758
FXUS63 KILX 201104
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
604 AM CDT TUE MAY 20 2025
KEY MESSAGES
- WIDESPREAD SHOWERS AND THUNDERSTORMS WILL DIMINISH EARLY THIS
MORNING OVER CENTRAL AND SOUTHEAST IL, WITH MANY AREAS SEEING 1
TO 1.5 INCH OF TOTAL RAINFALL BY 8 AM WITH LOCALLY 2-3 INCH
AMOUNTS POSSIBLE. SOME OF THE STORMS COULD BE STRONG TO SEVERE
IN RICHLAND AND LAWRENCE COUNTIES BEFORE DAWN.
- ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORMS IS POSSIBLE THIS
AFTERNOON AND EARLY EVENING UNTIL SUNSET, WITH A SLIGHT RISK
(LEVEL 2 OF 5) OVER NEARLY THE ENTIRE CWA EXCEPT FAR NORTHWEST
PORTIONS OF KNOX AND STARK COUNTIES WHERE THERE IS A MARGINAL
RISK (LEVEL 1 OF 5).
- BELOW NORMAL TEMPERATURES ARE LIKELY FROM WEDNESDAY THROUGH THE
HOLIDAY WEEKEND. WEDNESDAY AND THURSDAY WILL BE THE COOLEST DAY,
WITH HIGHS IN THE LOWER 60S OVER MUCH OF CENTRAL IL, WITH LOWS
IN THE LOW TO MID 40S WEDNESDAY NIGHT.
DISCUSSION
ISSUED AT 400 AM CDT TUE MAY 20 2025
A STRONG MCS WAS OVER CENTRAL/EASTERN IL AND INTO WESTERN INDIANA
EARLY THIS MORNING WITH WIDESPREAD SHOWERS AND SCATTERED
THUNDERSTORMS, THOUGH DIMINISHING SW OF A CANTON TO LINCOLN TO
SHELBYVILLE LINE AT 4 AM. THUNDERSTORMS WERE FOCUSED OVER COUNTIES
ALONG THE INDIANA BORDER. A TORNADO WATCH REMAINS IN EFFECT UNTIL
8 AM FOR RICHLAND AND LAWRENCE COUNTIES, THOUGH SEVERE THREAT MAY
PASS EAST OF THE WABASH RIVER BY SUNRISE.
THE 09Z/4 AM SURFACE MAP SHOWS 998 MB LOW PRESSURE OVER FAR
SOUTHEAST NEBRASKA WITH A WARM FRONT EXTENDING ESE THROUGH
NORTHERN MO INTO FAR WEST CENTRAL IL NEAR QUINCY AND EXTENDING SE
THROUGH LITCHFIELD AND FLORA. LOW PRESSURE TO TRACK INTO CENTRAL
IOWA BY 18Z/1 PM AS WARM FRONT LIFTS SLOWLY NE TOWARD I-74. LOW
PRESSURE SYSTEM STARTS OCCLUDING LATE THIS AFTERNOON AND EVENING
AS IT MOVES INTO NORTHERN IL AND CENTRAL IN BY LATE EVENING,
PUSHING COLD FRONT EAST THRU CENTRAL IL LATE AFTERNOON/EARLY
EVENING. THIS WILL LIKELY REDEVELOP SCATTERED CONVECTION IN
UNSTABLE AIR MASS DURING EARLY TO MID AFTERNOON AND PUSH EAST
INTO INDIANA DURING EARLY/MID EVENING.
PER LATEST SPC DAY1 OUTLOOK... WITHIN THE LEFT EXIT REGION OF THE
AFOREMENTIONED MID LEVEL JET, A DRY SLOT AND ATTENDANT CORRIDOR
OF STEEP LAPSE RATES WILL LIKELY EVOLVE ACROSS PORTIONS OF MO TO
IL/IN FROM MIDDAY INTO THIS AFTERNOON. TO THE NORTH OF THIS, A
CLUSTER OF SUSTAINED STORM DEVELOPMENT IS INITIALLY ANTICIPATED
TOWARDS MID AFTERNOON, CENTERED ON CENTRAL IL AHEAD OF THE SURFACE
LOW. ADDITIONAL STORMS SHOULD DEVELOP FARTHER SOUTH IN TIME
TOWARDS THE LOWER OHIO VALLEY. A MIX OF SUPERCELLS AND MULTICELL
CLUSTERING IS ANTICIPATED, WITH ISOLATED TO SCATTERED COVERAGE OF
SEVERE AND ALL HAZARDS POSSIBLE. SPC DAY1 HAS SLIGHT RISK OVER
MUCH OF CWA (EXCEPT MARGINAL RISK OVER NW PARTS OF KNOX AND STARK
COUNTIES) FOR THIS AFTERNOON AND EARLY EVENING. THERE IS A 5% RISK
OF TORNADOES AND 15% RISK OF LARGE HAIL IN THE SLIGHT RISK AREA.
THERE IS A 15% RISK OF DAMAGING WINDS EAST OF THE IL RIVER.
HIGHS TODAY WILL BE TRICKY DEPENDING ON HOW FAR WARM FRONT GETS
AND IF WE GET ANY BREAKS IN THE LOW CLOUDS. CURRENTLY WE HAVE
HIGHS IN THE LOWER 70S FROM PEORIA AND BLOOMINGTON NORTH TO THE
UPPER 70S TO AROUND 80F FROM SPRINGFIELD TO TERRE HAUTE SOUTH.
HAVE RATHER STRONG ESE TO SE WINDS GUSTING 25-35 MPH EARLY TO MID
MORNING AND TURNING SW TO WEST AFTER COLD FRONTAL PASSAGE LATE
THIS AFTERNOON OR EVENING. A SECONDARY COLD FRONT/TROF PUSHES SE
THRU CWA OVERNIGHT WITH BREEZY WEST TO NW WINDS GUSTING 25-30 MPH
ON WED AND BRINGING IN MUCH COOLER AIR. HIGHS WED IN THE LOWER 60S
OVER MUCH OF CENTRAL IL AND A FEW UPPER 50S NORTH OF I-74, WITH
MID TO UPPER 60S IN SOUTHEAST IL. SURFACE LOW MOVES INTO THE UPPER
OHIO RIVER VALLEY BY MIDDAY WED WHILE A TROF HANGS BACK ACROSS THE
SOUTHERN GREAT LAKES AND NORTHERN IL, KEEPING MORE LOW CLOUDS
AROUND ALONG WITH A CHANCE OF SHOWERS/DRIZZLE, ESPECIALLY FROM
I-74 NORTH.
A WEAK SYSTEM PUSHES EASTWARD ACROSS THE OZARKS AND INTO THE MID
MS RIVER VALLEY WED NIGHT WITH ITS SHOWERS PASSING SOUTH OF CWA.
THOUGH LINGERING TROF TO OUR NORTHEAST WILL KEEP SMALL CHANCES OF
SHOWERS AROUND INTO THU ESPECIALLY NORTHEAST/EASTERN CWA. HIGHS
THU IN THE LOWER 60S WITH BREEZY NW WINDS (THOUGH NOT QUITE AS
STRONG AS WED). LOWS IN THE MID TO UPPER 40S WED NIGHT IN CENTRAL
IL AND AROUND 50F SOUTHEAST OF I-70. COOLER LOWS IN THE LOW TO MID
40S THU NIGHT.
FORECAST MODELS DEEPEN MID/UPPER LEVEL TROF OVER THE EASTERN
STATES LATE THIS WEEK WITH IL IN A NW UPPER LEVEL FLOW AND KEEPING
TEMPS ON THE COOLER SIDE, THOUGH SOME SLIGHT MODIFICATION LATE
THIS WEEK INTO MEMORIAL DAY WEEKEND. CANADIAN HIGH PRESSURE NOSING
DOWN INTO IL FROM HUDSON BAY BY FRIDAY TO BRING DRIER WX FRIDAY.
STILL A SPECTRUM OF MODEL SOLUTIONS FOR WX SYSTEMS EJECTING OUT OF
THE CENTRAL PLAINS DURING THE MEMORIAL DAY WEEKEND. CONSENSUS HAS
20-30% CHANCE OF SHOWERS SW OF I-74 ON SATURDAY THEN 30-50% CHANCE
OF SHOWERS SAT NIGHT THROUGH MONDAY. A REINFORCING SHORT WAVE TROF
DIGGING INTO THE WESTERN GREAT LAKES AND IL ON MONDAY/MEMORIAL DAY
INTO TUE TO KEEP TEMPS BELOW NORMAL ALONG WITH CHANCES OF SHOWERS
AND MOSTLY CLOUDY SKIES/MORE CLOUD COVER.
07
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 555 AM CDT TUE MAY 20 2025
998 MB LOW PRESSURE OVER NW MO HAS A WARM FRONT OVER FAR NORTHERN
MO INTO SW IL AND STILL SOUTH OF THE I-72 AIRPORTS. THE WARM FRONT
TO SLOWLY LIFT NORTHWARD TOWARD I-74 BY EARLY AFTERNOON WHILE LOW
PRESSURE TRACKS INTO NORTH CENTRAL IL BY EARLY EVENING AND PUSHES
A COLD FRONT EAST THROUGH CENTRAL IL. ISOLATED SHOWERS AND
POSSIBLE THUNDERSTORMS LIFTING NNE OVER CENTRAL IL AND CARRIED
VCSH FOR THIS POSSIBLY WITH IFR TO LOW END MVFR CEILINGS THIS
MORNING. STRONG EAST TO SE WINDS 18-25 KTS WITH GUSTS 28-35 KTS
THROUGH 15Z TO VEER SOUTH TO SE AND DECREASE A BIT LATE MORNING
AND AFTERNOON BUT STILL GUSTING 20-30 KTS AT TIMES. SCATTERED
SHOWERS AND THUNDERSTORMS FROM 18Z-00Z THIS AFTERNOON WITH MVFR
CONDITIONS POSSIBLE AND WINDS TO TURN WEST TO SW BEHIND A COLD
FRONT LATER THIS AFTERNOON AND EVENING AND DIMINISH FURTHER DURING
THIS EVENING.
07
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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