530  
FXUS63 KILX 211058  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
558 AM CDT FRI AUG 21 2026  
   
KEY MESSAGES
 
 
- A SLIGHT RISK OF SEVERE THUNDERSTORMS EXISTS THIS  
AFTERNOON/EVENING NORTH OF A LINE FROM BEARDSTOWN TO LINCOLN  
TO GIBSON CITY. HAIL (15%), WIND (15%), AND TORNADO (2%)  
THREATS WILL EXIST IN THIS AREA, WITH LOWER PROBABILITIES  
FURTHER SOUTH.  
 

 
   
DISCUSSION
 
 
ISSUED AT 215 AM CDT FRI AUG 21 2026  
 
WEAK HIGH PRESSURE OVER IL THIS MORNING WILL GIVE WAY TO A WEAK  
COLD FRONT TONIGHT ALONG WITH AN UPPER LEVEL WAVE. WITH CAPES OF  
2000-3000 J/KG AND SHEAR AROUND 30-35 KTS, SEVERE STORMS WILL  
BE POSSIBLE LATE THIS AFTERNOON AND THIS EVENING. EXPECT SOME  
DISCRETE CELLS DEVELOPING IN NORTHERN IL/EASTERN IA EARLY IN THE  
AFTERNOON, DRIFTING SOUTH-SOUTHEAST THROUGH CENTRAL IL DURING  
THE LATE AFTERNOON AND EVENING HOURS. THE SPC HAS CENTRAL IL IN  
A SLIGHT RISK FOR TODAY (LEVEL 2 OUT OF 5) NORTH OF A LINE FROM  
BEARDSTOWN TO LINCOLN TO GIBSON CITY. HAIL (15%), WIND (15%),  
AND TORNADO (2%) THREATS WILL EXIST IN THE SLIGHT RISK AREA.  
FURTHER SOUTH A MARGINAL RISK EXISTS...NORTH OF A LINE FROM  
EFFINGHAM TO DANVILLE, WITH MAINLY LOW END HAIL/WIND (5%) THREATS  
FOR THIS EVENING IN THIS AREA.  
 
LATE TONIGHT, STORMS WILL LIKELY WIND DOWN BY MIDNIGHT OR  
SHORTLY THEREAFTER, WITH WINDS SHIFTING TO THE NORTHWEST AFTER  
THE COLD FRONT MOVES THROUGH THE AREA. EXPECT SUNNY SKIES, LIGHT  
NORTHWEST WINDS, AND TEMPERATURES REBOUNDING INTO THE LOW 80S  
DURING THE AFTERNOON. A FEW OF THE MODELS HAVE AN ISOLATED  
STORM OR TWO DEVELOPING IN CENTRAL IL ON SATURDAY AFTERNOON.  
HOWEVER, THE PROBABILITY IS AT 10% OR LESS, SO DID NOT INCLUDE  
IT IN THE FORECAST. LEAVING OUT THUNDER FOR SATURDAY MATCHES  
SPC'S GUIDANCE AS WELL.  
 
NORTHWESTERLY FLOW ALOFT WILL CONTINUE THROUGH THE WEEKEND AND  
INTO NEXT WEEK. AN UPPER LEVEL TROUGH MOVING SOUTHEAST ACROSS  
THE GREAT LAKES REGION BY MID WEEK COULD BRING A FEW SHOWERS OR  
STORMS TO THE AREA. BUT GENERALLY EXPECT A DRIER PATTERN ALONG  
WITH TEMPS NEAR TO SLIGHTLY BELOW NORMAL FOR THE REMAINDER OF  
THE PERIOD.  
 

 
   
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
 
 
ISSUED AT 558 AM CDT FRI AUG 21 2026  
 
EXPECT LIGHT WINDS TODAY ALONG WITH MOSTLY CLEAR SKIES. WE  
SHOULD SEE SOME CUMULUS AROUND 4 KFT THIS AFTERNOON AND WE  
STILL HAVE A 30-50% CHANCE FOR THUNDERSTORMS TODAY. HOWEVER, THE  
TIMING HAS SHIFTED BACK SOMEWHAT. THE LAST FEW RUNS OF THE CAMS  
HAVE PUSHED TS ACTIVITY BACK TO THE EVENING OR EVEN THE  
OVERNIGHT HOURS FOR THE CENTRAL IL TERMINALS. WILL SHIFT BACK  
THE TIMING A BIT.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
KEY MESSAGES...KNUTSVIG  
DISCUSSION...KNUTSVIG  
AVIATION...KNUTSVIG  
 
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