOR POP-UP
CONVECTION. MIDDAY SURFACE MAP SHOWS A COUPLE WEAK BOUNDARIES OVER
CENTRAL ILLINOIS AND LATEST VISIBLE SATELLITE SHOWING CUMULUS
STARTING TO DEVELOP ALONG THEM. THE BOUNDARIES SHOULD NOT MOVE
MUCH DURING THE AFTERNOON...BUT DRIER AIR IS SPREADING SOUTHWARD
TOWARD THEM. THUS...AM THINKING THAT ONLY KSPI/KDEC/KCMI MAY SEE A
THREAT OF THUNDER THIS AFTERNOON...AS THEY ARE CLOSEST TO THE
BOUNDARY. COVERAGE CURRENTLY NOT EXPECTED TO BE ENOUGH TO WARRANT
MORE THAN A VCTS MENTION AT THESE SITES. ANY THUNDER NEAR THE TAF
SITES SHOULD FADE WITH SUNSET. LATE IN THE PERIOD...MAY SEE SOME
MVFR CONDITIONS AT TIMES JUST BEFORE SUNRISE...BUT DO NOT THINK IT
WILL GET AS WIDESPREAD OR DENSE AS THIS MORNING...DUE TO HIGHER
RANGES BETWEEN TEMPERATURE AND DEW POINT.

GEELHART

&&

.PREV DISCUSSION...
ISSUED 252 AM CDT MON JUN 17 2013

SHORT TERM...TODAY THROUGH WEDNESDAY

VERY WEAK SURFACE BOUNDARY EXTENDING ACROSS SOUTH-CENTRAL ILLINOIS
WILL BE THE PRIMARY FOCUSING MECHANISM FOR SCATTERED THUNDERSTORMS
TODAY. WITH ONE UPPER-WAVE PASSING WELL TO THE NORTH ACROSS THE
GREAT LAKES AND ANOTHER TRACKING TO THE S/SW INTO THE LOWER OHIO
RIVER VALLEY...VERY LITTLE UPPER SUPPORT WILL BE IN PLACE FOR
WIDESPREAD CONVECTION ACROSS CENTRAL ILLINOIS. DESPITE LACK OF
UPPER DYNAMICS...VERY MOIST AIR MASS IN PRESENCE OF WEAK SURFACE
FORCING WILL BE ENOUGH TO TRIGGER A FEW SHOWERS/THUNDERSTORMS
LATER TODAY. HRRR SUGGESTS DEVELOPMENT AROUND MIDDAY...ESPECIALLY
IN CLOSER PROXIMITY TO BOUNDARY. WILL THEREFORE INCLUDE LOW CHANCE
POPS TODAY...WITH BEST RAIN CHANCES SOUTH OF I-72.

SHORT-WAVE TROUGH CURRENTLY EVIDENT ON WATER VAPOR IMAGERY OVER
SOUTHERN SASKATCHEWAN MAY PROVIDE A NEW WRINKLE IN THE FORECAST
FOR TUESDAY. WHILE WE PREVIOUSLY THOUGHT TUESDAY WOULD BE
DRY...LATEST MODEL GUIDANCE IS INDICATING THE POTENTIAL FOR
ISOLATED CONVECTION DURING THE AFTERNOON. THANKS TO A CONTINUED
MOIST AIR MASS AND THE ARRIVAL OF MODEST UPPER FORCING DURING PEAK
HEATING...HAVE INCLUDED A SLIGHT CHANCE FOR THUNDER TUESDAY
AFTERNOON. ONCE THE WAVE PUSHES FURTHER EAST...SURFACE HIGH
PRESSURE WILL BUILD INTO THE REGION FOR TUESDAY NIGHT AND
WEDNESDAY...PROVIDING SEASONABLY WARM AND DRY CONDITIONS.

LONG TERM...THURSDAY THROUGH SUNDAY

00Z 17 JUN MODELS CONTINUE TO SUGGEST A VERY WARM AND LARGELY DRY
EXTENDED FORECAST. ALL MODELS BUILD AN UPPER-LEVEL RIDGE ACROSS
THE PLAINS ON THURSDAY...THEN SHIFT IT INTO THE MIDWEST OVER THE
WEEKEND. PREVIOUS RUNS DISAGREED ON THE EXACT STRENGTH/POSITIONING
OF THE RIDGE...WHICH BROUGHT INTO QUESTION WHETHER ANY MCS
ACTIVITY COULD RIDE UP/OVER THE RIDGE INTO THE AREA DURING THE
PERIOD. LATEST GFS/ECMWF/GEM ARE ALL LOOKING STRONGER WITH THE
RIDGING...KEEPING BEST FORCING FOR NOCTURNAL MCS DEVELOPMENT
FURTHER NORTH ACROSS THE UPPER MIDWEST INTO THE GREAT LAKES. MODELS
INDICATE ONE CONVECTIVE COMPLEX MAY BRUSH THE KILX CWA TO THE
NORTH FRIDAY NIGHT...BEFORE RIDGE BUILDS EVEN FURTHER ON SATURDAY.
HAVE THEREFORE INCLUDED CHANCE POPS ALONG AND NORTH OF A CANTON TO
BLOOMINGTON LINE FRIDAY NIGHT...BUT HAVE GONE WITH A DRY FORECAST
ACROSS THE BOARD FOR THE REMAINDER OF THE EXTENDED. WILL LIKELY
HAVE TO WAIT UNTIL RIDGE BEGINS TO FLATTEN EARLY NEXT WEEK BEFORE
ANY WIDESPREAD RAIN CHANCES RETURN TO THE AREA. GIVEN BUILDING
UPPER HEIGHTS AND LACK OF CONVECTION...HIGH TEMPERATURES WILL
REACH THE UPPER 80S/LOWER 90S WHILE OVERNIGHT LOWS ONLY DROP INTO
THE LOWER 70S FRIDAY THROUGH SUNDAY.

BARNES


&&

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

$$