412
FXUS63 KILX 262250
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
550 PM CDT TUE MAY 26 2026
KEY MESSAGES
- SLOW-MOVING SHOWERS ARE LIKELY SOUTH OF I-72/DANVILLE (40-70%
CHANCE) TONIGHT INTO WEDNESDAY MORNING. A NARROW, LOCALIZED
CORRIDOR OF HEAVY RAIN IS POSSIBLE (10-30% CHANCE OF OVER 1").
- AIR QUALITY MAY BECOME UNHEALTHY FOR SENSITIVE GROUPS ACROSS
PORTIONS OF CENTRAL ILLINOIS ON WEDNESDAY DUE TO OZONE
CONCENTRATIONS.
- PRECIPITATION CHANCES ARE LOW (LESS THAN 15%) WEDNESDAY NIGHT
THROUGH THE WEEKEND.
DISCUSSION
ISSUED AT 231 PM CDT TUE MAY 26 2026
FORECAST LARGELY REMAINS ON TRACK, WITH A MOSTLY QUIET FORECAST
INTO THIS WEEKEND ASIDE FROM RAIN CHANCES DURING THE NEXT 24
HOURS. A WEAK UPPER LEVEL DISTURBANCE CONTINUES TO LIFT OUT OF
THE SOUTHERN PLAINS, JUST NORTH OF THE ARKLAXTEX PER LATEST IR
SATELLITE IMAGERY. REGIONAL RADAR AND SFC OBS SHOW LIGHT RAIN
EXTENDING AS FAR NORTH AS AREAS JUST SOUTH OF I-70, BUT PRECIP
COVERAGE IS MUCH GREATER OVER SOUTHERN MO. THESE LIGHT SHOWERS
MAY GRADUALLY EXPAND NORTHWARD IN THE COMING HOURS, BUT A MORE
CONCENTRATED CHANCE FOR SHOWERS SEEMS TO BE TIED TO A LOW-LEVEL
FGEN BAND THAT PIVOTS NORTHWARD INTO THE ILX CWA AFTER 06Z/1AM
WED. THERE IS STILL SOME UNCERTAINTY IN THE EXACT PLACEMENT OF
THIS NARROW BAND, BUT CAMS GENERALLY FOCUS IT SOMEWHERE BETWEEN
A SHELBYVILLE TO PARIS LINE AND THE I-70 CORRIDOR. WITH FORECAST
PWAT VALUES AROUND 1.75" AND WEAK CLOUD LAYER WINDS RESULTING
IN SLOW-MOVING SHOWERS, THERE COULD BE SOME VERY LOCALIZED
POCKETS OF 1-3" OF RAIN. DUE TO HIGH-RES MODEL DIFFERENCES IN
THE EXACT PLACEMENT, THE ENSEMBLE PROBABILITY OF EXCEEDING 1"
CAME IN AT JUST 10-30% SOUTH OF THAT AFOREMENTIONED SHELBYVILLE
TO PARIS LINE. CAMS ALSO TRENDED SLOWER ON THE DEPARTURE OF
THAT WAVE, SO KEPT THE RAIN CHANCES LINGERING ACROSS SE IL
THROUGH WED AFTERNOON.
THE UPPER LEVELS WILL FEATURE A BLOCKING PATTERN, WITH A CUT-OFF
LOW OVER THE SW US AND A BUILDING RIDGING OVER THE CENTRAL
PLAINS AND PORTIONS OF THE MIDWEST. A SFC HIGH SHIFTS SOUTH
TOWARDS THE GREAT LAKES TOMORROW, SENDING A BACKDOOR COLD FRONT
INTO IL. AS THIS FRONT ADVECTS AIR FROM CHICAGOLAND TOWARDS
CENTRAL IL, THE IL EPA HAS INDICATED THAT AIR QUALITY MAY
TEMPORARILY BECOME UNHEALTHY FOR SENSITIVE GROUPS OWING TO OZONE
CONCENTRATIONS. THESE POTENTIAL AIR QUALITY IMPACTS ARE NOT
EXPECTED TO PERSIST BEYOND WEDNESDAY.
SFC HIGH PRESSURE OVER THE GREAT LAKES WILL REMAIN A DOMINANT FEATURE
INTO THE WEEKEND. PRECIP CHANCES ARE EXPECTED TO STAY SOUTH AND
WEST OF THE ILX CWA, WITH PERSISTENT NORTHEASTERLY FLOW
FAVORING DRIER THAN NORMAL CONDITIONS IN THE LOW-LEVELS
(DEWPOINTS IN THE LOW TO MID 50S FRIDAY INTO THE WEEKEND).
WINDS WILL GENERALLY BE ON THE LIGHT SIDE AS WELL (GUSTS LESS
THAN 20 MPH), WHICH STYMIES ANY CONCERNS ABOUT BLOWING DUST OR
FIRE DANGER. FORECAST HIGHS REMAIN IN THE UPPER 70S TO MID 80S
THROUGH THE END OF MAY, AND GIVEN THIS PATTERN THE SEVERE
THUNDERSTORM POTENTIAL IS VERY LOW LOCALLY INTO EARLY JUNE.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 550 PM CDT TUE MAY 26 2026
MAIN CONCERN IS -SHRA AND MVFR CEILINGS OVER SOUTHERN IL THAT
ARE FORECAST TO EXPAND NORTH ACROSS EAST CENTRAL IL LATER
TONIGHT. MOST OF THE HIGH-RESOLUTION GUIDANCE KEEPS THIS JUST
SOUTHEAST OF KDEC-KCMI, BUT IT WILL BE A CLOSE CALL SO KEPT
PROB30 MENTION FROM 09-14Z. OTHERWISE, SCT-BKN HIGH CLOUDS WILL
AFFECT THE REGION THROUGH WED AFTERNOON. LIGHT SE WINDS WILL
BACK NE LATE TONIGHT AND WED MORNING AS A COOL FRONT MOVES
THROUGH FROM THE NORTHEAST. A BRIEF PERIOD OF 10-18 KT GUSTS IS
POSSIBLE IMMEDIATELY BEHIND THE FRONT, BUT WINDS SHOULD
GENERALLY BE UNDER 10 KT THROUGH THE FORECAST.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...ERWIN
DISCUSSION...ERWIN
AVIATION...25
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