370  
FXUS63 KILX 172302  
AFDILX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE LINCOLN IL  
602 PM CDT TUE JUN 17 2025  
   
KEY MESSAGES  
 
- THERE IS A RISK FOR SEVERE WEATHER ACROSS ALL OF CENTRAL  
ILLINOIS ON WEDNESDAY...WITH THE GREATEST RISK (LEVEL 3 OF 5)  
FOCUSED ALONG AND SOUTHEAST OF A CHAMPAIGN TO TAYLORVILLE LINE.  
 
- HOT AND HUMID WEATHER WILL DEVELOP BY THE END OF THE WEEK. HIGH  
TEMPERATURES ARE PROGGED TO RISE INTO THE LOWER TO MIDDLE 90S  
BOTH SATURDAY AND SUNDAY, RESULTING IN PEAK HEAT INDEX READINGS  
ABOVE 100 DEGREES.  
 
 
   
DISCUSSION  
 
ISSUED AT 236 PM CDT TUE JUN 17 2025  
   
..SCATTERED THUNDERSTORMS THIS EVENING  
 
A SHORT-WAVE TROUGH CURRENTLY OVER NORTHWEST MISSOURI WILL TRIGGER  
SCATTERED THUNDERSTORMS ACROSS WEST-CENTRAL ILLINOIS THIS EVENING.  
THE 19Z/2PM REGIONAL RADAR MOSAIC SHOWS ISOLATED STORMS FORMING  
AHEAD OF THE WAVE ACROSS FAR NORTHERN MISSOURI. MOST CAMS SUGGEST  
THIS AREA OF CONVECTION WILL INCREASE IN AREAL COVERAGE AS IT  
TRACKS E/NE INTO WESTERN ILLINOIS LATE THIS AFTERNOON AND EVENING.  
THE HRRR HAS CONSISTENTLY FOCUSED ON LOCATIONS ALONG/WEST OF I-55  
BETWEEN 5PM AND 10PM...AND THIS LOOKS REASONABLE BASED ON THE  
LATEST UPSTREAM SATELLITE/RADAR TRENDS. WHILE WIDESPREAD SEVERE  
WEATHER IS NOT LIKELY, A FEW CELLS MAY TAP INTO MLCAPES OF  
1500-2000J/KG TO PRODUCE GUSTY WINDS AND SMALL HAIL ALONG WITH  
LOCALLY HEAVY DOWNPOURS.  
   
..SEVERE WEATHER RISK ON WEDNESDAY  
 
AS THE NOCTURNAL LOW-LEVEL JET STRENGTHENS ACROSS THE SOUTHERN  
PLAINS TONIGHT, A PROMINENT OUTFLOW BOUNDARY EXTENDING ACROSS  
CENTRAL KANSAS WILL SERVE AS THE FOCUS FOR A CLUSTER OF SEVERE  
CONVECTION. WHILE THESE STORMS WILL FOLLOW THE BOUNDARY AND  
GRADUALLY SINK SOUTHEASTWARD TOWARD THE GREATEST INSTABILITY  
ACROSS THE OZARKS INTO ARKANSAS, AN OUTFLOW BOUNDARY FROM THE  
SYSTEM WILL SWEEP EASTWARD INTO WESTERN ILLINOIS TOWARD DAWN  
WEDNESDAY...THEN FURTHER EAST ACROSS MUCH OF THE KILX CWA DURING  
THE MORNING. SCATTERED NON-SEVERE THUNDERSTORMS MAY ACCOMPANY THE  
BOUNDARY, FOLLOWED BY A LULL IN PRECIP CHANCES FROM MID-MORNING  
THROUGH EARLY AFTERNOON. AFTER THAT, WE WILL NEED TO KEEP A CLOSE  
EYE ON BOTH THE REMNANT OUTFLOW BOUNDARY, AS WELL AS THE SYNOPTIC  
COLD FRONT AS IT PUSHES EASTWARD ACROSS THE MISSISSIPPI RIVER  
LATER IN THE DAY. THE ATMOSPHERE ACROSS THE REGION WILL ONLY BE  
MODESTLY UNSTABLE...WITH THE 12Z HREF SHOWING THE HIGHEST SBCAPES  
IN EXCESS OF 2500J/KG FOCUSING WELL EAST OF THE I-57 CORRIDOR INTO  
THE OHIO RIVER VALLEY. THE NAM CONTINUES TO SHOW 0-6KM BULK SHEAR  
INCREASING TO 30-40KT...WHICH WILL BE ENOUGH TO OVERCOME THE  
LIMITED INSTABILITY AND ALLOW SCATTERED CONVECTIVE DEVELOPMENT  
ALONG BOTH THE OUTFLOW AND COLD FRONT. THE MOST FAVORABLE  
INSTABILITY/SHEAR/FORCING WILL BE IN PLACE ALONG/SOUTHEAST OF A  
CHAMPAIGN TO TAYLORVILLE LINE WHERE SPC HAS UPGRADED THE SEVERE  
RISK TO ENHANCED (LEVEL 3 OF 5). THE PRIMARY STORM RISKS WILL BE  
DAMAGING WIND GUSTS GREATER THAN 60MPH AND HAIL LARGER THAN  
QUARTERS: HOWEVER, ISOLATED TORNADOES CANNOT BE RULED  
OUT...ESPECIALLY ALONG/SOUTH OF I-70 WHERE AN MCV MAY PROVIDE  
ENHANCED LOW-LEVEL SHEAR. THE PRIMARY TIME FRAME FOR SEVERE WILL  
BE 2PM TO 10PM.  
   
..HOT WEATHER BY THE END OF THE WEEK  
 
 
ONCE THE WEDNESDAY SYSTEM DEPARTS, A PERIOD OF SLIGHTLY COOLER AND  
DRIER CONDITIONS WILL BE ON TAP FOR THURSDAY BEFORE UPPER HEIGHTS  
RISE AND TEMPERATURES INCREASE MARKEDLY. 12Z NBM SHOWS A HIGH  
PROBABILITY (70-100% CHANCE) OF EXCEEDING 90 DEGREES ACROSS ALL  
OF CENTRAL ILLINOIS NEXT SATURDAY AND SUNDAY. THESE TEMPERATURES  
COMBINED WITH SEASONALLY HIGH DEWPOINTS IN THE LOWER TO MIDDLE  
70S WILL PRODUCE HEAT INDEX VALUES WELL OVER 100 DEGREES.  
 
BARNES  
 
 
   
AVIATION  
(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)  
ISSUED AT 601 PM CDT TUE JUN 17 2025  
 
A FEW WAVES OF SHOWERS AND STORMS ARE EXPECTED ACROSS CENTRAL  
ILLINOIS THROUGH THE PERIOD. THE FIRST WAVE OF STORMS CURRENTLY  
OVER NE MO WILL LIFT ACROSS THE I-55 CORRIDOR LATE THIS EVENING.  
WHILE EARLIER GUIDANCE KEPT THIS WEST OF CMI/DEC, THERE HAS BEEN A  
TREND FOR STORMS TO REACH FURTHER EAST SO HAVE INTRODUCED A PROB30  
AT THOSE TWO SITES WHILE A TEMPO REMAINS FOR THE WESTERN  
TERMINALS. THE NEXT WAVE OF STORMS WILL DEVELOP OVER KS/MO LATE  
THIS EVENING AND CONTINUE EAST OVERNIGHT. REMNANTS OF THIS LINE OF  
STORMS WILL PUSH ACROSS CENTRAL ILLINOIS WEDNESDAY MORNING. SOME  
WEAK CONVECTION IS POSSIBLE, BUT CONFIDENCE IN DETAILS PRECLUDES  
MORE THAN A PROB30 MENTION AT THIS TIME. THE LAST WAVE OF STORMS  
WILL BE WITH A SYNOPTIC COLD FRONT LATE WEDNESDAY AFTERNOON AND  
EVENING TURNING WINDS MORE SW TO WRLY LATE IN THE PERIOD.  
COVERAGE OF STORMS APPEARS MORE SCATTERED WITH THIS LAST WAVE AND  
DETAILS WILL HINGE ON OUT THE EARLIER LINE OF SHOWERS AND STORMS  
PANS OUT, SO AGAIN A PROB30 COVERS THIS THIRD WAVE OF STORMS.  
 
DEUBELBEISS  
 
 
   
ILX WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
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