109
FXUS63 KLOT 050011
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
611 PM CST WED MAR 4 2026
KEY MESSAGES
- PERIODS OF DENSE FOG MAY IMPACT PORTIONS OF THE AREA TONIGHT
THROUGH FRIDAY MORNING.
- WAVES OF SHOWERS AND DRIZZLE ARE EXPECTED TONIGHT INTO
THURSDAY. A FEW THUNDERSTORMS WILL BE POSSIBLE AS WELL.
- FRIDAY WILL BE WINDY AND UNSEASONABLY WARM, WITH A PERIOD OF
SHOWERS AND EMBEDDED THUNDERSTORMS DURING THE DAYTIME HOURS
AND THEN MORE WIDESPREAD SHOWERS AND SCATTERED STORMS LATE
FRIDAY NIGHT INTO EARLY SATURDAY. SOME OF THESE STORMS MAY BE
STRONG TO EVEN SEVERE, THOUGH CONFIDENCE IS LOW.
DISCUSSION
ISSUED AT 206 PM CST WED MAR 4 2026
THROUGH THURSDAY NIGHT...
FOLLOWING A FOGGY, DREARY START TO THE DAY, MUCH OF THE AREA
NORTH OF I-80 MANAGED TO SCATTER OUT ENOUGH TO LET IN A LITTLE
BIT OF SUNSHINE. BUT LOW CLOUDS ARE FILLING BACK IN FROM THE
SOUTH AS A WARM FRONT LIFTS INTO CENTRAL IL. WE'RE ALSO SEEING
SOME FOG THICKEN UP AND DRIZZLE DEVELOP ACROSS CENTRAL IL EARLY
THIS AFTERNOON, INCLUDING IN OUR SOUTHERN CWA, AND THAT TOO IS
EXPECTED TO TREND NORTHWARD OVER THE NEXT SEVERAL HOURS.
AS OF THIS WRITING, THE WARM FRONT HAS LIFTED TO JUST NORTH OF
THE I- 70 CORRIDOR IN CENTRAL IL. FOG AND POCKETS OF DRIZZLE
WILL PROPAGATE NORTHWARD AHEAD OF THE FRONT AND SPREAD INTO
NORTHERN IL LATER THIS AFTERNOON. THERE'S BEEN A GROWING SIGNAL
AMONG A HANDFUL OF HIGH RES CAMPS FOR A PLUME OF TRUE LIGHT RAIN
SHOWERS TO MOVE ACROSS THE AREA LATE THIS AFTERNOON INTO MID-
EVENING AHEAD OF A SHORTWAVE IMPULSE AND SURFACE REFLECTION
CURRENTLY WORKING ACROSS MO. WE CAN'T RULE OUT SOME HEAVIER
SHOWERS OR MAYBE EVEN AN ISOLATED THUNDERSTORM OR TWO IN OUR FAR
SOUTH LATE THIS AFTERNOON WITH A FEW HUNDRED JOULES OF MUCAPE
EXTENDING INTO THE AREA. THE WARM FRONT WILL STALL ACROSS
CENTRAL IL TONIGHT KEEPING THE HIGHER/HEAVIER PRECIP COVERAGE
SOUTH OF THE CWA THIS EVENING AND THROUGH MOST OF THE NIGHT.
OVERNIGHT INTO THURSDAY MORNING, A SURFACE LOW WILL LIFT
THROUGH CENTRAL IL INTO NORTHWESTERN IN DRAGGING THE WARM FRONT
UP INTO THE LOCAL AREA. A PUSH OF DENSELY SCATTERED TO
WIDESPREAD SHOWERS IS ANTICIPATED ALONG AND SOUTHEAST OF THE
LOW TRACK. LATEST GUIDANCE SUGGESTS THIS MAY EQUATE TO AREAS
ROUGHLY NEAR AND SOUTHEAST OF THE I-55 CORRIDOR FROM THE PREDAWN
HOURS INTO THURSDAY MORNING WITH ISOLATED, LIGHTER PRECIP
COVERAGE ANTICIPATED FARTHER NORTHWEST. NEAR AND SOUTHEAST OF
THE LOW TRACK WILL ALSO BE THE AREA TO WATCH FOR ELEVATED
CONVECTION LATE TONIGHT AND INTO THURSDAY AS A FEW TO SEVERAL
HUNDRED JOULES OF ELEVATED CAPE WILL BE FOUND IN THE STORM'S
WARM SECTOR. SOME LIGHT SHOWERS MAY LINGER IN OUR SOUTH AND
DRIZZLE INTO NORTHERN IL INTO EARLY AFTERNOON, BUT CONDITIONS
SHOULD GENERALLY BE DRYING OUT BY THE END OF THE MORNING BEHIND
THE DEPARTING LOW.
REGARDING THE FOG, VISIBILITIES AROUND THE AREA WILL TREND
LOWER THROUGH THE REST OF TODAY WITH AREA-WIDE FOG LIKELY
TONIGHT INTO THURSDAY. IT'S VERY POSSIBLE THAT WIDESPREAD AREAS
OF DENSE FOG DEVELOP, ESPECIALLY WHERE DRIZZLE IS FOUND.
CONFIDENCE IN ANY GIVEN AREA OR TIME WINDOW IS TOO LOW TO
CONSIDER A HEADLINE ANYWHERE, BUT WOULDN'T BE AT ALL SURPRISED
IF TARGETED ADVISORIES OR SPSS ARE IN OUR FUTURE. CONDITIONS
SHOULD LARGELY IMPROVE BEYOND THURSDAY MORNING, BUT VISIBILITY
REDUCTIONS MAY FESTER THROUGH THE DAY, ESPECIALLY AROUND THE
LAKESHORE.
DOOM
FRIDAY THROUGH WEDNESDAY:
FORECAST ATTENTION CONTINUES TO FOCUS ON THE THREAT FOR
POTENTIALLY TWO PERIODS OF SHOWERS AND THUNDERSTORMS FRIDAY AND
FRIDAY NIGHT.
A MID/UPPER-LEVEL TROUGH IS FORECAST TO TRAVERSE THE CENTRAL
AND SOUTHERN ROCKIES EARLY FRIDAY MORNING. THEREAFTER, A SHARP
MID- LEVEL IMPULSE, AND ACCOMPANYING MID AND UPPER LEVEL SPEED
MAX, IS EXPECTED TO EJECT NORTHEASTWARD ACROSS THE PLAINS INTO
THE UPPER MIDWEST FRIDAY INTO FRIDAY NIGHT. MEANWHILE, AT THE
SURFACE, A COLD FRONT, ALONG THE SOUTHWEST PERIPHERY OF A
SURFACE LOW, WILL SHIFT SOUTHEASTWARD FROM THE NORTHERN AND
CENTRAL PLAINS INTO THE WESTERN GREAT LAKES BY EARLY SATURDAY
MORNING.
THURSDAY NIGHT INTO FRIDAY MORNING, STRENGTHENING LOW-TO-MID
LEVEL WARM AIR ADVECTION, ATOP A NORTHWARD SHIFTING WARM FRONTAL
BOUNDARY, SHOULD RESULT IN AN UPTICK IN CONVECTION TO OUR WEST-
SOUTHWEST. WE WILL BE WATCHING THE EVOLUTION AND EXTENT OF THIS
ACTIVITY, AS ITS FOCUS SHOULD GENERALLY SPREAD NORTHEASTWARD
TOWARDS OUR AREA LATER FRIDAY MORNING. WITH NO REAL CHANGE IN
FORECAST THINKING WITH THIS ACTIVITY, WE CONTINUE TO FOCUS THE
HIGH CHANCES FOR SHOWERS AND STORMS ACROSS NORTHERN IL DURING
THE LATE MORNING AND EARLY AFTERNOON PERIOD.
OUTSIDE OF THE MORNING SHOWER AND THUNDERSTORM CHANCES,
TEMPERATURES FRIDAY AFTERNOON WILL SOAR WELL INTO THE 60S INTO
THE LOW 70S (NEAR RECORD TERRITORY FOR ORD AND RFD WHICH IS 70
AT BOTH SITES ON FRIDAY) AS THE SURFACE WARM FRONT SURGES
NORTHWARD ACROSS ILLINOIS AND INDIANA. HOWEVER, AS IS TYPICAL
THIS TIME OF YEAR, ONSHORE FLOW AHEAD OF THIS WARM FRONT ACROSS
FAR NORTHEASTERN IL (INCLUDING PARTS OF CHICAGO) WILL KEEP
CONDITIONS MUCH COOLER THROUGH MUCH OF THE DAY AS THE WARM FRONT
STRUGGLES (AT LEAST INITIALLY) TO OVERCOME THE COLDER MARINE
AIRMASS OVER SOUTHERN LAKE MICHIGAN. PATCHY FOG WOULD ALSO BE
LIKELY TO HANG ON NEAR THE ILLINOIS SHORE UNTIL SURFACE FLOW
TURNS OFFSHORE SOMETIME LATER IN THE DAY.
AS WE HAVE MENTIONED FOR THE PAST COUPLE OF DAYS NOW, THE
COMBINATION OF THE VERY WARM TEMPERATURES AND UNSEASONABLY HIGH
DEW POINTS INTO THE UPPER 50S TO NEAR 60F, WILL SUPPORT AN
UNSTABLE AND STRONGLY SHEARED WARM SECTOR SUPPORTIVE OF A
CONDITIONAL THREAT OF SEVERE THUNDERSTORMS FRIDAY AFTERNOON AND
NIGHT. THE MAIN QUESTION AT THIS POINT IS IF ANY OF THESE EARLY
AFTERNOON STORMS WILL BE ABLE TO BECOME SURFACE BASED NEAR THE
QUICKLY APPROACHING WARM FRONT BEFORE THE MAIN FOCUS FOR THEM
SHIFTS TO OUR NORTHEAST LATER IN THE DAY. IF THEY DO BECOME
SURFACE BASED, THEN SEVERE STORMS WOULD BE MORE OF THREAT FOR A
PERIOD FRIDAY AFTERNOON, PARTICULARLY NEAR THE SURFACE BOUNDARY.
HOWEVER, AT THIS TIME CONFIDENCE ON THE SEVERE THREAT WITH
THESE EARLY STORMS REMAINS LOW. HOWEVER, THE CURRENTLY MORE
LIKELY SCENARIO APPEARS TO BE THE CONVECTION REMAINING
ELEVATED/JUST NORTH OF THE FRONT. ULTIMATELY, IT IS GOING TO
COME DOWN TO THE TIMING OF THE NORTHWARD FRONTAL SURGE INTO
NORTHERN IL FRIDAY AFTERNOON.
A PERIOD OF NEARLY STORM FREE WEATHER STILL APPEARS PLAUSIBLE
FOR A TIME LATE FRIDAY AFTERNOON AND EVENING DUE TO PROMINENT
CAPPING FOLLOWING THIS INITIAL IMPULSE, THOUGH SOUTH-
SOUTHWESTERLY WINDS DO LOOK TO BECOME GUSTY (35+ MPH) IN THE
WARM SECTOR FRIDAY AFTERNOON AND EVENING. ASSUMING THESE
CAPPED/PRIMARILY DRY CONDITIONS COME TO FRUITION, IT WILL FEEL
LIKE A WARM, SLIGHTLY MUGGY, AND WINDY LATER SPRING SEASON NIGHT
FOR THOSE OUT AND ABOUT. EXPECT SHOWER AND THUNDERSTORM CHANCES
AND COVERAGE TO RAMP UP AGAIN LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING IN ASSOCIATION WITH A COLD FRONT SWEEPING
EASTWARD ACROSS THE AREA.
THE CURRENTLY UNFAVORABLE DIURNAL TIMING OF THE COLD FRONT
PASSAGE LATE FRIDAY NIGHT INTO EARLY SATURDAY DOES RAISE
QUESTIONS AS TO THE THREAT FOR ORGANIZED SEVERE WEATHER WITH
THIS ACTIVITY LOCALLY. HOWEVER, THE COMBINED PRESENCE OF NEAR
RECORD WARM TEMPERATURES AND DEW POINTS DEEP INTO FRIDAY NIGHT
WITHIN A STRONGLY SHEARED KINEMATIC ENVIRONMENT CERTAINLY WILL
SUPPORT AT LEAST A CONDITIONAL RISK FOR SOME STRONGER STORMS
CAPABLE OF DAMAGING WINDS LATE FRIDAY NIGHT.
RAIN CHANCES WILL COME TO AN END FOLLOWING THE COLD FRONTAL
PASSAGE ON SATURDAY, AT LEAST FOR A FEW DAYS. TEMPERATURES WILL
COOL DOWN A BIT IMMEDIATELY BEHIND THE FRONT SATURDAY PM, BUT
GENERALLY REMAIN WELL ABOVE AVERAGE THROUGH EARLY NEXT WORKWEEK.
FOR AREAS THAT DON'T RECEIVE MUCH RAIN IN THE UPCOMING STRETCH,
WE'LL NEED TO MONITOR FOR ELEVATED FIRE DANGER ON SUNDAY DUE TO
MILD TEMPS PAIRED WITH FAIRLY LOW DEW POINTS AND GUSTY
SOUTHWEST WINDS. BOTH NEXT MONDAY AND A PART OF TUESDAY LOOK
QUITE WARM (HIGHS POSSIBLY 70+ FOR A GOOD CHUNK OF THE AREA).
THEREAFTER, RECENT MEDIUM TO LONG-RANGE ENSEMBLES HAVE CONTINUED
POINT TOWARDS A STRONGER COLD FRONT PASSAGE IN THE WAKE OF A
POSSIBLE FORMIDABLE MID-LATITUDE CYCLONE WITH POTENTIALLY
WIDESPREAD PRECIPITATION MID NEXT WEEK, BRINGING A RETURN TO
COLDER CONDITIONS, POSSIBLY ACCOMPANIED BY WIND DRIVEN
ACCUMULATING SNOW SOMEWHERE IN THE GREATER REGION. IF THIS WERE
TO HAPPEN IN OUR AREA, IT WOULD BE A CLASSIC CASE OF MARCH
"WEATHER WHIPLASH".
KJB/CASTRO
AVIATION /00Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 611 PM CST WED MAR 4 2026
KEY MESSAGES:
- LOW STRATUS AND FOG WILL RESULT IN LIFR AND IFR CONDITIONS
THROUGH MOST OR ALL OF THE TAF PERIOD.
- PERIODS OF DRIZZLE AND RAIN SHOWERS WILL CONTINUE THROUGH
TOMORROW AFTERNOON.
ABUNDANT LOW-LEVEL MOISTURE AND RELATIVELY STAGNANT LOW-LEVEL
FLOW WILL MAINTAIN GLOOMY CONDITIONS WITH LOW STRATUS AND FOG
THROUGHOUT THE CURRENT TAF PERIOD. LIFR CEILINGS ARE ALREADY
BEING OBSERVED AT PRESS TIME AT THE CHICAGO METRO TERMINALS, AND
DON'T FORESEE MUCH, IF ANY, IMPROVEMENT OCCURRING UNTIL LATER
TOMORROW MORNING. RFD SHOULD MAINTAIN MVFR CEILINGS FOR A FEW
MORE HOURS THIS EVENING, BUT CEILINGS THERE ARE LIKELY TO
DETERIORATE TO IFR/LIFR LEVELS LATER TONIGHT AS THE BETTER LOW-
LEVEL MOISTURE OOZES NORTHWARD.
BETWEEN DRIZZLE, RAIN SHOWERS, AND FOG, VISIBILITIES WILL ALSO
LARGELY REMAIN AT 1SM OR LOWER AT THE CHICAGO METRO TERMINALS
THROUGH THE NIGHT AND INTO TOMORROW MORNING. POTENTIAL FOR VLIFR
VISIBILITIES WITH DENSE FOG IS ALSO EVIDENT, ESPECIALLY DURING
THE LATER OVERNIGHT AND EARLY MORNING HOURS. RFD MAY REMAIN
NORTHWEST OF THE DENSEST FOG TONIGHT, BUT AT LEAST MVFR
VISIBILITIES ARE STILL LIKELY TO BE OBSERVED THERE. VISIBILITIES
WILL BE SLOW TO IMPROVE AFTER SUNRISE TOMORROW, BUT THE DENSEST
FOG IS EXPECTED TO BE GONE BY THE EARLY AFTERNOON.
WINDS THROUGHOUT THE TAF PERIOD WILL REMAIN BELOW 10 KTS AND
PREDOMINANTLY BE FROM A NORTHEASTERLY DIRECTION WHEN NOT
CALM/VARIABLE.
OGOREK
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY UNTIL 9 AM CST THURSDAY FOR WINTHROP HARBOR
IL TO BURNS HARBOR IN.
VISIT US AT WEATHER.GOV/CHICAGO
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