803
FXUS63 KLOT 031140
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
640 AM CDT TUE JUN 3 2025
KEY MESSAGES
- SLOW MOVING BAND OF SHOWERS AND SOME THUNDERSTORMS WILL MOVE
ACROSS THE AREA TONIGHT AND WEDNESDAY.
- TRENDING DRIER WITH SEASONABLE TO SEASONABLY COOL CONDITIONS
LATE THIS WEEK AND INTO THE WEEKEND.
DISCUSSION
ISSUED AT 312 AM CDT TUE JUN 3 2025
THROUGH WEDNESDAY:
WINDY AND WARM WEATHER IS ON TAP FOR TODAY WITH THE WARMEST
READINGS OVER THE SOUTHEAST 2/3RD OR SO OF THE AREA WHERE THERE
WILL BE THE MOST (SMOKE FILTERED) PARTIAL SUNSHINE. DESPITE THE
SMOKE, TEMPERATURES ACROSS IA REACHED THE UPPER 80S TO AROUND 90
MONDAY. DESPITE THE SMOKE YESTERDAY, GUIDANCE PERFORMED WELL, SO
WITH THINNER SMOKE EXPECTED TODAY, FELT COMFORTABLE STICK WITH
MIDDLE OF THE PACK GUIDANCE TEMPS WITH MID TO A FEW UPPER 80S,
EXCEPT NORTHWEST CWA WHERE THICKER CLOUD COVER SHOULD ARRIVE BY
LATE THIS MORNING.
FORECAST BUFKIT SOUNDINGS TODAY SHOW A FAIRLY DEEP AND WELL
MIXED BOUNDARY LAYER THAT TAPS INTO AN SYNOPTIC LOW LEVEL JET.
THESE SOUNDINGS WOULD SUPPORT GUSTS OVER 30 KT AT TIMES THIS
AFTERNOON. WHILE INCREASING CLOUD COVER AND SOME LINGERING SMOKE
OVER EASTERN CWA DOES LOWER CONFIDENCE A BIT, DID OPT TO BUMP
WINDS/GUSTS UP THIS AFTERNOON. IF TEMPS UNDER-PERFORM THAT
WOULD LEAD TO LESS MIXING AND LIMIT THE GUSTINESS SOME.
SOME GUIDANCE DOES BRING SOME REMNANT PRECIP FROM THE
CONVECTION OVER THE PLAINS INTO OUR CWA THIS AFTERNOON, THOUGH
GIVEN IT WILL BE ENCOUNTERING A PROGRESSIVELY DRIER AND MORE
STABLE AIR MASS, OPTED TO KEEP POPS ON THE LOWER END OF THE
SPECTRUM TODAY AND MOSTLY CONFINED TO NORTHERN AND WESTERN CWA.
A STRONG SHORTWAVE TROUGH OVER CO/NM EARLY THIS MORNING IS
PROGGED TO RATHER QUICKLY DAMPEN TODAY AND ESPECIALLY TONIGHT AS
IT MOVES INTO AN INCREASINGLY CONFLUENT FLOW OVER THE MIDWEST.
EARLY THIS AFTERNOON, CONVECTION IS EXPECTED TO LIGHT UP FRONT
EASTERN KS INTO WESTERN MO AND SOUTHERN IS ALONG A SLOWLY
APPROACHING COLD FRONT, LIKELY AIDED BY THIS SHORTWAVE TROUGH.
THE COLD FRONT AND ASSOCIATED BAND OF SHOWERS AND THUNDERSTORMS
IS EXPECTED TO GRADUALLY MOVE INTO NW IL EARLY THIS EVENING.
FORWARD PROGRESS OF THE FRONT (AND SHOWERS/STORMS) WILL SLOW AS
IT BECOMING INCREASINGLY ALIGNED WITH THE MID-UPPER LEVEL FLOW
AND PARENT NORTHERN STREAM SHORTWAVE ZIPS AWAY, LEAVING THE
FRONT BEHIND OVER THE AREA.
WITH THE SOUTHERN STREAM SHORTWAVE QUICKLY DAMPENING AND LOW
LEVEL JET AXIS SHIFTING NORTH AND EAST OF OUR AREA LATER THIS
EVENING, WEAKENING FORCING SHOULD CONTRIBUTE TO WEAKENING OF
THIS BAND OF SHOWERS AND STORMS AS IT TRIES TO MOVE EAST ACROSS
OUR CWA OVERNIGHT. IN ADDITION TO WEAKENING FORCING, THE
CONVECTION WILL ENCOUNTER AN PROGRESSIVELY LESS UNSTABLE AIR
MASS AS IT SHIFTS EASTWARD. BEST CHANCE OF THUNDERSTORMS WITH A
VERY CONDITIONAL, LOW END THREAT OF AN ISOLATED SEVERE STORM IS
OVER OUR WESTERN CWA NEAR THE I-39 CORRIDOR. MAINTAINED
CATEGORICAL POPS INTO THE OVERNIGHT HOURS, BUT WOULDN'T BE
SURPRISED TO SEE COVERAGE AND ESPECIALLY INTENSITY OF THE
PRECIPITATION UNDER-PERFORM OVERNIGHT INTO WEDNESDAY MORNING VS
WHAT GUIDANCE IS DEPICTING. BY LATE EVENING AND ESPECIALLY
OVERNIGHT, THERE MAY WELL BE LITTLE IF ANY THUNDER/LIGHTNING
LEFT WITH THIS ACTIVITY.
BY EARLY WEDNESDAY MORNING THE FRONT IS EXPECTED TO ROUGHLY
BISECT OUR AREA FROM NE TO SW WITH A CONTINUED THREAT OF SHOWERS
AND PERHAPS A THUNDERSTORM OR TWO ALONG AND TRAILING A BIT
BEHIND THE FRONT AS IT BECOMING INCREASINGLY ANAFRONTAL IN
NATURE. IF THERE IS ANY HEATING/DESTABILIZATION THAT TAKES PLACE
AHEAD OF THE FRONT OVER OUR SOUTHEASTERN CWA WEDNESDAY
AFTERNOON, THERE COULD BE SOME REDEVELOPMENT OF SHOWERS AND
THUNDERSTORMS. WEAK INSTABILITY, POOR LOW-MID LEVEL LAPSE RATES,
AND MARGINAL DEEP LAYER SHEAR SUGGEST VERY LITTLE SEVERE THREAT.
GIVEN THE WARM MID LEVEL TEMPS, LIGHTNING MAY EVEN BE HARD TO
COME BY WEDNESDAY AFTERNOON.
WHILE CURRENT DETERMINISTIC QPF FORECAST HAS SOME FAIRLY
RESPECTABLE TOTALS ACROSS MOST OF OUR CWA, A VERY PLAUSIBLE
SCENARIO WOULD BE FOR A LARGE PART OF OUR CWA TO END UP WITH
LESS THAN A HALF INCH OF RAIN TOTAL, AND POSSIBLY LESS THAN A
QUARTER OF AN INCH BY THE TIME PRECIP ENDS LATE WEDNESDAY INTO
WEDNESDAY EVENING.
BEHIND THE COLD FRONT TOMORROW, NORTHEAST WINDS OFF THE
SEASONABLY CHILLY LAKE MICHIGAN WATERS, ALONG WITH CLOUD COVER
AND SOME SHOWERS, SHOULD LEAD TO MUCH COOLER CONDITIONS. THE
MOST DRAMATIC COOL DOWN WILL BE NEAR THE LAKE WHERE TEMPS WED
AFTERNOON SHOULD BE IN THE 50S, A STARK CONTRAST TO TODAY'S
FORECAST MID-UPPER 80S! FARTHER INLAND FROM THE LAKE,
TEMPERATURES OVER NORTHWESTERN IL AND NORTHWEST IN/CENTRAL IL
AHEAD OF THE FRONT COULD CLIMB INTO THE LOW/MID 70S.
- IZZI
WEDNESDAY NIGHT THROUGH MONDAY:
WEDNESDAY'S COLD FRONT WILL CONTINUE TO SAG SOUTHWARD WEDNESDAY
NIGHT, WITH THE REMAINING SOUTHEAST PORTIONS OF THE CWA CLEARED
OF THE FRONT BY MID-EVENING AND REMAINING SHOWERS AFTER
MIDNIGHT. THE FRONT WILL SETTLE JUST NORTH OF THE OHIO RIVER
VALLEY BY THURSDAY MORNING AS SURFACE HIGH PRESSURE DRIFTS
ACROSS THE UPPER GREAT LAKES. THIS WILL FAVOR A DRY AND MOSTLY
SUNNY DAY ON THURSDAY WITH HIGHS IN THE MID TO UPPER 70S INLAND
AND 60S ALONG THE LAKE.
CONSENSUS GUIDANCE IS FOR A WAVE ACROSS THE CENTRAL ROCKIES TO
PICKUP OR ABSORB AT LEAST SOME ENERGY FROM AN UPPER-LEVEL LOW
OVER THE SOUTHWEST U.S. WEDNESDAY INTO THURSDAY. A WEAK SURFACE
LOW DEVELOPING FROM CONVECTIVE FEEDBACK OVER THE CENTRAL GREAT
PLAINS THURSDAY EVENING WILL TRAVERSE THE FRONT ON FRIDAY.
GUIDANCE HAS COME INTO SOMEWHAT BETTER AGREEMENT THAT THE MAIN
IMPACTS FROM THIS SYSTEM DEVELOPING ALONG THE FRONT WILL REMAIN
SOUTH OF MUCH OF THE FORECAST AREA, THOUGH SOME SHOWERS COULD
BRUSH THE SOUTHERN CWA FRIDAY AFTERNOON AND EVENING. OTHERWISE,
SEASONABLY COOL CONDITIONS UNDER PARTLY TO MOSTLY CLOUDY SKIES
CAN BE EXPECTED ON FRIDAY.
HIGH PRESSURE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY ON
SATURDAY WILL PRODUCE SEASONABLE CONDITIONS AND DRY WEATHER. AN
UPPER-LEVEL LOW OVER THE FAR NORTHERN GREAT LAKES WILL THEN PUSH
A COLD FRONT WITH THE POTENTIAL FOR SHOWERS AND A FEW STORMS
ACROSS THE AREA LATE SUNDAY INTO MONDAY MORNING.
KLUBER
AVIATION /12Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 640 AM CDT TUE JUN 3 2025
VFR CONDITIONS ARE EXPECTED INTO THIS EVENING. SSW WINDS WILL
INCREASE WITH GUSTS OVER 20 KNOTS THIS MORNING AND OVER 30 KNOTS
THIS AFTERNOON INTO EARLY EVENING. WINDS WILL ABATE SOME AFTER
SUNSET WITH SW GUSTS TO AROUND 25 KNOTS THIS EVENING AND UNDER
15 KNOTS OVERNIGHT. A COLD FRONT WILL THEN SHIFT WINDS NNE
AROUND 10 KNOTS AFTER SUNRISE WEDNESDAY.
ISOLATED TS OVER MISSOURI SHOULD WEAKEN AS THEY MOVE INTO A
NOTABLY LESS FAVORABLE ENVIRONMENT WITH EASTWARD EXTENT.
HOWEVER, A REMNANT WAVE FROM EARLIER CONVECTION COULD GENERATE A
BAND OF MID-LEVEL SHRA ACROSS NORTHERN IL THIS AFTERNOON. HAVE
MAINTAINED A TEMPO FOR RFD AND PROB30 FOR THE CHICAGO TERMINALS.
TS CANNOT BE RULED OUT DURING THIS WINDOW, BUT CHANCES ARE
UNDER 20 PERCENT AT THIS TIME.
A FEED OF HIGHER MOISTURE WITH A LOW-LEVEL JET MAY CONTINUE TO
FOSTER ISOLATED SHRA ACROSS NORTHERN IL, PARTICULARLY WEST OF
THE CHICAGO METRO, DURING THE EVENING HOURS, WITH ADDITIONAL TS
CHANCES UNDER 20 PERCENT AT RFD. SHRA COVERAGE WILL BEGIN TO
INCREASE ALONG A COLD FRONT SHIFTING SOUTHEAST ACROSS THE
TERMINALS TOWARD SUNRISE WEDNESDAY. CONTINUED RA/SHRA WITH LOW-
END MVFR TO POSSIBLY IFR CEILINGS ARE EXPECTED TO SHIFT ACROSS
THE TERMINALS BEHIND THE FRONT WEDNESDAY MORNING.
KLUBER
MARINE
ISSUED AT 312 AM CDT TUE JUN 3 2025
POTENTIAL EXISTS FOR A PERIOD OF NEAR GALE TO LOW END GALE
FORCE SOUTH-SOUTHWEST WINDS THIS AFTERNOON AND EVENING. THERE IS
SOME UNCERTAINTY REGARDING JUST HOW STRONG THE WINDS WILL GET
GIVEN THE INCREASING CLOUD COVER, SO OPTED TO JUST MAINTAIN
MENTION OF GALE FORCE GUSTS AND HOLD OFF ON A GALE WARNING. IF
IT BECOMES CLEAR THAT THERE WILL BE A PERIOD OF SOLID GALES,
THEN A SHORT FUSED GALE WARNING COULD BE NEEDED FOR THE
NEARSHORE WATERS FOR THIS AFTERNOON AND EVENING. THE STRONGEST
WINDS AND ANY GALES WOULD LIKELY BE CONFINED TO AREAS CLOSE TO
THE SHORE WITH A STRONGLY STABLE MARINE LAYER LIMITING THE
MAGNITUDE OF WINDS/GUSTS FARTHER FROM THE SHORE.
- IZZI
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 10 PM CDT THIS
EVENING FOR THE IL AND IN NEARSHORE WATERS.
VISIT US AT WEATHER.GOV/CHICAGO
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