905
FXUS63 KLOT 022343
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
643 PM CDT MON JUN 2 2025
KEY MESSAGES
- SMOKE (MOSTLY ALOFT) WILL FILTER SUNSHINE UNTIL CLOUDINESS
ROLLS IN TUESDAY.
- SHOWERS AND THUNDERSTORMS WILL LIKELY OVERSPREAD THE AREA FROM
WEST TO EAST LATE TUESDAY AFTERNOON INTO TUESDAY EVENING. A
COUPLE OF STRONG TO MARGINALLY SEVERE STORMS COULD AFFECT
LOCATIONS NEAR AND WEST OF THE I-39 CORRIDOR.
- COOLER WITH RAIN ON WEDNESDAY, FOLLOWED BY ADDITIONAL PERIODS
OF SHOWERS AND PERHAPS SOME STORMS THURSDAY AND FRIDAY.
DISCUSSION
ISSUED AT 340 PM CDT MON JUN 2 2025
THROUGH TUESDAY NIGHT:
A MIX OF CIRRUS AND CANADIAN WILDFIRE SMOKE IS EVIDENT OVER THE
REGION THIS AFTERNOON ON GOES VISIBLE SATELLITE IMAGERY.
FORTUNATELY, THE OVERALL LACK OF VISIBILITY REDUCTIONS IN
REGIONAL METAR OBSERVATIONS HAS SUGGESTED THAT THE SMOKE HAS
LARGELY REMAINED SUSPENDED ALOFT, THOUGH HRRR-SMOKE CROSS-
SECTIONS INDICATE THAT THE BOTTOM OF THE THICK SMOKE LAYER IS
SITUATED ROUGHLY AT 1 KM AGL AND THAT LIGHT SMOKE CONCENTRATIONS
COULD STILL BE BROUGHT DOWN TO GROUND LEVEL WHILE MIXING
HEIGHTS ARE AT THEIR PEAK THIS AFTERNOON. THE LATEST HRRR, RAP,
AND CANADIAN SMOKE MODEL RUNS ALL FAVOR SMOKE PERSISTING ALOFT
THROUGH TOMORROW MORNING ACROSS OUR WHOLE FORECAST AREA BEFORE
FOCUSING ACROSS THE SOUTHEASTERN HALF OF OUR CWA TOMORROW
AFTERNOON, WHERE THERE WILL BE ANOTHER CHANCE FOR SOME LIGHT
SMOKE CONCENTRATIONS TO GET MIXED DOWN TO GROUND LEVEL AGAIN.
TONIGHT INTO TOMORROW, A NORTHEASTWARD-DRIFTING SOUTHERN STREAM
SHORTWAVE TROUGH WILL BECOME SHEARED OUT AND GET ABSORBED INTO
A MUCH BROADER POSITIVELY-TILTED NORTHERN STREAM LONGWAVE TROUGH
AS THE TROUGHS PASS OVER THE GREAT PLAINS. AS THIS OCCURS,
CONVECTION THAT HAS BLOSSOMED THIS AFTERNOON ALONG AN ELONGATED
FRONTAL ZONE SPANNING FROM TEXAS NORTHEASTWARD INTO ONTARIO WILL
EXPAND ITS SPATIAL FOOTPRINT AND PERSIST THROUGH THE NIGHT INTO
TOMORROW AS THE FRONTAL ZONE SLOWLY INCHES EASTWARD.
THIS FRONTAL ZONE SHOULD REMAIN FAR ENOUGH TO THE WEST FOR MOST
OF OUR FORECAST AREA TO REMAIN DRY DURING THE DAYTIME ON
TUESDAY. ONE THING TO KEEP AN EYE ON THOUGH WILL BE HOW QUICKLY
A BAND OF CONVECTION TRACKING ACROSS KANSAS AND OKLAHOMA DECAYS
AS IT ENCOUNTERS INCREASINGLY DEPLETED INSTABILITY WITH
NORTHEASTWARD EXTENT. MOST OF THE LATEST MODEL GUIDANCE SUPPORTS
AT LEAST ISOLATED SHOWERS SURVIVING INTO OUR NORTHWESTERN CWA
BEFORE FADING AWAY, SO HAVE MAINTAINED SLIGHT CHANCE AND CHANCE
POPS THERE FOR THE AFTERNOON. OTHERWISE, STRENGTHENING
SOUTHWESTERLY WIND FIELDS AHEAD OF THE FRONTAL ZONE WILL RESULT
IN WIND GUSTS EXCEEDING 30 MPH DURING THE AFTERNOON. THE WARM
AIR ADVECTION OFF OF THESE WINDS COUPLED WITH FILTERED SUNSHINE
WILL AFFORD US ANOTHER WARM DAY WITH HIGH TEMPERATURES IN THE
80S, WARMEST ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA,
WHERE CLOUD COVER SHOULD BE LESS OPAQUE AND EXPANSIVE COMPARED
TO POINTS FARTHER NORTHWEST.
CLOSER TO THE COLD FRONT, NEW THUNDERSTORM DEVELOPMENT IS
EXPECTED DURING THE DAYTIME ON TUESDAY AS THE PRE-FRONTAL AIR
MASS DESTABILIZES. DEEP-LAYER SHEAR VECTORS WILL BE ORIENTED
ROUGHLY PARALLEL TO THE INITIATING FRONTAL BOUNDARY, WHICH
SHOULD CAUSE THE DEEPER FRONTAL CONVECTION TO GROW UPSCALE
RELATIVELY QUICKLY. HOWEVER, SUBPAR LAPSE RATES AND ONLY A
MODEST OVERALL DEGREE OF INSTABILITY (ESPECIALLY IF THE DECAYING
MORNING CONVECTION GUNKS THE ENVIRONMENT UP A GOOD BIT TO OUR
WEST AND SOUTHWEST) PUTS INTO QUESTION HOW STRONG THE
THUNDERSTORMS DEVELOPING IN NORTHERN MISSOURI AND
SOUTHERN/EASTERN IOWA WILL BECOME AND HOW FAR NORTHEAST THEY
WILL BE ABLE TO SUSTAIN AN APPRECIABLE INTENSITY.
THAT SAID, LOW TO MID-LEVEL WIND FIELDS WILL BE FAIRLY STRONG,
SO IF ANY ROBUST STORMS THAT DEVELOP IN NORTHERN MISSOURI OR
SOUTHEASTERN IOWA MANAGE TO MAKE IT INTO OUR FORECAST AREA
BEFORE LOSING STEAM, THEN THEY COULD PRODUCE STRONG TO DAMAGING
WIND GUSTS TOMORROW EVENING. THIS WOULD ESPECIALLY BE THE CASE
WITHIN ANY ORGANIZED BOWING STRUCTURES THAT MATERIALIZE. THE
BEST OVERALL CHANCES FOR SEVERE WEATHER SHOULD REMAIN TO OUR
WEST AND SOUTHWEST, BUT WITHIN OUR FORECAST AREA, AREAS NEAR AND
WEST OF THE I-39 CORRIDOR WOULD BE MOST LIKELY TO BE AFFECTED BY
ANY STRONGER STORMS THAT MANAGE TO MAKE IT UP HERE. BY THE LATE
EVENING, DIMINISHING BOUNDARY LAYER INSTABILITY AND INCREASING
CONVECTIVE INHIBITION SHOULD KILL OFF ANY REMAINING STRONGER
CONVECTION, THOUGH A BAND OF SHOWERS (PERHAPS WITH SOME EMBEDDED
LIGHTNING) SHOULD PERSIST ACROSS NORTHWESTERN PORTIONS OF OUR
FORECAST AREA THROUGH THE NIGHT.
OGOREK
WEDNESDAY THROUGH MONDAY:
THE COLD FRONT ASSOCIATED WITH THE LONGWAVE TROUGH OVER
NORTHERN MANITOBA TODAY WILL DRIFT SOUTHEASTWARD ACROSS THE
FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY MORNING, BRINGING
PRIMARILY ANAFRONTAL SHOWERS/RAIN ACROSS THE AREA UNDER MODEST
FORCING WITH THE RIGHT ENTRANCE OF A MID TO UPPER-LEVEL JET.
THIS PATTERN RESEMBLES EARLY FALL MORE THAN EARLY SUMMER, WITH
MAX TEMPS FOR THE CALENDAR DAY WEDNESDAY FOR AT LEAST SOME OF
THE AREA OCCURRING PRIOR TO SUNRISE AHEAD OF THE FRONT. WHEREVER
THE RAIN BAND IS MORE PROMINENT DURING THE DAY, TEMPS SHOULD
HOLD IN THE 60S (50S NEAR THE LAKE).
A TROUGH OVER THE NORTHERN ROCKIES MIDWEEK IS PROGGED TO EITHER
PICKUP OR PARTIALLY SHEAR AN UPPER-LEVEL LOW CURRENTLY OVER THE
DESERT SOUTHWEST. GIVEN THE DISTANCE BETWEEN THE TWO FEATURES,
GUIDANCE NON-SURIPRSINGLY VARIES WITH THE BROADER MID-LEVEL
PATTERN ACROSS THE CENTRAL CONUS THURSDAY INTO FRIDAY. THE
CONSENSUS IS FOR MOST OF THE ENERGY FROM THE SOUTHWEST LOW TO
RESULT IN CYCLOGENESIS ALONG THE STALLED FRONT ACROSS MISSOURI
AND SOUTHERN IL/IN LATE THURSDAY, RESULTING IN A RENEWED CHANCE
OF RAIN OR PERIODS OF SHOWERS WITH SOME STORMS THURSDAY NIGHT
INTO FRIDAY.
BEHIND FRIDAY'S POTENTIAL PRECIP, THE FRONT SHOULD FINALLY
CLEAR THE AREA WELL TO THE SOUTHEAST. A SPRAWLING HIGH PRESSURE
ACROSS THE WESTERN GREAT LAKES THIS WEEKEND SHOULD PRODUCE
SEASONABLE CONDITIONS AND DRY WEATHER SATURDAY AND POSSIBLY
THROUGH SUNDAY.
KLUBER
AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 643 PM CDT MON JUN 2 2025
FORECAST CONCERNS FOR THE TERMINALS...
- LINGERING WILDFIRE SMOKE ALOFT LEADING TO HAZY SKIES THROUGH
THIS EVENING.
- GUSTY SOUTHWEST WINDS ON TUESDAY WITH 30-35 KT GUSTS LIKELY.
- WEATHER SYSTEM TO BRING PERIODS OF SHOWERS AND POSSIBLY
EMBEDDED THUNDERSTORMS TUESDAY NIGHT.
A POCKET OF WILDFIRE SMOKE ALOFT WILL CONTINUE TO GRADUALLY
ADVECT EASTWARD ACROSS NORTHERN IL AND NORTHWEST IN THIS EVENING
KEEPING A HAZE TO THE SKY IN THE MEANTIME. OTHERWISE, EXPECT
GENERALLY LIGHT WINDS (AROUND 8-10 KTS) TO PREVAIL THROUGH THE
NIGHT WITH DIRECTIONS BECOMING MORE SOUTHERLY THROUGH THE NIGHT.
THE WEATHER WILL BEGIN TO TURN MORE ACTIVE ON TUESDAY AS THE
UPPER TROUGH AND ASSOCIATED SURFACE LOW CURRENTLY OVER CO AND
NORTHERN NM MOVES INTO THE CENTRAL PLAINS AND EVENTUALLY THE
UPPER MIDWEST BY TUESDAY NIGHT. WHILE SHOWERS AND THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG THE SYSTEM'S COLD FRONT TUESDAY
AFTERNOON ACROSS IA, THE BULK OF ANY PRECIPITATION SHOULD REMAIN
WEST OF OUR AREA UNTIL THE VERY TAIL END OF THE 30-HOUR TAF
PERIOD. THAT SAID, HAVE DECIDED TO LEAVE THE 24-HOUR TAFS DRY
FOR NOW BUT DID INCLUDE A SHRA MENTION AT ORD AND MDW AFTER 04Z
TO HIGHLIGHT THE RAIN POTENTIAL. AS FOR THE THUNDER THREAT,
INSTABILITY IS FORECAST TO QUICKLY WANE WITH EASTWARD EXTENT SO
THE THUNDERSTORM POTENTIAL IS LESS THAN 20% AT THE TERMINALS AND
THUS HAVE LEFT OUT AT THIS TIME.
REGARDLESS, WINDS WILL QUICKLY INCREASE TUESDAY MORNING WITH
SOUTHWESTERLY GUSTS IN THE 30-35 KT RANGE EXPECTED THROUGH EARLY
TUESDAY EVENING. IN FACT, DEPENDING ON THE DEGREE OF MIXING
OCCASIONALLY HIGHER GUSTS IN EXCESS OF 35 KTS CANNOT BE RULED
OUT. GUSTS WILL GRADUALLY SUBSIDE TUESDAY NIGHT BUT EXPECT AT
LEAST OCCASIONAL 20 KT GUSTS TO LINGER TUESDAY NIGHT INTO
WEDNESDAY.
YACK
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM TO 10 PM CDT TUESDAY FOR THE
IL AND IN NEARSHORE WATERS.
VISIT US AT WEATHER.GOV/CHICAGO
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