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000
FXUS63 KLOT 281351
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
851 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING THIS AFTERNOON.

KREIN

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY PRODUCING LIGHT WINDS. A
LAKE BREEZE IS EXPECTED TO DEVELOP THIS AFTERNOON WITH WINDS
INCREASING UP TO AROUND 10-12 KT OUT OF THE NORTHEAST. WINDS WILL
BECOME LIGHT AND VARIABLE THIS EVENING AND OVERNIGHT. EXPECT VFR
CONDITIONS THROUGH THE PERIOD.

BMD

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

* MEDIUM CONFIDENCE IN TIMING AND WIND SPEED FOLLOWING LAKE BREEZE
  PASSAGE.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

KREIN

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

WEDNESDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH MONDAY...PERIODIC CHANCES FOR
THUNDERSTORMS.

BMD

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 281351
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
851 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING THIS AFTERNOON.

KREIN

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY PRODUCING LIGHT WINDS. A
LAKE BREEZE IS EXPECTED TO DEVELOP THIS AFTERNOON WITH WINDS
INCREASING UP TO AROUND 10-12 KT OUT OF THE NORTHEAST. WINDS WILL
BECOME LIGHT AND VARIABLE THIS EVENING AND OVERNIGHT. EXPECT VFR
CONDITIONS THROUGH THE PERIOD.

BMD

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

* MEDIUM CONFIDENCE IN TIMING AND WIND SPEED FOLLOWING LAKE BREEZE
  PASSAGE.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

KREIN

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

WEDNESDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH MONDAY...PERIODIC CHANCES FOR
THUNDERSTORMS.

BMD

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 281351
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
851 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING THIS AFTERNOON.

KREIN

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY PRODUCING LIGHT WINDS. A
LAKE BREEZE IS EXPECTED TO DEVELOP THIS AFTERNOON WITH WINDS
INCREASING UP TO AROUND 10-12 KT OUT OF THE NORTHEAST. WINDS WILL
BECOME LIGHT AND VARIABLE THIS EVENING AND OVERNIGHT. EXPECT VFR
CONDITIONS THROUGH THE PERIOD.

BMD

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

* MEDIUM CONFIDENCE IN TIMING AND WIND SPEED FOLLOWING LAKE BREEZE
  PASSAGE.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

KREIN

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

WEDNESDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH MONDAY...PERIODIC CHANCES FOR
THUNDERSTORMS.

BMD

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 281351
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
851 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING THIS AFTERNOON.

KREIN

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY PRODUCING LIGHT WINDS. A
LAKE BREEZE IS EXPECTED TO DEVELOP THIS AFTERNOON WITH WINDS
INCREASING UP TO AROUND 10-12 KT OUT OF THE NORTHEAST. WINDS WILL
BECOME LIGHT AND VARIABLE THIS EVENING AND OVERNIGHT. EXPECT VFR
CONDITIONS THROUGH THE PERIOD.

BMD

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

* MEDIUM CONFIDENCE IN TIMING AND WIND SPEED FOLLOWING LAKE BREEZE
  PASSAGE.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

KREIN

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

WEDNESDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH MONDAY...PERIODIC CHANCES FOR
THUNDERSTORMS.

BMD

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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


  [top]

000
FXUS63 KILX 281143
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
643 AM CDT TUE APR 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

ANOTHER CHILLY START TO THE DAY IS ON TAP...WITH MID 30S AND
PATCHY FROST TO START THE DAY NORTH OF I-74. A SURFACE RIDGE AXIS
EXTENDING ACROSS ILLINOIS FROM NE TO SW WILL PROVIDE SUBSIDENCE
AND RELATIVELY DRY AIR. THE HRRR AND RAP CONTINUE TO SHOW SLIGHTLY
HIGHER MOISTURE IN THE 850-925MB LAYER ACROSS OUR EASTERN
COUNTIES...WHICH IS ALSO SUPPORTED BY THE NAM AND GFS. FAIR
WEATHER CUMULUS FORMATION WILL BE MORE CONCENTRATED THERE... BUT
SUNSHINE SHOULD STILL BE THE RULE FOR THE DAY IN MOST AREAS. HIGH
TEMPS SHOULD REACH THE MID 60S NEAR INDIANA AND THE UPPER 60S WEST
OF THE ILLINOIS RIVER. FORECAST SOUNDINGS SHOW MIXING HEIGHTS WILL
PEAK BETWEEN 11 AM AND 1 PM...WHICH WILL COINCIDE WITH OUR HIGHER
WIND GUSTS FOR THE DAY. A FEW GUSTS MAY REACH 16-17 MPH... BUT
OVERALL WINDS SHOULD BE LESS GUSTY THAN THE LAST COUPLE OF DAYS.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

INITIAL CONCERN FOR THIS PART OF THE FORECAST IS WITH RAIN POTENTIAL
MID WEEK. UPPER TROUGH CURRENTLY PUSHING THROUGH THE DAKOTAS
NORTHEAST TO HUDSON BAY PROGGED BY ALL MODELS TO CARVE OUT A
SIZABLE CLOUDS LOW OVER ONTARIO ON WEDNESDAY...DROPPING SOUTHWARD
INTO THE MIDWEST BY THURSDAY MORNING. GFS IS A BIT FURTHER EAST WITH
THIS PROJECTION...WITH GENERAL MODEL CONSENSUS FAVORING A PATH ALONG
THE ILLINOIS/INDIANA BORDER. HAVE INTRODUCED SOME SHOWERS INTO THE
FORECAST FOR WEDNESDAY AFTERNOON...AS COLD CORE WITH THE UPPER LOW
(500 MB TEMPERATURES DIPPING BELOW -20C) INTRODUCES SOME STEEP LAPSE
RATES. ALSO MENTIONED SOME ISOLATED THUNDER AS WELL. HAVE LINGERED
SOME SLIGHT CHANCE POP`S ACROSS THE EASTERN CWA INTO WEDNESDAY
NIGHT. WITH THE LOW SETTLING INTO THE OHIO VALLEY ON THURSDAY...HAVE
ALSO MENTIONED SOME SCATTERED SHOWERS EAST OF I-57 CLOSER TO THE LOW
TRACK.

FURTHER OUT IN TIME...UPPER FLOW SHIFTS MORE ZONAL TO START THE
WEEKEND. BOTH THE GFS AND ECMWF SHOWING A TROUGH MOVING ALONG THE
CANADIAN BORDER...WITH THE ECMWF DEVELOPING MORE OF A BROADENING
EARLY NEXT WEEK WHILE THE GFS REMAINS A BIT MORE PROGRESSIVE AND
CLOSER TO THE BORDER. STILL NOT VERY GOOD AGREEMENT WITH RAIN
POTENTIAL ON SATURDAY...AND HAVE PULLED BACK SOME ON THE POP`S.
SATURDAY NIGHT...HAVE FOLLOWED MORE OF THE ECMWF SOLUTION OF A
POTENTIAL MCS SYSTEM ROLLING THROUGH THE AREA OVERNIGHT INTO SUNDAY.
RAIN CHANCES PERSIST INTO EARLY NEXT WEEK AS THE BROADENING TROUGH
APPROACHES THE MISSISSIPPI VALLEY.

THE GENERAL IDEA FOR TEMPERATURES WILL BE WITH WARMING CONDITIONS...
ALTHOUGH A BRIEF COOLDOWN IS EXPECTED THURSDAY AS 850 MB
TEMPERATURES DIP CLOSER TO 0C AS THE UPPER LOW PASSES. HIGHS SHOULD
REACH INTO THE MID 70S ACROSS THE AREA THIS WEEKEND AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 642 AM CDT TUE APR 28 2015

VFR CONDITIONS WILL CONTINUE OVER THE NEXT 24 HOURS. HIGH
PRESSURE CENTERED JUST NORTHEAST OF ILLINOIS WILL KEEP CLOUD COVER
AT A MINIMUM. HIGHER MOISTURE CONTENT OVER INDIANA COULD PUSH A
FEW MORE CLOUDS OVER CMI AND DEC, WHILE THE OTHER TERMINAL SITES
REMAIN RELATIVELY CLOUD-FREE. FORECAST SOUNDINGS SHOW NORTHEAST
WINDS WILL BE LESS GUSTY TODAY, WITH PEAK WIND GUSTS OF 15KT
GENERALLY BETWEEN 16Z-19Z. WIND SPEEDS WILL DECREASE TO 5 KTS OR
LESS AFTER 00Z, AS BOUNDARY LAYER WINDS DECOUPLE FROM THE MID-
LEVEL WINDS.

&&

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

$$

SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SHIMON



000
FXUS63 KILX 281143
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
643 AM CDT TUE APR 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

ANOTHER CHILLY START TO THE DAY IS ON TAP...WITH MID 30S AND
PATCHY FROST TO START THE DAY NORTH OF I-74. A SURFACE RIDGE AXIS
EXTENDING ACROSS ILLINOIS FROM NE TO SW WILL PROVIDE SUBSIDENCE
AND RELATIVELY DRY AIR. THE HRRR AND RAP CONTINUE TO SHOW SLIGHTLY
HIGHER MOISTURE IN THE 850-925MB LAYER ACROSS OUR EASTERN
COUNTIES...WHICH IS ALSO SUPPORTED BY THE NAM AND GFS. FAIR
WEATHER CUMULUS FORMATION WILL BE MORE CONCENTRATED THERE... BUT
SUNSHINE SHOULD STILL BE THE RULE FOR THE DAY IN MOST AREAS. HIGH
TEMPS SHOULD REACH THE MID 60S NEAR INDIANA AND THE UPPER 60S WEST
OF THE ILLINOIS RIVER. FORECAST SOUNDINGS SHOW MIXING HEIGHTS WILL
PEAK BETWEEN 11 AM AND 1 PM...WHICH WILL COINCIDE WITH OUR HIGHER
WIND GUSTS FOR THE DAY. A FEW GUSTS MAY REACH 16-17 MPH... BUT
OVERALL WINDS SHOULD BE LESS GUSTY THAN THE LAST COUPLE OF DAYS.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

INITIAL CONCERN FOR THIS PART OF THE FORECAST IS WITH RAIN POTENTIAL
MID WEEK. UPPER TROUGH CURRENTLY PUSHING THROUGH THE DAKOTAS
NORTHEAST TO HUDSON BAY PROGGED BY ALL MODELS TO CARVE OUT A
SIZABLE CLOUDS LOW OVER ONTARIO ON WEDNESDAY...DROPPING SOUTHWARD
INTO THE MIDWEST BY THURSDAY MORNING. GFS IS A BIT FURTHER EAST WITH
THIS PROJECTION...WITH GENERAL MODEL CONSENSUS FAVORING A PATH ALONG
THE ILLINOIS/INDIANA BORDER. HAVE INTRODUCED SOME SHOWERS INTO THE
FORECAST FOR WEDNESDAY AFTERNOON...AS COLD CORE WITH THE UPPER LOW
(500 MB TEMPERATURES DIPPING BELOW -20C) INTRODUCES SOME STEEP LAPSE
RATES. ALSO MENTIONED SOME ISOLATED THUNDER AS WELL. HAVE LINGERED
SOME SLIGHT CHANCE POP`S ACROSS THE EASTERN CWA INTO WEDNESDAY
NIGHT. WITH THE LOW SETTLING INTO THE OHIO VALLEY ON THURSDAY...HAVE
ALSO MENTIONED SOME SCATTERED SHOWERS EAST OF I-57 CLOSER TO THE LOW
TRACK.

FURTHER OUT IN TIME...UPPER FLOW SHIFTS MORE ZONAL TO START THE
WEEKEND. BOTH THE GFS AND ECMWF SHOWING A TROUGH MOVING ALONG THE
CANADIAN BORDER...WITH THE ECMWF DEVELOPING MORE OF A BROADENING
EARLY NEXT WEEK WHILE THE GFS REMAINS A BIT MORE PROGRESSIVE AND
CLOSER TO THE BORDER. STILL NOT VERY GOOD AGREEMENT WITH RAIN
POTENTIAL ON SATURDAY...AND HAVE PULLED BACK SOME ON THE POP`S.
SATURDAY NIGHT...HAVE FOLLOWED MORE OF THE ECMWF SOLUTION OF A
POTENTIAL MCS SYSTEM ROLLING THROUGH THE AREA OVERNIGHT INTO SUNDAY.
RAIN CHANCES PERSIST INTO EARLY NEXT WEEK AS THE BROADENING TROUGH
APPROACHES THE MISSISSIPPI VALLEY.

THE GENERAL IDEA FOR TEMPERATURES WILL BE WITH WARMING CONDITIONS...
ALTHOUGH A BRIEF COOLDOWN IS EXPECTED THURSDAY AS 850 MB
TEMPERATURES DIP CLOSER TO 0C AS THE UPPER LOW PASSES. HIGHS SHOULD
REACH INTO THE MID 70S ACROSS THE AREA THIS WEEKEND AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 642 AM CDT TUE APR 28 2015

VFR CONDITIONS WILL CONTINUE OVER THE NEXT 24 HOURS. HIGH
PRESSURE CENTERED JUST NORTHEAST OF ILLINOIS WILL KEEP CLOUD COVER
AT A MINIMUM. HIGHER MOISTURE CONTENT OVER INDIANA COULD PUSH A
FEW MORE CLOUDS OVER CMI AND DEC, WHILE THE OTHER TERMINAL SITES
REMAIN RELATIVELY CLOUD-FREE. FORECAST SOUNDINGS SHOW NORTHEAST
WINDS WILL BE LESS GUSTY TODAY, WITH PEAK WIND GUSTS OF 15KT
GENERALLY BETWEEN 16Z-19Z. WIND SPEEDS WILL DECREASE TO 5 KTS OR
LESS AFTER 00Z, AS BOUNDARY LAYER WINDS DECOUPLE FROM THE MID-
LEVEL WINDS.

&&

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

$$

SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SHIMON




000
FXUS63 KILX 281143
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
643 AM CDT TUE APR 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

ANOTHER CHILLY START TO THE DAY IS ON TAP...WITH MID 30S AND
PATCHY FROST TO START THE DAY NORTH OF I-74. A SURFACE RIDGE AXIS
EXTENDING ACROSS ILLINOIS FROM NE TO SW WILL PROVIDE SUBSIDENCE
AND RELATIVELY DRY AIR. THE HRRR AND RAP CONTINUE TO SHOW SLIGHTLY
HIGHER MOISTURE IN THE 850-925MB LAYER ACROSS OUR EASTERN
COUNTIES...WHICH IS ALSO SUPPORTED BY THE NAM AND GFS. FAIR
WEATHER CUMULUS FORMATION WILL BE MORE CONCENTRATED THERE... BUT
SUNSHINE SHOULD STILL BE THE RULE FOR THE DAY IN MOST AREAS. HIGH
TEMPS SHOULD REACH THE MID 60S NEAR INDIANA AND THE UPPER 60S WEST
OF THE ILLINOIS RIVER. FORECAST SOUNDINGS SHOW MIXING HEIGHTS WILL
PEAK BETWEEN 11 AM AND 1 PM...WHICH WILL COINCIDE WITH OUR HIGHER
WIND GUSTS FOR THE DAY. A FEW GUSTS MAY REACH 16-17 MPH... BUT
OVERALL WINDS SHOULD BE LESS GUSTY THAN THE LAST COUPLE OF DAYS.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

INITIAL CONCERN FOR THIS PART OF THE FORECAST IS WITH RAIN POTENTIAL
MID WEEK. UPPER TROUGH CURRENTLY PUSHING THROUGH THE DAKOTAS
NORTHEAST TO HUDSON BAY PROGGED BY ALL MODELS TO CARVE OUT A
SIZABLE CLOUDS LOW OVER ONTARIO ON WEDNESDAY...DROPPING SOUTHWARD
INTO THE MIDWEST BY THURSDAY MORNING. GFS IS A BIT FURTHER EAST WITH
THIS PROJECTION...WITH GENERAL MODEL CONSENSUS FAVORING A PATH ALONG
THE ILLINOIS/INDIANA BORDER. HAVE INTRODUCED SOME SHOWERS INTO THE
FORECAST FOR WEDNESDAY AFTERNOON...AS COLD CORE WITH THE UPPER LOW
(500 MB TEMPERATURES DIPPING BELOW -20C) INTRODUCES SOME STEEP LAPSE
RATES. ALSO MENTIONED SOME ISOLATED THUNDER AS WELL. HAVE LINGERED
SOME SLIGHT CHANCE POP`S ACROSS THE EASTERN CWA INTO WEDNESDAY
NIGHT. WITH THE LOW SETTLING INTO THE OHIO VALLEY ON THURSDAY...HAVE
ALSO MENTIONED SOME SCATTERED SHOWERS EAST OF I-57 CLOSER TO THE LOW
TRACK.

FURTHER OUT IN TIME...UPPER FLOW SHIFTS MORE ZONAL TO START THE
WEEKEND. BOTH THE GFS AND ECMWF SHOWING A TROUGH MOVING ALONG THE
CANADIAN BORDER...WITH THE ECMWF DEVELOPING MORE OF A BROADENING
EARLY NEXT WEEK WHILE THE GFS REMAINS A BIT MORE PROGRESSIVE AND
CLOSER TO THE BORDER. STILL NOT VERY GOOD AGREEMENT WITH RAIN
POTENTIAL ON SATURDAY...AND HAVE PULLED BACK SOME ON THE POP`S.
SATURDAY NIGHT...HAVE FOLLOWED MORE OF THE ECMWF SOLUTION OF A
POTENTIAL MCS SYSTEM ROLLING THROUGH THE AREA OVERNIGHT INTO SUNDAY.
RAIN CHANCES PERSIST INTO EARLY NEXT WEEK AS THE BROADENING TROUGH
APPROACHES THE MISSISSIPPI VALLEY.

THE GENERAL IDEA FOR TEMPERATURES WILL BE WITH WARMING CONDITIONS...
ALTHOUGH A BRIEF COOLDOWN IS EXPECTED THURSDAY AS 850 MB
TEMPERATURES DIP CLOSER TO 0C AS THE UPPER LOW PASSES. HIGHS SHOULD
REACH INTO THE MID 70S ACROSS THE AREA THIS WEEKEND AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 642 AM CDT TUE APR 28 2015

VFR CONDITIONS WILL CONTINUE OVER THE NEXT 24 HOURS. HIGH
PRESSURE CENTERED JUST NORTHEAST OF ILLINOIS WILL KEEP CLOUD COVER
AT A MINIMUM. HIGHER MOISTURE CONTENT OVER INDIANA COULD PUSH A
FEW MORE CLOUDS OVER CMI AND DEC, WHILE THE OTHER TERMINAL SITES
REMAIN RELATIVELY CLOUD-FREE. FORECAST SOUNDINGS SHOW NORTHEAST
WINDS WILL BE LESS GUSTY TODAY, WITH PEAK WIND GUSTS OF 15KT
GENERALLY BETWEEN 16Z-19Z. WIND SPEEDS WILL DECREASE TO 5 KTS OR
LESS AFTER 00Z, AS BOUNDARY LAYER WINDS DECOUPLE FROM THE MID-
LEVEL WINDS.

&&

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

$$

SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SHIMON



000
FXUS63 KILX 281143
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
643 AM CDT TUE APR 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

ANOTHER CHILLY START TO THE DAY IS ON TAP...WITH MID 30S AND
PATCHY FROST TO START THE DAY NORTH OF I-74. A SURFACE RIDGE AXIS
EXTENDING ACROSS ILLINOIS FROM NE TO SW WILL PROVIDE SUBSIDENCE
AND RELATIVELY DRY AIR. THE HRRR AND RAP CONTINUE TO SHOW SLIGHTLY
HIGHER MOISTURE IN THE 850-925MB LAYER ACROSS OUR EASTERN
COUNTIES...WHICH IS ALSO SUPPORTED BY THE NAM AND GFS. FAIR
WEATHER CUMULUS FORMATION WILL BE MORE CONCENTRATED THERE... BUT
SUNSHINE SHOULD STILL BE THE RULE FOR THE DAY IN MOST AREAS. HIGH
TEMPS SHOULD REACH THE MID 60S NEAR INDIANA AND THE UPPER 60S WEST
OF THE ILLINOIS RIVER. FORECAST SOUNDINGS SHOW MIXING HEIGHTS WILL
PEAK BETWEEN 11 AM AND 1 PM...WHICH WILL COINCIDE WITH OUR HIGHER
WIND GUSTS FOR THE DAY. A FEW GUSTS MAY REACH 16-17 MPH... BUT
OVERALL WINDS SHOULD BE LESS GUSTY THAN THE LAST COUPLE OF DAYS.

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

INITIAL CONCERN FOR THIS PART OF THE FORECAST IS WITH RAIN POTENTIAL
MID WEEK. UPPER TROUGH CURRENTLY PUSHING THROUGH THE DAKOTAS
NORTHEAST TO HUDSON BAY PROGGED BY ALL MODELS TO CARVE OUT A
SIZABLE CLOUDS LOW OVER ONTARIO ON WEDNESDAY...DROPPING SOUTHWARD
INTO THE MIDWEST BY THURSDAY MORNING. GFS IS A BIT FURTHER EAST WITH
THIS PROJECTION...WITH GENERAL MODEL CONSENSUS FAVORING A PATH ALONG
THE ILLINOIS/INDIANA BORDER. HAVE INTRODUCED SOME SHOWERS INTO THE
FORECAST FOR WEDNESDAY AFTERNOON...AS COLD CORE WITH THE UPPER LOW
(500 MB TEMPERATURES DIPPING BELOW -20C) INTRODUCES SOME STEEP LAPSE
RATES. ALSO MENTIONED SOME ISOLATED THUNDER AS WELL. HAVE LINGERED
SOME SLIGHT CHANCE POP`S ACROSS THE EASTERN CWA INTO WEDNESDAY
NIGHT. WITH THE LOW SETTLING INTO THE OHIO VALLEY ON THURSDAY...HAVE
ALSO MENTIONED SOME SCATTERED SHOWERS EAST OF I-57 CLOSER TO THE LOW
TRACK.

FURTHER OUT IN TIME...UPPER FLOW SHIFTS MORE ZONAL TO START THE
WEEKEND. BOTH THE GFS AND ECMWF SHOWING A TROUGH MOVING ALONG THE
CANADIAN BORDER...WITH THE ECMWF DEVELOPING MORE OF A BROADENING
EARLY NEXT WEEK WHILE THE GFS REMAINS A BIT MORE PROGRESSIVE AND
CLOSER TO THE BORDER. STILL NOT VERY GOOD AGREEMENT WITH RAIN
POTENTIAL ON SATURDAY...AND HAVE PULLED BACK SOME ON THE POP`S.
SATURDAY NIGHT...HAVE FOLLOWED MORE OF THE ECMWF SOLUTION OF A
POTENTIAL MCS SYSTEM ROLLING THROUGH THE AREA OVERNIGHT INTO SUNDAY.
RAIN CHANCES PERSIST INTO EARLY NEXT WEEK AS THE BROADENING TROUGH
APPROACHES THE MISSISSIPPI VALLEY.

THE GENERAL IDEA FOR TEMPERATURES WILL BE WITH WARMING CONDITIONS...
ALTHOUGH A BRIEF COOLDOWN IS EXPECTED THURSDAY AS 850 MB
TEMPERATURES DIP CLOSER TO 0C AS THE UPPER LOW PASSES. HIGHS SHOULD
REACH INTO THE MID 70S ACROSS THE AREA THIS WEEKEND AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 642 AM CDT TUE APR 28 2015

VFR CONDITIONS WILL CONTINUE OVER THE NEXT 24 HOURS. HIGH
PRESSURE CENTERED JUST NORTHEAST OF ILLINOIS WILL KEEP CLOUD COVER
AT A MINIMUM. HIGHER MOISTURE CONTENT OVER INDIANA COULD PUSH A
FEW MORE CLOUDS OVER CMI AND DEC, WHILE THE OTHER TERMINAL SITES
REMAIN RELATIVELY CLOUD-FREE. FORECAST SOUNDINGS SHOW NORTHEAST
WINDS WILL BE LESS GUSTY TODAY, WITH PEAK WIND GUSTS OF 15KT
GENERALLY BETWEEN 16Z-19Z. WIND SPEEDS WILL DECREASE TO 5 KTS OR
LESS AFTER 00Z, AS BOUNDARY LAYER WINDS DECOUPLE FROM THE MID-
LEVEL WINDS.

&&

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

$$

SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SHIMON




000
FXUS63 KLOT 281119
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
619 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING THIS AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY PRODUCING LIGHT WINDS. A
LAKE BREEZE IS EXPECTED TO DEVELOP THIS AFTERNOON WITH WINDS
INCREASING UP TO AROUND 10-12 KT OUT OF THE NORTHEAST. WINDS WILL
BECOME LIGHT AND VARIABLE THIS EVENING AND OVERNIGHT. EXPECT VFR
CONDITIONS THROUGH THE PERIOD.

BMD


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

* HIGH.

BMD

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

WEDNESDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH MONDAY...PERIODIC CHANCES FOR
THUNDERSTORMS.

BMD

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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000
FXUS63 KLOT 281119
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
619 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING THIS AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY PRODUCING LIGHT WINDS. A
LAKE BREEZE IS EXPECTED TO DEVELOP THIS AFTERNOON WITH WINDS
INCREASING UP TO AROUND 10-12 KT OUT OF THE NORTHEAST. WINDS WILL
BECOME LIGHT AND VARIABLE THIS EVENING AND OVERNIGHT. EXPECT VFR
CONDITIONS THROUGH THE PERIOD.

BMD


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

* HIGH.

BMD

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

WEDNESDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH MONDAY...PERIODIC CHANCES FOR
THUNDERSTORMS.

BMD

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 280902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
402 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
402 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
402 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
402 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280837
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
337 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 280837
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
337 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280837
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
337 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 280837
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
337 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

TEMPERATURES BEGIN A WARMING TREND BY FRIDAY THROUGH THE UPCOMING
WEEKEND. IT ALSO APPEARS THAT AREAS ALONG THE LAKE SHORES WILL BE
ABLE TO JOIN IN ON THIS WARMTH THIS WEEKEND AS THE SURFACE FLOW
BECOMES OFFSHORE. IT LOOKS LIKE TEMPERATURES WILL BE WELL INTO THE
70S FOR THE WEEKEND. THE UPPER-LEVEL PATTERN IS EXPECTED TO
TRANSITION TO A QUASI-ZONAL FLOW PATTERN OVER MUCH OF THE COUNTRY BY
THE WEEKEND...THEN TO MORE OF A WEST-SOUTHWESTERLY ORIENTATION LATER
IN THE WEEKEND AS A BROAD UPPER TROUGH SETS UP OVER CANADA AND THE
NORTHWESTERN CONUS. THIS COULD SET THE STAGE FOR A BIT MORE ACTIVE
PERIOD OF WEATHER...WITH A FEW PERIODS OF SHOWERS AND THUNDERSTORMS
LOOKING POSSIBLE SATURDAY NIGHT THROUGH MONDAY.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280822
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
322 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

COMING SOON.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 280822
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
322 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

COMING SOON.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 280822
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
322 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

COMING SOON.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 280822
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
322 AM CDT TUE APR 28 2015

.SHORT TERM...
321 AM CDT

THROUGH THURSDAY...

ANOTHER QUIET WEATHER DAY IS EXPECTED ACROSS THE REGION AS A SURFACE
RIDGE AXIS RESULTS IN A LIGHT NORTHEASTERLY WIND OVER THE AREA. AN
AFTERNOON LAKE BREEZE SHOULD PUSH INLAND...WITH A SLIGHT WIND
INCREASE AND TEMPERATURE DROP FOLLOWING ITS PASSAGE.
OVERALL...TEMPERATURES LOOK TO TOP OUT A FEW DEGREES WARMER THAN
YESTERDAYS HIGHS. THIS SHOULD PUT ALL AREAS INLAND FROM THE LAKE
INTO THE LOWER 60S...WITH MID TO UPPER 60S ACROSS NORTH CENTRAL
PORTIONS OF THE STATE. AREAS ALONG THE LAKE MICHGAN SHORES WILL
LIKELY REMAIN IN THE UPPER 40S TO LOW 50S DUE TO THE ONSHORE FLOW.

THE MAIN CHANGE TO THE GOING FORECAST WAS TO ADD IN A MENTION OF
SHOWERS AND THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING...MAINLY
FOR INLAND AREAS. IT APPEARS THAT A SIGNIFICANT MID-LEVEL IMPULSE
AND AN ASSOCIATED UPPER JET MAX WILL DIG SOUTHWARD ALONG THE EASTERN
PERIPHERY OF A SHARPENING UPPER LEVEL JET AXIS OVER THE WESTERN
CONUS. FORECAST GUIDANCE SUGGESTS THAT THIS SYSTEM WILL QUICKLY
DEVELOP A COLD POOL IN THE MID-LEVELS (500 MB TEMPERATURES AROUND
-24 C) AS IT MOVES OVER THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT.
WITH SURFACE TEMPERATURES LIKELY TO REACH INTO THE MID TO UPPER 60S
INLAND BENEATH THIS POCKET OF COLD MID-LEVEL AIR...LAPSE RATES
SHOULD BECOME STEEP ENOUGH...THOUGH A DEEP ENOUGH LAYER TO SUPPORT
AT LEAST SOME SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER
PORTIONS OF NORTHERN ILLINOIS WEDNESDAY AFTERNOON. IT CURRENTLY
APPEARS THE BEST CHANCE FOR THIS WILL BE AREAS INLAND FROM LAKE
MICHIGAN...MAINLY FROM THE WESTERN CHICAGO SUBURBS WESTWARD ACROSS
NORTH CENTRAL ILLINOIS. AN AFTERNOON LAKE BREEZE IS AGAIN LIKELY
WEDNESDAY AND THIS COULD HELP FOCUS SOME OF THE DEVELOPMENT AS IT
BECOMES COMPLEMENTED BY THE LARGER SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE DEEPENING MID-LEVEL SYSTEM AND THE LEFT EXIT
REGION OF AN UPPER JET. NO SEVERE WEATHER IS EXPECTED WITH THIS
ACTIVITY...THOUGH WITH LOWER FREEZING HEIGHTS...SOME SMALL HAIL
COULD BE POSSIBLE WITH ANY STRONGER UPDRAFTS THAT DEVELOP.

SHOWERS LOOK TO LINGER OVER SOUTHERN PORTIONS OF THE AREA
WEDNESDAY NIGHT AS THE UPPER SYSTEM CLOSES OFF OVER THE AREA.
TEMPERATURES WILL BE COOLER ON THURSDAY AS A COLDER LOW LEVEL
AIR MASS SHIFTS OVER THE AREA. EXPECT TEMPERATURES TO MAINLY BE
IN THE UPPER 50S TO LOW 60S INLAND AND IN THE UPPER 40S LAKESIDE.

KJB

&&

.LONG TERM...
321 AM CDT

THURSDAY NIGHT THROUGH MONDAY...

COMING SOON.

KJB

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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



000
FXUS63 KLOT 280807
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
307 AM CDT TUE APR 28 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280807
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
307 AM CDT TUE APR 28 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280807
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
307 AM CDT TUE APR 28 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280807
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
307 AM CDT TUE APR 28 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KLOT 280807
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
307 AM CDT TUE APR 28 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
305 AM CDT

QUIET WEATHER CONTINUES ACROSS LAKE MICHIGAN TODAY AS HIGH
PRESSURE LIES JUST TO THE WEST OF THE LAKE. EXPECT LIGHT NORTH
WIND TO GIVE WAY TO LAKE BREEZES THIS AFTERNOON WITH WINDS TURNING
ONSHORE. LOW PRESSURE MOVING ACROSS THE GULF OF MEXICO TODAY WILL
LIFT ACROSS THE SOUTHEASTERN STATES WEDNESDAY RESULTING IN A
MODEST INCREASE IN NORTHERLY FLOW ACROSS LAKE MICHIGAN WEDNESDAY
AND THURSDAY. THE RIDGE AXIS WILL MOVE OVER LAKE MICHIGAN FRIDAY
WITH WINDS TURNING SOUTH/SOUTHWEST BUT REMAINING RELATIVELY LIGHT
FRIDAY NIGHT INTO SATURDAY. BMD

&&

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

$$

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

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




000
FXUS63 KILX 280804
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
304 AM CDT TUE APR 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

ANOTHER CHILLY START TO THE DAY IS ON TAP...WITH MID 30S AND
PATCHY FROST TO START THE DAY NORTH OF I-74. HOWEVER, A SURFACE
RIDGE AXIS EXTENDING ACROSS ILLINOIS FROM NE TO SW WILL PROVIDE
SUBSIDENCE AND RELATIVELY DRY AIR. THE HRRR AND RAP CONTINUE TO
SHOW SLIGHTLY HIGHER MOISTURE IN THE 850-925MB LAYER ACROSS OUR
EASTERN COUNTIES...WHICH IS ALSO SUPPORTED BY THE NAM AND GFS.
FAIR WEATHER CUMULUS FORMATION WILL BE MORE CONCENTRATED THERE...
BUT SUNSHINE SHOULD STILL BE THE RULE FOR THE DAY IN MOST AREAS.
HIGH TEMPS SHOULD REACH THE MID 60S NEAR INDIANA AND THE UPPER 60S
WEST OF THE ILLINOIS RIVER. FORECAST SOUNDINGS SHOW MIXING HEIGHTS
WILL PEAK BETWEEN 11 AM AND 1 PM...WHICH WILL COINCIDE WITH OUR
HIGHER WIND GUSTS FOR THE DAY. A FEW GUSTS MAY REACH 16-17 MPH...
BUT OVERALL WINDS SHOULD BE LESS GUSTY THAN THE LAST COUPLE OF
DAYS.

&&

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

INITIAL CONCERN FOR THIS PART OF THE FORECAST IS WITH RAIN POTENTIAL
MID WEEK. UPPER TROUGH CURRENTLY PUSHING THROUGH THE DAKOTAS
NORTHEAST TO HUDSON BAY PROGGED BY ALL MODELS TO CARVE OUT A
SIZABLE CLOUDS LOW OVER ONTARIO ON WEDNESDAY...DROPPING SOUTHWARD
INTO THE MIDWEST BY THURSDAY MORNING. GFS IS A BIT FURTHER EAST WITH
THIS PROJECTION...WITH GENERAL MODEL CONSENSUS FAVORING A PATH ALONG
THE ILLINOIS/INDIANA BORDER. HAVE INTRODUCED SOME SHOWERS INTO THE
FORECAST FOR WEDNESDAY AFTERNOON...AS COLD CORE WITH THE UPPER LOW
(500 MB TEMPERATURES DIPPING BELOW -20C) INTRODUCES SOME STEEP LAPSE
RATES. ALSO MENTIONED SOME ISOLATED THUNDER AS WELL. HAVE LINGERED
SOME SLIGHT CHANCE POP`S ACROSS THE EASTERN CWA INTO WEDNESDAY
NIGHT. WITH THE LOW SETTLING INTO THE OHIO VALLEY ON THURSDAY...HAVE
ALSO MENTIONED SOME SCATTERED SHOWERS EAST OF I-57 CLOSER TO THE LOW
TRACK.

FURTHER OUT IN TIME...UPPER FLOW SHIFTS MORE ZONAL TO START THE
WEEKEND. BOTH THE GFS AND ECMWF SHOWING A TROUGH MOVING ALONG THE
CANADIAN BORDER...WITH THE ECMWF DEVELOPING MORE OF A BROADENING
EARLY NEXT WEEK WHILE THE GFS REMAINS A BIT MORE PROGRESSIVE AND
CLOSER TO THE BORDER. STILL NOT VERY GOOD AGREEMENT WITH RAIN
POTENTIAL ON SATURDAY...AND HAVE PULLED BACK SOME ON THE POP`S.
SATURDAY NIGHT...HAVE FOLLOWED MORE OF THE ECMWF SOLUTION OF A
POTENTIAL MCS SYSTEM ROLLING THROUGH THE AREA OVERNIGHT INTO SUNDAY.
RAIN CHANCES PERSIST INTO EARLY NEXT WEEK AS THE BROADENING TROUGH
APPROACHES THE MISSISSIPPI VALLEY.

THE GENERAL IDEA FOR TEMPERATURES WILL BE WITH WARMING CONDITIONS...
ALTHOUGH A BRIEF COOLDOWN IS EXPECTED THURSDAY AS 850 MB
TEMPERATURES DIP CLOSER TO 0C AS THE UPPER LOW PASSES. HIGHS SHOULD
REACH INTO THE MID 70S ACROSS THE AREA THIS WEEKEND AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1115 PM CDT MON APR 27 2015

VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THRU THIS FORECAST
PERIOD. HIGH PRESSURE WILL HOLD TO THE NORTH OF THE REGION THRU
TUESDAY BRINGING ONLY A SCATTERING OF CLOUDS AND A NORTHEAST
FLOW. LATEST MODEL DATA PULLING BACK A BIT ON THE AMOUNT OF
MIXING EXPECTED TOMORROW AFTERNOON RESULTING IN LIGHTER WINDS
THAN WHAT WE HAVE EXPERIENCED OVER THE AREA THE PAST FEW
AFTERNOONS. LOOK FOR A LIGHT AND VARIABLE WIND TONIGHT TO BECOME
NORTHEAST TUESDAY AT 8 TO 13 KTS...AND THEN A LIGHT NORTHEASTERLY
FLOW FOR TOMORROW NIGHT WITH WIND SPEEDS DROPPING TO 5 KTS OR LESS
AFTER 00Z.


&&

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

$$

SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SMITH




000
FXUS63 KILX 280804
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
304 AM CDT TUE APR 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

ANOTHER CHILLY START TO THE DAY IS ON TAP...WITH MID 30S AND
PATCHY FROST TO START THE DAY NORTH OF I-74. HOWEVER, A SURFACE
RIDGE AXIS EXTENDING ACROSS ILLINOIS FROM NE TO SW WILL PROVIDE
SUBSIDENCE AND RELATIVELY DRY AIR. THE HRRR AND RAP CONTINUE TO
SHOW SLIGHTLY HIGHER MOISTURE IN THE 850-925MB LAYER ACROSS OUR
EASTERN COUNTIES...WHICH IS ALSO SUPPORTED BY THE NAM AND GFS.
FAIR WEATHER CUMULUS FORMATION WILL BE MORE CONCENTRATED THERE...
BUT SUNSHINE SHOULD STILL BE THE RULE FOR THE DAY IN MOST AREAS.
HIGH TEMPS SHOULD REACH THE MID 60S NEAR INDIANA AND THE UPPER 60S
WEST OF THE ILLINOIS RIVER. FORECAST SOUNDINGS SHOW MIXING HEIGHTS
WILL PEAK BETWEEN 11 AM AND 1 PM...WHICH WILL COINCIDE WITH OUR
HIGHER WIND GUSTS FOR THE DAY. A FEW GUSTS MAY REACH 16-17 MPH...
BUT OVERALL WINDS SHOULD BE LESS GUSTY THAN THE LAST COUPLE OF
DAYS.

&&

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

INITIAL CONCERN FOR THIS PART OF THE FORECAST IS WITH RAIN POTENTIAL
MID WEEK. UPPER TROUGH CURRENTLY PUSHING THROUGH THE DAKOTAS
NORTHEAST TO HUDSON BAY PROGGED BY ALL MODELS TO CARVE OUT A
SIZABLE CLOUDS LOW OVER ONTARIO ON WEDNESDAY...DROPPING SOUTHWARD
INTO THE MIDWEST BY THURSDAY MORNING. GFS IS A BIT FURTHER EAST WITH
THIS PROJECTION...WITH GENERAL MODEL CONSENSUS FAVORING A PATH ALONG
THE ILLINOIS/INDIANA BORDER. HAVE INTRODUCED SOME SHOWERS INTO THE
FORECAST FOR WEDNESDAY AFTERNOON...AS COLD CORE WITH THE UPPER LOW
(500 MB TEMPERATURES DIPPING BELOW -20C) INTRODUCES SOME STEEP LAPSE
RATES. ALSO MENTIONED SOME ISOLATED THUNDER AS WELL. HAVE LINGERED
SOME SLIGHT CHANCE POP`S ACROSS THE EASTERN CWA INTO WEDNESDAY
NIGHT. WITH THE LOW SETTLING INTO THE OHIO VALLEY ON THURSDAY...HAVE
ALSO MENTIONED SOME SCATTERED SHOWERS EAST OF I-57 CLOSER TO THE LOW
TRACK.

FURTHER OUT IN TIME...UPPER FLOW SHIFTS MORE ZONAL TO START THE
WEEKEND. BOTH THE GFS AND ECMWF SHOWING A TROUGH MOVING ALONG THE
CANADIAN BORDER...WITH THE ECMWF DEVELOPING MORE OF A BROADENING
EARLY NEXT WEEK WHILE THE GFS REMAINS A BIT MORE PROGRESSIVE AND
CLOSER TO THE BORDER. STILL NOT VERY GOOD AGREEMENT WITH RAIN
POTENTIAL ON SATURDAY...AND HAVE PULLED BACK SOME ON THE POP`S.
SATURDAY NIGHT...HAVE FOLLOWED MORE OF THE ECMWF SOLUTION OF A
POTENTIAL MCS SYSTEM ROLLING THROUGH THE AREA OVERNIGHT INTO SUNDAY.
RAIN CHANCES PERSIST INTO EARLY NEXT WEEK AS THE BROADENING TROUGH
APPROACHES THE MISSISSIPPI VALLEY.

THE GENERAL IDEA FOR TEMPERATURES WILL BE WITH WARMING CONDITIONS...
ALTHOUGH A BRIEF COOLDOWN IS EXPECTED THURSDAY AS 850 MB
TEMPERATURES DIP CLOSER TO 0C AS THE UPPER LOW PASSES. HIGHS SHOULD
REACH INTO THE MID 70S ACROSS THE AREA THIS WEEKEND AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1115 PM CDT MON APR 27 2015

VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THRU THIS FORECAST
PERIOD. HIGH PRESSURE WILL HOLD TO THE NORTH OF THE REGION THRU
TUESDAY BRINGING ONLY A SCATTERING OF CLOUDS AND A NORTHEAST
FLOW. LATEST MODEL DATA PULLING BACK A BIT ON THE AMOUNT OF
MIXING EXPECTED TOMORROW AFTERNOON RESULTING IN LIGHTER WINDS
THAN WHAT WE HAVE EXPERIENCED OVER THE AREA THE PAST FEW
AFTERNOONS. LOOK FOR A LIGHT AND VARIABLE WIND TONIGHT TO BECOME
NORTHEAST TUESDAY AT 8 TO 13 KTS...AND THEN A LIGHT NORTHEASTERLY
FLOW FOR TOMORROW NIGHT WITH WIND SPEEDS DROPPING TO 5 KTS OR LESS
AFTER 00Z.


&&

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

$$

SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SMITH



000
FXUS63 KILX 280804
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
304 AM CDT TUE APR 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

ANOTHER CHILLY START TO THE DAY IS ON TAP...WITH MID 30S AND
PATCHY FROST TO START THE DAY NORTH OF I-74. HOWEVER, A SURFACE
RIDGE AXIS EXTENDING ACROSS ILLINOIS FROM NE TO SW WILL PROVIDE
SUBSIDENCE AND RELATIVELY DRY AIR. THE HRRR AND RAP CONTINUE TO
SHOW SLIGHTLY HIGHER MOISTURE IN THE 850-925MB LAYER ACROSS OUR
EASTERN COUNTIES...WHICH IS ALSO SUPPORTED BY THE NAM AND GFS.
FAIR WEATHER CUMULUS FORMATION WILL BE MORE CONCENTRATED THERE...
BUT SUNSHINE SHOULD STILL BE THE RULE FOR THE DAY IN MOST AREAS.
HIGH TEMPS SHOULD REACH THE MID 60S NEAR INDIANA AND THE UPPER 60S
WEST OF THE ILLINOIS RIVER. FORECAST SOUNDINGS SHOW MIXING HEIGHTS
WILL PEAK BETWEEN 11 AM AND 1 PM...WHICH WILL COINCIDE WITH OUR
HIGHER WIND GUSTS FOR THE DAY. A FEW GUSTS MAY REACH 16-17 MPH...
BUT OVERALL WINDS SHOULD BE LESS GUSTY THAN THE LAST COUPLE OF
DAYS.

&&

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

INITIAL CONCERN FOR THIS PART OF THE FORECAST IS WITH RAIN POTENTIAL
MID WEEK. UPPER TROUGH CURRENTLY PUSHING THROUGH THE DAKOTAS
NORTHEAST TO HUDSON BAY PROGGED BY ALL MODELS TO CARVE OUT A
SIZABLE CLOUDS LOW OVER ONTARIO ON WEDNESDAY...DROPPING SOUTHWARD
INTO THE MIDWEST BY THURSDAY MORNING. GFS IS A BIT FURTHER EAST WITH
THIS PROJECTION...WITH GENERAL MODEL CONSENSUS FAVORING A PATH ALONG
THE ILLINOIS/INDIANA BORDER. HAVE INTRODUCED SOME SHOWERS INTO THE
FORECAST FOR WEDNESDAY AFTERNOON...AS COLD CORE WITH THE UPPER LOW
(500 MB TEMPERATURES DIPPING BELOW -20C) INTRODUCES SOME STEEP LAPSE
RATES. ALSO MENTIONED SOME ISOLATED THUNDER AS WELL. HAVE LINGERED
SOME SLIGHT CHANCE POP`S ACROSS THE EASTERN CWA INTO WEDNESDAY
NIGHT. WITH THE LOW SETTLING INTO THE OHIO VALLEY ON THURSDAY...HAVE
ALSO MENTIONED SOME SCATTERED SHOWERS EAST OF I-57 CLOSER TO THE LOW
TRACK.

FURTHER OUT IN TIME...UPPER FLOW SHIFTS MORE ZONAL TO START THE
WEEKEND. BOTH THE GFS AND ECMWF SHOWING A TROUGH MOVING ALONG THE
CANADIAN BORDER...WITH THE ECMWF DEVELOPING MORE OF A BROADENING
EARLY NEXT WEEK WHILE THE GFS REMAINS A BIT MORE PROGRESSIVE AND
CLOSER TO THE BORDER. STILL NOT VERY GOOD AGREEMENT WITH RAIN
POTENTIAL ON SATURDAY...AND HAVE PULLED BACK SOME ON THE POP`S.
SATURDAY NIGHT...HAVE FOLLOWED MORE OF THE ECMWF SOLUTION OF A
POTENTIAL MCS SYSTEM ROLLING THROUGH THE AREA OVERNIGHT INTO SUNDAY.
RAIN CHANCES PERSIST INTO EARLY NEXT WEEK AS THE BROADENING TROUGH
APPROACHES THE MISSISSIPPI VALLEY.

THE GENERAL IDEA FOR TEMPERATURES WILL BE WITH WARMING CONDITIONS...
ALTHOUGH A BRIEF COOLDOWN IS EXPECTED THURSDAY AS 850 MB
TEMPERATURES DIP CLOSER TO 0C AS THE UPPER LOW PASSES. HIGHS SHOULD
REACH INTO THE MID 70S ACROSS THE AREA THIS WEEKEND AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1115 PM CDT MON APR 27 2015

VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THRU THIS FORECAST
PERIOD. HIGH PRESSURE WILL HOLD TO THE NORTH OF THE REGION THRU
TUESDAY BRINGING ONLY A SCATTERING OF CLOUDS AND A NORTHEAST
FLOW. LATEST MODEL DATA PULLING BACK A BIT ON THE AMOUNT OF
MIXING EXPECTED TOMORROW AFTERNOON RESULTING IN LIGHTER WINDS
THAN WHAT WE HAVE EXPERIENCED OVER THE AREA THE PAST FEW
AFTERNOONS. LOOK FOR A LIGHT AND VARIABLE WIND TONIGHT TO BECOME
NORTHEAST TUESDAY AT 8 TO 13 KTS...AND THEN A LIGHT NORTHEASTERLY
FLOW FOR TOMORROW NIGHT WITH WIND SPEEDS DROPPING TO 5 KTS OR LESS
AFTER 00Z.


&&

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

$$

SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SMITH




000
FXUS63 KILX 280804
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
304 AM CDT TUE APR 28 2015

.SHORT TERM...(TODAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

ANOTHER CHILLY START TO THE DAY IS ON TAP...WITH MID 30S AND
PATCHY FROST TO START THE DAY NORTH OF I-74. HOWEVER, A SURFACE
RIDGE AXIS EXTENDING ACROSS ILLINOIS FROM NE TO SW WILL PROVIDE
SUBSIDENCE AND RELATIVELY DRY AIR. THE HRRR AND RAP CONTINUE TO
SHOW SLIGHTLY HIGHER MOISTURE IN THE 850-925MB LAYER ACROSS OUR
EASTERN COUNTIES...WHICH IS ALSO SUPPORTED BY THE NAM AND GFS.
FAIR WEATHER CUMULUS FORMATION WILL BE MORE CONCENTRATED THERE...
BUT SUNSHINE SHOULD STILL BE THE RULE FOR THE DAY IN MOST AREAS.
HIGH TEMPS SHOULD REACH THE MID 60S NEAR INDIANA AND THE UPPER 60S
WEST OF THE ILLINOIS RIVER. FORECAST SOUNDINGS SHOW MIXING HEIGHTS
WILL PEAK BETWEEN 11 AM AND 1 PM...WHICH WILL COINCIDE WITH OUR
HIGHER WIND GUSTS FOR THE DAY. A FEW GUSTS MAY REACH 16-17 MPH...
BUT OVERALL WINDS SHOULD BE LESS GUSTY THAN THE LAST COUPLE OF
DAYS.

&&

.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 303 AM CDT TUE APR 28 2015

INITIAL CONCERN FOR THIS PART OF THE FORECAST IS WITH RAIN POTENTIAL
MID WEEK. UPPER TROUGH CURRENTLY PUSHING THROUGH THE DAKOTAS
NORTHEAST TO HUDSON BAY PROGGED BY ALL MODELS TO CARVE OUT A
SIZABLE CLOUDS LOW OVER ONTARIO ON WEDNESDAY...DROPPING SOUTHWARD
INTO THE MIDWEST BY THURSDAY MORNING. GFS IS A BIT FURTHER EAST WITH
THIS PROJECTION...WITH GENERAL MODEL CONSENSUS FAVORING A PATH ALONG
THE ILLINOIS/INDIANA BORDER. HAVE INTRODUCED SOME SHOWERS INTO THE
FORECAST FOR WEDNESDAY AFTERNOON...AS COLD CORE WITH THE UPPER LOW
(500 MB TEMPERATURES DIPPING BELOW -20C) INTRODUCES SOME STEEP LAPSE
RATES. ALSO MENTIONED SOME ISOLATED THUNDER AS WELL. HAVE LINGERED
SOME SLIGHT CHANCE POP`S ACROSS THE EASTERN CWA INTO WEDNESDAY
NIGHT. WITH THE LOW SETTLING INTO THE OHIO VALLEY ON THURSDAY...HAVE
ALSO MENTIONED SOME SCATTERED SHOWERS EAST OF I-57 CLOSER TO THE LOW
TRACK.

FURTHER OUT IN TIME...UPPER FLOW SHIFTS MORE ZONAL TO START THE
WEEKEND. BOTH THE GFS AND ECMWF SHOWING A TROUGH MOVING ALONG THE
CANADIAN BORDER...WITH THE ECMWF DEVELOPING MORE OF A BROADENING
EARLY NEXT WEEK WHILE THE GFS REMAINS A BIT MORE PROGRESSIVE AND
CLOSER TO THE BORDER. STILL NOT VERY GOOD AGREEMENT WITH RAIN
POTENTIAL ON SATURDAY...AND HAVE PULLED BACK SOME ON THE POP`S.
SATURDAY NIGHT...HAVE FOLLOWED MORE OF THE ECMWF SOLUTION OF A
POTENTIAL MCS SYSTEM ROLLING THROUGH THE AREA OVERNIGHT INTO SUNDAY.
RAIN CHANCES PERSIST INTO EARLY NEXT WEEK AS THE BROADENING TROUGH
APPROACHES THE MISSISSIPPI VALLEY.

THE GENERAL IDEA FOR TEMPERATURES WILL BE WITH WARMING CONDITIONS...
ALTHOUGH A BRIEF COOLDOWN IS EXPECTED THURSDAY AS 850 MB
TEMPERATURES DIP CLOSER TO 0C AS THE UPPER LOW PASSES. HIGHS SHOULD
REACH INTO THE MID 70S ACROSS THE AREA THIS WEEKEND AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1115 PM CDT MON APR 27 2015

VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THRU THIS FORECAST
PERIOD. HIGH PRESSURE WILL HOLD TO THE NORTH OF THE REGION THRU
TUESDAY BRINGING ONLY A SCATTERING OF CLOUDS AND A NORTHEAST
FLOW. LATEST MODEL DATA PULLING BACK A BIT ON THE AMOUNT OF
MIXING EXPECTED TOMORROW AFTERNOON RESULTING IN LIGHTER WINDS
THAN WHAT WE HAVE EXPERIENCED OVER THE AREA THE PAST FEW
AFTERNOONS. LOOK FOR A LIGHT AND VARIABLE WIND TONIGHT TO BECOME
NORTHEAST TUESDAY AT 8 TO 13 KTS...AND THEN A LIGHT NORTHEASTERLY
FLOW FOR TOMORROW NIGHT WITH WIND SPEEDS DROPPING TO 5 KTS OR LESS
AFTER 00Z.


&&

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

$$

SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SMITH



000
FXUS63 KLOT 280519
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1219 AM CDT TUE APR 28 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

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

$$

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

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



000
FXUS63 KLOT 280519
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1219 AM CDT TUE APR 28 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LAKE BREEZE TIMING TUESDAY AFTERNOON.

BMD

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

HIGH PRESSURE WILL BE IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA THROUGH MUCH OF THE DAY TUESDAY PRODUCING LIGHT
WINDS...GENERALLY OUT OF THE NORTH OR NORTHEAST BUT POSSIBLY
VARIABLE AT TIMES. A LAKE BREEZE IS EXPECTED TO DEVELOP TUESDAY
AFTERNOON WITH WINDS PICKUP UP TO AROUND 10-12 KT OUT OF THE
NORTHEAST. WINDS WILL BECOME LIGHT AND VARIABLE TUESDAY EVENING
AND OVERNIGHT. EXPECT VFR CONDITIONS THROUGH THE PERIOD.

BMD

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

* HIGH.

BMD

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

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

$$

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

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




000
FXUS63 KILX 280418
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1118 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 840 PM CDT MON APR 27 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING WILL CONTINUE TO BRING
QUIET WEATHER TO THE REGION FOR THE NEXT SEVERAL DAYS.
MEANWHILE...ALL THE ACTIVE WEATHER IS LOCATED OVER THE SOUTHERN
PLAINS AS AN UPPER LEVEL STORM SLOWLY TRACKS EAST INTO THE LOWER
MISSISSIPPI VALLEY OVER THE NEXT SEVERAL DAYS...WELL SOUTH OF OUR
AREA. ONCE AGAIN...THE COMBINATION OF A MOSTLY CLEAR SKY AND
DIMINISHING WINDS SHOULD LEAD TO ANOTHER VERY CHILLY NIGHT ACROSS
THE FORECAST AREA WITH EARLY MORNING LOWS DIPPING INTO THE MID AND
UPPER 30S. THIS SHOULD BRING ABOUT ANOTHER THREAT FOR PATCHY FROST
OVER THE NORTHEAST THIRD OF THE FORECAST AREA...WHICH WILL BE
CLOSER TO THE SURFACE RIDGE AXIS. THE PRIMARY TIME OF CONCERN FOR
FROST WILL BE ROUGHLY FROM 200 AM THRU 700 AM WHERE SURFACE TEMPS
WILL BE IN THE 34 TO 37 DEGREE RANGE ACROSS THE NORTH AND EAST.
LIKE THIS MORNING...BETWEEN 730 AND 800 AM...WE SHOULD SEE THE
TEMPERATURES RAPIDLY RISE THEREAFTER. HAVE MADE SOME ADJUSTMENTS
TO THE EARLY EVENING TEMPERATURE DECLINE AND SOME OVERNIGHT LOWS
OVER THE FAR EAST AND NORTHEAST COUNTIES...OTHERWISE...THE REST
OF THE FORECAST LOOKS ON TARGET. SHOULD HAVE THE UPDATE OUT BY
900 PM.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1115 PM CDT MON APR 27 2015

VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THRU THIS FORECAST
PERIOD. HIGH PRESSURE WILL HOLD TO THE NORTH OF THE REGION THRU
TUESDAY BRINGING ONLY A SCATTERING OF CLOUDS AND A NORTHEAST
FLOW. LATEST MODEL DATA PULLING BACK A BIT ON THE AMOUNT OF
MIXING EXPECTED TOMORROW AFTERNOON RESULTING IN LIGHTER WINDS
THAN WHAT WE HAVE EXPERIENCED OVER THE AREA THE PAST FEW
AFTERNOONS. LOOK FOR A LIGHT AND VARIABLE WIND TONIGHT TO BECOME
NORTHEAST TUESDAY AT 8 TO 13 KTS...AND THEN A LIGHT NORTHEASTERLY
FLOW FOR TOMORROW NIGHT WITH WIND SPEEDS DROPPING TO 5 KTS OR LESS
AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KILX 280418
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1118 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 840 PM CDT MON APR 27 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING WILL CONTINUE TO BRING
QUIET WEATHER TO THE REGION FOR THE NEXT SEVERAL DAYS.
MEANWHILE...ALL THE ACTIVE WEATHER IS LOCATED OVER THE SOUTHERN
PLAINS AS AN UPPER LEVEL STORM SLOWLY TRACKS EAST INTO THE LOWER
MISSISSIPPI VALLEY OVER THE NEXT SEVERAL DAYS...WELL SOUTH OF OUR
AREA. ONCE AGAIN...THE COMBINATION OF A MOSTLY CLEAR SKY AND
DIMINISHING WINDS SHOULD LEAD TO ANOTHER VERY CHILLY NIGHT ACROSS
THE FORECAST AREA WITH EARLY MORNING LOWS DIPPING INTO THE MID AND
UPPER 30S. THIS SHOULD BRING ABOUT ANOTHER THREAT FOR PATCHY FROST
OVER THE NORTHEAST THIRD OF THE FORECAST AREA...WHICH WILL BE
CLOSER TO THE SURFACE RIDGE AXIS. THE PRIMARY TIME OF CONCERN FOR
FROST WILL BE ROUGHLY FROM 200 AM THRU 700 AM WHERE SURFACE TEMPS
WILL BE IN THE 34 TO 37 DEGREE RANGE ACROSS THE NORTH AND EAST.
LIKE THIS MORNING...BETWEEN 730 AND 800 AM...WE SHOULD SEE THE
TEMPERATURES RAPIDLY RISE THEREAFTER. HAVE MADE SOME ADJUSTMENTS
TO THE EARLY EVENING TEMPERATURE DECLINE AND SOME OVERNIGHT LOWS
OVER THE FAR EAST AND NORTHEAST COUNTIES...OTHERWISE...THE REST
OF THE FORECAST LOOKS ON TARGET. SHOULD HAVE THE UPDATE OUT BY
900 PM.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1115 PM CDT MON APR 27 2015

VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THRU THIS FORECAST
PERIOD. HIGH PRESSURE WILL HOLD TO THE NORTH OF THE REGION THRU
TUESDAY BRINGING ONLY A SCATTERING OF CLOUDS AND A NORTHEAST
FLOW. LATEST MODEL DATA PULLING BACK A BIT ON THE AMOUNT OF
MIXING EXPECTED TOMORROW AFTERNOON RESULTING IN LIGHTER WINDS
THAN WHAT WE HAVE EXPERIENCED OVER THE AREA THE PAST FEW
AFTERNOONS. LOOK FOR A LIGHT AND VARIABLE WIND TONIGHT TO BECOME
NORTHEAST TUESDAY AT 8 TO 13 KTS...AND THEN A LIGHT NORTHEASTERLY
FLOW FOR TOMORROW NIGHT WITH WIND SPEEDS DROPPING TO 5 KTS OR LESS
AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KILX 280418
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1118 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 840 PM CDT MON APR 27 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING WILL CONTINUE TO BRING
QUIET WEATHER TO THE REGION FOR THE NEXT SEVERAL DAYS.
MEANWHILE...ALL THE ACTIVE WEATHER IS LOCATED OVER THE SOUTHERN
PLAINS AS AN UPPER LEVEL STORM SLOWLY TRACKS EAST INTO THE LOWER
MISSISSIPPI VALLEY OVER THE NEXT SEVERAL DAYS...WELL SOUTH OF OUR
AREA. ONCE AGAIN...THE COMBINATION OF A MOSTLY CLEAR SKY AND
DIMINISHING WINDS SHOULD LEAD TO ANOTHER VERY CHILLY NIGHT ACROSS
THE FORECAST AREA WITH EARLY MORNING LOWS DIPPING INTO THE MID AND
UPPER 30S. THIS SHOULD BRING ABOUT ANOTHER THREAT FOR PATCHY FROST
OVER THE NORTHEAST THIRD OF THE FORECAST AREA...WHICH WILL BE
CLOSER TO THE SURFACE RIDGE AXIS. THE PRIMARY TIME OF CONCERN FOR
FROST WILL BE ROUGHLY FROM 200 AM THRU 700 AM WHERE SURFACE TEMPS
WILL BE IN THE 34 TO 37 DEGREE RANGE ACROSS THE NORTH AND EAST.
LIKE THIS MORNING...BETWEEN 730 AND 800 AM...WE SHOULD SEE THE
TEMPERATURES RAPIDLY RISE THEREAFTER. HAVE MADE SOME ADJUSTMENTS
TO THE EARLY EVENING TEMPERATURE DECLINE AND SOME OVERNIGHT LOWS
OVER THE FAR EAST AND NORTHEAST COUNTIES...OTHERWISE...THE REST
OF THE FORECAST LOOKS ON TARGET. SHOULD HAVE THE UPDATE OUT BY
900 PM.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1115 PM CDT MON APR 27 2015

VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THRU THIS FORECAST
PERIOD. HIGH PRESSURE WILL HOLD TO THE NORTH OF THE REGION THRU
TUESDAY BRINGING ONLY A SCATTERING OF CLOUDS AND A NORTHEAST
FLOW. LATEST MODEL DATA PULLING BACK A BIT ON THE AMOUNT OF
MIXING EXPECTED TOMORROW AFTERNOON RESULTING IN LIGHTER WINDS
THAN WHAT WE HAVE EXPERIENCED OVER THE AREA THE PAST FEW
AFTERNOONS. LOOK FOR A LIGHT AND VARIABLE WIND TONIGHT TO BECOME
NORTHEAST TUESDAY AT 8 TO 13 KTS...AND THEN A LIGHT NORTHEASTERLY
FLOW FOR TOMORROW NIGHT WITH WIND SPEEDS DROPPING TO 5 KTS OR LESS
AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KLOT 280300
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1000 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LIGHT NORTH-NORTHEAST OVERNIGHT. WINDS BECOME NORTHEAST AGAIN
  TUESDAY...AROUND 10 KT WITH LAKE BREEZE IN THE AFTERNOON.

RATZER

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

NORTH-NORTHEAST WINDS CONTINUE THROUGH THE PERIOD WITH SURFACE
HIGH PRESSURE RIDGE STILL OFF TO THE NORTHWEST OF THE TERMINALS.
GRADIENT BECOMING WEAKER THAN THE PAST COUPLE OF DAYS HOWEVER...
WITH WINDS AROUND 10 KT TUESDAY. CHICAGO TERMINALS WILL SEE
TYPICAL AFTERNOON LAKE BREEZE PUSH...WITH NORTHEAST WINDS A BIT
OVER 10 KT AT TIMES IN THE AFTERNOON. OTHERWISE...VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.

RATZER

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

* HIGH FOR ALL ELEMENTS.

RATZER

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

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

$$

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

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




000
FXUS63 KLOT 280300
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1000 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LIGHT NORTH-NORTHEAST OVERNIGHT. WINDS BECOME NORTHEAST AGAIN
  TUESDAY...AROUND 10 KT WITH LAKE BREEZE IN THE AFTERNOON.

RATZER

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

NORTH-NORTHEAST WINDS CONTINUE THROUGH THE PERIOD WITH SURFACE
HIGH PRESSURE RIDGE STILL OFF TO THE NORTHWEST OF THE TERMINALS.
GRADIENT BECOMING WEAKER THAN THE PAST COUPLE OF DAYS HOWEVER...
WITH WINDS AROUND 10 KT TUESDAY. CHICAGO TERMINALS WILL SEE
TYPICAL AFTERNOON LAKE BREEZE PUSH...WITH NORTHEAST WINDS A BIT
OVER 10 KT AT TIMES IN THE AFTERNOON. OTHERWISE...VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.

RATZER

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

* HIGH FOR ALL ELEMENTS.

RATZER

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

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

$$

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

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



000
FXUS63 KLOT 280300
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1000 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LIGHT NORTH-NORTHEAST OVERNIGHT. WINDS BECOME NORTHEAST AGAIN
  TUESDAY...AROUND 10 KT WITH LAKE BREEZE IN THE AFTERNOON.

RATZER

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

NORTH-NORTHEAST WINDS CONTINUE THROUGH THE PERIOD WITH SURFACE
HIGH PRESSURE RIDGE STILL OFF TO THE NORTHWEST OF THE TERMINALS.
GRADIENT BECOMING WEAKER THAN THE PAST COUPLE OF DAYS HOWEVER...
WITH WINDS AROUND 10 KT TUESDAY. CHICAGO TERMINALS WILL SEE
TYPICAL AFTERNOON LAKE BREEZE PUSH...WITH NORTHEAST WINDS A BIT
OVER 10 KT AT TIMES IN THE AFTERNOON. OTHERWISE...VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.

RATZER

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

* HIGH FOR ALL ELEMENTS.

RATZER

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

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

$$

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

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



000
FXUS63 KLOT 280300
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1000 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* LIGHT NORTH-NORTHEAST OVERNIGHT. WINDS BECOME NORTHEAST AGAIN
  TUESDAY...AROUND 10 KT WITH LAKE BREEZE IN THE AFTERNOON.

RATZER

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

NORTH-NORTHEAST WINDS CONTINUE THROUGH THE PERIOD WITH SURFACE
HIGH PRESSURE RIDGE STILL OFF TO THE NORTHWEST OF THE TERMINALS.
GRADIENT BECOMING WEAKER THAN THE PAST COUPLE OF DAYS HOWEVER...
WITH WINDS AROUND 10 KT TUESDAY. CHICAGO TERMINALS WILL SEE
TYPICAL AFTERNOON LAKE BREEZE PUSH...WITH NORTHEAST WINDS A BIT
OVER 10 KT AT TIMES IN THE AFTERNOON. OTHERWISE...VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.

RATZER

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

* HIGH FOR ALL ELEMENTS.

RATZER

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

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

$$

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

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




000
FXUS63 KILX 280150
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
850 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 840 PM CDT MON APR 27 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING WILL CONTINUE TO BRING
QUIET WEATHER TO THE REGION FOR THE NEXT SEVERAL DAYS.
MEANWHILE...ALL THE ACTIVE WEATHER IS LOCATED OVER THE SOUTHERN
PLAINS AS AN UPPER LEVEL STORM SLOWLY TRACKS EAST INTO THE LOWER
MISSISSIPPI VALLEY OVER THE NEXT SEVERAL DAYS...WELL SOUTH OF OUR
AREA. ONCE AGAIN...THE COMBINATION OF A MOSTLY CLEAR SKY AND
DIMINISHING WINDS SHOULD LEAD TO ANOTHER VERY CHILLY NIGHT ACROSS
THE FORECAST AREA WITH EARLY MORNING LOWS DIPPING INTO THE MID AND
UPPER 30S. THIS SHOULD BRING ABOUT ANOTHER THREAT FOR PATCHY FROST
OVER THE NORTHEAST THIRD OF THE FORECAST AREA...WHICH WILL BE
CLOSER TO THE SURFACE RIDGE AXIS. THE PRIMARY TIME OF CONCERN FOR
FROST WILL BE ROUGHLY FROM 200 AM THRU 700 AM WHERE SURFACE TEMPS
WILL BE IN THE 34 TO 37 DEGREE RANGE ACROSS THE NORTH AND EAST.
LIKE THIS MORNING...BETWEEN 730 AND 800 AM...WE SHOULD SEE THE
TEMPERATURES RAPIDLY RISE THEREAFTER. HAVE MADE SOME ADJUSTMENTS
TO THE EARLY EVENING TEMPERATURE DECLINE AND SOME OVERNIGHT LOWS
OVER THE FAR EAST AND NORTHEAST COUNTIES...OTHERWISE...THE REST
OF THE FORECAST LOOKS ON TARGET. SHOULD HAVE THE UPDATE OUT BY
900 PM.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.


&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 280150
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
850 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 840 PM CDT MON APR 27 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING WILL CONTINUE TO BRING
QUIET WEATHER TO THE REGION FOR THE NEXT SEVERAL DAYS.
MEANWHILE...ALL THE ACTIVE WEATHER IS LOCATED OVER THE SOUTHERN
PLAINS AS AN UPPER LEVEL STORM SLOWLY TRACKS EAST INTO THE LOWER
MISSISSIPPI VALLEY OVER THE NEXT SEVERAL DAYS...WELL SOUTH OF OUR
AREA. ONCE AGAIN...THE COMBINATION OF A MOSTLY CLEAR SKY AND
DIMINISHING WINDS SHOULD LEAD TO ANOTHER VERY CHILLY NIGHT ACROSS
THE FORECAST AREA WITH EARLY MORNING LOWS DIPPING INTO THE MID AND
UPPER 30S. THIS SHOULD BRING ABOUT ANOTHER THREAT FOR PATCHY FROST
OVER THE NORTHEAST THIRD OF THE FORECAST AREA...WHICH WILL BE
CLOSER TO THE SURFACE RIDGE AXIS. THE PRIMARY TIME OF CONCERN FOR
FROST WILL BE ROUGHLY FROM 200 AM THRU 700 AM WHERE SURFACE TEMPS
WILL BE IN THE 34 TO 37 DEGREE RANGE ACROSS THE NORTH AND EAST.
LIKE THIS MORNING...BETWEEN 730 AND 800 AM...WE SHOULD SEE THE
TEMPERATURES RAPIDLY RISE THEREAFTER. HAVE MADE SOME ADJUSTMENTS
TO THE EARLY EVENING TEMPERATURE DECLINE AND SOME OVERNIGHT LOWS
OVER THE FAR EAST AND NORTHEAST COUNTIES...OTHERWISE...THE REST
OF THE FORECAST LOOKS ON TARGET. SHOULD HAVE THE UPDATE OUT BY
900 PM.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.


&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 280150
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
850 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 840 PM CDT MON APR 27 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING WILL CONTINUE TO BRING
QUIET WEATHER TO THE REGION FOR THE NEXT SEVERAL DAYS.
MEANWHILE...ALL THE ACTIVE WEATHER IS LOCATED OVER THE SOUTHERN
PLAINS AS AN UPPER LEVEL STORM SLOWLY TRACKS EAST INTO THE LOWER
MISSISSIPPI VALLEY OVER THE NEXT SEVERAL DAYS...WELL SOUTH OF OUR
AREA. ONCE AGAIN...THE COMBINATION OF A MOSTLY CLEAR SKY AND
DIMINISHING WINDS SHOULD LEAD TO ANOTHER VERY CHILLY NIGHT ACROSS
THE FORECAST AREA WITH EARLY MORNING LOWS DIPPING INTO THE MID AND
UPPER 30S. THIS SHOULD BRING ABOUT ANOTHER THREAT FOR PATCHY FROST
OVER THE NORTHEAST THIRD OF THE FORECAST AREA...WHICH WILL BE
CLOSER TO THE SURFACE RIDGE AXIS. THE PRIMARY TIME OF CONCERN FOR
FROST WILL BE ROUGHLY FROM 200 AM THRU 700 AM WHERE SURFACE TEMPS
WILL BE IN THE 34 TO 37 DEGREE RANGE ACROSS THE NORTH AND EAST.
LIKE THIS MORNING...BETWEEN 730 AND 800 AM...WE SHOULD SEE THE
TEMPERATURES RAPIDLY RISE THEREAFTER. HAVE MADE SOME ADJUSTMENTS
TO THE EARLY EVENING TEMPERATURE DECLINE AND SOME OVERNIGHT LOWS
OVER THE FAR EAST AND NORTHEAST COUNTIES...OTHERWISE...THE REST
OF THE FORECAST LOOKS ON TARGET. SHOULD HAVE THE UPDATE OUT BY
900 PM.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.


&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 280150
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
850 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 840 PM CDT MON APR 27 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING WILL CONTINUE TO BRING
QUIET WEATHER TO THE REGION FOR THE NEXT SEVERAL DAYS.
MEANWHILE...ALL THE ACTIVE WEATHER IS LOCATED OVER THE SOUTHERN
PLAINS AS AN UPPER LEVEL STORM SLOWLY TRACKS EAST INTO THE LOWER
MISSISSIPPI VALLEY OVER THE NEXT SEVERAL DAYS...WELL SOUTH OF OUR
AREA. ONCE AGAIN...THE COMBINATION OF A MOSTLY CLEAR SKY AND
DIMINISHING WINDS SHOULD LEAD TO ANOTHER VERY CHILLY NIGHT ACROSS
THE FORECAST AREA WITH EARLY MORNING LOWS DIPPING INTO THE MID AND
UPPER 30S. THIS SHOULD BRING ABOUT ANOTHER THREAT FOR PATCHY FROST
OVER THE NORTHEAST THIRD OF THE FORECAST AREA...WHICH WILL BE
CLOSER TO THE SURFACE RIDGE AXIS. THE PRIMARY TIME OF CONCERN FOR
FROST WILL BE ROUGHLY FROM 200 AM THRU 700 AM WHERE SURFACE TEMPS
WILL BE IN THE 34 TO 37 DEGREE RANGE ACROSS THE NORTH AND EAST.
LIKE THIS MORNING...BETWEEN 730 AND 800 AM...WE SHOULD SEE THE
TEMPERATURES RAPIDLY RISE THEREAFTER. HAVE MADE SOME ADJUSTMENTS
TO THE EARLY EVENING TEMPERATURE DECLINE AND SOME OVERNIGHT LOWS
OVER THE FAR EAST AND NORTHEAST COUNTIES...OTHERWISE...THE REST
OF THE FORECAST LOOKS ON TARGET. SHOULD HAVE THE UPDATE OUT BY
900 PM.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.


&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KLOT 280126
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
826 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* NORTHEAST WINDS 10-15 KT DIMINISHING TO LESS THAN 10 KT AND
  BECOMING NORTH-NORTHEAST EARLY THIS EVENING. WINDS BECOMING
  NORTHEAST AGAIN TUESDAY...AROUND 10 KT WITH LAKE BREEZE IN THE
  AFTERNOON.

RATZER

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

NORTH-NORTHEAST WINDS CONTINUE THROUGH THE PERIOD WITH SURFACE
HIGH PRESSURE RIDGE STILL OFF TO THE NORTHWEST OF THE TERMINALS.
GRADIENT BECOMING WEAKER THAN THE PAST COUPLE OF DAYS HOWEVER...
WITH WINDS AROUND 10 KT TUESDAY. CHICAGO TERMINALS WILL SEE
TYPICAL AFTERNOON LAKE BREEZE PUSH...WITH NORTHEAST WINDS A BIT
OVER 10 KT AT TIMES IN THE AFTERNOON. OTHERWISE...VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.

RATZER


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

* HIGH FOR ALL ELEMENTS.

RATZER

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 280126
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
826 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* NORTHEAST WINDS 10-15 KT DIMINISHING TO LESS THAN 10 KT AND
  BECOMING NORTH-NORTHEAST EARLY THIS EVENING. WINDS BECOMING
  NORTHEAST AGAIN TUESDAY...AROUND 10 KT WITH LAKE BREEZE IN THE
  AFTERNOON.

RATZER

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

NORTH-NORTHEAST WINDS CONTINUE THROUGH THE PERIOD WITH SURFACE
HIGH PRESSURE RIDGE STILL OFF TO THE NORTHWEST OF THE TERMINALS.
GRADIENT BECOMING WEAKER THAN THE PAST COUPLE OF DAYS HOWEVER...
WITH WINDS AROUND 10 KT TUESDAY. CHICAGO TERMINALS WILL SEE
TYPICAL AFTERNOON LAKE BREEZE PUSH...WITH NORTHEAST WINDS A BIT
OVER 10 KT AT TIMES IN THE AFTERNOON. OTHERWISE...VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.

RATZER


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

* HIGH FOR ALL ELEMENTS.

RATZER

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

WEDNESDAY...VFR. NORTH-NORTHEAST WINDS.

THURSDAY...BRIEF PERIOD OF MVFR CIGS POSSIBLE...OTHERWISE VFR.
NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. WEST WINDS...EAST
LAKE BREEZE WINDS POSSIBLE IN THE AFTERNOON.

SATURDAY...VFR. SLIGHT CHANCE OF THUNDERSTORMS. SOUTHWEST WINDS.

SUNDAY...PRIMARILY VFR. CHANCE OF THUNDERSTORMS. SOUTH-SOUTHEAST
WINDS.

RATZER

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KILX 272308
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
608 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.

&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 272308
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
608 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.

&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 272308
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
608 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.

&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 272308
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
608 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.

&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 272308
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
608 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM CDT MON APR 27 2015

VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. HIGH
PRESSURE WILL REMAIN ANCHORED TO OUR NORTH THRU TUESDAY BRINGING
QUIET WEATHER TO THE FORECAST AREA WITH MAINLY SCATTERED CLOUDS
DURING THE AFTERNOON ALONG WITH A GUSTY NORTHEAST WIND. THOSE
WINDS QUICKLY DIMINISH DURING THE EVENING TO LESS THAN 5 KTS WITH
A MOSTLY CLEAR SKY OVERNIGHT. FORECAST SOUNDINGS SUGGEST THE
WIND TOMORROW MAY NOT BE QUITE AS GUSTY OUT OF THE NORTHEAST WITH
PREDOMINATE SPEEDS IN THE 8 TO 13 KT RANGE FOR MOST OF THE DAY.

&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KLOT 272203
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
503 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* NORTHEAST WINDS 030-050-ISH NEAR 15 KT LATE THIS AFTERNOON.

* WINDS DIMINISH AROUND SUNSET...BACKING MORE NORTH LESS THAN 10
  KT OVERNIGHT.

RATZER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH FOR ALL ELEMENTS.

RATZER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 272203
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
503 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* NORTHEAST WINDS 030-050-ISH NEAR 15 KT LATE THIS AFTERNOON.

* WINDS DIMINISH AROUND SUNSET...BACKING MORE NORTH LESS THAN 10
  KT OVERNIGHT.

RATZER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH FOR ALL ELEMENTS.

RATZER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 272203
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
503 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* NORTHEAST WINDS 030-050-ISH NEAR 15 KT LATE THIS AFTERNOON.

* WINDS DIMINISH AROUND SUNSET...BACKING MORE NORTH LESS THAN 10
  KT OVERNIGHT.

RATZER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH FOR ALL ELEMENTS.

RATZER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 272203
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
503 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* NORTHEAST WINDS 030-050-ISH NEAR 15 KT LATE THIS AFTERNOON.

* WINDS DIMINISH AROUND SUNSET...BACKING MORE NORTH LESS THAN 10
  KT OVERNIGHT.

RATZER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH FOR ALL ELEMENTS.

RATZER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 272003
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
303 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 272003
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
303 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
300 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

AS WE FLIP THE CALENDAR FROM APRIL TO MAY...THE DRY BENIGN
CONDITIONS AT THE END OF APRIL WILL TRANSITION TO A WARMER...MORE
HUMID...AND POTENTIALLY ACTIVE PATTERN. MID AND UPPER PATTERN WILL
BECOME GENERALLY ZONAL. WHILE STRONGER FLOW ALOFT WILL REMAIN NEAR
OR NORTH OF THE CANADIAN BORDER...MIDLEVEL SHORTWAVE ENERGY SHOULD
STILL PROPAGATE ACROSS THE REGION IN WARM ADVECTION REGIME ALSO
ACCOMPANIED BY LOW PRESSURE SYSTEMS DEVELOPING OVER PLAINS AND
WORKING THEIR WAY EAST-NORTHEAST. BETTER MOISTURE RETURN WILL ALSO
OCCUR AROUND PERIPHERY OF HIGH PRESSURE EXPECTED TO SETUP NEAR OR
OFF SOUTHEAST COAST OVER THE WEEKEND INTO EARLY NEXT WEEK.

END RESULT IN SENSIBLE WEATHER IS GENERALLY DRY DAY ON FRIDAY
WITH ONSHORE FLOW...BUT START OF WARM-UP WITH HIGHS OF ABOUT 65 TO
70 INLAND. MODEL THERMAL PROGS AND LOCAL CLIMO SUPPORTS HIGHS
INTO 70S SATURDAY THROUGH MONDAY...AND POSSIBLY WELL INTO 70S AT
THAT. GIVEN PROGGED MOISTURE RETURN/50+ DEWPOINTS IN THIS
PERIOD...SHOULD BE ENOUGH INSTABILITY TO SUPPORT OCCASIONAL
THUNDER CHANCES IN DISTURBED FLOW OVER THE WEEKEND INTO NEXT
WEEK...BUT POPS WILL UNDOUBTEDLY BE REFINED IN LATER FORECASTS.
UNCERTAINTY WITH HOW WARM TEMPERATURES MAY GET OVER THE WEEKEND
INTO EARLY NEXT WEEK WILL LIKELY BE TIED TO IMPACT OF CLOUDS AND
PRECIP...AND ANY DAYS THAT HAVE ONSHORE FLOW.

RC

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KILX 271957
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
257 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

&&

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 104 PM CDT MON APR 27 2015

VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING LIGHT
AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS...WITH A SCT CU FIELD DEVELOPING BTWN 4500 AND 5000 FT.  WILL
WATCH CLOSELY FOR THE XOVER VALUES THIS AFTERNOON, BUT SO FAR,
WINDS SHOULD STAY UP JUST ENOUGH TO COUNTER FOG DEVELOPMENT
TONIGHT, SIMILAR TO LAST NIGHT. KEEPING VFR THROUGHOUT.


&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...HJS



000
FXUS63 KILX 271957
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
257 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

&&

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 104 PM CDT MON APR 27 2015

VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING LIGHT
AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS...WITH A SCT CU FIELD DEVELOPING BTWN 4500 AND 5000 FT.  WILL
WATCH CLOSELY FOR THE XOVER VALUES THIS AFTERNOON, BUT SO FAR,
WINDS SHOULD STAY UP JUST ENOUGH TO COUNTER FOG DEVELOPMENT
TONIGHT, SIMILAR TO LAST NIGHT. KEEPING VFR THROUGHOUT.


&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...HJS




000
FXUS63 KILX 271957
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
257 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

&&

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 104 PM CDT MON APR 27 2015

VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING LIGHT
AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS...WITH A SCT CU FIELD DEVELOPING BTWN 4500 AND 5000 FT.  WILL
WATCH CLOSELY FOR THE XOVER VALUES THIS AFTERNOON, BUT SO FAR,
WINDS SHOULD STAY UP JUST ENOUGH TO COUNTER FOG DEVELOPMENT
TONIGHT, SIMILAR TO LAST NIGHT. KEEPING VFR THROUGHOUT.


&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...HJS




000
FXUS63 KILX 271957
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
257 PM CDT MON APR 27 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT MON APR 27 2015

HIGH PRESSURE DOMINATING CENTRAL ILLINOIS AGAIN FOR
TONIGHT. NORTHERLY WINDS WILL BECOME LIGHT AND SOMEWHAT VARIABLE
TONIGHT AS THE RIDGE AXIS MOVES OVER THE REGION. EFFICIENT
RADIATIONAL COOLING SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET
AGAIN. SWRN PORTIONS OF THE CWA MAY REACH TOWARDS A LOW OF 40,
LIMITING THE POTENTIAL FOR FROST.  NERN CWA NOT  AS WARM AND PATCHY
FROST STILL LIKELY. WILL HAVE TO WATCH XOVER TEMPS LATER THIS
AFTERNOON, BUT WINDS SHOULD STAY UP A LITTLE BIT AND PREVENT A BIG
DROP IN VIS.

&&

.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 256 PM CDT MON APR 27 2015

NORTH-NORTHEASTERLY FLOW CONTINUES TO PUSH COOLER THAN NORMAL AIR
INTO CENTRAL IL AND WILL KEEP A VERY SLOW WARMING TREND GOING
THROUGH WEDNESDAY. AFTER A COOL MORNING TUESDAY WITH LOWS IN THE
UPPER 30S IN MUCH OF CENTRAL IL...HIGHS WILL REACH THE MID 60S
TUESDAY AND AGAIN WEDNESDAY...WITH LIGHT NORTH-NORTHEAST BREEZES.

FAIRLY COMPLICATED PATTERN SETTING UP FOR WEDNESDAY INTO THURSDAY AS
A DEEP UPPER LOW PASSES BY THROUGH THE SOUTHERN STATES AND A
CANADIAN SHORTWAVE LOOKS AS THOUGH IT WILL DROP RAPIDLY SOUTHWARD AS
IT BECOMES BLOCKED BY A DEEP LOW OFF THE NOVA SCOTIA COAST. CURRENT
MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE UPPER LOW SOUTH
THROUGH INDIANA WEDNESDAY NIGHT...PUSHING A COLD FRONT INTO
ILLINOIS...AND PERHAPS PRODUCING SOME LIGHT PRECIPITATION IN THE
REGION. GIVEN THE WIDE VARIATIONS IN MODEL HANDLING OF THIS FEATURE
THE PAST FEW DAYS...HAVE HELD OFF INTRODUCING POPS INTO THE FORECAST
BUT HAVE TRIMMED BACK HIGHS FOR THURSDAY AS THIS COULD TURN OUT TO
BE A COOL BREEZY DAY.

THROUGH THE WEEKEND...MODERATELY STRONG ZONAL WILL SET UP OVER THE
NORTHERN U.S. WHILE SOUTHERLY LOW LEVEL FLOW OVER THE PLAINS
TRANSPORTS GULF MOISTURE NORTHWARD. ENOUGH MOISTURE AND INSTABILITY
WILL MOVE INTO CENTRAL IL FOR CHANCES OF SHOWERS AND THUNDERSTORMS
DEVELOPING FRIDAY NIGHT THROUGH THE WEEKEND AS UPPER LEVEL
DISTURBANCES INTERACT WITH THE MOISTURE AND INSTABILITY. WARM
TEMPERATURES EXPECTED THROUGH THIS PERIOD WITH HIGHS IN THE 70S AND
LOWS MAINLY 50S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 104 PM CDT MON APR 27 2015

VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING LIGHT
AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS...WITH A SCT CU FIELD DEVELOPING BTWN 4500 AND 5000 FT.  WILL
WATCH CLOSELY FOR THE XOVER VALUES THIS AFTERNOON, BUT SO FAR,
WINDS SHOULD STAY UP JUST ENOUGH TO COUNTER FOG DEVELOPMENT
TONIGHT, SIMILAR TO LAST NIGHT. KEEPING VFR THROUGHOUT.


&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...HJS



000
FXUS63 KLOT 271950
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
250 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
246 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

WILL BE ISSUED SHORTLY.

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 271950
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
250 PM CDT MON APR 27 2015

.SHORT TERM...
250 PM CDT

THROUGH THURSDAY...

A QUIET FORECAST CYCLE CONTINUES WITH A SLOW MOVING UPPER PATTERN
AND THUS SURFACE REFLECTION ACROSS THE AREA. THIS IS PREVENTING
TEMPERATURES FROM CLIMBING BACK TO NORMAL AT A MORE SPEEDY RATE
ACROSS MOST OF THE FORECAST AREA WITH NORTHERLY LOW-LEVEL WINDS
PERSISTING AND THUS LAKE INFLUENCE CONTINUING MODIFY THE AIR MASS
SOME. A 16 DEGREE RANGE IS SEEN ACROSS THE FORECAST AREA AS OF 230
PM THIS AFTERNOON FROM LAKESIDE OF 47 DEGREES TO 63 OUT IN PARTS
OF NORTH CENTRAL ILLINOIS. THIS SIMILARLY IS EXPECTED TO RESULT A
GOOD PART OF THE WORKWEEK.

GIVEN THE ANTICIPATED SURFACE RIDGE PLACEMENT LATER TONIGHT FROM THE
U.P. OF MICHIGAN THROUGH EASTERN IOWA...LESS WIND IS FORECAST THAN
LAST...ALTHOUGH STILL A SLIGHT COMPONENT IS EXPECTED THIS EVE.
CONDITIONS WARRANT A SLIGHTLY BETTER FROST POTENTIAL THAN LAST
NIGHT IN EXPOSED AREAS...BUT CONSIDERING THAT TEMPERATURES DID NOT
DROP AS FAR LAST NIGHT IN MANY PLACES AS ANTICIPATED...STILL
MARGINAL CONFIDENCE FOR AN ADVISORY. PATCHY TO SOME AREAS OF FROST
ARE MENTIONED IN THE FORECAST ALONG WITH OUR OTHER MESSAGING WHICH
SHOULD SUFFICE.

GUIDANCE HAS TRENDED STRONGER WITH A BUCKLE IN THE NORTHERN FLOW OF
THE JET STREAM ON WEDNESDAY. THE FORCING FOR ANY RAIN REMAINS
WEAK...BUT THE LOW-LEVEL REFLECTION OF COOLER AIR ADVECTING IN
LOOKS MORE PRONOUNCED WEDNESDAY NIGHT INTO THURSDAY AS A CLOSED
UPPER LOW IS FORECAST NOW OVER LAKE MICHIGAN DROPPING SOUTHWARD.
THIS PATTERN SHOULD RESULT IN MORE CLOUDS DURING THAT
PERIOD...ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN DURING THE
AFTERNOON. HAVE HIGHS ON THURSDAY SIMILAR TO WHAT THEY WERE TODAY
WITH SYNOPTIC NORTHEAST WINDS.

MTF

&&

.LONG TERM...
246 PM CDT

THURSDAY NIGHT THROUGH MONDAY...

WILL BE ISSUED SHORTLY.

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORTHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 271912
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
212 PM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 271912
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
212 PM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 271912
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
212 PM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 271912
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
212 PM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER

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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
212 PM CDT

HIGH PRESSURE WILL CONTINUE TO EXPAND OVER THE NORTHERN UNITED
STATES IN THE COMING DAYS. WINDS WILL LIGHTEN UP SOME AS THIS
OCCURS...WHICH SHOULD ALLOW WAVES TO SUBSIDE ALONG THE SOUTHERN
TIP OF THE LAKE. WAVES HAVE BEEN HOLDING AROUND 4-5 FT ALONG THE
NEARSHORE...SO WILL LET THE ADVISORY RIDE THROUGH THE EVENING. THE
CORE OF HIGH PRESSURE WILL REMAIN NORTH OF THE AREA THROUGH
MIDWEEK. MEANWHILE...LOW PRESSURE WILL MOVE EAST ALONG THE GULF
COAST THROUGH THURSDAY. THEN NORHEAST ALONG THE ATLANTIC COAST
THURSDAY INTO FRIDAY. THIS WILL MAINTAIN NORTH-NORTHEAST WINDS
ACROSS THE LAKE MOST OF THE WEEK...WITH AN UPTICK EXPECTED ON
THURSDAY AS THE SOUTHERN LOW DEEPENS SLIGHTLY. THE HIGH WILL MOVE
OVERHEAD FRIDAY FOR A LAKE BREEZE CIRCULATION DOMINATED WIND
FIELD.

KMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KILX 271807
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
107 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 1049 AM CDT MON APR 27 2015

MOSTLY SUNNY FOR THE MAJORITY OF CENTRAL ILLINOIS, WITH SOME
CIRRUS STREAMING ACROSS THE SOUTH AND SOUTHEAST. HIGH PRESSURE
BUILDING IN AND TEMPERATURES ON THEIR WAY TO A DEGREE OR TWO
WARMER THAN YESTERDAY IN MOST PLACES. QUIET WEATHER DOMINATES WITH
BREEZY CONDITIONS OUT OF THE NORTH/NORTHEAST. NO UPDATES TO THE
FORECAST ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 104 PM CDT MON APR 27 2015

VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING LIGHT
AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS...WITH A SCT CU FIELD DEVELOPING BTWN 4500 AND 5000 FT.  WILL
WATCH CLOSELY FOR THE XOVER VALUES THIS AFTERNOON, BUT SO FAR,
WINDS SHOULD STAY UP JUST ENOUGH TO COUNTER FOG DEVELOPMENT
TONIGHT, SIMILAR TO LAST NIGHT. KEEPING VFR THROUGHOUT.

&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...HJS




000
FXUS63 KILX 271807
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
107 PM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 1049 AM CDT MON APR 27 2015

MOSTLY SUNNY FOR THE MAJORITY OF CENTRAL ILLINOIS, WITH SOME
CIRRUS STREAMING ACROSS THE SOUTH AND SOUTHEAST. HIGH PRESSURE
BUILDING IN AND TEMPERATURES ON THEIR WAY TO A DEGREE OR TWO
WARMER THAN YESTERDAY IN MOST PLACES. QUIET WEATHER DOMINATES WITH
BREEZY CONDITIONS OUT OF THE NORTH/NORTHEAST. NO UPDATES TO THE
FORECAST ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 104 PM CDT MON APR 27 2015

VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING LIGHT
AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS...WITH A SCT CU FIELD DEVELOPING BTWN 4500 AND 5000 FT.  WILL
WATCH CLOSELY FOR THE XOVER VALUES THIS AFTERNOON, BUT SO FAR,
WINDS SHOULD STAY UP JUST ENOUGH TO COUNTER FOG DEVELOPMENT
TONIGHT, SIMILAR TO LAST NIGHT. KEEPING VFR THROUGHOUT.

&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...HJS



000
FXUS63 KLOT 271744
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1244 PM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER


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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 271744
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1244 PM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER


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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 271744
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1244 PM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER


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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 271744
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1244 PM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS FROM 030-050 DIR THRU SUNSET WITH OCCASIONAL
  GUSTS TO 22KT.

* GUSTS DIMINISH ARND SUNSET...WIND DIR REMAINS 020-040 THRU TUE
  MORNING.

BEACHLER

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

HIGH PRESSURE CENTERED NORTHWEST OF THE REGION WILL MAINTAIN A
NORTHEAST WIND DIR THIS AFTN THRU TUE...WITH OCCASIONAL GUSTS
UNTIL SUNSET TONIGHT UP TO 22KT. VISIBLE IMAGERY THIS AFTN SHOWS A
CHANNEL OF SCT/BKN DECK AT 4KFT AGL...HOWEVER THIS CLOUD DECK WAS
THINNING AS THE AFTN PROGRESSES. EXPECT ONLY A FEW CLOUDS LATER
THIS EVENING EXCEPT FOR A FEW CIRRUS OVERNIGHT. WINDS WILL REMAIN
NORTHEASTERLY FOR TUE...HOWEVER THE GRADIENT LOOKS TO BE LESS WITH
HIGH PRESSURE DRIFTING CLOSER TO THE REGION.

BEACHLER


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

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 271628
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1128 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT THIS AFTERNOON.

BEACHLER

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN
RESULT IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH
GUSTS POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE
SURFACE PRESSURE GRADIENT WILL WEAKEN TONIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 271628
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1128 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT THIS AFTERNOON.

BEACHLER

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN
RESULT IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH
GUSTS POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE
SURFACE PRESSURE GRADIENT WILL WEAKEN TONIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 271628
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1128 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT THIS AFTERNOON.

BEACHLER

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN
RESULT IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH
GUSTS POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE
SURFACE PRESSURE GRADIENT WILL WEAKEN TONIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 271628
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1128 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT THIS AFTERNOON.

BEACHLER

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN
RESULT IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH
GUSTS POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE
SURFACE PRESSURE GRADIENT WILL WEAKEN TONIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KILX 271553
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 1049 AM CDT MON APR 27 2015

MOSTLY SUNNY FOR THE MAJORITY OF CENTRAL ILLINOIS, WITH SOME
CIRRUS STREAMING ACROSS THE SOUTH AND SOUTHEAST. HIGH PRESSURE
BUILDING IN AND TEMPERATURES ON THEIR WAY TO A DEGREE OR TWO
WARMER THAN YESTERDAY IN MOST PLACES. QUIET WEATHER DOMINATES WITH
BREEZY CONDITIONS OUT OF THE NORTH/NORTHEAST. NO UPDATES TO THE
FORECAST ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.


&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER



000
FXUS63 KILX 271553
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 1049 AM CDT MON APR 27 2015

MOSTLY SUNNY FOR THE MAJORITY OF CENTRAL ILLINOIS, WITH SOME
CIRRUS STREAMING ACROSS THE SOUTH AND SOUTHEAST. HIGH PRESSURE
BUILDING IN AND TEMPERATURES ON THEIR WAY TO A DEGREE OR TWO
WARMER THAN YESTERDAY IN MOST PLACES. QUIET WEATHER DOMINATES WITH
BREEZY CONDITIONS OUT OF THE NORTH/NORTHEAST. NO UPDATES TO THE
FORECAST ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.


&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER



000
FXUS63 KILX 271553
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 1049 AM CDT MON APR 27 2015

MOSTLY SUNNY FOR THE MAJORITY OF CENTRAL ILLINOIS, WITH SOME
CIRRUS STREAMING ACROSS THE SOUTH AND SOUTHEAST. HIGH PRESSURE
BUILDING IN AND TEMPERATURES ON THEIR WAY TO A DEGREE OR TWO
WARMER THAN YESTERDAY IN MOST PLACES. QUIET WEATHER DOMINATES WITH
BREEZY CONDITIONS OUT OF THE NORTH/NORTHEAST. NO UPDATES TO THE
FORECAST ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.


&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER



000
FXUS63 KILX 271553
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 1049 AM CDT MON APR 27 2015

MOSTLY SUNNY FOR THE MAJORITY OF CENTRAL ILLINOIS, WITH SOME
CIRRUS STREAMING ACROSS THE SOUTH AND SOUTHEAST. HIGH PRESSURE
BUILDING IN AND TEMPERATURES ON THEIR WAY TO A DEGREE OR TWO
WARMER THAN YESTERDAY IN MOST PLACES. QUIET WEATHER DOMINATES WITH
BREEZY CONDITIONS OUT OF THE NORTH/NORTHEAST. NO UPDATES TO THE
FORECAST ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.


&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER



000
FXUS63 KILX 271553
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 1049 AM CDT MON APR 27 2015

MOSTLY SUNNY FOR THE MAJORITY OF CENTRAL ILLINOIS, WITH SOME
CIRRUS STREAMING ACROSS THE SOUTH AND SOUTHEAST. HIGH PRESSURE
BUILDING IN AND TEMPERATURES ON THEIR WAY TO A DEGREE OR TWO
WARMER THAN YESTERDAY IN MOST PLACES. QUIET WEATHER DOMINATES WITH
BREEZY CONDITIONS OUT OF THE NORTH/NORTHEAST. NO UPDATES TO THE
FORECAST ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.


&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER



000
FXUS63 KILX 271553
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT MON APR 27 2015

.UPDATE...
ISSUED AT 1049 AM CDT MON APR 27 2015

MOSTLY SUNNY FOR THE MAJORITY OF CENTRAL ILLINOIS, WITH SOME
CIRRUS STREAMING ACROSS THE SOUTH AND SOUTHEAST. HIGH PRESSURE
BUILDING IN AND TEMPERATURES ON THEIR WAY TO A DEGREE OR TWO
WARMER THAN YESTERDAY IN MOST PLACES. QUIET WEATHER DOMINATES WITH
BREEZY CONDITIONS OUT OF THE NORTH/NORTHEAST. NO UPDATES TO THE
FORECAST ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.


&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER




000
FXUS63 KLOT 271410
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
910 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT THIS AFTERNOON.

KJB/BEACHLER

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN
RESULT IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH
GUSTS POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE
SURFACE PRESSURE GRADIENT WILL WEAKEN TONIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

KJB/BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 271410
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
910 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT THIS AFTERNOON.

KJB/BEACHLER

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN
RESULT IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH
GUSTS POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE
SURFACE PRESSURE GRADIENT WILL WEAKEN TONIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

KJB/BEACHLER

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KILX 271138
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
638 AM CDT MON APR 27 2015

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.

&&

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

$$

SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER



000
FXUS63 KILX 271138
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
638 AM CDT MON APR 27 2015

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.

&&

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

$$

SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER



000
FXUS63 KILX 271138
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
638 AM CDT MON APR 27 2015

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.

&&

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

$$

SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER




000
FXUS63 KILX 271138
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
638 AM CDT MON APR 27 2015

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CDT MON APR 27 2015

VFR CONDITIONS CAN BE EXPECTED IN ALL OF CENTRAL AND EASTERN IL
THE NEXT 24 HOURS. THE RAP AND HRRR MODELS, ALONG WITH THE MANY OF
THE FORECAST SOUNDINGS, INDICATE ENOUGH LOW LEVEL MOISTURE AND
LIFT ON THE WESTERN EDGE OF A SHORTWAVE TROUGH ROTATING THROUGH
THE GREAT LAKES REGION TO PRODUCE SCATTERED CUMULUS IN THE EASTERN
HALF OF IL FROM LATE MORNING THROUGH THE AFTERNOON.

THE ONLY CONCERN FOR TODAY WILL BE WITH PERIODS OF WIND GUSTS
ANTICIPATED AS THE LOWER ATMOSPHERE MIXES FROM 15Z THROUGH 00/01Z.
THE RESULTING MOMENTUM TRANSFER WILL PRODUCE SUSTAINED NORTH
WINDS OF 12-15 KTS WITH GUSTS NEAR 20 KTS.

&&

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

$$

SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER




000
FXUS63 KLOT 271112
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
612 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT THIS AFTERNOON.

KJB

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN
RESULT IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH
GUSTS POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE
SURFACE PRESSURE GRADIENT WILL WEAKEN TONIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB


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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 271112
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
612 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT THIS AFTERNOON.

KJB

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN
RESULT IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH
GUSTS POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE
SURFACE PRESSURE GRADIENT WILL WEAKEN TONIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB


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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY NIGHT THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING EAST-SOUTHEAST IN THE
AFTERNOON.

SUNDAY...CHANCE OF TSRA. SOUTH WINDS.

KJB

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 270848
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
348 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT MONDAY AFTERNOON.

KJB

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

THE REGION WILL AGAIN REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN RESULT
IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH GUSTS
POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE SURFACE
PRESSURE GRADIENT WILL WEAKEN MONDAY NIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 270848
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
348 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT MONDAY AFTERNOON.

KJB

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

THE REGION WILL AGAIN REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN RESULT
IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH GUSTS
POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE SURFACE
PRESSURE GRADIENT WILL WEAKEN MONDAY NIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 270825
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
325 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT MONDAY AFTERNOON.

KJB

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

THE REGION WILL AGAIN REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN RESULT
IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH GUSTS
POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE SURFACE
PRESSURE GRADIENT WILL WEAKEN MONDAY NIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 270825
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
325 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT MONDAY AFTERNOON.

KJB

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

THE REGION WILL AGAIN REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN RESULT
IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH GUSTS
POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE SURFACE
PRESSURE GRADIENT WILL WEAKEN MONDAY NIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 270825
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
325 AM CDT MON APR 27 2015

.SHORT TERM...
320 AM CDT

THROUGH TUESDAY...

QUIET WEATHER IS EXPECTED OVER MUCH OF THE UPCOMING WEEK. FOR
MONDAY AND TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
ACROSS THE CANADIAN PRAIRIES AND UPPER MIDWEST. WEATHER TODAY WILL
BE ALMOST A CARBON COPY OF YESTERDAY OUTSIDE OF A FEW ADDITIONAL
CLOUDS. EXPECT A MODEST NORTH/NORTHEAST WIND TO KEEP CONDITIONS
COOL AROUND 50 ALONG THE LAKE FRONT...BUT EXPECT UPPER 50S TO
AROUND 60 INLAND. UPPER RIDGING WILL GRADUALLY BUILD ACROSS THE
GREAT LAKES WITH MID LEVEL TEMPS WARMING AS THE THERMAL TROUGH
GETS SHUNTED OFF TOWARDS THE EAST COAST. SURFACE WINDS WILL BE
LIGHTER ON TUESDAY BUT STILL EXPECT ONSHORE FLOW KEEPING TEMPS
LOWER ALONG THE LAKE FRONT. INLAND...EXPECT A 4-5 DEGREE WARMUP
WITH TEMPS IN THE LOW TO MID 60S.

BMD

&&

.LONG TERM...
320 AM CDT

WEDNESDAY THROUGH SUNDAY... TEMPERATURES WILL INCH A COUPLE
DEGREES WARMER ON WEDNESDAY AHEAD OF AN UPPER LEVEL DISTURBANCE
PROGGED TO DIVE INTO THE MIDWEST WEDNESDAY EVENING BRINGING AT
LEAST A GLANCING BLOW OF SLIGHTLY COOLER AIR. MODELS HAVE GONE
BACK AND FORTH ON CHANCES FOR SHOWERS WITH THIS SYSTEM. ECMWF IS
NOW DRY WHILE THE GFS PRODUCES SOME CONVECTIVE PRECIP ACROSS NORTH
CENTRAL IL. LOOKING AT SOUNDINGS THOUGH...WARM NOSE AROUND 700 MB
SHOULD CAP DEEP CONVECTION AND THE ARRIVAL OF THE COLDER AIR LOOKS
TO JUST MIX PEAK HEATING. SUPPOSE I CANT RULE OUT A FEW SPRINKLES
BUT GIVEN THE DRYNESS OF THE AIRMASS THE POSSIBILITY IS PRETTY
MINIMAL. MORE LIKELY WOULD EXPECT DEWPOINTS TO MIX DOWN FARTHER IN
THE AFTERNOON RESULTING IN HIGH BASED CU AND MAYBE VIRGA. AT ANY
RATE NOT WORTH MORE THAN A SILENT 10 POP. AFTER A SLIGHT STEP BACK
IN TEMPS THURSDAY WITH HIGHS IN THE LOW TO MID 60S...THE WARMING
TREND KICKS BACK INTO GEAR TO END THE WEEK AND HEAD INTO THE
WEEKEND WITH 70S SATURDAY AS THE SURFACE RIDGE MOVES TO OUR EAST
AND RETURN FLOW OVERSPREADS THE FORECAST AREA...AND THEN POSSIBLY
EVEN UPPER 70S SUNDAY. MODELS AGAIN TRY TO PRODUCE SOME CONVECTION
OVER THE WEEKEND THOUGH SYNOPTIC FORCING IS FAIRLY WEAK...MAINLY
SOME MODEST MID LEVEL WARM AIR ADVECTION. DETAILS ARE FUZZY THIS
FAR OUT GIVEN THE SUBTLETY OF THE FORCING.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT MONDAY AFTERNOON.

KJB

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

THE REGION WILL AGAIN REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN RESULT
IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH GUSTS
POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE SURFACE
PRESSURE GRADIENT WILL WEAKEN MONDAY NIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KILX 270805
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
305 AM CDT MON APR 27 2015

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

&&

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.


&&

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

$$

SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...SMITH



000
FXUS63 KILX 270805
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
305 AM CDT MON APR 27 2015

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

&&

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.


&&

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

$$

SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...SMITH




000
FXUS63 KILX 270805
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
305 AM CDT MON APR 27 2015

.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT MON APR 27 2015

A SURFACE RIDGE EXTENDING FROM A HIGH CENTERED IN WESTERN ONTARIO
INTO WEST CENTRAL IL WILL KEEP US COOL AND GENERALLY CLEAR TODAY.
THE RAP AND HRRR BOTH INDICATE THAT SCATTERED CLOUDS WILL DEVELOP IN
PARTS OF CENTRAL AND EASTERN IL BY EARLY THIS AFTERNOON...ESPECIALLY
IN EAST CENTRAL IL. IN ADDITION, PLENTY OF LOW LEVEL MIXING WILL
RESULT IN PERIODICALLY GUSTY NORTH WINDS THIS AFTERNOON. BECAUSE OF
THE SURFACE RIDGING AND A DEEP NORTHERLY FLOW...TEMPERATURES WILL
ONCE AGAIN RANGE FROM 5 TO 10 DEGREES BELOW SEASONAL NORMALS FOR
LATE APRIL.

&&

.LONG TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON APR 27 2015

GENERAL NORTH/NORTHEAST FLOW TO CONTINUE ACROSS THE REGION INTO MID
WEEK...AS AN UPPER LOW CURRENTLY JUST SOUTH OF NOVA SCOTIA CONTINUES
TO WOBBLE OFF THE NEW ENGLAND COAST. DESPITE THIS...HIGH
TEMPERATURES WILL BE WELL INTO THE 60S THE NEXT FEW DAYS.

UPPER LOW CURRENTLY OVER NEW MEXICO WILL DRIFT EAST INTO THE LOWER
MISSISSIPPI VALLEY...BUT THE PRECIPITATION WITH THIS FEATURE REMAINS
WELL TO OUR SOUTH. MEANWHILE...A LARGE UPPER WAVE OVER WESTERN
SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL BE REACHING THE
GREAT LAKES TUESDAY EVENING. EARLIER MODEL RUNS HAD BEEN STRUGGLING
WITH A PIECE OF ENERGY PINCHING OFF SOMEWHERE IN THE VICINITY AS THE
WAVE ARRIVED...BUT LATEST RUNS SHOW A SIZABLE UPPER LOW DROPPING
INTO LOWER MICHIGAN WEDNESDAY NIGHT. THIS WOULD BE SOMETHING TO
WATCH...AS THE CIRCULATION AROUND IT COULD RESULT IN SOME SHOWERS
OVER AT LEAST THE EASTERN CWA BY THURSDAY...BUT GENERAL CONSENSUS
NOW KEEPS THE PRECIPITATION JUST TO OUR EAST. HOWEVER, IT WILL
RESULT IN ANOTHER DAY OF HIGHS IN THE 60S...BEFORE A MORE
SUBSTANTIAL WARMING TREND TAKES PLACE FRIDAY/SATURDAY AS THE UPPER
FLOW TURNS MORE ZONAL. HIGHS WELL INTO THE 70S EXPECTED THIS WEEKEND.

WEEKEND PRECIPITATION CHANCES REMAIN A CHALLENGE...WITH THE GFS AND
ECMWF BOTH SHOWING SOME POTENTIAL FOR MCS ACTIVITY IN THE VICINITY
AS WEAK UPPER IMPULSES ZIP THROUGH. HAVE KEPT SATURDAY POP`S IN THE
SLIGHT CHANCE RANGE...WHILE INCREASING THEM ACROSS THE NORTHWEST ON
SUNDAY AS A STRONGER WAVE ARRIVES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.


&&

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

$$

SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...SMITH




000
FXUS63 KLOT 270720
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
220 AM CDT MON APR 27 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT MONDAY AFTERNOON.

KJB

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

THE REGION WILL AGAIN REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN RESULT
IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH GUSTS
POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE SURFACE
PRESSURE GRADIENT WILL WEAKEN MONDAY NIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB

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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
219 AM CDT

NORTHERLY WINDS UP AROUND 20 KT WILL CONTINUE OVER TODAY...AND DUE
TO THE PROLONGED ONSHORE FLOW OVER THE PAST FEW DAYS OVER THE
ILLINOIS AND INDIANA NEAR SHORES...I HAVE DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING. WAVES FROM THE
MICHIGAN CITY BUOY HAVE BEEN HOVERING RIGHT AROUND 4 FEET FOR THE
LAST SEVERAL HOURS...AND I DONT SEE ANY REASON WHY THESE WAVES WOULD
SUBSIDE MUCH GIVEN THE CONTINUED ONSHORE FLOW TODAY. THESE NORTHERLY
WINDS WILL EASE TONIGHT AS THE SURFACE RIDGE OF HIGH PRESSURE BEGINS
TO SHIFT OVER THE LAKE. THIS WILL SET UP LIGHTER ONSHORE LAKE BREEZE
INFLUENCED WINDS ON TUESDAY.

WIND SPEEDS COULD END UP INCREASING A BIT AGAIN OUT OF THE NORTH BY
LATE IN THE WEEK AS IT APPEARS THAT A LOW PRESSURE SYSTEM WILL OVER
THE NORTHEASTERN CONUS...AND THIS COULD SET UP ANOTHER ENHANCED
SURFACE GRADIENT SUPPORTIVE OF MODERATELY STRENGTH NORTHERLY WINDS
LATER WEDNESDAY AND THURSDAY. THIS COULD AGAIN CAUSE MY NEAR SHORE
WATERS TO FLIRT WITH SMALL CRAFT ADVISORY CRITERIA WAVES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 270455
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1155 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT MONDAY AFTERNOON.

KJB

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

THE REGION WILL AGAIN REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN RESULT
IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH GUSTS
POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE SURFACE
PRESSURE GRADIENT WILL WEAKEN MONDAY NIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB


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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 270455
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1155 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS WITH GUSTS OF 15 TO 20 KT MONDAY AFTERNOON.

KJB

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

THE REGION WILL AGAIN REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE
HIGH PRESSURE RIDGE OVER UPPER MIDWEST TODAY. THIS WILL AGAIN RESULT
IN A NORTHEASTERLY WIND COMPONENT AROUND 10-15 KTS WITH GUSTS
POTENTIALLY AS HIGH AS 20 KT GUSTS THIS AFTERNOON. THE SURFACE
PRESSURE GRADIENT WILL WEAKEN MONDAY NIGHT ALLOWING WINDS TO
DIMINISH BELOW 10 KTS. ASIDE FROM A DECK OF SCT TO PERHAPS BRIEFLY
BKN CLOUD COVER AT OR JUST ABOVE 3,000 FEET AGL DURING THE DAY
TODAY...VFR CONDITIONS ARE EXPECTED DURING THE PERIOD.

KJB


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

* HIGH FOR ALL ELEMENTS.

KJB

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KILX 270404
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1104 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 844 PM CDT SUN APR 26 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING CONTINUES TO FEED COOL AND
DRY AIR INTO THE REGION WITH TEMPERATURES QUICKLY FALLING THROUGH
INTO THE UPPER 40S TO LOWER 50S THIS PAST HOUR. THE COMBINATION
OF A CLEAR SKY AND LIGHT WINDS LATE TONIGHT SHOULD ALLOW
TEMPERATURES TO BOTTOM OUT IN THE MIDDLE TO UPPER 30S...WITH THE
COLDEST READINGS ACROSS THE NORTH AND EAST COUNTIES WHERE A FEW
OF OUR MORE FAVORED COLD SPOTS MAY SEE THE MERCURY BRIEFLY DIP
TO NEAR FREEZING. THE PRIMARY TIME FRAME LOOKS TO BE IN THE 3AM
TO 7AM PERIOD WHERE WINDS WILL BE THE LIGHTEST...ESPECIALLY ALONG
AND NORTH OF I-74. AFTER THAT...WE SHOULD SEE TEMPERATURES RAPIDLY
WARM WITH ANOTHER NICE DAY SHAPING UP ON MONDAY...ALTHOUGH STILL
AVERAGING ABOUT 5 DEGREES BELOW NORMAL FOR THE LAST WEEK OF APRIL.
OTHER THAN THE USUAL ADJUSTMENTS TO THE EARLY EVENING TEMPERATURE
DECLINE...NO OTHER CHANGES WERE MADE TO THE CURRENT ZFP. AS A
RESULT...NO EVENING ZFP UPDATE WILL BE NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 270404
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1104 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 844 PM CDT SUN APR 26 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING CONTINUES TO FEED COOL AND
DRY AIR INTO THE REGION WITH TEMPERATURES QUICKLY FALLING THROUGH
INTO THE UPPER 40S TO LOWER 50S THIS PAST HOUR. THE COMBINATION
OF A CLEAR SKY AND LIGHT WINDS LATE TONIGHT SHOULD ALLOW
TEMPERATURES TO BOTTOM OUT IN THE MIDDLE TO UPPER 30S...WITH THE
COLDEST READINGS ACROSS THE NORTH AND EAST COUNTIES WHERE A FEW
OF OUR MORE FAVORED COLD SPOTS MAY SEE THE MERCURY BRIEFLY DIP
TO NEAR FREEZING. THE PRIMARY TIME FRAME LOOKS TO BE IN THE 3AM
TO 7AM PERIOD WHERE WINDS WILL BE THE LIGHTEST...ESPECIALLY ALONG
AND NORTH OF I-74. AFTER THAT...WE SHOULD SEE TEMPERATURES RAPIDLY
WARM WITH ANOTHER NICE DAY SHAPING UP ON MONDAY...ALTHOUGH STILL
AVERAGING ABOUT 5 DEGREES BELOW NORMAL FOR THE LAST WEEK OF APRIL.
OTHER THAN THE USUAL ADJUSTMENTS TO THE EARLY EVENING TEMPERATURE
DECLINE...NO OTHER CHANGES WERE MADE TO THE CURRENT ZFP. AS A
RESULT...NO EVENING ZFP UPDATE WILL BE NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KILX 270404
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1104 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 844 PM CDT SUN APR 26 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING CONTINUES TO FEED COOL AND
DRY AIR INTO THE REGION WITH TEMPERATURES QUICKLY FALLING THROUGH
INTO THE UPPER 40S TO LOWER 50S THIS PAST HOUR. THE COMBINATION
OF A CLEAR SKY AND LIGHT WINDS LATE TONIGHT SHOULD ALLOW
TEMPERATURES TO BOTTOM OUT IN THE MIDDLE TO UPPER 30S...WITH THE
COLDEST READINGS ACROSS THE NORTH AND EAST COUNTIES WHERE A FEW
OF OUR MORE FAVORED COLD SPOTS MAY SEE THE MERCURY BRIEFLY DIP
TO NEAR FREEZING. THE PRIMARY TIME FRAME LOOKS TO BE IN THE 3AM
TO 7AM PERIOD WHERE WINDS WILL BE THE LIGHTEST...ESPECIALLY ALONG
AND NORTH OF I-74. AFTER THAT...WE SHOULD SEE TEMPERATURES RAPIDLY
WARM WITH ANOTHER NICE DAY SHAPING UP ON MONDAY...ALTHOUGH STILL
AVERAGING ABOUT 5 DEGREES BELOW NORMAL FOR THE LAST WEEK OF APRIL.
OTHER THAN THE USUAL ADJUSTMENTS TO THE EARLY EVENING TEMPERATURE
DECLINE...NO OTHER CHANGES WERE MADE TO THE CURRENT ZFP. AS A
RESULT...NO EVENING ZFP UPDATE WILL BE NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KILX 270404
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1104 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 844 PM CDT SUN APR 26 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING CONTINUES TO FEED COOL AND
DRY AIR INTO THE REGION WITH TEMPERATURES QUICKLY FALLING THROUGH
INTO THE UPPER 40S TO LOWER 50S THIS PAST HOUR. THE COMBINATION
OF A CLEAR SKY AND LIGHT WINDS LATE TONIGHT SHOULD ALLOW
TEMPERATURES TO BOTTOM OUT IN THE MIDDLE TO UPPER 30S...WITH THE
COLDEST READINGS ACROSS THE NORTH AND EAST COUNTIES WHERE A FEW
OF OUR MORE FAVORED COLD SPOTS MAY SEE THE MERCURY BRIEFLY DIP
TO NEAR FREEZING. THE PRIMARY TIME FRAME LOOKS TO BE IN THE 3AM
TO 7AM PERIOD WHERE WINDS WILL BE THE LIGHTEST...ESPECIALLY ALONG
AND NORTH OF I-74. AFTER THAT...WE SHOULD SEE TEMPERATURES RAPIDLY
WARM WITH ANOTHER NICE DAY SHAPING UP ON MONDAY...ALTHOUGH STILL
AVERAGING ABOUT 5 DEGREES BELOW NORMAL FOR THE LAST WEEK OF APRIL.
OTHER THAN THE USUAL ADJUSTMENTS TO THE EARLY EVENING TEMPERATURE
DECLINE...NO OTHER CHANGES WERE MADE TO THE CURRENT ZFP. AS A
RESULT...NO EVENING ZFP UPDATE WILL BE NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KILX 270404
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1104 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 844 PM CDT SUN APR 26 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING CONTINUES TO FEED COOL AND
DRY AIR INTO THE REGION WITH TEMPERATURES QUICKLY FALLING THROUGH
INTO THE UPPER 40S TO LOWER 50S THIS PAST HOUR. THE COMBINATION
OF A CLEAR SKY AND LIGHT WINDS LATE TONIGHT SHOULD ALLOW
TEMPERATURES TO BOTTOM OUT IN THE MIDDLE TO UPPER 30S...WITH THE
COLDEST READINGS ACROSS THE NORTH AND EAST COUNTIES WHERE A FEW
OF OUR MORE FAVORED COLD SPOTS MAY SEE THE MERCURY BRIEFLY DIP
TO NEAR FREEZING. THE PRIMARY TIME FRAME LOOKS TO BE IN THE 3AM
TO 7AM PERIOD WHERE WINDS WILL BE THE LIGHTEST...ESPECIALLY ALONG
AND NORTH OF I-74. AFTER THAT...WE SHOULD SEE TEMPERATURES RAPIDLY
WARM WITH ANOTHER NICE DAY SHAPING UP ON MONDAY...ALTHOUGH STILL
AVERAGING ABOUT 5 DEGREES BELOW NORMAL FOR THE LAST WEEK OF APRIL.
OTHER THAN THE USUAL ADJUSTMENTS TO THE EARLY EVENING TEMPERATURE
DECLINE...NO OTHER CHANGES WERE MADE TO THE CURRENT ZFP. AS A
RESULT...NO EVENING ZFP UPDATE WILL BE NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KILX 270404
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1104 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 844 PM CDT SUN APR 26 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING CONTINUES TO FEED COOL AND
DRY AIR INTO THE REGION WITH TEMPERATURES QUICKLY FALLING THROUGH
INTO THE UPPER 40S TO LOWER 50S THIS PAST HOUR. THE COMBINATION
OF A CLEAR SKY AND LIGHT WINDS LATE TONIGHT SHOULD ALLOW
TEMPERATURES TO BOTTOM OUT IN THE MIDDLE TO UPPER 30S...WITH THE
COLDEST READINGS ACROSS THE NORTH AND EAST COUNTIES WHERE A FEW
OF OUR MORE FAVORED COLD SPOTS MAY SEE THE MERCURY BRIEFLY DIP
TO NEAR FREEZING. THE PRIMARY TIME FRAME LOOKS TO BE IN THE 3AM
TO 7AM PERIOD WHERE WINDS WILL BE THE LIGHTEST...ESPECIALLY ALONG
AND NORTH OF I-74. AFTER THAT...WE SHOULD SEE TEMPERATURES RAPIDLY
WARM WITH ANOTHER NICE DAY SHAPING UP ON MONDAY...ALTHOUGH STILL
AVERAGING ABOUT 5 DEGREES BELOW NORMAL FOR THE LAST WEEK OF APRIL.
OTHER THAN THE USUAL ADJUSTMENTS TO THE EARLY EVENING TEMPERATURE
DECLINE...NO OTHER CHANGES WERE MADE TO THE CURRENT ZFP. AS A
RESULT...NO EVENING ZFP UPDATE WILL BE NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 26 2015

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY NIGHT. HIGH PRESSURE
WILL DOMINATE THE WEATHER ACROSS THE AREA BRINGING A MOSTLY CLEAR
SKY AND LIGHT WINDS TONIGHT...WITH THE SURFACE WINDS BECOMING
NORTHEAST ON MONDAY AT 10 TO 15 KTS WITH AN OCCASIONAL GUST UP TO
20 KTS POSSIBLE BY LATE MORNING THRU THE AFTERNOON HOURS. WINDS
WILL DIMINISH TO AROUND 5 KTS OR LESS AFTER 00Z.

&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KLOT 270300
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1000 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTH WINDS LESS THAN 10 KT OVERNIGHT...INCREASING TO 10-15 KT
  WITH A FEW HIGHER GUSTS MID/LATE MORNING MONDAY.

* POTENTIAL FOR BRIEF PERIOD OF HIGH-END MVFR CEILINGS MONDAY
  MORNING-EARLY AFTERNOON.

RATZER

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

TERMINALS WILL REMAIN SOUTHEAST OF SURFACE HIGH PRESSURE OVER
ONTARIO AND THE UPPER MIDWEST THROUGH THE TAF PERIOD. SIMILAR WIND
TREND EXPECTED MONDAY AS TODAY...THOUGH LIKELY A LITTLE LOWER
SPEED/GUSTS. LIGHT WINDS OVERNIGHT MAY SHIFT TO 340-350 DEG...BUT
EXPECTED TO BE PRIMARILY NORTH-NORTHEAST DURING DAYTIME HOURS.

PRIMARILY VFR CONDITIONS EXPECTED THROUGH THE PERIOD...THOUGH LOW
LEVEL MOISTURE WRAPPING SOUTH AROUND LOW PRESSURE SYSTEM OFF NEW
ENGLAND COAST WILL SWIPE AREA MONDAY AND MAY PRODUCE BRIEF PERIOD
OF HIGH-END MVFR CEILINGS MONDAY MORNING/EARLY AFTERNOON...THOUGH
FORECAST SOUNDINGS INDICATE FAIRLY SHALLOW MOIST LAYER WITH LOW
CONFIDENCE IN A PERSISTENT CEILING OVER TERMINALS. CLOUDS LIKELY
LIFT TO VFR ESPECIALLY INLAND IN THE AFTERNOON...AND SCATTER BY
MONDAY EVENING.

RATZER

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

* LOW IN MVFR CIGS MONDAY...THOUGH HIGH ANY CIG WILL BE ABOVE
  1500 FT.

* HIGH ALL OTHER ELEMENTS.

RATZER

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 270300
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1000 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTH WINDS LESS THAN 10 KT OVERNIGHT...INCREASING TO 10-15 KT
  WITH A FEW HIGHER GUSTS MID/LATE MORNING MONDAY.

* POTENTIAL FOR BRIEF PERIOD OF HIGH-END MVFR CEILINGS MONDAY
  MORNING-EARLY AFTERNOON.

RATZER

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

TERMINALS WILL REMAIN SOUTHEAST OF SURFACE HIGH PRESSURE OVER
ONTARIO AND THE UPPER MIDWEST THROUGH THE TAF PERIOD. SIMILAR WIND
TREND EXPECTED MONDAY AS TODAY...THOUGH LIKELY A LITTLE LOWER
SPEED/GUSTS. LIGHT WINDS OVERNIGHT MAY SHIFT TO 340-350 DEG...BUT
EXPECTED TO BE PRIMARILY NORTH-NORTHEAST DURING DAYTIME HOURS.

PRIMARILY VFR CONDITIONS EXPECTED THROUGH THE PERIOD...THOUGH LOW
LEVEL MOISTURE WRAPPING SOUTH AROUND LOW PRESSURE SYSTEM OFF NEW
ENGLAND COAST WILL SWIPE AREA MONDAY AND MAY PRODUCE BRIEF PERIOD
OF HIGH-END MVFR CEILINGS MONDAY MORNING/EARLY AFTERNOON...THOUGH
FORECAST SOUNDINGS INDICATE FAIRLY SHALLOW MOIST LAYER WITH LOW
CONFIDENCE IN A PERSISTENT CEILING OVER TERMINALS. CLOUDS LIKELY
LIFT TO VFR ESPECIALLY INLAND IN THE AFTERNOON...AND SCATTER BY
MONDAY EVENING.

RATZER

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

* LOW IN MVFR CIGS MONDAY...THOUGH HIGH ANY CIG WILL BE ABOVE
  1500 FT.

* HIGH ALL OTHER ELEMENTS.

RATZER

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KILX 270152
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
852 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 844 PM CDT SUN APR 26 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING CONTINUES TO FEED COOL AND
DRY AIR INTO THE REGION WITH TEMPERATURES QUICKLY FALLING THROUGH
INTO THE UPPER 40S TO LOWER 50S THIS PAST HOUR. THE COMBINATION
OF A CLEAR SKY AND LIGHT WINDS LATE TONIGHT SHOULD ALLOW
TEMPERATURES TO BOTTOM OUT IN THE MIDDLE TO UPPER 30S...WITH THE
COLDEST READINGS ACROSS THE NORTH AND EAST COUNTIES WHERE A FEW
OF OUR MORE FAVORED COLD SPOTS MAY SEE THE MERCURY BRIEFLY DIP
TO NEAR FREEZING. THE PRIMARY TIME FRAME LOOKS TO BE IN THE 3AM
TO 7AM PERIOD WHERE WINDS WILL BE THE LIGHTEST...ESPECIALLY ALONG
AND NORTH OF I-74. AFTER THAT...WE SHOULD SEE TEMPERATURES RAPIDLY
WARM WITH ANOTHER NICE DAY SHAPING UP ON MONDAY...ALTHOUGH STILL
AVERAGING ABOUT 5 DEGREES BELOW NORMAL FOR THE LAST WEEK OF APRIL.
OTHER THAN THE USUAL ADJUSTMENTS TO THE EARLY EVENING TEMPERATURE
DECLINE...NO OTHER CHANGES WERE MADE TO THE CURRENT ZFP. AS A
RESULT...NO EVENING ZFP UPDATE WILL BE NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 600 PM CDT SUN APR 26 2015

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THIS FORECAST
PERIOD. HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE NEXT
SEVERAL DAYS BRINGING QUIET WEATHER TO THE MIDWEST. THIS WILL
RESULT IN A MOSTLY CLEAR SKY AND RATHER LIGHT NORTHERLY WINDS
TONIGHT...WITH NORTHEAST WINDS PICKING UP TO BETWEEN 10 TO
15 KTS LATE MONDAY MORNING THRU THE AFTERNOON HOURS.


&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 270152
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
852 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 844 PM CDT SUN APR 26 2015

HIGH PRESSURE TO OUR NORTH THIS EVENING CONTINUES TO FEED COOL AND
DRY AIR INTO THE REGION WITH TEMPERATURES QUICKLY FALLING THROUGH
INTO THE UPPER 40S TO LOWER 50S THIS PAST HOUR. THE COMBINATION
OF A CLEAR SKY AND LIGHT WINDS LATE TONIGHT SHOULD ALLOW
TEMPERATURES TO BOTTOM OUT IN THE MIDDLE TO UPPER 30S...WITH THE
COLDEST READINGS ACROSS THE NORTH AND EAST COUNTIES WHERE A FEW
OF OUR MORE FAVORED COLD SPOTS MAY SEE THE MERCURY BRIEFLY DIP
TO NEAR FREEZING. THE PRIMARY TIME FRAME LOOKS TO BE IN THE 3AM
TO 7AM PERIOD WHERE WINDS WILL BE THE LIGHTEST...ESPECIALLY ALONG
AND NORTH OF I-74. AFTER THAT...WE SHOULD SEE TEMPERATURES RAPIDLY
WARM WITH ANOTHER NICE DAY SHAPING UP ON MONDAY...ALTHOUGH STILL
AVERAGING ABOUT 5 DEGREES BELOW NORMAL FOR THE LAST WEEK OF APRIL.
OTHER THAN THE USUAL ADJUSTMENTS TO THE EARLY EVENING TEMPERATURE
DECLINE...NO OTHER CHANGES WERE MADE TO THE CURRENT ZFP. AS A
RESULT...NO EVENING ZFP UPDATE WILL BE NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 600 PM CDT SUN APR 26 2015

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THIS FORECAST
PERIOD. HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE NEXT
SEVERAL DAYS BRINGING QUIET WEATHER TO THE MIDWEST. THIS WILL
RESULT IN A MOSTLY CLEAR SKY AND RATHER LIGHT NORTHERLY WINDS
TONIGHT...WITH NORTHEAST WINDS PICKING UP TO BETWEEN 10 TO
15 KTS LATE MONDAY MORNING THRU THE AFTERNOON HOURS.


&&

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

$$

UPDATE...SMITH
SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KLOT 262338
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
638 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTH-NORTHEAST WINDS DIMINISHING BELOW 10 KT EARLY THIS
  EVENING...AND INCREASING NEAR 15 KT WITH A FEW HIGHER GUSTS
  MID/LATE MORNING MONDAY.

* POTENTIAL FOR BRIEF PERIOD OF HIGH-END MVFR CEILINGS MONDAY
  MORNING-EARLY AFTERNOON.

RATZER

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

TERMINALS WILL REMAIN SOUTHEAST OF SURFACE HIGH PRESSURE OVER
ONTARIO AND THE UPPER MIDWEST THROUGH THE TAF PERIOD. SIMILAR WIND
TREND EXPECTED MONDAY AS TODAY...THOUGH LIKELY A LITTLE LOWER
SPEED/GUSTS. LIGHT WINDS OVERNIGHT MAY SHIFT TO 340-350 DEG...BUT
EXPECTED TO BE PRIMARILY NORTH-NORTHEAST DURING DAYTIME HOURS.

PRIMARILY VFR CONDITIONS EXPECTED THROUGH THE PERIOD...THOUGH LOW
LEVEL MOISTURE WRAPPING SOUTH AROUND LOW PRESSURE SYSTEM OFF NEW
ENGLAND COAST WILL SWIPE AREA MONDAY AND MAY PRODUCE BRIEF PERIOD
OF HIGH-END MVFR CEILINGS MONDAY MORNING/EARLY AFTERNOON...THOUGH
FORECAST SOUNDINGS INDICATE FAIRLY SHALLOW MOIST LAYER WITH LOW
CONFIDENCE IN A PERSISTENT CEILING OVER TERMINALS. CLOUDS LIKELY
LIFT TO VFR ESPECIALLY INLAND IN THE AFTERNOON...AND SCATTER BY
MONDAY EVENING.

RATZER


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

* LOW IN MVFR CIGS MONDAY...THOUGH HIGH ANY CIG WILL BE ABOVE
  1500 FT.

* HIGH ALL OTHER ELEMENTS.

RATZER

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 262338
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
638 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTH-NORTHEAST WINDS DIMINISHING BELOW 10 KT EARLY THIS
  EVENING...AND INCREASING NEAR 15 KT WITH A FEW HIGHER GUSTS
  MID/LATE MORNING MONDAY.

* POTENTIAL FOR BRIEF PERIOD OF HIGH-END MVFR CEILINGS MONDAY
  MORNING-EARLY AFTERNOON.

RATZER

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

TERMINALS WILL REMAIN SOUTHEAST OF SURFACE HIGH PRESSURE OVER
ONTARIO AND THE UPPER MIDWEST THROUGH THE TAF PERIOD. SIMILAR WIND
TREND EXPECTED MONDAY AS TODAY...THOUGH LIKELY A LITTLE LOWER
SPEED/GUSTS. LIGHT WINDS OVERNIGHT MAY SHIFT TO 340-350 DEG...BUT
EXPECTED TO BE PRIMARILY NORTH-NORTHEAST DURING DAYTIME HOURS.

PRIMARILY VFR CONDITIONS EXPECTED THROUGH THE PERIOD...THOUGH LOW
LEVEL MOISTURE WRAPPING SOUTH AROUND LOW PRESSURE SYSTEM OFF NEW
ENGLAND COAST WILL SWIPE AREA MONDAY AND MAY PRODUCE BRIEF PERIOD
OF HIGH-END MVFR CEILINGS MONDAY MORNING/EARLY AFTERNOON...THOUGH
FORECAST SOUNDINGS INDICATE FAIRLY SHALLOW MOIST LAYER WITH LOW
CONFIDENCE IN A PERSISTENT CEILING OVER TERMINALS. CLOUDS LIKELY
LIFT TO VFR ESPECIALLY INLAND IN THE AFTERNOON...AND SCATTER BY
MONDAY EVENING.

RATZER


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

* LOW IN MVFR CIGS MONDAY...THOUGH HIGH ANY CIG WILL BE ABOVE
  1500 FT.

* HIGH ALL OTHER ELEMENTS.

RATZER

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 262338
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
638 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTH-NORTHEAST WINDS DIMINISHING BELOW 10 KT EARLY THIS
  EVENING...AND INCREASING NEAR 15 KT WITH A FEW HIGHER GUSTS
  MID/LATE MORNING MONDAY.

* POTENTIAL FOR BRIEF PERIOD OF HIGH-END MVFR CEILINGS MONDAY
  MORNING-EARLY AFTERNOON.

RATZER

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

TERMINALS WILL REMAIN SOUTHEAST OF SURFACE HIGH PRESSURE OVER
ONTARIO AND THE UPPER MIDWEST THROUGH THE TAF PERIOD. SIMILAR WIND
TREND EXPECTED MONDAY AS TODAY...THOUGH LIKELY A LITTLE LOWER
SPEED/GUSTS. LIGHT WINDS OVERNIGHT MAY SHIFT TO 340-350 DEG...BUT
EXPECTED TO BE PRIMARILY NORTH-NORTHEAST DURING DAYTIME HOURS.

PRIMARILY VFR CONDITIONS EXPECTED THROUGH THE PERIOD...THOUGH LOW
LEVEL MOISTURE WRAPPING SOUTH AROUND LOW PRESSURE SYSTEM OFF NEW
ENGLAND COAST WILL SWIPE AREA MONDAY AND MAY PRODUCE BRIEF PERIOD
OF HIGH-END MVFR CEILINGS MONDAY MORNING/EARLY AFTERNOON...THOUGH
FORECAST SOUNDINGS INDICATE FAIRLY SHALLOW MOIST LAYER WITH LOW
CONFIDENCE IN A PERSISTENT CEILING OVER TERMINALS. CLOUDS LIKELY
LIFT TO VFR ESPECIALLY INLAND IN THE AFTERNOON...AND SCATTER BY
MONDAY EVENING.

RATZER


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

* LOW IN MVFR CIGS MONDAY...THOUGH HIGH ANY CIG WILL BE ABOVE
  1500 FT.

* HIGH ALL OTHER ELEMENTS.

RATZER

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 262338
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
638 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTH-NORTHEAST WINDS DIMINISHING BELOW 10 KT EARLY THIS
  EVENING...AND INCREASING NEAR 15 KT WITH A FEW HIGHER GUSTS
  MID/LATE MORNING MONDAY.

* POTENTIAL FOR BRIEF PERIOD OF HIGH-END MVFR CEILINGS MONDAY
  MORNING-EARLY AFTERNOON.

RATZER

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

TERMINALS WILL REMAIN SOUTHEAST OF SURFACE HIGH PRESSURE OVER
ONTARIO AND THE UPPER MIDWEST THROUGH THE TAF PERIOD. SIMILAR WIND
TREND EXPECTED MONDAY AS TODAY...THOUGH LIKELY A LITTLE LOWER
SPEED/GUSTS. LIGHT WINDS OVERNIGHT MAY SHIFT TO 340-350 DEG...BUT
EXPECTED TO BE PRIMARILY NORTH-NORTHEAST DURING DAYTIME HOURS.

PRIMARILY VFR CONDITIONS EXPECTED THROUGH THE PERIOD...THOUGH LOW
LEVEL MOISTURE WRAPPING SOUTH AROUND LOW PRESSURE SYSTEM OFF NEW
ENGLAND COAST WILL SWIPE AREA MONDAY AND MAY PRODUCE BRIEF PERIOD
OF HIGH-END MVFR CEILINGS MONDAY MORNING/EARLY AFTERNOON...THOUGH
FORECAST SOUNDINGS INDICATE FAIRLY SHALLOW MOIST LAYER WITH LOW
CONFIDENCE IN A PERSISTENT CEILING OVER TERMINALS. CLOUDS LIKELY
LIFT TO VFR ESPECIALLY INLAND IN THE AFTERNOON...AND SCATTER BY
MONDAY EVENING.

RATZER


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

* LOW IN MVFR CIGS MONDAY...THOUGH HIGH ANY CIG WILL BE ABOVE
  1500 FT.

* HIGH ALL OTHER ELEMENTS.

RATZER

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

TUESDAY THROUGH THURSDAY. PRIMARILY VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT. SOUTHWEST WINDS
BECOMING EAST IN THE AFTERNOON.

SATURDAY...VFR. SOUTHWEST WINDS BECOMING SOUTHEAST IN THE
AFTERNOON.

RATZER

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KILX 262303
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
603 PM CDT SUN APR 26 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 600 PM CDT SUN APR 26 2015

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THIS FORECAST
PERIOD. HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE NEXT
SEVERAL DAYS BRINGING QUIET WEATHER TO THE MIDWEST. THIS WILL
RESULT IN A MOSTLY CLEAR SKY AND RATHER LIGHT NORTHERLY WINDS
TONIGHT...WITH NORTHEAST WINDS PICKING UP TO BETWEEN 10 TO
15 KTS LATE MONDAY MORNING THRU THE AFTERNOON HOURS.

&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH



000
FXUS63 KILX 262303
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
603 PM CDT SUN APR 26 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 600 PM CDT SUN APR 26 2015

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THIS FORECAST
PERIOD. HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE NEXT
SEVERAL DAYS BRINGING QUIET WEATHER TO THE MIDWEST. THIS WILL
RESULT IN A MOSTLY CLEAR SKY AND RATHER LIGHT NORTHERLY WINDS
TONIGHT...WITH NORTHEAST WINDS PICKING UP TO BETWEEN 10 TO
15 KTS LATE MONDAY MORNING THRU THE AFTERNOON HOURS.

&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...SMITH




000
FXUS63 KLOT 262203
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
503 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS GUSTING NEAR 25 KTS THROUGH LATE AFTN.

* POTENTIAL FOR MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ/RATZER

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

QUIET/DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AS HIGH
PRESSURE IN PLACE WILL REMAIN SITUATED ACROSS THE REGION.
GENERALLY CLEAR SKIES TODAY INTO TONIGHT COULD TRANSITION OVER TO
A PERIOD OF MVFR CEILINGS MONDAY MORNING. IF THIS WERE TO
OCCUR...THESE WOULD LIKELY CONTINUE INTO THE AFTERNOON AND BE
AROUND 2500 FT. NORTHEAST WINDS TODAY WILL CONTINUE AND DIMINISH
OVERNIGHT...BUT INCREASE ONCE AGAIN EARLY MONDAY MORNING.

RODRIGUEZ

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

* LOW IN MVFR CEILINGS MONDAY MORNING.

* HIGH IN ALL OTHER ELEMENTS.

RODRIGUEZ/RATZER

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 262203
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
503 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS GUSTING NEAR 25 KTS THROUGH LATE AFTN.

* POTENTIAL FOR MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ/RATZER

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

QUIET/DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AS HIGH
PRESSURE IN PLACE WILL REMAIN SITUATED ACROSS THE REGION.
GENERALLY CLEAR SKIES TODAY INTO TONIGHT COULD TRANSITION OVER TO
A PERIOD OF MVFR CEILINGS MONDAY MORNING. IF THIS WERE TO
OCCUR...THESE WOULD LIKELY CONTINUE INTO THE AFTERNOON AND BE
AROUND 2500 FT. NORTHEAST WINDS TODAY WILL CONTINUE AND DIMINISH
OVERNIGHT...BUT INCREASE ONCE AGAIN EARLY MONDAY MORNING.

RODRIGUEZ

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

* LOW IN MVFR CEILINGS MONDAY MORNING.

* HIGH IN ALL OTHER ELEMENTS.

RODRIGUEZ/RATZER

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KILX 262020
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
320 PM CDT SUN APR 26 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

&&

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.


&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...HJS




000
FXUS63 KILX 262020
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
320 PM CDT SUN APR 26 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

&&

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.


&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...HJS



000
FXUS63 KILX 262020
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
320 PM CDT SUN APR 26 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 319 PM CDT SUN APR 26 2015

HIGH PRESSURE BUILDING BACK INTO THE REGION TONIGHT WITH A RIDGE
AXIS JUST TO THE WEST...NORTHERLY WINDS WILL BECOME LIGHT AND
VARIABLE TONIGHT.  AS A RESULT, RATHER EFFICIENT RADIATIONAL COOLING
SET UP EXPECTED AS TEMPS DROP INTO THE 30S YET AGAIN.  TODAYS MIXING
WITH PLENTY OF SUNSHINE HAS DROPPED THE DEWPOINTS A BIT...BUT NOT
ENOUGH TO COUNTER THE POTENTIAL FOR FROST AS THE TEMPS APPROACH 35
DEGREES OR LESS IN THE NORTHERN TIER OF THE STATE.  WINDS WILL BE
LIGHTER IN THE WEST THAN THE EAST WHERE SOME SEMBLANCE OF A PRESSURE
GRADIENT STILL EXISTS.  SO...THE HIGHER RH AIRMASS IS COLOCATED WITH
WIND THAT WILL MITIGATE THE POTENTIAL FOR FOG DEVELOPMENT...AS LONG
AS THE WINDS HOLD OUT.  NO FOG MENTION FOR NOW...PATCHY FROST
POTENTIAL, PARTICULARLY IN LOW LYING AREAS...BUT NOT WIDESPREAD
ENOUGH AT THIS POINT TO WARRANT A HEADLINE.

&&

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 319 PM CDT SUN APR 26 2015

COOL AND DRY NORTHERLY FLOW WILL PRODUCE DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WORK
WEEK...THEN A HIGH PRESSURE RIDGE WILL SHIFT EASTWARD INTO THE
PLAINS AND MIDWEST LATE IN THE WEEK PRODUCING A CONTINUED WARMING
TREND INTO NEXT WEEKEND. TEMPERATURES SHOULD RISE TO ABOVE NORMAL BY
FRIDAY.

PATCHY MORNING FROST WILL START THE DAY FROM THE I-74 CORRIDOR
NORTHWARD MONDAY MORNING...THEN POTENTIALLY AGAIN TUESDAY
MORNING...HOWEVER WINDS MAY BE JUST ENOUGH TO KEEP FROST FROM
FORMING.

WEDNESDAY...MODELS ARE CONSISTENT MOVING A LOW ACROSS THE SOUTHERN
U.S. WHILE KEEPING PRECIPITATION JUST SOUTH OF THE CENTRAL/SE
ILLINOIS FORECAST AREA...WHILE ANOTHER NORTHERN STREAM WAVE PASSES
BY WELL TO THE NORTH. MAIN IMPACT FOR CENTRAL IL SHOULD BE INCREASED
CLOUDINESS.

AS THE LARGE SCALE RIDGE AXIS SHIFTS PAST CENTRAL IL OVER THE
WEEKEND...CHANCES FOR PRECIPITATION DEVELOP OVER THE WEEKEND AS
MOIST SW RETURN FLOW DEVELOPS OVER THE SOUTHERN PLAINS AND INTERACTS
WITH DISTURBANCES IN THE NORTHERN STREAM.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.


&&

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

$$

SHORT TERM...HJS
LONG TERM...ONTON
AVIATION...HJS



000
FXUS63 KLOT 261957
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
257 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT.

* POTENTIAL FOR MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

QUIET/DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AS HIGH
PRESSURE IN PLACE WILL REMAIN SITUATED ACROSS THE REGION.
GENERALLY CLEAR SKIES TODAY INTO TONIGHT COULD TRANSITION OVER TO
A PERIOD OF MVFR CEILINGS MONDAY MORNING. IF THIS WERE TO
OCCUR...THESE WOULD LIKELY CONTINUE INTO THE AFTERNOON AND BE
AROUND 2500 FT. NORTHEAST WINDS TODAY WILL CONTINUE AND DIMINISH
OVERNIGHT...BUT INCREASE ONCE AGAIN EARLY MONDAY MORNING.

RODRIGUEZ

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

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* LOW CONFIDENCE WITH MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 261957
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
257 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT.

* POTENTIAL FOR MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

QUIET/DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AS HIGH
PRESSURE IN PLACE WILL REMAIN SITUATED ACROSS THE REGION.
GENERALLY CLEAR SKIES TODAY INTO TONIGHT COULD TRANSITION OVER TO
A PERIOD OF MVFR CEILINGS MONDAY MORNING. IF THIS WERE TO
OCCUR...THESE WOULD LIKELY CONTINUE INTO THE AFTERNOON AND BE
AROUND 2500 FT. NORTHEAST WINDS TODAY WILL CONTINUE AND DIMINISH
OVERNIGHT...BUT INCREASE ONCE AGAIN EARLY MONDAY MORNING.

RODRIGUEZ

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

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* LOW CONFIDENCE WITH MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
257 PM CDT

NORTHERLY WINDS WILL CONTINUE OVER THE OPEN WATER AS WELL AS
ONSHORE FLOW IN ILLINOIS AND INDIANA NEARSHORE AREAS THROUGH THE
WEEK. WINDS LOOK TO HOLD STEADY INTO THIS EVENING AND MAYBE EVEN
INTO OVERNIGHT. WITH THE FLOW HAVING BEEN NORTHERLY OVER THE LONG
FETCH OF THE LAKE...WILL CONTINUE THE SMALL CRAFT ADVISORY AT
LEAST FOR WAVES AND OCCASIONALLY FOR GUSTS THROUGH TONIGHT AND
INTO EARLY MONDAY MORNING. HIGH PRESSURE WILL GENERALLY PREVAIL
THROUGH MIDWEEK BEFORE SOUTHERLY FLOW KICKS IN EITHER LATE IN THE
WEEK OR MORE LIKELY NEXT WEEKEND.

MTF

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 261953
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
253 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT.

* POTENTIAL FOR MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

QUIET/DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AS HIGH
PRESSURE IN PLACE WILL REMAIN SITUATED ACROSS THE REGION.
GENERALLY CLEAR SKIES TODAY INTO TONIGHT COULD TRANSITION OVER TO
A PERIOD OF MVFR CEILINGS MONDAY MORNING. IF THIS WERE TO
OCCUR...THESE WOULD LIKELY CONTINUE INTO THE AFTERNOON AND BE
AROUND 2500 FT. NORTHEAST WINDS TODAY WILL CONTINUE AND DIMINISH
OVERNIGHT...BUT INCREASE ONCE AGAIN EARLY MONDAY MORNING.

RODRIGUEZ

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

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* LOW CONFIDENCE WITH MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 261953
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
253 PM CDT SUN APR 26 2015

.SHORT TERM...
252 PM CDT

THROUGH TUESDAY...

A QUIET WEEK OF WEATHER IS STILL SET TO UNFOLD WITH A
QUASI-BLOCKED PATTERN DURING THE FIRST HALF OF THE WEEK KEEPING
SYSTEMS FROM IMPACTING THE AREA...AND THEN ONLY GRADUAL
MOISTENING OF THE ATMOSPHERE DURING THE LATTER PART. FOR
TONIGHT...THE SURFACE HIGH CENTER WILL BE POISED FROM ONTARIO
THROUGH THE TWIN CITIES...WITH STILL A LIGHT GRADIENT ACROSS THE
FORECAST AREA. THIS SHOULD RESULT IN SOME WIND ACROSS THE CHICAGO
METRO AND INTO NORTHWEST INDIANA. AS FOR NORTH CENTRAL
ILLINOIS...WIND SPEEDS WILL LIKELY FALL OFF TO NEAR OR CALM BY
LATE EVENING AS AN INVERSION SETS UP. AFTERNOON DEW POINTS AND
TEMPERATURE TRENDS UPSTREAM LAST NIGHT WOULD SUPPORT LOWER TO MID
30S AND HAVE GENERALLY GONE WITH THAT...WHICH LINES UP WELL WITH
BIAS-CORRECTED GUIDANCE. THE COLLABORATIVE DECISION WITH
NEIGHBORING WFOS WAS TO HOLD OFF ON A FROST ADVISORY HEADLINE FOR
NORTHWEST...NORTH CENTRAL...AND CENTRAL ILLINOIS...BUT SOME FROST
IS STILL EXPECTED AND IN THE FORECAST FOR OUTLYING AREAS WEST OF
I-57.

THE SYNOPTIC GRADIENT WILL EASE FURTHER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY. ONSHORE FLOW WILL BE SEEN MONDAY AND THEN MORE
OF A TRUE LAKE BREEZE PUSH IS LIKELY ON TUESDAY. THE CLIMATOLOGICAL
TEMPERATURE DIFFERENCE BETWEEN LAKESIDE AND THE FAR WEST/SOUTHWEST
METRO FOR AN ALL-DAY ONSHORE FLOW IN LATE APRIL IS AROUND 10
DEGREES...WITH SLIGHTLY LESS ON A LAKE BREEZE DAY. THOSE TRENDS
WERE CAPTURED WELL BY THE PREVIOUS FORECAST...SO HAVE MADE LITTLE
CHANGES. TEMPERATURES SHOULD BE FAIRLY SIMILAR MONDAY AS TO
TODAY...WITH AN OVERALL MODERATION ON TUESDAY INTO WEDNESDAY.

MTF

&&

.LONG TERM...
252 PM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER RIDGING WILL MOVE OVER THE AREA TUESDAY AND BASICALLY BE
HELD IN PLACE WITH A DEEP CLOSED LOW DOWNSTREAM OFF THE NEW
ENGLAND COAST. THIS WILL DOMINO EFFECT TO WEAKENING A COLD FRONT
APPROACHING THE AREA WEDNESDAY. HAVE CONTINUED THE FORECAST DRY IN
THAT TIME PERIOD. TEMPERATURES LOOK TO RE-MODERATE ON FRIDAY INTO
THE WEEKEND WITH GLOBAL MODELS INDICATING HEIGHTS AND 850/925MB
TEMPERATURES ABOVE EARLY MAY NORMALS. RIGHT NOW CONFIDENCE IS
INCREASING ON HIGHS IN THE 70S AT LEAST FOR ONE OR TWO DAYS IN
THAT FRIDAY-SUNDAY PERIOD. DEPENDING ON HOW STRONG SOUTHERLY FLOW
MATERIALIZES...THEN THE WARMTH MAY REACH ALL THE DAY TO THE LAKE
SHORE / DOWNTOWN CHICAGO. THE ATMOSPHERE LOOKS TO MOISTEN INTO THE
WEEKEND BUT SLOWLY IN A QUASI-ZONAL FLOW.

MTF

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT.

* POTENTIAL FOR MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

QUIET/DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AS HIGH
PRESSURE IN PLACE WILL REMAIN SITUATED ACROSS THE REGION.
GENERALLY CLEAR SKIES TODAY INTO TONIGHT COULD TRANSITION OVER TO
A PERIOD OF MVFR CEILINGS MONDAY MORNING. IF THIS WERE TO
OCCUR...THESE WOULD LIKELY CONTINUE INTO THE AFTERNOON AND BE
AROUND 2500 FT. NORTHEAST WINDS TODAY WILL CONTINUE AND DIMINISH
OVERNIGHT...BUT INCREASE ONCE AGAIN EARLY MONDAY MORNING.

RODRIGUEZ

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

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* LOW CONFIDENCE WITH MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KILX 261757
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1257 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 1041 AM CDT SUN APR 26 2015
HIGH PRESSURE BUILDING BACK INTO THE REGION WITH A SFC RIDGE AXIS
JUST TO THE WEST. NORTH/NORTHEASTERLY WINDS CONTINUE THROUGH THE
DAY, GETTING A LITTLE GUSTY LATER THIS AFTERNOON WITH A LITTLE BIT
OF MIXING. MODELS HINTING AT A LITTLE BIT OF MOISTURE BTWN
5000-8000 FT OR SO. CU RULE NOT PARTICULARLY STRONG UNDER THE
RIDGE AND MIXING MAY INHIBIT A LOT OF CU...BUT STILL POSSIBLE TO
SEE A FEW LATER THIS AFTERNOON. OTHERWISE QUIET, AND NO
SIGNIFICANT UPDATES ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

LOW CLOUDS CONTINUE TO GRADUALLY WORK THEIR WAY SOUTH THROUGH
CENTRAL AND EAST CENTRAL IL EARLY THIS MORNING AS DRIER AIR
ADVECTS FROM THE NORTHEAST. MOSTLY CLOUDY CONDITIONS WILL LINGER
IN SOUTHEAST IL FROM DAYBREAK UNTIL MID-MORNING. PLENTY OF LOW
LEVEL MIXING IN THE LOWER ATMOSPHERE LATE THIS MORNING THROUGH THE
AFTERNOON WILL RESULT IN NORTHEAST WINDS GUSTING CLOSE TO 20 MPH
ESPECIALLY EAST OF THE I-55 CORRIDOR. DESPITE PLENTY OF SUNSHINE
BY AFTERNOON...HIGHS TODAY WILL MAINLY BE AROUND 60 DEGREES DUE
TO THE DEEP LOW LEVEL NORTHEAST FLOW.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

FAIRLY QUIET WEATHER ON TAP ACROSS THE FORECAST AREA MUCH OF THE
WEEK. PERSISTENT NORTHEAST FLOW TO KEEP DRY CONDITIONS IN PLACE...
WITH HIGH TEMPERATURES RISING A COUPLE DEGREES EACH DAY UNTIL WE
FINALLY GET NEAR OR JUST ABOVE NORMAL BY THE END OF THE WORK WEEK.

UPPER LOW CURRENTLY IN THE PROCESS OF CLOSING OFF OVER WESTERN
ARIZONA...AND THIS WILL BE TRACKING ACROSS THE SOUTHERN U.S. OVER
THE NEXT FEW DAYS. ALL OF THE MODELS KEEP THE ASSOCIATED MOISTURE
SOUTH OF THE OHIO VALLEY. A SHORTWAVE WILL ALSO BE TRACKING ALONG
THE CANADIAN BORDER...AND AS PREVIOUS MODEL RUNS INDICATED, A SMALL
CLOSED LOW WILL PINCH OFF IN THE SOUTHERN PART OF THE WAVE. THE
ECMWF AND CANADIAN MODELS HAVE THIS SMALL LOW DROPPING ACROSS
MINNESOTA AND IOWA TUESDAY NIGHT...WHILE THE TAIL END OF THE NAM
BRINGS THIS INTO NORTHERN ILLINOIS AND THE GFS PROGRESSES THE WAVE
WELL EAST BEFORE THE LOW CAN FORM. NET RESULT OF ALL OF THIS IS FOR
DRY CONDITIONS MID WEEK.

AS WE GET LATER IN THE WEEK...UPPER RIDGING WILL BUILD NORTHEAST
ACROSS THE PLAINS INTO MANITOBA...WHILE GENERAL BROAD TROUGHING
CONTINUES ACROSS THE EASTERN U.S. THIS RIDGE FLATTENS BY FRIDAY AS
THE NORTHERN STREAM BECOMES MORE ACTIVE ALONG THE CANADIAN BORDER.
BOTH THE GFS AND ECMWF BRING A SURFACE BOUNDARY THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY...WITH SOME LIGHT PRECIPITATION. THE
SOLUTIONS BEGIN TO DIVERGE BY EVENING...AS THE GFS BRINGS A STRONGER
UPPER WAVE AND SURFACE FRONT THROUGH SATURDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...ALTHOUGH THE ECMWF DOES HINT AT POTENTIAL MCS
ACTIVITY AS WELL. WITH THE MORE DIVERGENT SOLUTIONS...HAVE KEPT THE
LATE WEEKEND FORECAST DRY FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.

&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...HJS



000
FXUS63 KILX 261757
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1257 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 1041 AM CDT SUN APR 26 2015
HIGH PRESSURE BUILDING BACK INTO THE REGION WITH A SFC RIDGE AXIS
JUST TO THE WEST. NORTH/NORTHEASTERLY WINDS CONTINUE THROUGH THE
DAY, GETTING A LITTLE GUSTY LATER THIS AFTERNOON WITH A LITTLE BIT
OF MIXING. MODELS HINTING AT A LITTLE BIT OF MOISTURE BTWN
5000-8000 FT OR SO. CU RULE NOT PARTICULARLY STRONG UNDER THE
RIDGE AND MIXING MAY INHIBIT A LOT OF CU...BUT STILL POSSIBLE TO
SEE A FEW LATER THIS AFTERNOON. OTHERWISE QUIET, AND NO
SIGNIFICANT UPDATES ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

LOW CLOUDS CONTINUE TO GRADUALLY WORK THEIR WAY SOUTH THROUGH
CENTRAL AND EAST CENTRAL IL EARLY THIS MORNING AS DRIER AIR
ADVECTS FROM THE NORTHEAST. MOSTLY CLOUDY CONDITIONS WILL LINGER
IN SOUTHEAST IL FROM DAYBREAK UNTIL MID-MORNING. PLENTY OF LOW
LEVEL MIXING IN THE LOWER ATMOSPHERE LATE THIS MORNING THROUGH THE
AFTERNOON WILL RESULT IN NORTHEAST WINDS GUSTING CLOSE TO 20 MPH
ESPECIALLY EAST OF THE I-55 CORRIDOR. DESPITE PLENTY OF SUNSHINE
BY AFTERNOON...HIGHS TODAY WILL MAINLY BE AROUND 60 DEGREES DUE
TO THE DEEP LOW LEVEL NORTHEAST FLOW.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

FAIRLY QUIET WEATHER ON TAP ACROSS THE FORECAST AREA MUCH OF THE
WEEK. PERSISTENT NORTHEAST FLOW TO KEEP DRY CONDITIONS IN PLACE...
WITH HIGH TEMPERATURES RISING A COUPLE DEGREES EACH DAY UNTIL WE
FINALLY GET NEAR OR JUST ABOVE NORMAL BY THE END OF THE WORK WEEK.

UPPER LOW CURRENTLY IN THE PROCESS OF CLOSING OFF OVER WESTERN
ARIZONA...AND THIS WILL BE TRACKING ACROSS THE SOUTHERN U.S. OVER
THE NEXT FEW DAYS. ALL OF THE MODELS KEEP THE ASSOCIATED MOISTURE
SOUTH OF THE OHIO VALLEY. A SHORTWAVE WILL ALSO BE TRACKING ALONG
THE CANADIAN BORDER...AND AS PREVIOUS MODEL RUNS INDICATED, A SMALL
CLOSED LOW WILL PINCH OFF IN THE SOUTHERN PART OF THE WAVE. THE
ECMWF AND CANADIAN MODELS HAVE THIS SMALL LOW DROPPING ACROSS
MINNESOTA AND IOWA TUESDAY NIGHT...WHILE THE TAIL END OF THE NAM
BRINGS THIS INTO NORTHERN ILLINOIS AND THE GFS PROGRESSES THE WAVE
WELL EAST BEFORE THE LOW CAN FORM. NET RESULT OF ALL OF THIS IS FOR
DRY CONDITIONS MID WEEK.

AS WE GET LATER IN THE WEEK...UPPER RIDGING WILL BUILD NORTHEAST
ACROSS THE PLAINS INTO MANITOBA...WHILE GENERAL BROAD TROUGHING
CONTINUES ACROSS THE EASTERN U.S. THIS RIDGE FLATTENS BY FRIDAY AS
THE NORTHERN STREAM BECOMES MORE ACTIVE ALONG THE CANADIAN BORDER.
BOTH THE GFS AND ECMWF BRING A SURFACE BOUNDARY THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY...WITH SOME LIGHT PRECIPITATION. THE
SOLUTIONS BEGIN TO DIVERGE BY EVENING...AS THE GFS BRINGS A STRONGER
UPPER WAVE AND SURFACE FRONT THROUGH SATURDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...ALTHOUGH THE ECMWF DOES HINT AT POTENTIAL MCS
ACTIVITY AS WELL. WITH THE MORE DIVERGENT SOLUTIONS...HAVE KEPT THE
LATE WEEKEND FORECAST DRY FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.

&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...HJS



000
FXUS63 KILX 261757
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1257 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 1041 AM CDT SUN APR 26 2015
HIGH PRESSURE BUILDING BACK INTO THE REGION WITH A SFC RIDGE AXIS
JUST TO THE WEST. NORTH/NORTHEASTERLY WINDS CONTINUE THROUGH THE
DAY, GETTING A LITTLE GUSTY LATER THIS AFTERNOON WITH A LITTLE BIT
OF MIXING. MODELS HINTING AT A LITTLE BIT OF MOISTURE BTWN
5000-8000 FT OR SO. CU RULE NOT PARTICULARLY STRONG UNDER THE
RIDGE AND MIXING MAY INHIBIT A LOT OF CU...BUT STILL POSSIBLE TO
SEE A FEW LATER THIS AFTERNOON. OTHERWISE QUIET, AND NO
SIGNIFICANT UPDATES ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

LOW CLOUDS CONTINUE TO GRADUALLY WORK THEIR WAY SOUTH THROUGH
CENTRAL AND EAST CENTRAL IL EARLY THIS MORNING AS DRIER AIR
ADVECTS FROM THE NORTHEAST. MOSTLY CLOUDY CONDITIONS WILL LINGER
IN SOUTHEAST IL FROM DAYBREAK UNTIL MID-MORNING. PLENTY OF LOW
LEVEL MIXING IN THE LOWER ATMOSPHERE LATE THIS MORNING THROUGH THE
AFTERNOON WILL RESULT IN NORTHEAST WINDS GUSTING CLOSE TO 20 MPH
ESPECIALLY EAST OF THE I-55 CORRIDOR. DESPITE PLENTY OF SUNSHINE
BY AFTERNOON...HIGHS TODAY WILL MAINLY BE AROUND 60 DEGREES DUE
TO THE DEEP LOW LEVEL NORTHEAST FLOW.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

FAIRLY QUIET WEATHER ON TAP ACROSS THE FORECAST AREA MUCH OF THE
WEEK. PERSISTENT NORTHEAST FLOW TO KEEP DRY CONDITIONS IN PLACE...
WITH HIGH TEMPERATURES RISING A COUPLE DEGREES EACH DAY UNTIL WE
FINALLY GET NEAR OR JUST ABOVE NORMAL BY THE END OF THE WORK WEEK.

UPPER LOW CURRENTLY IN THE PROCESS OF CLOSING OFF OVER WESTERN
ARIZONA...AND THIS WILL BE TRACKING ACROSS THE SOUTHERN U.S. OVER
THE NEXT FEW DAYS. ALL OF THE MODELS KEEP THE ASSOCIATED MOISTURE
SOUTH OF THE OHIO VALLEY. A SHORTWAVE WILL ALSO BE TRACKING ALONG
THE CANADIAN BORDER...AND AS PREVIOUS MODEL RUNS INDICATED, A SMALL
CLOSED LOW WILL PINCH OFF IN THE SOUTHERN PART OF THE WAVE. THE
ECMWF AND CANADIAN MODELS HAVE THIS SMALL LOW DROPPING ACROSS
MINNESOTA AND IOWA TUESDAY NIGHT...WHILE THE TAIL END OF THE NAM
BRINGS THIS INTO NORTHERN ILLINOIS AND THE GFS PROGRESSES THE WAVE
WELL EAST BEFORE THE LOW CAN FORM. NET RESULT OF ALL OF THIS IS FOR
DRY CONDITIONS MID WEEK.

AS WE GET LATER IN THE WEEK...UPPER RIDGING WILL BUILD NORTHEAST
ACROSS THE PLAINS INTO MANITOBA...WHILE GENERAL BROAD TROUGHING
CONTINUES ACROSS THE EASTERN U.S. THIS RIDGE FLATTENS BY FRIDAY AS
THE NORTHERN STREAM BECOMES MORE ACTIVE ALONG THE CANADIAN BORDER.
BOTH THE GFS AND ECMWF BRING A SURFACE BOUNDARY THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY...WITH SOME LIGHT PRECIPITATION. THE
SOLUTIONS BEGIN TO DIVERGE BY EVENING...AS THE GFS BRINGS A STRONGER
UPPER WAVE AND SURFACE FRONT THROUGH SATURDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...ALTHOUGH THE ECMWF DOES HINT AT POTENTIAL MCS
ACTIVITY AS WELL. WITH THE MORE DIVERGENT SOLUTIONS...HAVE KEPT THE
LATE WEEKEND FORECAST DRY FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.

&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...HJS



000
FXUS63 KILX 261757
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1257 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 1041 AM CDT SUN APR 26 2015
HIGH PRESSURE BUILDING BACK INTO THE REGION WITH A SFC RIDGE AXIS
JUST TO THE WEST. NORTH/NORTHEASTERLY WINDS CONTINUE THROUGH THE
DAY, GETTING A LITTLE GUSTY LATER THIS AFTERNOON WITH A LITTLE BIT
OF MIXING. MODELS HINTING AT A LITTLE BIT OF MOISTURE BTWN
5000-8000 FT OR SO. CU RULE NOT PARTICULARLY STRONG UNDER THE
RIDGE AND MIXING MAY INHIBIT A LOT OF CU...BUT STILL POSSIBLE TO
SEE A FEW LATER THIS AFTERNOON. OTHERWISE QUIET, AND NO
SIGNIFICANT UPDATES ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

LOW CLOUDS CONTINUE TO GRADUALLY WORK THEIR WAY SOUTH THROUGH
CENTRAL AND EAST CENTRAL IL EARLY THIS MORNING AS DRIER AIR
ADVECTS FROM THE NORTHEAST. MOSTLY CLOUDY CONDITIONS WILL LINGER
IN SOUTHEAST IL FROM DAYBREAK UNTIL MID-MORNING. PLENTY OF LOW
LEVEL MIXING IN THE LOWER ATMOSPHERE LATE THIS MORNING THROUGH THE
AFTERNOON WILL RESULT IN NORTHEAST WINDS GUSTING CLOSE TO 20 MPH
ESPECIALLY EAST OF THE I-55 CORRIDOR. DESPITE PLENTY OF SUNSHINE
BY AFTERNOON...HIGHS TODAY WILL MAINLY BE AROUND 60 DEGREES DUE
TO THE DEEP LOW LEVEL NORTHEAST FLOW.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

FAIRLY QUIET WEATHER ON TAP ACROSS THE FORECAST AREA MUCH OF THE
WEEK. PERSISTENT NORTHEAST FLOW TO KEEP DRY CONDITIONS IN PLACE...
WITH HIGH TEMPERATURES RISING A COUPLE DEGREES EACH DAY UNTIL WE
FINALLY GET NEAR OR JUST ABOVE NORMAL BY THE END OF THE WORK WEEK.

UPPER LOW CURRENTLY IN THE PROCESS OF CLOSING OFF OVER WESTERN
ARIZONA...AND THIS WILL BE TRACKING ACROSS THE SOUTHERN U.S. OVER
THE NEXT FEW DAYS. ALL OF THE MODELS KEEP THE ASSOCIATED MOISTURE
SOUTH OF THE OHIO VALLEY. A SHORTWAVE WILL ALSO BE TRACKING ALONG
THE CANADIAN BORDER...AND AS PREVIOUS MODEL RUNS INDICATED, A SMALL
CLOSED LOW WILL PINCH OFF IN THE SOUTHERN PART OF THE WAVE. THE
ECMWF AND CANADIAN MODELS HAVE THIS SMALL LOW DROPPING ACROSS
MINNESOTA AND IOWA TUESDAY NIGHT...WHILE THE TAIL END OF THE NAM
BRINGS THIS INTO NORTHERN ILLINOIS AND THE GFS PROGRESSES THE WAVE
WELL EAST BEFORE THE LOW CAN FORM. NET RESULT OF ALL OF THIS IS FOR
DRY CONDITIONS MID WEEK.

AS WE GET LATER IN THE WEEK...UPPER RIDGING WILL BUILD NORTHEAST
ACROSS THE PLAINS INTO MANITOBA...WHILE GENERAL BROAD TROUGHING
CONTINUES ACROSS THE EASTERN U.S. THIS RIDGE FLATTENS BY FRIDAY AS
THE NORTHERN STREAM BECOMES MORE ACTIVE ALONG THE CANADIAN BORDER.
BOTH THE GFS AND ECMWF BRING A SURFACE BOUNDARY THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY...WITH SOME LIGHT PRECIPITATION. THE
SOLUTIONS BEGIN TO DIVERGE BY EVENING...AS THE GFS BRINGS A STRONGER
UPPER WAVE AND SURFACE FRONT THROUGH SATURDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...ALTHOUGH THE ECMWF DOES HINT AT POTENTIAL MCS
ACTIVITY AS WELL. WITH THE MORE DIVERGENT SOLUTIONS...HAVE KEPT THE
LATE WEEKEND FORECAST DRY FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.

&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...HJS



000
FXUS63 KILX 261757
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1257 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 1041 AM CDT SUN APR 26 2015
HIGH PRESSURE BUILDING BACK INTO THE REGION WITH A SFC RIDGE AXIS
JUST TO THE WEST. NORTH/NORTHEASTERLY WINDS CONTINUE THROUGH THE
DAY, GETTING A LITTLE GUSTY LATER THIS AFTERNOON WITH A LITTLE BIT
OF MIXING. MODELS HINTING AT A LITTLE BIT OF MOISTURE BTWN
5000-8000 FT OR SO. CU RULE NOT PARTICULARLY STRONG UNDER THE
RIDGE AND MIXING MAY INHIBIT A LOT OF CU...BUT STILL POSSIBLE TO
SEE A FEW LATER THIS AFTERNOON. OTHERWISE QUIET, AND NO
SIGNIFICANT UPDATES ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

LOW CLOUDS CONTINUE TO GRADUALLY WORK THEIR WAY SOUTH THROUGH
CENTRAL AND EAST CENTRAL IL EARLY THIS MORNING AS DRIER AIR
ADVECTS FROM THE NORTHEAST. MOSTLY CLOUDY CONDITIONS WILL LINGER
IN SOUTHEAST IL FROM DAYBREAK UNTIL MID-MORNING. PLENTY OF LOW
LEVEL MIXING IN THE LOWER ATMOSPHERE LATE THIS MORNING THROUGH THE
AFTERNOON WILL RESULT IN NORTHEAST WINDS GUSTING CLOSE TO 20 MPH
ESPECIALLY EAST OF THE I-55 CORRIDOR. DESPITE PLENTY OF SUNSHINE
BY AFTERNOON...HIGHS TODAY WILL MAINLY BE AROUND 60 DEGREES DUE
TO THE DEEP LOW LEVEL NORTHEAST FLOW.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

FAIRLY QUIET WEATHER ON TAP ACROSS THE FORECAST AREA MUCH OF THE
WEEK. PERSISTENT NORTHEAST FLOW TO KEEP DRY CONDITIONS IN PLACE...
WITH HIGH TEMPERATURES RISING A COUPLE DEGREES EACH DAY UNTIL WE
FINALLY GET NEAR OR JUST ABOVE NORMAL BY THE END OF THE WORK WEEK.

UPPER LOW CURRENTLY IN THE PROCESS OF CLOSING OFF OVER WESTERN
ARIZONA...AND THIS WILL BE TRACKING ACROSS THE SOUTHERN U.S. OVER
THE NEXT FEW DAYS. ALL OF THE MODELS KEEP THE ASSOCIATED MOISTURE
SOUTH OF THE OHIO VALLEY. A SHORTWAVE WILL ALSO BE TRACKING ALONG
THE CANADIAN BORDER...AND AS PREVIOUS MODEL RUNS INDICATED, A SMALL
CLOSED LOW WILL PINCH OFF IN THE SOUTHERN PART OF THE WAVE. THE
ECMWF AND CANADIAN MODELS HAVE THIS SMALL LOW DROPPING ACROSS
MINNESOTA AND IOWA TUESDAY NIGHT...WHILE THE TAIL END OF THE NAM
BRINGS THIS INTO NORTHERN ILLINOIS AND THE GFS PROGRESSES THE WAVE
WELL EAST BEFORE THE LOW CAN FORM. NET RESULT OF ALL OF THIS IS FOR
DRY CONDITIONS MID WEEK.

AS WE GET LATER IN THE WEEK...UPPER RIDGING WILL BUILD NORTHEAST
ACROSS THE PLAINS INTO MANITOBA...WHILE GENERAL BROAD TROUGHING
CONTINUES ACROSS THE EASTERN U.S. THIS RIDGE FLATTENS BY FRIDAY AS
THE NORTHERN STREAM BECOMES MORE ACTIVE ALONG THE CANADIAN BORDER.
BOTH THE GFS AND ECMWF BRING A SURFACE BOUNDARY THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY...WITH SOME LIGHT PRECIPITATION. THE
SOLUTIONS BEGIN TO DIVERGE BY EVENING...AS THE GFS BRINGS A STRONGER
UPPER WAVE AND SURFACE FRONT THROUGH SATURDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...ALTHOUGH THE ECMWF DOES HINT AT POTENTIAL MCS
ACTIVITY AS WELL. WITH THE MORE DIVERGENT SOLUTIONS...HAVE KEPT THE
LATE WEEKEND FORECAST DRY FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.

&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...HJS



000
FXUS63 KILX 261757
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1257 PM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 1041 AM CDT SUN APR 26 2015
HIGH PRESSURE BUILDING BACK INTO THE REGION WITH A SFC RIDGE AXIS
JUST TO THE WEST. NORTH/NORTHEASTERLY WINDS CONTINUE THROUGH THE
DAY, GETTING A LITTLE GUSTY LATER THIS AFTERNOON WITH A LITTLE BIT
OF MIXING. MODELS HINTING AT A LITTLE BIT OF MOISTURE BTWN
5000-8000 FT OR SO. CU RULE NOT PARTICULARLY STRONG UNDER THE
RIDGE AND MIXING MAY INHIBIT A LOT OF CU...BUT STILL POSSIBLE TO
SEE A FEW LATER THIS AFTERNOON. OTHERWISE QUIET, AND NO
SIGNIFICANT UPDATES ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

LOW CLOUDS CONTINUE TO GRADUALLY WORK THEIR WAY SOUTH THROUGH
CENTRAL AND EAST CENTRAL IL EARLY THIS MORNING AS DRIER AIR
ADVECTS FROM THE NORTHEAST. MOSTLY CLOUDY CONDITIONS WILL LINGER
IN SOUTHEAST IL FROM DAYBREAK UNTIL MID-MORNING. PLENTY OF LOW
LEVEL MIXING IN THE LOWER ATMOSPHERE LATE THIS MORNING THROUGH THE
AFTERNOON WILL RESULT IN NORTHEAST WINDS GUSTING CLOSE TO 20 MPH
ESPECIALLY EAST OF THE I-55 CORRIDOR. DESPITE PLENTY OF SUNSHINE
BY AFTERNOON...HIGHS TODAY WILL MAINLY BE AROUND 60 DEGREES DUE
TO THE DEEP LOW LEVEL NORTHEAST FLOW.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

FAIRLY QUIET WEATHER ON TAP ACROSS THE FORECAST AREA MUCH OF THE
WEEK. PERSISTENT NORTHEAST FLOW TO KEEP DRY CONDITIONS IN PLACE...
WITH HIGH TEMPERATURES RISING A COUPLE DEGREES EACH DAY UNTIL WE
FINALLY GET NEAR OR JUST ABOVE NORMAL BY THE END OF THE WORK WEEK.

UPPER LOW CURRENTLY IN THE PROCESS OF CLOSING OFF OVER WESTERN
ARIZONA...AND THIS WILL BE TRACKING ACROSS THE SOUTHERN U.S. OVER
THE NEXT FEW DAYS. ALL OF THE MODELS KEEP THE ASSOCIATED MOISTURE
SOUTH OF THE OHIO VALLEY. A SHORTWAVE WILL ALSO BE TRACKING ALONG
THE CANADIAN BORDER...AND AS PREVIOUS MODEL RUNS INDICATED, A SMALL
CLOSED LOW WILL PINCH OFF IN THE SOUTHERN PART OF THE WAVE. THE
ECMWF AND CANADIAN MODELS HAVE THIS SMALL LOW DROPPING ACROSS
MINNESOTA AND IOWA TUESDAY NIGHT...WHILE THE TAIL END OF THE NAM
BRINGS THIS INTO NORTHERN ILLINOIS AND THE GFS PROGRESSES THE WAVE
WELL EAST BEFORE THE LOW CAN FORM. NET RESULT OF ALL OF THIS IS FOR
DRY CONDITIONS MID WEEK.

AS WE GET LATER IN THE WEEK...UPPER RIDGING WILL BUILD NORTHEAST
ACROSS THE PLAINS INTO MANITOBA...WHILE GENERAL BROAD TROUGHING
CONTINUES ACROSS THE EASTERN U.S. THIS RIDGE FLATTENS BY FRIDAY AS
THE NORTHERN STREAM BECOMES MORE ACTIVE ALONG THE CANADIAN BORDER.
BOTH THE GFS AND ECMWF BRING A SURFACE BOUNDARY THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY...WITH SOME LIGHT PRECIPITATION. THE
SOLUTIONS BEGIN TO DIVERGE BY EVENING...AS THE GFS BRINGS A STRONGER
UPPER WAVE AND SURFACE FRONT THROUGH SATURDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...ALTHOUGH THE ECMWF DOES HINT AT POTENTIAL MCS
ACTIVITY AS WELL. WITH THE MORE DIVERGENT SOLUTIONS...HAVE KEPT THE
LATE WEEKEND FORECAST DRY FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1254 PM CDT SUN APR 26 2015
VFR AND BREEZY NNE WINDS THROUGH THE AFTERNOON, BECOMING MORE
LIGHT AND VARIABLE IN THE OVERNIGHT. LITTLE EXPECTED IN THE WAY OF
CIGS AND DIURNAL MIXING TODAY ALREADY PLUMMETING THE DWPTS
CONSIDERABLY. WILL WATCH CLOSELY FOR THE XOVER VALUES THIS
AFTERNOON, AS RADIATIONAL COOLING WILL DROP TEMPS TONIGHT
EFFICIENTLY. SO FAR, NOT LOOKING LIKE A GOOD FOG SET UP, BUT WILL
CONTINUE TO WATCH THE BOUNDARY LAYER RH.

&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...HJS




000
FXUS63 KLOT 261749
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1249 PM CDT SUN APR 26 2015

.SHORT TERM...
315 AM CDT

THROUGH MONDAY NIGHT...

REALLY QUIET WEATHER ON TAP THROUGH THE REMAINDER OF THE WEEKEND AND
THROUGH MOST OF THE UPCOMING WEEK. LOW PRESSURE HAS MOVED FROM THE
MID MISSISSIPPI VALLEY TOWARDS THIS MID ATLANTIC COAST THIS MORNING
WITH DRY NORTHEASTERLY FLOW IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA IN ADVANCE OF HIGH PRESSURE BUILDING DOWN FROM THE
CANADIAN PRAIRIES. ONSHORE FLOW AND A MODEST NORTHEAST WIND WILL BE
IN PLACE TODAY KEEPING CONDITIONS COOL ALONG THE LAKE FRONT...WHERE
LOW 50S ARE IN THE FORECAST FOR HIGHS...BUT FARTHER INLAND EXPECT
MID TO UPPER 50S THIS AFTERNOON UNDER MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE A FEW DEGREES WARMER MONDAY...THOUGH SIMILAR
ALONG THE LAKE FRONT. VERY DRY COLUMN OF AIR ADVECTING OVERHEAD WILL
MIX DOWN TO THE SURFACE THIS AFTERNOON WITH DEWPOINTS FALLING INTO
THE MID TO UPPER 20S RESULTING IN RELATIVE HUMIDITY DROPPING INTO
THE 25 TO 35 PERCENT RANGE. THE DRY AIRMASS WILL HELP LEAD TO BIG
DIURNAL CURVES AROUND 30 DEGREES FOR SOME LOCATIONS. LEANED HEAVILY
ON BIAS CORRECTED GUIDANCE TO RESOLVE THE TYPICAL COLD SPOTS AS WE
SHOULD BE UNDER FAVORABLE RADIATIVE COOLING CONDITIONS NEXT COUPLE
NIGHTS...BUT ESPECIALLY MONDAY NIGHT WHEN WINDS BECOME CALM. ADDED
PATCHY FROST TONIGHT AND MONDAY NIGHT OUTSIDE THE CHICAGO METRO.
WINDS REMAIN A LITTLE MORE ELEVATED SO CONFIDENCE IS LOWER FOR
TONIGHT AS COMPARED TO MONDAY NIGHT...SO WILL HOLD OFF ON AN
ADVISORY FOR NOW BUT ONE MAY BE NEEDED.

BMD

&&

.LONG TERM...
315 AM CDT

TUESDAY THROUGH SATURDAY...

OVERALL VERY WEAK SURFACE FIELD WILL BE IN PLACE TUESDAY INTO
WEDNESDAY AS MODEST HIGH PRESSURE SPANS MUCH OF THE MID-SECTION OF
THE COUNTRY. BARELY 8MB PRESSURE DIFFERENCES BETWEEN BOTH EAST AND
WEST COASTS AND THE PLAINS WILL RESULT IN FAIRLY LIGHT WINDS
ACROSS THE MIDWEST WITH LAKE BREEZES EXPECTED EACH DAY. MODERATING
AIRMASS WILL RESULT IN A WARMING TREND TUESDAY INTO
WEDNESDAY...BUT A SHORTWAVE TROUGH DIGGING INTO THE MIDWEST WILL
BRING A GLANCING BLOW OF COLDER AIR INTO THE REGION THURSDAY.
UPPER RIDGING WILL TRY TO BUILD OVER THE AREA BY LATE IN THE WEEK
INTO THE WEEKEND AND MAY BRING TEMPS WELL INTO THE 70S.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT.

* POTENTIAL FOR MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

QUIET/DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AS HIGH
PRESSURE IN PLACE WILL REMAIN SITUATED ACROSS THE REGION.
GENERALLY CLEAR SKIES TODAY INTO TONIGHT COULD TRANSITION OVER TO
A PERIOD OF MVFR CEILINGS MONDAY MORNING. IF THIS WERE TO
OCCUR...THESE WOULD LIKELY CONTINUE INTO THE AFTERNOON AND BE
AROUND 2500 FT. NORTHEAST WINDS TODAY WILL CONTINUE AND DIMINISH
OVERNIGHT...BUT INCREASE ONCE AGAIN EARLY MONDAY MORNING.

RODRIGUEZ


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

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* LOW CONFIDENCE WITH MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 261749
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1249 PM CDT SUN APR 26 2015

.SHORT TERM...
315 AM CDT

THROUGH MONDAY NIGHT...

REALLY QUIET WEATHER ON TAP THROUGH THE REMAINDER OF THE WEEKEND AND
THROUGH MOST OF THE UPCOMING WEEK. LOW PRESSURE HAS MOVED FROM THE
MID MISSISSIPPI VALLEY TOWARDS THIS MID ATLANTIC COAST THIS MORNING
WITH DRY NORTHEASTERLY FLOW IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA IN ADVANCE OF HIGH PRESSURE BUILDING DOWN FROM THE
CANADIAN PRAIRIES. ONSHORE FLOW AND A MODEST NORTHEAST WIND WILL BE
IN PLACE TODAY KEEPING CONDITIONS COOL ALONG THE LAKE FRONT...WHERE
LOW 50S ARE IN THE FORECAST FOR HIGHS...BUT FARTHER INLAND EXPECT
MID TO UPPER 50S THIS AFTERNOON UNDER MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE A FEW DEGREES WARMER MONDAY...THOUGH SIMILAR
ALONG THE LAKE FRONT. VERY DRY COLUMN OF AIR ADVECTING OVERHEAD WILL
MIX DOWN TO THE SURFACE THIS AFTERNOON WITH DEWPOINTS FALLING INTO
THE MID TO UPPER 20S RESULTING IN RELATIVE HUMIDITY DROPPING INTO
THE 25 TO 35 PERCENT RANGE. THE DRY AIRMASS WILL HELP LEAD TO BIG
DIURNAL CURVES AROUND 30 DEGREES FOR SOME LOCATIONS. LEANED HEAVILY
ON BIAS CORRECTED GUIDANCE TO RESOLVE THE TYPICAL COLD SPOTS AS WE
SHOULD BE UNDER FAVORABLE RADIATIVE COOLING CONDITIONS NEXT COUPLE
NIGHTS...BUT ESPECIALLY MONDAY NIGHT WHEN WINDS BECOME CALM. ADDED
PATCHY FROST TONIGHT AND MONDAY NIGHT OUTSIDE THE CHICAGO METRO.
WINDS REMAIN A LITTLE MORE ELEVATED SO CONFIDENCE IS LOWER FOR
TONIGHT AS COMPARED TO MONDAY NIGHT...SO WILL HOLD OFF ON AN
ADVISORY FOR NOW BUT ONE MAY BE NEEDED.

BMD

&&

.LONG TERM...
315 AM CDT

TUESDAY THROUGH SATURDAY...

OVERALL VERY WEAK SURFACE FIELD WILL BE IN PLACE TUESDAY INTO
WEDNESDAY AS MODEST HIGH PRESSURE SPANS MUCH OF THE MID-SECTION OF
THE COUNTRY. BARELY 8MB PRESSURE DIFFERENCES BETWEEN BOTH EAST AND
WEST COASTS AND THE PLAINS WILL RESULT IN FAIRLY LIGHT WINDS
ACROSS THE MIDWEST WITH LAKE BREEZES EXPECTED EACH DAY. MODERATING
AIRMASS WILL RESULT IN A WARMING TREND TUESDAY INTO
WEDNESDAY...BUT A SHORTWAVE TROUGH DIGGING INTO THE MIDWEST WILL
BRING A GLANCING BLOW OF COLDER AIR INTO THE REGION THURSDAY.
UPPER RIDGING WILL TRY TO BUILD OVER THE AREA BY LATE IN THE WEEK
INTO THE WEEKEND AND MAY BRING TEMPS WELL INTO THE 70S.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT.

* POTENTIAL FOR MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

QUIET/DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AS HIGH
PRESSURE IN PLACE WILL REMAIN SITUATED ACROSS THE REGION.
GENERALLY CLEAR SKIES TODAY INTO TONIGHT COULD TRANSITION OVER TO
A PERIOD OF MVFR CEILINGS MONDAY MORNING. IF THIS WERE TO
OCCUR...THESE WOULD LIKELY CONTINUE INTO THE AFTERNOON AND BE
AROUND 2500 FT. NORTHEAST WINDS TODAY WILL CONTINUE AND DIMINISH
OVERNIGHT...BUT INCREASE ONCE AGAIN EARLY MONDAY MORNING.

RODRIGUEZ


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

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* LOW CONFIDENCE WITH MVFR CEILINGS MONDAY MORNING.

RODRIGUEZ

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 261604
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1104 AM CDT SUN APR 26 2015

.SHORT TERM...
315 AM CDT

THROUGH MONDAY NIGHT...

REALLY QUIET WEATHER ON TAP THROUGH THE REMAINDER OF THE WEEKEND AND
THROUGH MOST OF THE UPCOMING WEEK. LOW PRESSURE HAS MOVED FROM THE
MID MISSISSIPPI VALLEY TOWARDS THIS MID ATLANTIC COAST THIS MORNING
WITH DRY NORTHEASTERLY FLOW IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA IN ADVANCE OF HIGH PRESSURE BUILDING DOWN FROM THE
CANADIAN PRAIRIES. ONSHORE FLOW AND A MODEST NORTHEAST WIND WILL BE
IN PLACE TODAY KEEPING CONDITIONS COOL ALONG THE LAKE FRONT...WHERE
LOW 50S ARE IN THE FORECAST FOR HIGHS...BUT FARTHER INLAND EXPECT
MID TO UPPER 50S THIS AFTERNOON UNDER MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE A FEW DEGREES WARMER MONDAY...THOUGH SIMILAR
ALONG THE LAKE FRONT. VERY DRY COLUMN OF AIR ADVECTING OVERHEAD WILL
MIX DOWN TO THE SURFACE THIS AFTERNOON WITH DEWPOINTS FALLING INTO
THE MID TO UPPER 20S RESULTING IN RELATIVE HUMIDITY DROPPING INTO
THE 25 TO 35 PERCENT RANGE. THE DRY AIRMASS WILL HELP LEAD TO BIG
DIURNAL CURVES AROUND 30 DEGREES FOR SOME LOCATIONS. LEANED HEAVILY
ON BIAS CORRECTED GUIDANCE TO RESOLVE THE TYPICAL COLD SPOTS AS WE
SHOULD BE UNDER FAVORABLE RADIATIVE COOLING CONDITIONS NEXT COUPLE
NIGHTS...BUT ESPECIALLY MONDAY NIGHT WHEN WINDS BECOME CALM. ADDED
PATCHY FROST TONIGHT AND MONDAY NIGHT OUTSIDE THE CHICAGO METRO.
WINDS REMAIN A LITTLE MORE ELEVATED SO CONFIDENCE IS LOWER FOR
TONIGHT AS COMPARED TO MONDAY NIGHT...SO WILL HOLD OFF ON AN
ADVISORY FOR NOW BUT ONE MAY BE NEEDED.

BMD

&&

.LONG TERM...
315 AM CDT

TUESDAY THROUGH SATURDAY...

OVERALL VERY WEAK SURFACE FIELD WILL BE IN PLACE TUESDAY INTO
WEDNESDAY AS MODEST HIGH PRESSURE SPANS MUCH OF THE MID-SECTION OF
THE COUNTRY. BARELY 8MB PRESSURE DIFFERENCES BETWEEN BOTH EAST AND
WEST COASTS AND THE PLAINS WILL RESULT IN FAIRLY LIGHT WINDS
ACROSS THE MIDWEST WITH LAKE BREEZES EXPECTED EACH DAY. MODERATING
AIRMASS WILL RESULT IN A WARMING TREND TUESDAY INTO
WEDNESDAY...BUT A SHORTWAVE TROUGH DIGGING INTO THE MIDWEST WILL
BRING A GLANCING BLOW OF COLDER AIR INTO THE REGION THURSDAY.
UPPER RIDGING WILL TRY TO BUILD OVER THE AREA BY LATE IN THE WEEK
INTO THE WEEKEND AND MAY BRING TEMPS WELL INTO THE 70S.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT WITH GUSTS OF 15 TO 20 KT
  THROUGH THIS AFTERNOON.

RODRIGUEZ/KJB

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE HIGH
PRESSURE RIDGE OVER UPPER MIDWEST THROUGH THE FORECAST PERIOD.
THIS WILL MAINTAIN NORTHEAST WINDS OF 10-15 KTS WITH GUSTS
POTENTIALLY NEAR 20 KT GUSTS THIS AFTERNOON. THE SURFACE PRESSURE
GRADIENT WILL WEAKEN A BIT TONIGHT ALLOWING WINDS TO DIMINISH
BELOW 10 KTS. HOWEVER...NORTH-NORTHEASTERLY WINDS COULD AGAIN
CLIMB INTO THE 10 TO 15 KT RANGE ON MONDAY. OTHERWISE EXPECT VFR
CONDITIONS...WITH MAINLY CLEAR SKIES DURING DAY.

KJB

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

* HIGH FOR ALL ELEMENTS.

RODRIGUEZ/KJB

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 261604
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1104 AM CDT SUN APR 26 2015

.SHORT TERM...
315 AM CDT

THROUGH MONDAY NIGHT...

REALLY QUIET WEATHER ON TAP THROUGH THE REMAINDER OF THE WEEKEND AND
THROUGH MOST OF THE UPCOMING WEEK. LOW PRESSURE HAS MOVED FROM THE
MID MISSISSIPPI VALLEY TOWARDS THIS MID ATLANTIC COAST THIS MORNING
WITH DRY NORTHEASTERLY FLOW IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA IN ADVANCE OF HIGH PRESSURE BUILDING DOWN FROM THE
CANADIAN PRAIRIES. ONSHORE FLOW AND A MODEST NORTHEAST WIND WILL BE
IN PLACE TODAY KEEPING CONDITIONS COOL ALONG THE LAKE FRONT...WHERE
LOW 50S ARE IN THE FORECAST FOR HIGHS...BUT FARTHER INLAND EXPECT
MID TO UPPER 50S THIS AFTERNOON UNDER MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE A FEW DEGREES WARMER MONDAY...THOUGH SIMILAR
ALONG THE LAKE FRONT. VERY DRY COLUMN OF AIR ADVECTING OVERHEAD WILL
MIX DOWN TO THE SURFACE THIS AFTERNOON WITH DEWPOINTS FALLING INTO
THE MID TO UPPER 20S RESULTING IN RELATIVE HUMIDITY DROPPING INTO
THE 25 TO 35 PERCENT RANGE. THE DRY AIRMASS WILL HELP LEAD TO BIG
DIURNAL CURVES AROUND 30 DEGREES FOR SOME LOCATIONS. LEANED HEAVILY
ON BIAS CORRECTED GUIDANCE TO RESOLVE THE TYPICAL COLD SPOTS AS WE
SHOULD BE UNDER FAVORABLE RADIATIVE COOLING CONDITIONS NEXT COUPLE
NIGHTS...BUT ESPECIALLY MONDAY NIGHT WHEN WINDS BECOME CALM. ADDED
PATCHY FROST TONIGHT AND MONDAY NIGHT OUTSIDE THE CHICAGO METRO.
WINDS REMAIN A LITTLE MORE ELEVATED SO CONFIDENCE IS LOWER FOR
TONIGHT AS COMPARED TO MONDAY NIGHT...SO WILL HOLD OFF ON AN
ADVISORY FOR NOW BUT ONE MAY BE NEEDED.

BMD

&&

.LONG TERM...
315 AM CDT

TUESDAY THROUGH SATURDAY...

OVERALL VERY WEAK SURFACE FIELD WILL BE IN PLACE TUESDAY INTO
WEDNESDAY AS MODEST HIGH PRESSURE SPANS MUCH OF THE MID-SECTION OF
THE COUNTRY. BARELY 8MB PRESSURE DIFFERENCES BETWEEN BOTH EAST AND
WEST COASTS AND THE PLAINS WILL RESULT IN FAIRLY LIGHT WINDS
ACROSS THE MIDWEST WITH LAKE BREEZES EXPECTED EACH DAY. MODERATING
AIRMASS WILL RESULT IN A WARMING TREND TUESDAY INTO
WEDNESDAY...BUT A SHORTWAVE TROUGH DIGGING INTO THE MIDWEST WILL
BRING A GLANCING BLOW OF COLDER AIR INTO THE REGION THURSDAY.
UPPER RIDGING WILL TRY TO BUILD OVER THE AREA BY LATE IN THE WEEK
INTO THE WEEKEND AND MAY BRING TEMPS WELL INTO THE 70S.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT WITH GUSTS OF 15 TO 20 KT
  THROUGH THIS AFTERNOON.

RODRIGUEZ/KJB

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE HIGH
PRESSURE RIDGE OVER UPPER MIDWEST THROUGH THE FORECAST PERIOD.
THIS WILL MAINTAIN NORTHEAST WINDS OF 10-15 KTS WITH GUSTS
POTENTIALLY NEAR 20 KT GUSTS THIS AFTERNOON. THE SURFACE PRESSURE
GRADIENT WILL WEAKEN A BIT TONIGHT ALLOWING WINDS TO DIMINISH
BELOW 10 KTS. HOWEVER...NORTH-NORTHEASTERLY WINDS COULD AGAIN
CLIMB INTO THE 10 TO 15 KT RANGE ON MONDAY. OTHERWISE EXPECT VFR
CONDITIONS...WITH MAINLY CLEAR SKIES DURING DAY.

KJB

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

* HIGH FOR ALL ELEMENTS.

RODRIGUEZ/KJB

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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




000
FXUS63 KLOT 261604
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1104 AM CDT SUN APR 26 2015

.SHORT TERM...
315 AM CDT

THROUGH MONDAY NIGHT...

REALLY QUIET WEATHER ON TAP THROUGH THE REMAINDER OF THE WEEKEND AND
THROUGH MOST OF THE UPCOMING WEEK. LOW PRESSURE HAS MOVED FROM THE
MID MISSISSIPPI VALLEY TOWARDS THIS MID ATLANTIC COAST THIS MORNING
WITH DRY NORTHEASTERLY FLOW IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA IN ADVANCE OF HIGH PRESSURE BUILDING DOWN FROM THE
CANADIAN PRAIRIES. ONSHORE FLOW AND A MODEST NORTHEAST WIND WILL BE
IN PLACE TODAY KEEPING CONDITIONS COOL ALONG THE LAKE FRONT...WHERE
LOW 50S ARE IN THE FORECAST FOR HIGHS...BUT FARTHER INLAND EXPECT
MID TO UPPER 50S THIS AFTERNOON UNDER MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE A FEW DEGREES WARMER MONDAY...THOUGH SIMILAR
ALONG THE LAKE FRONT. VERY DRY COLUMN OF AIR ADVECTING OVERHEAD WILL
MIX DOWN TO THE SURFACE THIS AFTERNOON WITH DEWPOINTS FALLING INTO
THE MID TO UPPER 20S RESULTING IN RELATIVE HUMIDITY DROPPING INTO
THE 25 TO 35 PERCENT RANGE. THE DRY AIRMASS WILL HELP LEAD TO BIG
DIURNAL CURVES AROUND 30 DEGREES FOR SOME LOCATIONS. LEANED HEAVILY
ON BIAS CORRECTED GUIDANCE TO RESOLVE THE TYPICAL COLD SPOTS AS WE
SHOULD BE UNDER FAVORABLE RADIATIVE COOLING CONDITIONS NEXT COUPLE
NIGHTS...BUT ESPECIALLY MONDAY NIGHT WHEN WINDS BECOME CALM. ADDED
PATCHY FROST TONIGHT AND MONDAY NIGHT OUTSIDE THE CHICAGO METRO.
WINDS REMAIN A LITTLE MORE ELEVATED SO CONFIDENCE IS LOWER FOR
TONIGHT AS COMPARED TO MONDAY NIGHT...SO WILL HOLD OFF ON AN
ADVISORY FOR NOW BUT ONE MAY BE NEEDED.

BMD

&&

.LONG TERM...
315 AM CDT

TUESDAY THROUGH SATURDAY...

OVERALL VERY WEAK SURFACE FIELD WILL BE IN PLACE TUESDAY INTO
WEDNESDAY AS MODEST HIGH PRESSURE SPANS MUCH OF THE MID-SECTION OF
THE COUNTRY. BARELY 8MB PRESSURE DIFFERENCES BETWEEN BOTH EAST AND
WEST COASTS AND THE PLAINS WILL RESULT IN FAIRLY LIGHT WINDS
ACROSS THE MIDWEST WITH LAKE BREEZES EXPECTED EACH DAY. MODERATING
AIRMASS WILL RESULT IN A WARMING TREND TUESDAY INTO
WEDNESDAY...BUT A SHORTWAVE TROUGH DIGGING INTO THE MIDWEST WILL
BRING A GLANCING BLOW OF COLDER AIR INTO THE REGION THURSDAY.
UPPER RIDGING WILL TRY TO BUILD OVER THE AREA BY LATE IN THE WEEK
INTO THE WEEKEND AND MAY BRING TEMPS WELL INTO THE 70S.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT WITH GUSTS OF 15 TO 20 KT
  THROUGH THIS AFTERNOON.

RODRIGUEZ/KJB

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE HIGH
PRESSURE RIDGE OVER UPPER MIDWEST THROUGH THE FORECAST PERIOD.
THIS WILL MAINTAIN NORTHEAST WINDS OF 10-15 KTS WITH GUSTS
POTENTIALLY NEAR 20 KT GUSTS THIS AFTERNOON. THE SURFACE PRESSURE
GRADIENT WILL WEAKEN A BIT TONIGHT ALLOWING WINDS TO DIMINISH
BELOW 10 KTS. HOWEVER...NORTH-NORTHEASTERLY WINDS COULD AGAIN
CLIMB INTO THE 10 TO 15 KT RANGE ON MONDAY. OTHERWISE EXPECT VFR
CONDITIONS...WITH MAINLY CLEAR SKIES DURING DAY.

KJB

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

* HIGH FOR ALL ELEMENTS.

RODRIGUEZ/KJB

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 261604
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1104 AM CDT SUN APR 26 2015

.SHORT TERM...
315 AM CDT

THROUGH MONDAY NIGHT...

REALLY QUIET WEATHER ON TAP THROUGH THE REMAINDER OF THE WEEKEND AND
THROUGH MOST OF THE UPCOMING WEEK. LOW PRESSURE HAS MOVED FROM THE
MID MISSISSIPPI VALLEY TOWARDS THIS MID ATLANTIC COAST THIS MORNING
WITH DRY NORTHEASTERLY FLOW IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA IN ADVANCE OF HIGH PRESSURE BUILDING DOWN FROM THE
CANADIAN PRAIRIES. ONSHORE FLOW AND A MODEST NORTHEAST WIND WILL BE
IN PLACE TODAY KEEPING CONDITIONS COOL ALONG THE LAKE FRONT...WHERE
LOW 50S ARE IN THE FORECAST FOR HIGHS...BUT FARTHER INLAND EXPECT
MID TO UPPER 50S THIS AFTERNOON UNDER MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE A FEW DEGREES WARMER MONDAY...THOUGH SIMILAR
ALONG THE LAKE FRONT. VERY DRY COLUMN OF AIR ADVECTING OVERHEAD WILL
MIX DOWN TO THE SURFACE THIS AFTERNOON WITH DEWPOINTS FALLING INTO
THE MID TO UPPER 20S RESULTING IN RELATIVE HUMIDITY DROPPING INTO
THE 25 TO 35 PERCENT RANGE. THE DRY AIRMASS WILL HELP LEAD TO BIG
DIURNAL CURVES AROUND 30 DEGREES FOR SOME LOCATIONS. LEANED HEAVILY
ON BIAS CORRECTED GUIDANCE TO RESOLVE THE TYPICAL COLD SPOTS AS WE
SHOULD BE UNDER FAVORABLE RADIATIVE COOLING CONDITIONS NEXT COUPLE
NIGHTS...BUT ESPECIALLY MONDAY NIGHT WHEN WINDS BECOME CALM. ADDED
PATCHY FROST TONIGHT AND MONDAY NIGHT OUTSIDE THE CHICAGO METRO.
WINDS REMAIN A LITTLE MORE ELEVATED SO CONFIDENCE IS LOWER FOR
TONIGHT AS COMPARED TO MONDAY NIGHT...SO WILL HOLD OFF ON AN
ADVISORY FOR NOW BUT ONE MAY BE NEEDED.

BMD

&&

.LONG TERM...
315 AM CDT

TUESDAY THROUGH SATURDAY...

OVERALL VERY WEAK SURFACE FIELD WILL BE IN PLACE TUESDAY INTO
WEDNESDAY AS MODEST HIGH PRESSURE SPANS MUCH OF THE MID-SECTION OF
THE COUNTRY. BARELY 8MB PRESSURE DIFFERENCES BETWEEN BOTH EAST AND
WEST COASTS AND THE PLAINS WILL RESULT IN FAIRLY LIGHT WINDS
ACROSS THE MIDWEST WITH LAKE BREEZES EXPECTED EACH DAY. MODERATING
AIRMASS WILL RESULT IN A WARMING TREND TUESDAY INTO
WEDNESDAY...BUT A SHORTWAVE TROUGH DIGGING INTO THE MIDWEST WILL
BRING A GLANCING BLOW OF COLDER AIR INTO THE REGION THURSDAY.
UPPER RIDGING WILL TRY TO BUILD OVER THE AREA BY LATE IN THE WEEK
INTO THE WEEKEND AND MAY BRING TEMPS WELL INTO THE 70S.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT WITH GUSTS OF 15 TO 20 KT
  THROUGH THIS AFTERNOON.

RODRIGUEZ/KJB

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE HIGH
PRESSURE RIDGE OVER UPPER MIDWEST THROUGH THE FORECAST PERIOD.
THIS WILL MAINTAIN NORTHEAST WINDS OF 10-15 KTS WITH GUSTS
POTENTIALLY NEAR 20 KT GUSTS THIS AFTERNOON. THE SURFACE PRESSURE
GRADIENT WILL WEAKEN A BIT TONIGHT ALLOWING WINDS TO DIMINISH
BELOW 10 KTS. HOWEVER...NORTH-NORTHEASTERLY WINDS COULD AGAIN
CLIMB INTO THE 10 TO 15 KT RANGE ON MONDAY. OTHERWISE EXPECT VFR
CONDITIONS...WITH MAINLY CLEAR SKIES DURING DAY.

KJB

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

* HIGH FOR ALL ELEMENTS.

RODRIGUEZ/KJB

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 261604
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1104 AM CDT SUN APR 26 2015

.SHORT TERM...
315 AM CDT

THROUGH MONDAY NIGHT...

REALLY QUIET WEATHER ON TAP THROUGH THE REMAINDER OF THE WEEKEND AND
THROUGH MOST OF THE UPCOMING WEEK. LOW PRESSURE HAS MOVED FROM THE
MID MISSISSIPPI VALLEY TOWARDS THIS MID ATLANTIC COAST THIS MORNING
WITH DRY NORTHEASTERLY FLOW IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA IN ADVANCE OF HIGH PRESSURE BUILDING DOWN FROM THE
CANADIAN PRAIRIES. ONSHORE FLOW AND A MODEST NORTHEAST WIND WILL BE
IN PLACE TODAY KEEPING CONDITIONS COOL ALONG THE LAKE FRONT...WHERE
LOW 50S ARE IN THE FORECAST FOR HIGHS...BUT FARTHER INLAND EXPECT
MID TO UPPER 50S THIS AFTERNOON UNDER MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE A FEW DEGREES WARMER MONDAY...THOUGH SIMILAR
ALONG THE LAKE FRONT. VERY DRY COLUMN OF AIR ADVECTING OVERHEAD WILL
MIX DOWN TO THE SURFACE THIS AFTERNOON WITH DEWPOINTS FALLING INTO
THE MID TO UPPER 20S RESULTING IN RELATIVE HUMIDITY DROPPING INTO
THE 25 TO 35 PERCENT RANGE. THE DRY AIRMASS WILL HELP LEAD TO BIG
DIURNAL CURVES AROUND 30 DEGREES FOR SOME LOCATIONS. LEANED HEAVILY
ON BIAS CORRECTED GUIDANCE TO RESOLVE THE TYPICAL COLD SPOTS AS WE
SHOULD BE UNDER FAVORABLE RADIATIVE COOLING CONDITIONS NEXT COUPLE
NIGHTS...BUT ESPECIALLY MONDAY NIGHT WHEN WINDS BECOME CALM. ADDED
PATCHY FROST TONIGHT AND MONDAY NIGHT OUTSIDE THE CHICAGO METRO.
WINDS REMAIN A LITTLE MORE ELEVATED SO CONFIDENCE IS LOWER FOR
TONIGHT AS COMPARED TO MONDAY NIGHT...SO WILL HOLD OFF ON AN
ADVISORY FOR NOW BUT ONE MAY BE NEEDED.

BMD

&&

.LONG TERM...
315 AM CDT

TUESDAY THROUGH SATURDAY...

OVERALL VERY WEAK SURFACE FIELD WILL BE IN PLACE TUESDAY INTO
WEDNESDAY AS MODEST HIGH PRESSURE SPANS MUCH OF THE MID-SECTION OF
THE COUNTRY. BARELY 8MB PRESSURE DIFFERENCES BETWEEN BOTH EAST AND
WEST COASTS AND THE PLAINS WILL RESULT IN FAIRLY LIGHT WINDS
ACROSS THE MIDWEST WITH LAKE BREEZES EXPECTED EACH DAY. MODERATING
AIRMASS WILL RESULT IN A WARMING TREND TUESDAY INTO
WEDNESDAY...BUT A SHORTWAVE TROUGH DIGGING INTO THE MIDWEST WILL
BRING A GLANCING BLOW OF COLDER AIR INTO THE REGION THURSDAY.
UPPER RIDGING WILL TRY TO BUILD OVER THE AREA BY LATE IN THE WEEK
INTO THE WEEKEND AND MAY BRING TEMPS WELL INTO THE 70S.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT WITH GUSTS OF 15 TO 20 KT
  THROUGH THIS AFTERNOON.

RODRIGUEZ/KJB

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE HIGH
PRESSURE RIDGE OVER UPPER MIDWEST THROUGH THE FORECAST PERIOD.
THIS WILL MAINTAIN NORTHEAST WINDS OF 10-15 KTS WITH GUSTS
POTENTIALLY NEAR 20 KT GUSTS THIS AFTERNOON. THE SURFACE PRESSURE
GRADIENT WILL WEAKEN A BIT TONIGHT ALLOWING WINDS TO DIMINISH
BELOW 10 KTS. HOWEVER...NORTH-NORTHEASTERLY WINDS COULD AGAIN
CLIMB INTO THE 10 TO 15 KT RANGE ON MONDAY. OTHERWISE EXPECT VFR
CONDITIONS...WITH MAINLY CLEAR SKIES DURING DAY.

KJB

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

* HIGH FOR ALL ELEMENTS.

RODRIGUEZ/KJB

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KLOT 261604
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1104 AM CDT SUN APR 26 2015

.SHORT TERM...
315 AM CDT

THROUGH MONDAY NIGHT...

REALLY QUIET WEATHER ON TAP THROUGH THE REMAINDER OF THE WEEKEND AND
THROUGH MOST OF THE UPCOMING WEEK. LOW PRESSURE HAS MOVED FROM THE
MID MISSISSIPPI VALLEY TOWARDS THIS MID ATLANTIC COAST THIS MORNING
WITH DRY NORTHEASTERLY FLOW IN PLACE ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA IN ADVANCE OF HIGH PRESSURE BUILDING DOWN FROM THE
CANADIAN PRAIRIES. ONSHORE FLOW AND A MODEST NORTHEAST WIND WILL BE
IN PLACE TODAY KEEPING CONDITIONS COOL ALONG THE LAKE FRONT...WHERE
LOW 50S ARE IN THE FORECAST FOR HIGHS...BUT FARTHER INLAND EXPECT
MID TO UPPER 50S THIS AFTERNOON UNDER MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE A FEW DEGREES WARMER MONDAY...THOUGH SIMILAR
ALONG THE LAKE FRONT. VERY DRY COLUMN OF AIR ADVECTING OVERHEAD WILL
MIX DOWN TO THE SURFACE THIS AFTERNOON WITH DEWPOINTS FALLING INTO
THE MID TO UPPER 20S RESULTING IN RELATIVE HUMIDITY DROPPING INTO
THE 25 TO 35 PERCENT RANGE. THE DRY AIRMASS WILL HELP LEAD TO BIG
DIURNAL CURVES AROUND 30 DEGREES FOR SOME LOCATIONS. LEANED HEAVILY
ON BIAS CORRECTED GUIDANCE TO RESOLVE THE TYPICAL COLD SPOTS AS WE
SHOULD BE UNDER FAVORABLE RADIATIVE COOLING CONDITIONS NEXT COUPLE
NIGHTS...BUT ESPECIALLY MONDAY NIGHT WHEN WINDS BECOME CALM. ADDED
PATCHY FROST TONIGHT AND MONDAY NIGHT OUTSIDE THE CHICAGO METRO.
WINDS REMAIN A LITTLE MORE ELEVATED SO CONFIDENCE IS LOWER FOR
TONIGHT AS COMPARED TO MONDAY NIGHT...SO WILL HOLD OFF ON AN
ADVISORY FOR NOW BUT ONE MAY BE NEEDED.

BMD

&&

.LONG TERM...
315 AM CDT

TUESDAY THROUGH SATURDAY...

OVERALL VERY WEAK SURFACE FIELD WILL BE IN PLACE TUESDAY INTO
WEDNESDAY AS MODEST HIGH PRESSURE SPANS MUCH OF THE MID-SECTION OF
THE COUNTRY. BARELY 8MB PRESSURE DIFFERENCES BETWEEN BOTH EAST AND
WEST COASTS AND THE PLAINS WILL RESULT IN FAIRLY LIGHT WINDS
ACROSS THE MIDWEST WITH LAKE BREEZES EXPECTED EACH DAY. MODERATING
AIRMASS WILL RESULT IN A WARMING TREND TUESDAY INTO
WEDNESDAY...BUT A SHORTWAVE TROUGH DIGGING INTO THE MIDWEST WILL
BRING A GLANCING BLOW OF COLDER AIR INTO THE REGION THURSDAY.
UPPER RIDGING WILL TRY TO BUILD OVER THE AREA BY LATE IN THE WEEK
INTO THE WEEKEND AND MAY BRING TEMPS WELL INTO THE 70S.

BMD

&&

.AVIATION...

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

* NORTHEAST WINDS AT/ABOVE 10 KT WITH GUSTS OF 15 TO 20 KT
  THROUGH THIS AFTERNOON.

RODRIGUEZ/KJB

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

THE REGION WILL REMAIN WITHIN SOUTHERN PERIPHERY OF A SURFACE HIGH
PRESSURE RIDGE OVER UPPER MIDWEST THROUGH THE FORECAST PERIOD.
THIS WILL MAINTAIN NORTHEAST WINDS OF 10-15 KTS WITH GUSTS
POTENTIALLY NEAR 20 KT GUSTS THIS AFTERNOON. THE SURFACE PRESSURE
GRADIENT WILL WEAKEN A BIT TONIGHT ALLOWING WINDS TO DIMINISH
BELOW 10 KTS. HOWEVER...NORTH-NORTHEASTERLY WINDS COULD AGAIN
CLIMB INTO THE 10 TO 15 KT RANGE ON MONDAY. OTHERWISE EXPECT VFR
CONDITIONS...WITH MAINLY CLEAR SKIES DURING DAY.

KJB

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

* HIGH FOR ALL ELEMENTS.

RODRIGUEZ/KJB

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

MONDAY NIGHT THROUGH THURSDAY...PRIMARILY VFR. NORTH-NORTHEAST
WINDS.

FRIDAY...VFR. CHANCE OF SHOWERS FRIDAY NIGHT SOUTHWEST WINDS.

SATURDAY...VFR. SOUTHWEST WINDS.

KJB

&&

.MARINE...
126 AM CDT

THE COMBINATION OF A SURFACE RIDGE OF HIGH PRESSURE OVER ONTARIO AND
THE UPPER MIDWEST AND LOWER PRESSURE OVER THE EASTERN LAKES
REGION...WILL CONTINUE TO RESULT IN A MODERATE NORTHERLY WIND UP
AROUND 25 KT TODAY THROUGH MONDAY. THIS WILL PARTICULARLY BE THE
CASE OVER THE SOUTHERN HALF OF THE LAKE. THE SURFACE GRADIENT WILL
WEAKEN CONSIDERABLE LATER MONDAY AND TUESDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE SETS UP OVER THE LAKES REGION. THIS SHOULD RESULT IN A
WEAK WIND REGIME THROUGH AT LEAST MIDWEEK OVER THE LAKE.
THEREFORE...WIND SPEEDS AND DIRECTIONS WILL LIKELY BE LARGELY DRIVEN
BY LAKE AND LAND BREEZE INFLUENCES.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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

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



000
FXUS63 KILX 261545
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1045 AM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 1041 AM CDT SUN APR 26 2015
HIGH PRESSURE BUILDING BACK INTO THE REGION WITH A SFC RIDGE AXIS
JUST TO THE WEST. NORTH/NORTHEASTERLY WINDS CONTINUE THROUGH THE
DAY, GETTING A LITTLE GUSTY LATER THIS AFTERNOON WITH A LITTLE BIT
OF MIXING. MODELS HINTING AT A LITTLE BIT OF MOISTURE BTWN
5000-8000 FT OR SO. CU RULE NOT PARTICULARLY STRONG UNDER THE
RIDGE AND MIXING MAY INHIBIT A LOT OF CU...BUT STILL POSSIBLE TO
SEE A FEW LATER THIS AFTERNOON. OTHERWISE QUIET, AND NO
SIGNIFICANT UPDATES ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

LOW CLOUDS CONTINUE TO GRADUALLY WORK THEIR WAY SOUTH THROUGH
CENTRAL AND EAST CENTRAL IL EARLY THIS MORNING AS DRIER AIR
ADVECTS FROM THE NORTHEAST. MOSTLY CLOUDY CONDITIONS WILL LINGER
IN SOUTHEAST IL FROM DAYBREAK UNTIL MID-MORNING. PLENTY OF LOW
LEVEL MIXING IN THE LOWER ATMOSPHERE LATE THIS MORNING THROUGH THE
AFTERNOON WILL RESULT IN NORTHEAST WINDS GUSTING CLOSE TO 20 MPH
ESPECIALLY EAST OF THE I-55 CORRIDOR. DESPITE PLENTY OF SUNSHINE
BY AFTERNOON...HIGHS TODAY WILL MAINLY BE AROUND 60 DEGREES DUE
TO THE DEEP LOW LEVEL NORTHEAST FLOW.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

FAIRLY QUIET WEATHER ON TAP ACROSS THE FORECAST AREA MUCH OF THE
WEEK. PERSISTENT NORTHEAST FLOW TO KEEP DRY CONDITIONS IN PLACE...
WITH HIGH TEMPERATURES RISING A COUPLE DEGREES EACH DAY UNTIL WE
FINALLY GET NEAR OR JUST ABOVE NORMAL BY THE END OF THE WORK WEEK.

UPPER LOW CURRENTLY IN THE PROCESS OF CLOSING OFF OVER WESTERN
ARIZONA...AND THIS WILL BE TRACKING ACROSS THE SOUTHERN U.S. OVER
THE NEXT FEW DAYS. ALL OF THE MODELS KEEP THE ASSOCIATED MOISTURE
SOUTH OF THE OHIO VALLEY. A SHORTWAVE WILL ALSO BE TRACKING ALONG
THE CANADIAN BORDER...AND AS PREVIOUS MODEL RUNS INDICATED, A SMALL
CLOSED LOW WILL PINCH OFF IN THE SOUTHERN PART OF THE WAVE. THE
ECMWF AND CANADIAN MODELS HAVE THIS SMALL LOW DROPPING ACROSS
MINNESOTA AND IOWA TUESDAY NIGHT...WHILE THE TAIL END OF THE NAM
BRINGS THIS INTO NORTHERN ILLINOIS AND THE GFS PROGRESSES THE WAVE
WELL EAST BEFORE THE LOW CAN FORM. NET RESULT OF ALL OF THIS IS FOR
DRY CONDITIONS MID WEEK.

AS WE GET LATER IN THE WEEK...UPPER RIDGING WILL BUILD NORTHEAST
ACROSS THE PLAINS INTO MANITOBA...WHILE GENERAL BROAD TROUGHING
CONTINUES ACROSS THE EASTERN U.S. THIS RIDGE FLATTENS BY FRIDAY AS
THE NORTHERN STREAM BECOMES MORE ACTIVE ALONG THE CANADIAN BORDER.
BOTH THE GFS AND ECMWF BRING A SURFACE BOUNDARY THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY...WITH SOME LIGHT PRECIPITATION. THE
SOLUTIONS BEGIN TO DIVERGE BY EVENING...AS THE GFS BRINGS A STRONGER
UPPER WAVE AND SURFACE FRONT THROUGH SATURDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...ALTHOUGH THE ECMWF DOES HINT AT POTENTIAL MCS
ACTIVITY AS WELL. WITH THE MORE DIVERGENT SOLUTIONS...HAVE KEPT THE
LATE WEEKEND FORECAST DRY FOR NOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 638 AM CDT SUN APR 26 2015

THE BACK EDGE OF MVFR/IFR CLOUDS IS JUST SOUTH OF I-70 AS OF
1130Z. A DEEP NORTHEAST FLOW IN THE LOWER ATMOSPHERE WILL
CONTINUE TO BRING DRY AIR INTO CENTRAL IL TODAY AND PUSH THE LOW
CLOUDS FARTHER AWAY FROM THE REGION. HAVE SEEN MVFR VISIBILITY
JUST DEVELOP IN EAST CENTRAL IL...SO WILL CONTINUE THIS IN THE TAF
FOR KCMI UNTIL 14Z WHEN INCREASING WIND SPEEDS WILL MIX OUT THE
LIGHT FOG.

NAM FORECAST SOUNDINGS INDICATE THAT THE LOW LEVEL MIXING WILL
RESULT IN A TREND TOWARD SOMEWHAT GUSTY WINDS IN THE 15-20 KT
RANGE FROM LATE MORNING THROUGH THE AFTERNOON IN ALL OF CENTRAL
AND EASTERN IL. THE RAP AND NAM MODELS BOTH INDICATE THAT THERE
SHOULD BE ENOUGH MOISTURE FOR AT LEAST SCATTERED CUMULUS LATER
THIS MORNING AND ESPECIALLY DURING THE AFTERNOON.

THE LOWER LEVELS WILL GO THROUGH THE TYPICAL EARLY EVENING
DECOUPLING WITH A CLEAR SKY AND VERY LIGHT WIND OVERNIGHT. AM NOT
EXPECTING ANY FOG AT THIS POINT SINCE THE BREEZY CONDITIONS AND
MIXING THIS AFTERNOON SHOULD HELP DRY OUT THE LOWEST LAYERS AND
SURFACE.


&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER



000
FXUS63 KILX 261545
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1045 AM CDT SUN APR 26 2015

.UPDATE...
ISSUED AT 1041 AM CDT SUN APR 26 2015
HIGH PRESSURE BUILDING BACK INTO THE REGION WITH A SFC RIDGE AXIS
JUST TO THE WEST. NORTH/NORTHEASTERLY WINDS CONTINUE THROUGH THE
DAY, GETTING A LITTLE GUSTY LATER THIS AFTERNOON WITH A LITTLE BIT
OF MIXING. MODELS HINTING AT A LITTLE BIT OF MOISTURE BTWN
5000-8000 FT OR SO. CU RULE NOT PARTICULARLY STRONG UNDER THE
RIDGE AND MIXING MAY INHIBIT A LOT OF CU...BUT STILL POSSIBLE TO
SEE A FEW LATER THIS AFTERNOON. OTHERWISE QUIET, AND NO
SIGNIFICANT UPDATES ANTICIPATED AT THIS TIME.

&&

.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

LOW CLOUDS CONTINUE TO GRADUALLY WORK THEIR WAY SOUTH THROUGH
CENTRAL AND EAST CENTRAL IL EARLY THIS MORNING AS DRIER AIR
ADVECTS FROM THE NORTHEAST. MOSTLY CLOUDY CONDITIONS WILL LINGER
IN SOUTHEAST IL FROM DAYBREAK UNTIL MID-MORNING. PLENTY OF LOW
LEVEL MIXING IN THE LOWER ATMOSPHERE LATE THIS MORNING THROUGH THE
AFTERNOON WILL RESULT IN NORTHEAST WINDS GUSTING CLOSE TO 20 MPH
ESPECIALLY EAST OF THE I-55 CORRIDOR. DESPITE PLENTY OF SUNSHINE
BY AFTERNOON...HIGHS TODAY WILL MAINLY BE AROUND 60 DEGREES DUE
TO THE DEEP LOW LEVEL NORTHEAST FLOW.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 26 2015

FAIRLY QUIET WEATHER ON TAP ACROSS THE FORECAST AREA MUCH OF THE
WEEK. PERSISTENT NORTHEAST FLOW TO KEEP DRY CONDITIONS IN PLACE...
WITH HIGH TEMPERATURES RISING A COUPLE DEGREES EACH DAY UNTIL WE
FINALLY GET NEAR OR JUST ABOVE NORMAL BY THE END OF THE WORK WEEK.

UPPER LOW CURRENTLY IN THE PROCESS OF CLOSING OFF OVER WESTERN
ARIZONA...AND THIS WILL BE TRACKING ACROSS THE SOUTHERN U.S. OVER
THE NEXT FEW DAYS. ALL OF THE MODELS KEEP THE ASSOCIATED MOISTURE
SOUTH OF THE OHIO VALLEY. A SHORTWAVE WILL ALSO BE TRACKING ALONG
THE CANADIAN BORDER...AND AS PREVIOUS MODEL RUNS INDICATED, A SMALL
CLOSED LOW WILL PINCH OFF IN THE SOUTHERN PART OF THE WAVE. THE
ECMWF AND CANADIAN MODELS HAVE THIS SMALL LOW DROPPING ACROSS
MINNESOTA AND IOWA TUESDAY NIGHT...WHILE THE TAIL END OF THE NAM
BRINGS THIS INTO NORTHERN ILLINOIS AND THE GFS PROGRESSES THE WAVE
WELL EAST BEFORE THE LOW CAN FORM. NET RESULT OF ALL OF THIS IS FOR
DRY CONDITIONS MID WEEK.

AS WE GET LATER IN THE WEEK...UPPER RIDGING WILL BUILD NORTHEAST
ACROSS THE PLAINS INTO MANITOBA...WHILE GENERAL BROAD TROUGHING
CONTINUES ACROSS THE EASTERN U.S. THIS RIDGE FLATTENS BY FRIDAY AS
THE NORTHERN STREAM BECOMES MORE ACTIVE ALONG THE CANADIAN BORDER.
BOTH THE GFS AND ECMWF BRING A SURFACE BOUNDARY THROUGH THE AREA
FRIDAY NIGHT AND SATURDAY...WITH SOME LIGHT PRECIPITATION. THE
SOLUTIONS BEGIN TO DIVERGE BY EVENING...AS THE GFS BRINGS A STRONGER
UPPER WAVE AND SURFACE FRONT THROUGH SATURDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...ALTHOUGH THE ECMWF DOES HINT AT POTENTIAL MCS
ACTIVITY AS WELL. WITH THE MORE DIVERGENT SOLUTIONS...HAVE KEPT THE
LATE WEEKEND FORECAST DRY FOR NOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 638 AM CDT SUN APR 26 2015

THE BACK EDGE OF MVFR/IFR CLOUDS IS JUST SOUTH OF I-70 AS OF
1130Z. A DEEP NORTHEAST FLOW IN THE LOWER ATMOSPHERE WILL
CONTINUE TO BRING DRY AIR INTO CENTRAL IL TODAY AND PUSH THE LOW
CLOUDS FARTHER AWAY FROM THE REGION. HAVE SEEN MVFR VISIBILITY
JUST DEVELOP IN EAST CENTRAL IL...SO WILL CONTINUE THIS IN THE TAF
FOR KCMI UNTIL 14Z WHEN INCREASING WIND SPEEDS WILL MIX OUT THE
LIGHT FOG.

NAM FORECAST SOUNDINGS INDICATE THAT THE LOW LEVEL MIXING WILL
RESULT IN A TREND TOWARD SOMEWHAT GUSTY WINDS IN THE 15-20 KT
RANGE FROM LATE MORNING THROUGH THE AFTERNOON IN ALL OF CENTRAL
AND EASTERN IL. THE RAP AND NAM MODELS BOTH INDICATE THAT THERE
SHOULD BE ENOUGH MOISTURE FOR AT LEAST SCATTERED CUMULUS LATER
THIS MORNING AND ESPECIALLY DURING THE AFTERNOON.

THE LOWER LEVELS WILL GO THROUGH THE TYPICAL EARLY EVENING
DECOUPLING WITH A CLEAR SKY AND VERY LIGHT WIND OVERNIGHT. AM NOT
EXPECTING ANY FOG AT THIS POINT SINCE THE BREEZY CONDITIONS AND
MIXING THIS AFTERNOON SHOULD HELP DRY OUT THE LOWEST LAYERS AND
SURFACE.


&&

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

$$

UPDATE...HJS
SHORT TERM...MILLER
LONG TERM...GEELHART
AVIATION...MILLER




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