310
FXUS63 KILX 280158
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
858 PM CDT MON APR 27 2026
KEY MESSAGES
- THERE IS A LEVEL 3 OF 5 (ENHANCED) RISK FOR SEVERE WEATHER THIS
EVENING. DAMAGING WINDS, LARGE HAIL, A COUPLE TORNADOES, AND
FLASH FLOODING ARE ALL CONCERNS, ESPECIALLY NEAR AND SOUTH OF
I-70.
- THERE IS A 30-50% CHANCE FOR FROST FRIDAY NIGHT. TENDER
VEGETATION MAY NEED TO BE COVERED IN ORDER TO PREVENT DAMAGE.
UPDATE
ISSUED AT 858 PM CDT MON APR 27 2026
WE EXTENDED THE TORNADO WATCH ANOTHER 2 HOURS UNTIL 11 PM CDT IN
EAST CENTRAL AND SOUTHEAST IL. WE ALSO EXTENDED THE FLOOD WATCH
ANOTHER HOUR UNTIL 11 PM CDT FROM CHRISTIAN, MACON, MOULTRIE,
DOUGLAS AND EDGAR COUNTIES SOUTH.
THE SQUALL LINE WITH STRONG TO SEVERE THUNDERTORMS (INCLUDING
POSSIBLE TORNADOES) WAS NEAR OR SOUTHEAST OF A DANVILLE TO
EFFINGHAM LINE, AND WEST OF MOUNT VERNON, RACING EASTWARD AT
50-60 MPH. THE HRRR HAS BEEN HANDLING THIS CONVECTION FAIRLY
WELL AND HAS THE SQUALL LINE PASSING SOUTHEAST OF LAWRENCE
COUNTY IL BY 04Z/11 PM. WILL STILL BE RISK OF SEVERE STORMS WITH
DAMAGING WINDS, LARGE HAIL AND POSSIBLE TORNADOES WITH THIS LINE
NEXT 1-2 HOURS. ALSO RAINFALL AMOUNTS OF 1-2 INCHES IN 2-3
HOURS WITH LOCALLY 2-3 INCHES POSSIBLE IN SOUTHEAST IL WHICH
ALREADY SEEN 1.5-3 INCHES OF RAIN SO FAR TODAY. THE COLD FRONT
WAS PUSHING EAST TOWARD THE IL RIVER AT MID EVENING AND WILL
PUSH THROUGH SE IL BETWEEN 1-3 AM OVERNIGHT. MOST OF THE
CONVECTION SHOULD BE EAST/SE OF CWA AFTER 1 AM TONIGHT WITH
QUIETER WEATHER RETURNING. LOWS OVERNIGHT TO RANGE FROM UPPER
40S OVER THE IL RIVER VALLEY FROM I-55 WEST (MID 40S BY
GALESBURG) AND 55-60F IN SOUTHEAST IL.
DISCUSSION
ISSUED AT 226 PM CDT MON APR 27 2026
***** SEVERE WEATHER THIS EVENING *****
MID LEVEL WATER VAPOR SATELLITE REVEALS A NEGATIVELY TILTED UPPER
LEVEL TROUGH SPINNING OVER THE MIDWEST. AT THE SURFACE, WPC HAS
ANALYZED A 996MB LOW IN EASTERN IOWA WHICH IS FORECAST TO LIFT
NORTHEASTWARD ACROSS WISCONSIN THIS EVENING. MUCH OF THE WARM SECTOR
HAS BEEN WORKED OVER AT THIS POINT VIA A MORNING-EARLY AFTERNOON
MCS, BUT THESE STORMS LEFT AN OUTFLOW BOUNDARY NEAR/SOUTH OF THE I-
70 CORRIDOR WHICH WILL SERVE AS A DIFFERENTIAL HEATING/CONVERGENCE
ZONE FOR RENEWED STORMS LATER THIS AFTERNOON. A WAKE LOW CONTINUES
TO FOSTER WIND GUSTS UP TO 35MPH FROM THE SOUTHEAST, WHICH SHOULD
HELP MAINTAIN STABLE LOW LEVELS FURTHER NORTH. NONETHELESS, A FEW
ELEVATED STORMS COULD GENERATE LOCALLY SEVERE HAIL AND WIND IN
THOSE AREAS. MEANWHILE, SOUTH OF THE I-70 CORRIDOR, DEWPOINTS
SHOULD SURGE INTO THE MID-UPPER 60S WHILE A 50 KT LLJ MAINTAINS
40-55 KT EFFECTIVE BULK WIND SHEAR AND 400-700 (679 ON THE VWX
VAD PROFILER) M^2/S^2 0-3KM SRH VIA STRONGLY CYCLONICALLY
CURVED HODOGRAPHS. CAMS GENERALLY SUGGEST CONVECTIVE ACTIVITY
DEVELOPING UPSTREAM OVER THE NEXT COUPLE HOURS AND MOVING
THROUGH THIS ENVIRONMENT DURING THE EVENING WILL START DISCRETE
AND EVENTUALLY GROW UPSCALE INTO ANOTHER MCS. HENCE, THE INITIAL
HAZARDS WILL BE VERY LARGE HAIL AND TORNADOES, WITH THE RISK
TRANSITIONING TO DAMAGING WINDS, LOCALLY SEVERE HAIL, AND QLCS
TORNADOES WITH TIME. TRAINING STORMS WILL POSE A RISK FOR FLASH
FLOODING (REFS AND HREF ENSEMBLE MAX PRECIP HAVE SWATHS OF 4+
INCHES OF RAIN FALLING IN <6 HOURS), FOR WHICH WE HAVE ISSUED A
FLOOD WATCH WHICH EXTENDS THROUGH 10PM. A TORNADO WATCH IS IN
EFFECT FOR EFFINGHAM TO CRAWFORD COUNTIES AND AREAS FURTHER
SOUTH, WHERE THE CHANCE OF SURFACE BASED (AND HENCE POTENTIALLY
TORNADIC) STORMS IS HIGHEST. STORMS SHOULD EXIT THE ILX COUNTY
WARNING AREA BY 11PM, WHILE A COOLER AND MORE STABLE AIRMASS
ARRIVES FROM THE WEST-NORTHWEST BEHIND A COLD FRONT.
***** DRY CONDITIONS LIKELY WEDNESDAY AND BEYOND *****
ANOTHER SHORTWAVE WILL LIFT NORTHEAST THROUGH THE AREA TOMORROW
NIGHT, BRINGING ANOTHER OPPORTUNITY FOR SOME RAIN AND PERHAPS A
RUMBLE OF THUNDER. THANKFULLY QPF WITH THIS SYSTEM IS LIGHTER, WITH
A LOW (<20%) CHANCE FOR AN ADDITIONAL INCH OF RAINFALL. SINCE THIS
WILL OCCUR AROUND 24 HOURS AFTER THIS EVENING'S HEAVY RAINFALL IN
SOUTHEAST ILLINOIS, THE GROUND MAY HAVE SOME TIME TO ABSORB THE
WATER, THOUGH WE'LL STILL BE KEEPING ONE EYE ON IT.
BY WEDNESDAY MORNING, A DRIER PATTERN SHOULD TAKE HOLD OF THE
REGION, WITH LESS THAN A 20% CHANCE FOR RAIN THROUGH THE WEEKEND.
HIGH TEMPERATURES EACH DAY ARE FORECAST IN THE 60S, WITH LOCATIONS
NEAR AND NORTH OF THE I-74 CORRIDOR POTENTIALLY (60% CHANCE) NOT
CLIMBING OUT OF THE 50S ON FRIDAY. THE NATIONAL BLEND OF MODELS
(NBM) INDICATES A 30-50% CHANCE TEMPERATURES FALL BELOW 37 DEGF
FRIDAY NIGHT INTO SATURDAY MORNING, WHICH SHOULD BE COLD ENOUGH FOR
FROST GIVEN THE EXPECTED LIGHT WINDS.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 640 PM CDT MON APR 27 2026
A SQUALL LINE CONSISTING OF STRONG TO SEVERE THUNDERSTORMS WAS
ALONG I-55 AT 640 PM WITH A SEVERE CELL AHEAD OF THIS LINE
BETWEEN DEC AND CMI AND RACING EASTWARD AT 50-60 MPH.
CONVECTION WAS ALSO OVER PIA WHICH WAS ON THE BACK SIDE OF THIS
COMPLEX. WE HAVE GRADIENT SE WINDS 25-35 KTS WITH GUSTS 40-50
KTS AHEAD OF THIS SQUALL LINE ESPECIALLY AT DEC AND CMI. A
SEVERE STORM WOULD PRODUCE WIND GUSTS OVER 50 KTS POSSIBLE AT
DEC AND CMI NEXT HOUR. IFR TO MVF CONDITIONS EXPECTED WITH THIS
STRONG TO SEVERE CONVECTION AS HRRR HAS IT TRACKING EAST OF DEC
AND CMI BETWEEN 01-02Z AT MID EVENING. MAY SEE A BRIEF PERIOD
OF VFR CONDITIONS LATE EVENING/EARLY OVERNIGHT BEFORE MVFR
CEILINGS LIKELY SPREAD INTO CENTRAL IL DURING OVERNIGHT AND
LINGER INTO TUE MORNING. THE MVFR CEILINGS COULD SCATTER OUT AT
PIA AND POSSIBLY AS FAR SE AS I-55 AT BMI AND SPI DURING TUE
AFTERNOON. BREEZY SOUTH TO SE WINDS GUSTING 25-35 KTS TO WEAKEN
AND SHIFT WEST TO WNW BEHIND COLD FRONTAL PASSAGE OVERNIGHT.
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH UNTIL 11 PM CDT THIS EVENING FOR ILZ052>057-
061>063-066>068-071>073.
KEY MESSAGES...BUMGARDNER
UPDATE...07
DISCUSSION...BUMGARDNER
AVIATION...07
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