236  
FXUS63 KILX 090236  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
936 PM CDT MON JUN 8 2026  
   
KEY MESSAGES
 
 
- A HEAVY RAIN THREAT WILL PERSIST THROUGH THIS EVENING,  
CONTINUING INTO THE OVERNIGHT HOURS SOUTH OF I-72/DANVILLE.  
RATES OF TWO INCHES PER HOUR OR GREATER MAY LEAD TO LOCALIZED  
FLASH FLOODING.  
 
- THE COMBINATION OF HEAT AND HUMIDITY WILL LEAD TO HEAT INDEX  
VALUES PEAKING BETWEEN 95 AND 105 DEGREES ON TUESDAY AND  
WEDNESDAY. THOSE SENSITIVE TO HEAT SHOULD TAKE EXTRA  
PRECAUTIONS.  
 
- THE THREAT FOR SEVERE WEATHER WILL INCREASE THROUGH THIS  
WEEK, PEAKING IN THE LATE WEDNESDAY NIGHT-THURSDAY TIME FRAME.  
 

 
   
UPDATE
 
 
ISSUED AT 935 PM CDT MON JUN 8 2026  
 
MADE SOME TWEEKS TO THE POP/WX GRIDS TO BETTER REFLECT RADAR  
TRENDS FOR THE REST OF THE NIGHT. SOME OF THE NEW MODELS ARE  
INDICATING CHANCES OF PRECIP TOMORROW IN THE EAST AND CENTRAL  
PARTS OF THE STATE, SO MADE SOME ADJUSTMENTS FOR TOMORROW AS  
WELL. ADDITIONAL SHOWERS ARE POSSIBLE OVERNIGHT, BUT CHANCES ARE  
LESS THAN EARLIER FORECASTED. UPDATE SHOULD HAVE ALREADY GONE  
OUT.  
 

 
   
DISCUSSION
 
 
ISSUED AT 241 PM CDT MON JUN 8 2026  
 
NEAR RECORD PRECIPITABLE WATER VALUES OF JUST OVER 2" ALONG WITH  
AN APPROACHING UPPER LOW ARE DRIVING A HEAVY RAIN THREAT TODAY,  
WITH MULTIPLE REPORTS OF 2"/HOUR RAIN RATES. EAST CENTRAL IL  
WILL SEE THE GREATEST THREAT FOR HEAVY RAIN OVER THE NEXT FEW  
HOURS. AN MCV MOVING OUT OF SOUTHEAST MO MAY LEAD TO  
THUNDERSTORM DEVELOPMENT IN PORTIONS OF SOUTHEASTERN IL THAT  
HAVE YET TO SEE MUCH ACTIVITY. SOME WILL SEE A BRIEF BREAK THIS  
AFTERNOON, BUT WITH MORE SHOWERS/STORMS CAPABLE OF HEAVY  
RAINFALL MOVING IN FROM THE WEST WE ANTICIPATE THE FLOOD THREAT  
TO PERSIST THROUGH AT LEAST THIS EVENING. A FEW CAMS DEPICT A  
CONVECTIVE COMPLEX WITH AN ASSOCIATED MCV MOVING ACROSS MO AND  
WEAKENING DURING THE OVERNIGHT HOURS. THE SOUTHERN PORTION OF  
THE FLOOD WATCH HAS BEEN EXTENDED TO 7 AM TO ACCOUNT FOR THIS  
POSSIBILITY, AS WELL AS TO ACCOUNT FOR THE PERSISTENT NEAR  
RECORD PW VALUES.  
 
THE COMBINATION OF HEAT AND HUMIDITY THEN BECOME A CONCERN FOR  
TUESDAY AND WEDNESDAY. HEAT INDEX VALUES IN THE MID 90S UP TO  
A FEW DEGREES OVER 100 ARE ANTICIPATED. PARTICULARLY FOLLOWING  
THE EXTENDED PERIOD OF DRY AND COOL CONDITIONS EXPERIENCED  
TOWARD THE END OF MAY/IN THE FIRST WEEK OF JUNE, THIS PERIOD OF  
HEAT AND HUMIDITY COULD HAVE MORE IMPACT THAN USUAL. ON TUESDAY,  
A WEAK MOISTURE BOUNDARY MAY TRIGGER ISOLATED THUNDERSTORMS BUT  
LITTLE RELIEF FROM THE HEAT WILL PROBABLY RESULT. INSTABILITY IS  
QUITE STRONG, BUT WITH SHEAR LIMITED THE SEVERE THREAT SHOULD BE  
LIMITED AS WELL. THE MAIN CONCERN WOULD BE ISOLATED STRONG TO  
SEVERE WIND GUSTS.  
 
THE SEVERE WEATHER THREAT IS FORECAST TO INCREASE LATER IN THE  
WEEK FOR CENTRAL AND SOUTHEAST ILLINOIS. LATE WEDNESDAY NIGHT  
INTO THURSDAY MORNING, SEVERE STORMS COMING OUT OF THE UPPER  
MISSISSIPPI VALLEY ARE FORECAST TO WEAKEN AS THEY MOVE TOWARD  
CENTRAL ILLINOIS. THE GREATER THREAT IS ANTICIPATED ON THURSDAY  
AFTERNOON/EVENING, WITH SPC DELINEATING A 30% CONTOUR  
APPROXIMATELY NEAR AND WEST OF I-55.  
 

 
   
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
 
 
ISSUED AT 658 PM CDT MON JUN 8 2026  
 
SHOWERS AND STORMS WILL BE MOVING OVER MOST SITES, EXCEPT PIA  
THROUGH THE EVENING, ENDING AROUND 06Z AT CMI. WILL KEEP BMI  
WITH NO THUNDER, BUT WILL HAVE PROB30 FOR THUNDERSTORMS AT SPI,  
DEC, AND CMI THIS EVENING. CIGS WILL DROP TO MVFR AS WELL AS  
MORE LOWER CLOUDS ADVECT OVER THE SITES. THESE LOWER CIGS WILL  
CONTINUE OVERNIGHT AT ALL SITES, BUT WILL IMPROVE TO VFR IN THE  
MORNING AT SPI, DEC, AND CMI...AND THEN IN THE AFTERNOON AT PIA  
AND BMI. CLOUDS WILL CONTINUE TIL END OF THE PERIOD AT PIA AND  
BMI, BUT COULD SCATTER OUT AT THE OTHER SITES IN THE LATE  
AFTERNOON. WINDS WILL BE SOUTH TO SOUTHEAST THIS EVENING AND  
THEN SOUTHWEST LATE TONIGHT THROUGH TOMORROW. SPEEDS WILL BE  
LIGHTER OVERNIGHT BUT THEN BE AROUND 10KTS TOMORROW.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
FLOOD WATCH UNTIL 1 AM CDT TUESDAY FOR ILZ027>031-036>038-  
041>046-053-055-057.  
FLOOD WATCH UNTIL 7 AM CDT TUESDAY FOR ILZ040-047>052-054-056-  
061>063-066>068-071>073.  
 

 
 

 
 
KEY MESSAGES...AAT  
UPDATE...AUTEN  
DISCUSSION...AAT  
AVIATION...AUTEN  
 
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