544
FXUS63 KILX 312310
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
610 PM CDT TUE MAR 31 2026
KEY MESSAGES
- THERE IS A THREAT OF SEVERE WEATHER BOTH THIS EVENING (MAINLY
FOR LARGE HAIL), AND AGAIN ON THURSDAY (MAINLY FOR DAMAGING
WINDS). A LEVEL 2 SEVERE WEATHER RISK EXISTS IN BOTH CASES.
- A STALLED FRONT WILL BRING AN EXTENDED PERIOD OF WET WEATHER
THROUGH MIDWEEK, WITH A 30 PERCENT CHANCE OF SEEING MORE THAN
2 INCHES OF RAIN IN AN AREA FOCUSED FROM BEARDSTOWN EAST TO
DANVILLE.
- A WIND ADVISORY MAY BE NEEDED FOR EASTERN ILLINOIS THURSDAY,
WITH A HIGH LIKELIHOOD OF WINDS GUSTING OVER 40 MPH.
- FROST AND FREEZE CONDITIONS WILL BE A THREAT SATURDAY NIGHT
AND ESPECIALLY SUNDAY NIGHT, WHICH MAY CAUSE SOME DAMAGE TO
SENSITIVE VEGETATION.
DISCUSSION
ISSUED AT 218 PM CDT TUE MAR 31 2026
MUCH OF THE EARLIER CONVECTION HAS MOVED OUT, ASIDE FROM SOME
RESIDUAL STORMS BETWEEN MATTOON AND TERRE HAUTE. AN AREA OF
SUBSIDENCE BEHIND THE STORMS RESULTED IN MOSTLY SUNNY CONDITIONS
WEST OF I-55 BY LATE MORNING, THOUGH SOME DIURNAL CUMULUS HAS
BEEN FILLING IN SINCE THEN. MESOSCALE ANALYSIS INDICATES SOME
CAPPING IN PLACE IN WAKE OF THE EARLIER CONVECTION, THOUGH THIS
SHOULD ERODE THROUGH THE AFTERNOON. ON A LARGER SCALE, THE COLD
FRONT EXTENDS FROM THE NORTHEAST TIP OF ILLINOIS TO NEAR KANSAS
CITY EARLY THIS AFTERNOON.
TONIGHT THROUGH THURSDAY NIGHT:
THE COLD FRONT IS EXPECTED TO STALL SOMEWHERE BETWEEN I-72 AND
I-70 BY LATE TONIGHT, LARGELY REMAINING IN PLACE UNTIL THE UPPER
LOW OVER NEBRASKA CAUSES A NORTHWARD SURGE LATE WEDNESDAY NIGHT.
HREF GUIDANCE SHOWS PRECIPITABLE WATER VALUES BEING NEAR THE TOP
OF SEASONAL CLIMATOLOGY THROUGH THE PERIOD, WITH PROBABILITIES
OF SEEING MORE THAN 2 INCHES OF RAIN AROUND 30% IN AN AREA
FOCUSED FROM BEARDSTOWN EAST TO DANVILLE. CURRENTLY NOT LOOKING
AT AN EXCESSIVE AMOUNT OF RAIN AT ANY GIVEN TIME, THOUGH
6-HOURLY AMOUNTS OF A HALF TO 3/4 INCH ARE NOT OUT OF THE
QUESTION TONIGHT AND WEDNESDAY MORNING. HOWEVER, RAIN CHANCES
WILL REMAIN VERY HIGH UNTIL THE FRONT SURGES NORTHWARD, THEN
EASE BACK UNTIL THE TRAILING COLD FRONT ARRIVES LATER THURSDAY.
IN TERMS OF THE SEVERE WEATHER POTENTIAL, THE EARLIER DAY1
OUTLOOK HAD EXPANDED THE LEVEL 2 (SLIGHT) RISK TO COVER MOST
AREAS EAST OF THE ILLINOIS RIVER AND NORTH OF I-70. HREF
GUIDANCE DOES SHOW SURFACE BASED CAPE'S OF 1000-1500 J/KG AHEAD
OF THE FRONT BY LATE AFTERNOON. THE HRRR, RRFS, AND NAM-NEST ARE
ALL SHOWING DEVELOPMENT ALONG THE FRONT IN THE 5-6 PM TIME
FRAME, ALONG WITH MIGRATION OF STORMS IN MISSOURI NORTHEAST
AHEAD OF THE BOUNDARY. LOW LEVEL SHEAR WEAKENS SOME EARLY IN THE
EVENING OVER CENTRAL ILLINOIS, THOUGH MID LEVEL LAPSE RATES RISE
BACK TO AROUND 7.5 C/KM OR SO BEFORE DIMINISHING LATE EVENING.
LARGE HAIL WILL BE THE PRIMARY SEVERE WEATHER RISK. LOOKING
AHEAD TO THURSDAY, THE FRONT SHOULD BE ARRIVING TOWARD PEAK
HEATING, THOUGH THE AMOUNT OF RESIDUAL CLOUD COVER FROM EARLIER
CONVECTION REMAINS IN QUESTION. THIS SEVERE WEATHER THREAT
SHOULD BE MORE OF A WIND ISSUE, WITH MORE OF AN INVERTED-V
SIGNATURE ON FORECAST SOUNDINGS.
SPEAKING OF THE WIND, THURSDAY LOOKS TO BE A RATHER WINDY DAY
AHEAD OF THE COLD FRONT. NAM AND GFS SOUNDINGS FROM EASTERN
ILLINOIS SUGGEST 50 KNOT WINDS AROUND 900 MB MIXING TOWARD THE
SURFACE, SUPPORTING WIND GUSTS 40-45 MPH. NBM BOX-AND-WHISKERS
PLOT FOR MATTOON SUGGESTS SOME POTENTIAL FOR OVER 50 MPH IF A
LONGER PERIOD OF MIXING OCCURS. WILL NEED TO WATCH THIS TIME
FRAME FOR ANY POTENTIAL ADVISORIES.
FRIDAY THROUGH TUESDAY:
WHILE A PERIOD OF DRY CONDITIONS FOLLOWS THE FRONT THURSDAY
NIGHT, MORE SHOWERS AND THUNDERSTORMS ARRIVE LATER FRIDAY AS A
DEEP UPPER LOW MOVES OUT OF WYOMING INTO THE DAKOTAS. BY
SATURDAY EVENING, THIS LOW SHOULD BE CENTERED NEAR THE SOUTHWEST
TIP OF LAKE SUPERIOR. VARIOUS MACHINE LEARNING ALGORITHMS HAVE
BEEN SUGGESTING SOME ADDITIONAL POTENTIAL FOR STRONG TO LOCALLY
SEVERE STORMS FRIDAY INTO SATURDAY, THOUGH TIMING OF THE COLD
FRONT PASSAGE WITH THE LATEST SET OF SYNOPTIC MODELS MAY
PRECLUDE THE THREAT LINGERING INTO SATURDAY.
GOING INTO THE WEEKEND, FOCUS SHIFTS TOWARD A PERIOD OF COOL
WEATHER, WITH SATURDAY AND SUNDAY NIGHTS BOTH SEEING LOWS IN THE
LOWER TO MID 30S. LREF PROBABILITIES OF SUB-FREEZING LOWS ARE
HIGHEST SUNDAY NIGHT (40-60%). THE NORMAL LAST FREEZE OF THE
SEASON IN CENTRAL ILLINOIS IS GENERALLY IN THE APRIL 11-20 RANGE
PER CLIMATOLOGY, THOUGH SPRING GROWTH HAS GOTTEN AN EARLY START
DUE TO THE RECENT WARM WEATHER. COORDINATION WITH NEIGHBORING
OFFICES WILL TAKE PLACE TO DETERMINE WHETHER OR NOT TO START
FROST/FREEZE HEADLINES, BUT THE POTENTIAL WILL BE HIGHLIGHTED IN
OTHER PRODUCTS.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 610 PM CDT TUE MAR 31 2026
A COLD FRONT WILL CONTINUE MOVING THROUGH THE CENTRAL IL
TERMINALS THIS EVENING, LIKELY STALLING SOUTH OF THE TERMINALS
WEDNESDAY MORNING UNTIL WEDNESDAY EVENING. THIS FRONT WILL BE
THE FOCUS FOR THUNDERSTORM DEVELOPMENT THIS EVENING, AND PERIODS
OF ADDITIONAL SHOWERS AND THUNDERSTORMS THE REMAINDER OF THE
NEXT 24 HOURS AS MULTIPLE DISTURBANCES TRACK ALONG THE FRONT.
HOWEVER KPIA WILL LIKELY BE OUT OF SHRA/TSRA ACTIVITY FOR THE
FIRST SEVERAL HOURS AS THE FRONT HAS ALREADY PUSHED SOUTH OF
THIS AREA, AND KBMI MAY SEE A FEW HOUR BREAK IN ACTIVITY THROUGH
05Z. GUIDANCE POINTS TO DECREASING CIGS OVERNIGHT, RESULTING IN
WIDESPREAD MVFR BY 02Z-05Z, AND IFR BY OVER MOST OF THE AREA BY
12Z. WINDS SW 15G25 KTS AHEAD OF THE COLD FRONT, SHIFTING
CLOCKWISE TO NE BEHIND THE FRONT.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...GEELHART
DISCUSSION...GEELHART
AVIATION...37
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