610
FXUS63 KILX 311744
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1244 PM CDT TUE MAR 31 2026
KEY MESSAGES
- PERIODS OF SHOWERS AND THUNDERSTORMS ARE FORECAST THROUGH
SATURDAY. THERE IS A 50-80% CHANCE RAIN TOTALS EXCEED 2
INCHES, WITH THE HIGHEST CHANCES NORTH OF I-72/DANVILLE; THIS
WOULD HELP ALLEVIATE ONGOING DROUGHT CONDITIONS.
- THERE IS A LEVEL 2 OF 5 (MARGINAL) RISK FOR SEVERE WEATHER INTO
TONIGHT, WITH HAIL UP TO THE SIZE OF QUARTERS AND LOCALIZED
WIND GUSTS TO 60 MPH THE PRIMARY RISKS. AT LEAST A LOW RISK
FOR SEVERE WEATHER WILL EXIST THURSDAY, AND LIKELY LATE FRIDAY
INTO SATURDAY AS WELL.
- GUSTY (25-40 MPH) SOUTHWEST WINDS ARE FORECAST TODAY.
THURSDAY WILL BE EVEN WINDIER, HAVING A 30-50% CHANCE FOR
GUSTS TO EXCEED 45 MPH. THIS COULD CAUSE DIFFICULT DRIVING
CONDITIONS FOR HIGH PROFILE VEHICLES, AND BLOW AROUND
LIGHTWEIGHT OBJECTS SUCH AS UNANCHORED HOLIDAY DECORATIONS.
- THERE IS A 30-50% CHANCE FOR FREEZING TEMPERATURES SUNDAY
NIGHT NORTH OF ROUGHLY I-70. ACTION MAY BE NEEDED TO COVER
NEWLY-EMERGED, TENDER VEGETATION.
UPDATE
ISSUED AT 910 AM CDT TUE MAR 31 2026
THUNDERSTORMS HAVE BEEN INCREASING IN COVERAGE OVER THE LAST
COUPLE OF HOURS NEAR AND WEST OF I-55, WITH A NUMBER OF THE
STORMS PRODUCING HAIL. AREA DOPPLER RADAR WIND PROFILES ARE
SHOWING A 40-45 KNOT LOW LEVEL JET AT 925 MB, WITH MESOANALYSIS
INDICATING STEEP MID LEVEL LAPSE RATES AROUND 8C/KM AIDING IN
THE HAIL PRODUCTION. LATEST RAP GUIDANCE SHOWS A SUBTLE
SHORTWAVE MOVING ACROSS CENTRAL AND NORTHWEST ILLINOIS AS WELL.
HIGH-RES MODELS HAVE BEEN STRUGGLING SOME WITH THIS ACTIVITY,
THOUGH THE HRRR HASN'T BEEN TOO BAD THE LAST FEW HOURS. ITS MAIN
FOCUS REMAINS WITH THE MORNING ACTIVITY LIFTING NORTHEAST, WITH
A PERIOD OF MOSTLY QUIET WEATHER UNTIL LATER THIS AFTERNOON.
LATEST SPC DAY1 OUTLOOK EXPANDED THE SLIGHT RISK TO COVER MOST
AREAS EAST OF THE ILLINOIS RIVER AND NORTH OF I-70, WITH THE
EXPECTED DEVELOPMENT THIS EVENING. HRRR HAS BEEN FOCUSING ON
DEVELOPMENT WEST OF ST. LOUIS LATE AFTERNOON, COMBINED WITH
ACTIVITY NEAR THE COLD FRONT ITSELF NEAR PEORIA. THE FRONT IS
PROGGED TO DROP TO NEAR SPRINGFIELD/DECATUR BY 8 PM, WITH THE
SEVERE WEATHER THREAT NORTH OF THERE WANING EARLY IN THE
EVENING.
DISCUSSION
ISSUED AT 149 AM CDT TUE MAR 31 2026
***** WARM AND BREEZY TODAY, STORMS TONIGHT *****
AT 130AM, A QUASISTATIONARY FRONT EXTENDED FROM NEBRASKA THROUGH
IOWA AND ACROSS SOUTHERN WISCONSIN. A SHORTWAVE TROUGH WAS FOSTERING
SHOWERS AND THUNDERSTORMS NEAR THE I-80 CORRIDOR IN EASTERN IOWA AND
NORTHWEST ILLINOIS. MEANWHILE, CENTRAL ILLINOIS LIES SOLIDLY IN THE
WARM SECTOR WHERE SOUTH-SOUTHWESTERLY WINDS GUSTING 20-25 MPH HAVE
HELD TEMPERATURES IN THE MID 60S TO LOW 70S. EVEN SO, SEVERAL CAMS
SUGGEST A FEW SHOWERS AND STORMS MAY FIRE ACROSS NORTHEAST MISSOURI
OR SOUTHEAST IOWA AROUND DAWN AS AN OUTFLOW BOUNDARY FROM ONGOING
CONVECTION INTERACTS WITH THE LLJ. HREF NEIGHBORHOOD PROBS (USING A
20KM RADIUS) ADVERTISE 50%+ CHANCES FOR CONVECTIVE PRECIPITATION IN
AREAS NORTHWEST OF A ROUGHLY BEARDSTOWN TO BLOOMINGTON LINE FROM 6-
10AM, WHICH IS REFLECTED IN OUR POPS. WHILE THIS ACTIVITY WILL BE
PROPAGATING TOWARDS THE EAST-NORTHEAST, IT COULD SEND A REMNANT
OUTFLOW BOUNDARY SOUTHEASTWARD ACROSS CENTRAL ILLINOIS DURING THE
LATE MORNING OR EARLY AFTERNOON, HOWEVER IT APPEARS UNLIKELY (20%
CHANCE) THAT THIS WILL FOCUS CONVECTIVE DEVELOPMENT GIVEN THE STRONG
CAPPING INVERSION IN PLACE. INSTEAD, THE EARLY-MID AFTERNOON IS
LIKELY (80% CHANCE) TO REMAIN DRY, WITH STRONG WARM ADVECTION
(SOUTHWEST WINDS GUSTING 25-40MPH) BRINGING TEMPERATURES INTO THE
UPPER 70S TO MID 80S - ALMOST A REPEAT OF YESTERDAY.
STORM CHANCES WILL RAMP UP DURING THE EVENING AS A COLD FRONT SINKS
SOUTHWARD INTO CENTRAL ILLINOIS, STALLING BETWEEN I-70 AND I-72 BY
SUNRISE TUESDAY. THANKFULLY, MOST HIGHRES GUIDANCE HAS THE STORMS
DEVELOPING BEHIND THE COLD FRONT WHERE A FEW HUNDRED J/KG OF
ELEVATED INSTABILITY WILL LINGER THROUGHOUT THE NIGHT. GIVEN THE
WEAK INSTABILITY, WE'RE NOT OVERLY THRILLED ABOUT THE SEVERE WEATHER
RISK, THOUGH ADMITTEDLY THE 30-45 KT 0-6KM SHEAR COULD SUPPORT SOME
HAIL UP TO QUARTER SIZE, AND ANY STORMS THAT DEVELOP RIGHT ALONG THE
FRONT COULD GENERATE LOCALLY GUSTY WINDS; SPC'S LEVEL 1 OF 5
(MARGINAL) SEEMS REASONABLE.
***** COOLER WITH ADDITIONAL SHOWERS AND STORMS WEDNESDAY *****
WAVES OF SHOWERS AND STORMS WILL LIKELY (70% CHANCE) BE ONGOING
WEDNESDAY MORNING NEAR AND NORTH OF THE BOUNDARY, WITH NBM/HREF
INDICATING RAIN TOTALS GENERALLY BETWEEN 0.5 AND 1.5 INCHES NEAR AND
NORTH OF I-70 BY NOON WEDNESDAY. ONE OR MORE NARROW CORRIDORS OF
HIGHER AMOUNTS EXCEEDING 2.5 INCHES SEEMS LIKE A REASONABLE
EXPECTATION GIVING THE TRAINING NATURE OF STORMS WHERE THE FRONT
SLOWS DOWN/STALLS, AND PER HREF LPMM, THOUGH TRYING TO PIN DOWN
PRECISELY WHERE WOULD BE A FUTILE ENDEAVOR AT THIS TIME. IT WOULDN'T
BE SURPRISING TO HAVE SOME LOCALIZED NUISANCE FLOODING OF SMALL
STREAMS OR URBAN AREAS IF THIS WATER COMES DOWN IN A SHORT ENOUGH
TIME PERIOD, THOUGH THE RISK APPEARS TO BE GENERALLY LOW GIVEN THE
DRY ANTECEDENT CONDITIONS; THE OVERNIGHT RAIN SHOULD INSTEAD BE
BENEFICIAL FOR MOST, IF NOT ALL, OF THE AREA.
THE FRONT IS FORECAST TO LIFT BACK NORTHWARD SOMETIME WEDNESDAY
AFTERNOON OR EVENING, WITH ISENTROPIC UPGLIDE POTENTIALLY (60-80%
CHANCE) SPARKING RENEWED SHOWERS AND STORMS ACROSS MUCH OF THE AREA.
WHILE FORECAST SOUNDINGS SUGGEST THESE WILL BE ELEVATED IN NATURE,
ROOTED AROUND 850MB, ONE SHOULDN'T BE SURPRISED IF WE GET SOME SMALL
HAIL GIVEN MODEST (7-7.5 C/KM) 700-500MB LAPSE RATES AND 35-45 KT
DEEP LAYER SHEAR - WITH THE MOST FAVORABLE DYNAMICS ACROSS OUR
SOUTHWEST COUNTIES DURING THE EVENING. MEANWHILE, IT'LL BE A COOL
DAY NORTH OF THE FRONT WHERE AFTERNOON TEMPS WILL STAY IN THE MID
40S TO LOW 50S; SOUTH OF THE BOUNDARY, TEMPERATURES WILL RUN MUCH
WARMER WITH THE REFS GIVING A 40-60% CHANCE HIGHS CLIMB INTO THE 80S
NEAR HWY 50 IN SOUTHEAST ILLINOIS.
***** WARM AND WINDY WITH MORE STORMS THURSDAY *****
THE DETERMINISTIC MODELS GENERALLY AGREE THAT A SFC LOW WILL DEVELOP
BENEATH AN INCREASINGLY NEGATIVELY TILTED SHORTWAVE TROUGH LIFTING
FROM THE SOUTHERN PLAINS INTO THE UPPER MIDWEST THURSDAY INTO
THURSDAY NIGHT. THE GEFS AND EPS GENERALLY INDICATE THE SFC LOW WILL
TRACK THROUGH CENTRAL IOWA, PLACING OUR AREA IN THE WARM SECTOR ON
THURSDAY. WHILE DEWPOINTS WILL CLIMB SOLIDLY INTO THE 60S, SFC
HEATING WILL BE LIMITED BY CLOUD COVER AND ANY ONGOING EARLY-DAY
CONVECTION, AND MID LEVEL LAPSE RATES APPEAR POOR AT ONLY 6.5-7
DEGC/KM - CONFINING MUCAPES TO AROUND 500-1500 J/KG. NONETHELESS,
THE 30-45 KT OF DEEP LAYER SHEAR THE GFS AND ECMWF ARE ADVERTISING
SUGGESTS THIS SET-UP WILL BEAR WATCHING FOR A FEW SEVERE STORMS,
WITH INVERTED V SOUNDINGS SUGGESTING THE PRIMARY RISK WILL BE FROM
GUSTY TO LOCALLY DAMAGING WINDS WITH ANY BOWING MULTICELL CLUSTERS.
A TIGHT PRESSURE GRADIENT ASSOCIATED WITH THAT LOW WILL ALSO PROMOTE
ANOTHER DAY OF STRONG SOUTHWEST GRADIENT WINDS, WITH THE EPS MEAN
NORTH OF 40 MPH. FORECAST SOUNDINGS FROM THE NAM AND GFS EVEN
SUGGEST MEAN (TOP OF CHANNEL) PBL WINDS AROUND 30-35 (40-45) KT, SO
IT'S POSSIBLE (30-50% CHANCE) WE'LL NEED A WIND ADVISORY, WITH THE
PRIMARY DRIVER OF UNCERTAINTY BEING CLOUD COVER LIMITING MIXING.
***** STRONGER SYSTEM ARRIVING THIS WEEKEND *****
ON THE HEELS OF THE THURSDAY SYSTEM, A STRONGER UPPER LEVEL TROUGH
WILL DIG INTO THE NORTHERN PLAINS AND UPPER MIDWEST LATE FRIDAY INTO
SATURDAY, WITH AN ATTENDANT SURFACE LOW DRAGGING A COLD FRONT
THROUGH THE ILX CWA SOMETIME ON SATURDAY. INSTABILITY WILL BE
HIGHEST FRIDAY EVENING INTO FRIDAY NIGHT, ESPECIALLY ACROSS THE
WESTERN CWA WHERE COOLING TEMPS ALOFT WILL FOSTER MODEST (7-7.5
DEGC/KM) MID LEVEL LAPSE RATES, THOUGH A FORCING MECHANISM DURING
THAT TIME IS UNCLEAR. THE COLD FRONT WILL LIKELY (60-70% CHANCE)
GENERATE A LINE OF SHOWERS AND THUNDERSTORMS SOMETIME SATURDAY
MORNING INTO EARLY AFTERNOON, WHICH COULD BRING GUSTY TO LOCALLY
SEVERE WINDS AS IT SWEEPS ACROSS THE AREA, PARTICULARLY EAST OF I-55
WHERE SURFACE BASED INSTABILITY WILL BEGIN TO DIURNALLY INCREASE
AHEAD OF IT. THE GFS AND ECMWF SUGGEST 30-35 KT 0-3KM DEEP LAYER
SHEAR FROM THE WEST-SOUTHWEST, WHICH COULD THEORETICALLY FAVOR A
QLCS TORNADO RISK WITH ANY BOWING SEGMENTS WHICH MAXIMIZE THE LINE-
NORMAL COMPONENT. STILL, LOTS CAN CHANGE BETWEEN NOW AND THEN; STAY
TUNED FOR UPDATES.
BEHIND THE COLD FRONT, CONDITIONS WILL TURN SHARPLY COOLER WITH
FORECAST HIGHS IN THE 50S ON SUNDAY. LOWS COULD DIP INTO THE 30S AS
EARLY AS SATURDAY NIGHT, BUT THE HIGHER CHANCE FOR FROST/FREEZE
HEADLINES (NOW THAT MUCH OF CENTRAL AND SOUTHEAST ILLINOIS HAS
ENTERED THE GROWING SEASON) WILL BE SUNDAY NIGHT WHEN NBM GIVES A 30-
50% CHANCE FOR A FREEZE NORTH OF I-70.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1244 PM CDT TUE MAR 31 2026
PRIMARY AVIATION FORECAST CHALLENGE WILL BE TIMING CONVECTION AT
THE TERMINALS THIS EVENING INTO THE OVERNIGHT HOURS. SCATTERED
THUNDERSTORMS WILL FORM ALONG A COLD FRONT CROSSING THE
MISSISSIPPI RIVER INTO WEST-CENTRAL ILLINOIS LATE THIS
AFTERNOON. HRRR/RRFS SUGGEST CONVECTIVE DEVELOPMENT IN THE
ILLINOIS RIVER VALLEY BETWEEN 20Z AND 23Z, WITH THE FRONT
PUSHING EAST OF THE RIVER AND ALLOWING A PERIOD OF DRY
CONDITIONS AT KPIA FOR MUCH OF THE EVENING. MEANWHILE FURTHER
E/SE, SCATTERED CELLS WILL BECOME MORE NUMEROUS AS THE EVENING
PROGRESSES ALONG THE I-72 CORRIDOR. HAVE THEREFORE CARRIED
PREDOMINANT THUNDER AT KSPI/KDEC/KCMI FROM THIS EVENING THROUGH
ABOUT 10Z WHEN THE RISK FOR THUNDER GRADUALLY WANES. THE
SHOWERS/STORMS WILL SLOWLY BUILD BACK NORTHWARD BY LATE EVENING,
RESULTING IN A PERIOD OF THUNDER AT KPIA BETWEEN 07Z AND 10Z.
AFTER 10Z, WIDESPREAD SHOWERS WILL PERSIST THROUGH LATE
WEDNESDAY MORNING AT ALL SITES. CEILINGS WILL LOWER TO MVFR
ACROSS THE BOARD THIS EVENING THROUGH THE OVERNIGHT AND TO IFR
AT THE I-72 TAF SITES BY MORNING. WINDS WILL INITIALLY BE SW
WITH GUSTS OF 20-30KT THIS AFTERNOON, THEN WILL SWITCH TO NE AND
BECOME GUSTY AFTER FROPA FROM LATE EVENING THROUGH THE
REMAINDER OF THE 18Z TAF PERIOD.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...BUMGARDNER
UPDATE...GEELHART
DISCUSSION...BUMGARDNER
AVIATION...BARNES
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