Area Forecast Discussion
Issued by NWS Chicago, IL

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156
FXUS63 KLOT 021915
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
215 PM CDT MON MAY 2 2016

.SHORT TERM...
215 PM CDT

THROUGH TUESDAY...

DRY AIR CONTINUES TO SLIDE SOUTH/SOUTHWEST ACROSS NORTHERN IL...AS
DEW POINTS HAVE FALLEN INTO THE MID/UPR 30S ACROSS FAR NORTHCENTRAL
IL. FURTHER SOUTH DEW POINTS ARE GENERALLY AROUND 40 THE LOWER 40S.
CLOUDS HAVE REMAINED MINIMAL ACROSS MUCH OF THE AREA...WITH SOME
DIURNAL CUMULUS WEST OF THE CHICAGO METRO AREA. JUST BEYOND PEAK
HEATING OF THE AFTERNOON THE DIURNAL CUMULUS SHOULD BEGIN TO
DISSIPATE...WITH THE NORTHEAST WINDS DIMINISHING TO AROUND 5 TO 10
MPH. HIGH PRESSURE CENTERED TO THE NORTH OF THE AREA WILL KEEP WINDS
LIGHT AND VARIABLE OVERNIGHT...WHICH COULD ALLOW TEMPERATURES TO
STEADILY RADIATE INTO THE LOWER 40S. HOWEVER AREAS THAT HAVE HAD DEW
POINTS THIS AFTERNOON FALL INTO THE MIDDLE 30S...TEMPS TONIGHT COULD
DIP INTO THE UPPER 30S BETWEEN ROCKFORD AND WAUKEGAN DOWN TO DEKALB.
HAVE INCLUDED PATCHY FROST WORDING OVERNIGHT.

TUESDAY... BROAD SFC RIDGING WILL CONSOLIDATE TO A RIDGE OVER THE
CENTRAL ROCKIES/PLAINS...WHICH WILL ALLOW A WEST/EAST GRADIENT TO
DEVELOP MIDDAY TUESDAY. WITH MINIMAL CLOUD COVER TO START THE DAY
TEMPS WILL QUICKLY WARM INTO THE 50S AND EVENTUALLY MIDDLE TO UPPER
60S BY EARLY AFTERNOON ACROSS NORTHERN IL. WEST WINDS WILL INCREASE
AS WELL...WITH THE FOCUS FOR LATE AFTERNOON/EVENING TURNING TOWARDS
A SHORTWAVE SLIDING EAST ACROSS LAKE SUPERIOR AND A TRAILING FRONTAL
BOUNDARY PROGGED TO DIVE SOUTH ACROSS THE WESTERN GREAT LAKES.
GUIDANCE HAS REMAINED RELATIVELY CONSISTENT WITH THE BEST CHANCE FOR
PRECIP ARRIVING AROUND THE EVENING HOURS FROM THE NORTH TUESDAY.

BEACHLER

&&

.LONG TERM...
356 AM CDT

TUESDAY NIGHT THROUGH SUNDAY...

UPPER PATTERN IS HIGHLY AMPLIFIED BY MID-WEEK...WITH DEEP TROUGHS
OVER BOTH COASTS AND AN UPPER RIDGE ACROSS THE CENTRAL CONUS. AS
THE RIDGE DRIFTS EASTWARD...RISING HEIGHTS/SUBSIDENCE RESULT IN
SURFACE HIGH PRESSURE BUILDING INTO THE REGION THURSDAY AND
BRINGING DRY AND WARMER WEATHER TO THE AREA FOR THE END OF THE
WEEK. THURSDAY WILL STILL BE A BIT ON THE COOL SIDE WITH TEMPS IN
THE UPPER 50S-LOW 60S IN THE VICINITY OF THE SURFACE RIDGE AND
WITH LIGHT NORTHERLY WINDS AND LAKE BREEZES. 70S RETURN FRIDAY AND
SATURDAY HOWEVER AS WINDS TURN SOUTHWEST AS AN AREA OF LOW
PRESSURE TRACKS NORTH OF LAKE SUPERIOR AND TRAILS A COLD FRONT
ACROSS THE UPPER MIDWEST. THIS FRONT WILL SAG ACROSS THE AREA LATE
SATURDAY...WITH AN ATTENDANT CHANCE OF THUNDERSTORMS...THEN BECOME
STATIONARY SOUTH OF THE CWA SUNDAY AS WEAK HIGH PRESSURE SPREADS
ACROSS THE NORTHERN LAKES. THIS WILL LIKELY SET UP A NORTH-SOUTH
GRADIENT OF TEMPS WITH 70S ACROSS CENTRAL IL/IN SUNDAY...AND
COOLER 50S-60S ACROSS FAR NORTHEAST IL NEAR LAKE MICHIGAN.
PRESENCE OF THE SURFACE FRONT AND ELEVATED BAROCLINIC ZONE TO ITS
NORTH WILL MAINTAIN THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH SUNDAY.

RATZER

&&

.AVIATION...
FOR THE 18Z TAFS...

DRY AIR CONTINUES TO SLIDE SOUTH FROM SOUTHERN WISCONSIN INTO
NORTHERN IL AIRFIELDS...WITH MINIMAL CLOUD COVER AND VFR CONDS
EXPECTED TO PERSIST THROUGH THE NEXT 24 HOURS. WITH HIGH PRESSURE
CENTERED TO THE NORTH...WINDS HAVE REMAINED NORTHEASTERLY BETWEEN
030 TO 050 DEGREES AND SPEEDS OF 10 TO 12KT WITH OCCASIONAL GUSTS
TO 20KT. CLOSER TO SUNSET WINDS ARE EXPECTED TO FURTHER
DIMINISH...THEN BEGIN TO TURN NORTHERLY WITH SPEEDS AROUND 4-6KT
BY 3Z. WINDS WILL THEN BECOME VARIABLE TO NORTHWESTERLY OVERNIGHT
WITH NEAR CLOUDLESS SKIES. SHORTLY AFTER DAYBREAK TUE WINDS WILL
BECOME WESTERLY WITH INCREASING SPEEDS TO AROUND 12-15KT AND
OCCASIONAL GUSTS DEVELOPING BY MIDDAY TO 18KT. CLOUDS WILL BE
SLOWLY ON THE INCREASE BY LATE AFTERNOON INTO EARLY TUESDAY
EVENING.

BEACHLER

&&

.MARINE...
300 AM CDT

LOW PRESSURE IS DEPARTING THE REGION EARLY THIS MORNING WITH SOME
LINGERING 15 TO 20 KT WINDS STILL IN PLACE ACROSS SOUTHERN LAKE
MICHIGAN...BUT PROGGED TO CONTINUE TO DIMINISH THROUGH THE
MORNING. HIGH PRESSURE WILL BUILD ACROSS LAKE MICHIGAN THIS
EVENING AND TONIGHT...THEN SOUTHWESTERLY FLOW WILL DEVELOP ON
TUESDAY AS LOW PRESSURE MOVES ACROSS ONTARIO. THE LOW WILL MOVE
SOUTHEAST TO THE EASTERN GREAT LAKES REGION BY WEDNESDAY...BUT A
TRAILING COLD FRONT IS PROGGED TO MOVE SOUTH ACROSS LAKE MICHIGAN
TUESDAY NIGHT. NORTH WINDS GUSTING TO 30 KT ARE EXPECTED TO
DEVELOP BEHIND THE FRONT LATE TUESDAY NIGHT AND CONTINUE THROUGH
THE DAY WEDNESDAY. WINDS SHOULD BEGIN TO DIMINISH THURSDAY AS
ANOTHER RIDGE APPROACHES THE REGION.

BMD

&&

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

$$

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