322
FXUS63 KILX 012313
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
613 PM CDT WED APR 1 2026
KEY MESSAGES
- THERE IS A LOW (5-15%) CHANCE FOR LOCALIZED FLASH FLOODING
TONIGHT DUE TO ADDITIONAL HEAVY RAINFALL.
- THE SEVERE WEATHER POTENTIAL IS INCREASING FOR THURSDAY,
PRIMARILY BETWEEN 4PM AND 9PM. TORNADOES AND DAMAGING
THUNDERSTORM WINDS ARE THE PRIMARY HAZARDS.
- GUSTY, NON- THUNDERSTORM WINDS WILL GRIP THE REGION ON
THURSDAY. OCCASIONAL GUSTS BETWEEN 30-50 MPH ARE LIKELY,
POSING A RISK TO HIGH-PROFILE VEHICLES TRAVELING ALONG EAST-
WEST HIGHWAYS.
DISCUSSION
ISSUED AT 401 PM CDT WED APR 1 2026
THIS AFTERNOON MARKS A BRIEF RETURN TO DRIER AND COOLER
CONDITIONS AS AN ELONGATED SURFACE HIGH-PRESSURE SYSTEM QUICKLY
MOVES ACROSS THE REGION UNDER RISING MID-LEVEL HEIGHTS.
TEMPERATURES HAVE DROPPED SIGNIFICANTLY, NEARLY 30 DEGREES
BEHIND THE FRONT, RESULTING IN AFTERNOON HIGHS IN THE UPPER 40S
AREAWIDE.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS EXPECTED TONIGHT
INTO THURSDAY AS A ROBUST SHORTWAVE TROUGH MOVES OVER THE
CENTRAL U.S. LOCALLY HEAVY RAINFALL IS POSSIBLE, MAINLY FOCUSED NEAR
AND NORTH OF THE ILLINOIS RIVER VALLEY, WHERE 0.75"-2" IS FORECAST
BASED ON THE LATEST HREF LPMM QPF GUIDANCE. ACTIVITY WILL BLOSSOM
ALONG AND NORTH OF A LIFTING WARM FRONT. THE NECESSARY LIFT,
MOISTURE, AND FORCING WILL BE PROVIDED BY A STRONG LOW-LEVEL JET
OVERRUNNING THIS SURFACE BOUNDARY, COMBINED WITH SUBTLE SHORTWAVE
ENERGY RIPPLING-IN PARALLEL TO THE BOUNDARY, SUPPORTING ANOTHER
ROUND OF LOCALLY HEAVY RAIN CLOSER TO THE SURFACE LOW.
THE RISK OF SEVERE WEATHER THEN LOOMS FOR THURSDAY WITH CENTRAL
ILLINOIS POSITIONED WELL WITHIN THE WARM SECTOR, AHEAD OF AN
ADVANCING DRY LINE. TEMPERATURES AND DEWPOINTS WILL SURGE ON THE
NOSE OF GUSTY SOUTHERLY WINDS WITH AFTERNOON HIGHS PUSHING WELL
INTO THE 70S AND DEWPOINTS INTO THE 60S. PARTIAL SUNSHINE
SHOULD SUPPORT DEEP BOUNDARY MIXING IN AREAS EAST OF THE
ILLINOIS RIVER VALLEY, WITHIN OCCASIONAL GUSTS UP TO 50 MPH. A
WIND ADVISORY IS NOW IN EFFECT FOR A GOOD CHUNK OF THURSDAY TO
COVER THIS NON-THUNDERSTORM WIND THREAT.
THE TORNADO POTENTIAL, SPECIFICALLY, REMAINS SOMEWHAT
UNCERTAIN. FAVORABLE CONDITIONS FOR SUPERCELL AND MULTICELL
CLUSTER DEVELOPMENT EXIST: AN INCOMING 500-MB SPEED MAXIMUM
PUSHING DEEP LAYER SHEAR INTO THE 40-50 KT RANGE, AND AMPLE
BUOYANCY ACROSS THE WARM SECTOR (1500 J/KG). FURTHERMORE, A
STRONG LLJ OF 50-60 KTS WILL VEER IN, SUPPORTING ELONGATED
HODOGRAPHS CONDUCIVE TO ROBUST LOW-LEVEL SPIN.
DESPITE THESE FACTORS, TWO ELEMENTS MAY LIMIT TORNADO
PRODUCTION DURING THE AFTERNOON: RELATIVELY HIGH LCLS AND THE
FACT THAT THE BETTER STORM RELATIVE HELICITY (SRH) IS EXPECTED
TO BE DISPLACED OVER PARTS OF NORTHERN ILLINOIS AND SOUTHERN
WISCONSIN. CONSEQUENTLY, THE HIGHEST TORNADO RISK MAY BE DELAYED
UNTIL THE EVENING HOURS, DIRECTLY ALONG THE DRY LINE AS IT
MOVES ACROSS CENTRAL ILLINOIS.
GLOBAL FORECAST MODELS CONTINUE TO INDICATE A SIGNIFICANT
UPPER- LEVEL TROUGH AND FRONTAL SYSTEM APPROACHING BY FRIDAY
EVENING, LIKELY BRINGING ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS. THE CURRENT EXPECTATION IS FOR A DECAYING LINE OF
STORMS TO ENTER WEST-CENTRAL ILLINOIS LATE FRIDAY NIGHT,
PERHAPS WASHING OUT SATURDAY MORNING BEFORE CONVECTION
REDEVELOPS ALONG IT SATURDAY AFTERNOON ACROSS THE EASTERN THIRD
OF ILLINOIS. SEVERE WEATHER MAY ACCOMPANY THIS FRONTAL PASSAGE
AS WELL, WITH THE SPC CURRENTLY OUTLINING CENTRAL ILLINOIS IN A
MARGINAL RISK (LEVEL 1 OF 5) FOR FRIDAY NIGHT.
FOLLOWING THE WEEKEND SYSTEM, DRIER AND SEASONABLY COOLER
WEATHER IS STRONGLY ANTICIPATED STARTING SUNDAY. THIS IS DUE TO
A PERSISTENT UPPER-LEVEL RIDGE THAT WILL DEVELOP ACROSS THE
WESTERN CONUS, RESULTING IN HIGH PRESSURE DOMINATING OUR AREA.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 613 PM CDT WED APR 1 2026
IFR CEILINGS AND MVFR VISIBILITIES WILL BE COMMON TONIGHT, AHEAD
OF A WARM FRONT ADVANCING NORTH FROM SOUTHERN IL. AFTER THE
FRONT PASSES WED MORNING, CEILINGS SHOULD RISE TO MVFR, THEN VFR
A FEW HOURS LATER. WINDS WILL BE GUSTY THROUGH THE FORECAST,
INITIALLY NORTHEAST THIS EVENING, THEN SOUTHEAST WED MORNING,
AND S-SSW BY MIDDAY. THE HIGHEST GUSTS SHOULD OCCUR MIDDAY
THROUGH AFTERNOON, NEAR 40 KT AT TIMES. A FEW PERIODS OF TSRA
ARE LIKELY, THOUGH TIMING AT A PARTICULAR TERMINAL IS LOW
CONFIDENCE AT THIS POINT. THE BETTER CHANCES OF STORMS TONIGHT
WILL BE WEST OF I-55, WHERE A PROB30 WAS INCLUDED AT KPIA-
KSPI- KBMI. ANOTHER ROUND OF STORMS IS FORECAST WED AFTERNOON
AND INTRODUCED A TEMPO TSRA GROUP AREA-WIDE.
ILX WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY FROM 10 AM TO 6 PM CDT THURSDAY FOR ILZ038-
042>046-051>057-061>063-067-068.
KEY MESSAGES...MJA
DISCUSSION...MJA
AVIATION...25
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