200  
FXUS63 KILX 180603  
AFDILX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE LINCOLN IL  
103 AM CDT WED JUN 18 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 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 103 AM CDT WED JUN 18 2025  
 
SCATTERED SHOWERS AND VFR CONDITIONS WILL GIVE WAY TO MORE  
WIDESPREAD THUNDERSTORMS IN THE MORNING AS A DISTURBANCE MOVES  
NORTHEASTWARD INTO THE AREA. HAVE INCLUDED TEMPO GROUPS FOR THESE  
THUNDERSTORMS, ALONG WITH MVFR CIGS/VSBYS FROM AROUND 13Z-18Z,  
HOWEVER TIMING OF THIS DISTURBANCE REMAINS SOMEWHAT UNCERTAIN, AND  
IT COULD HAVE LINGERING IMPACTS PAST 18Z. ADDITIONAL THUNDERSTORM  
RE-DEVELOPMENT WILL BE POSSIBLE SHORTLY AFTER THIS INITIAL  
DISTURBANCE MOVES OUT OF THE AREA AS A FRONTAL BOUNDARY CONTINUES  
TO PROGRESS EASTWARD ACROSS THE AREA. HIGHER PROBABILITIES FOR  
ADDITIONAL STORMS, LIKELY AFTER 20Z-21Z WILL BE FOR KDEC-KCMI AND  
LOCATIONS EASTWARD. ADDITIONAL CONCERNS INVOLVE CIG HEIGHTS,  
LIKELY TO BE MVFR MUCH OF THE MORNING THROUGH AFTERNOON. WINDS  
LIGHT AND VARIABLE TO S 10 KTS OVERNIGHT, BECOMING GUSTY UP TO  
20G30 KTS FROM THE SW AFTER 18Z-20Z.  
 
37  
 
 
   
ILX WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
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