254  
FXUS63 KILX 061114  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
614 AM CDT SAT JUN 6 2026  
   
KEY MESSAGES  
 
- ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE  
THIS WEEKEND OVER CENTRAL IL, MAINLY NORTH OF I-70. A FEW  
STORMS COULD HAVE THE POTENTIAL TO BECOME STRONG TO SEVERE,  
POSING A RISK FOR LOCALLY HEAVY RAIN OF 1-2 INCHES, LARGE  
HAIL AND DAMAGING WINDS.  
 
- MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED OVER  
CENTRAL AND SOUTHEAST IL SUNDAY NIGHT THROUGH MONDAY NIGHT.  
 
- EXPECT A WARM AND MUGGY CONDITIONS TODAY WITH FEEL-LIKE  
TEMPERATURES CLIMBING INTO THE LOWER 90S THIS AFTERNOON.  
 
- A STRONGER WARMING TREND ARRIVES TUESDAY THROUGH FRIDAY,  
PUSHING AFTERNOON HEAT INDEX VALUES 95 TO 105 DEGREES.  
 
 
   
DISCUSSION  
 
ISSUED AT 330 AM CDT SAT JUN 6 2026  
 
RADAR MOSAIC SHOWS SCATTERED SHOWERS/THUNDERSTORMS OVER NORTHERN  
PARTS OF IL/IN INTO SOUTHERN IOWA AND NORTHERN MO. OVER IL THIS  
DEVELOPING CONVECTION WAS NORTH OF A MACOMB TO PEORIA TO  
KANKAKEE LINE AND TRACKING EASTWARD. THIS CONVECTION AIDED BY A  
WSW 25-40 KT LOW LEVEL JET (STRONGEST WINDS NE OF CENTRAL IL  
OVER SOUTHERN GREAT LAKES) AND TROPICAL PW VALUES OF 1.4-1.7  
INCHES OVER MUCH OF IL. UNSTABLE AIR MASS OVER NORTHERN IL WITH  
MLCAPES OF 1800-2500 J/KG FROM I-74 NORTH. BULK SHEAR VALUES  
WERE LESS THAN 25 KTS OVER CENTRAL IL AND 30-45 KTS FROM I-80  
NORTH, OVER NORTHERN IL. THE 08Z/3 AM SURFACE MAP SHOWS A COLD  
FRONT OVER SOUTHEAST WI INTO NORTHERN IOWA AND SOUTHEAST  
NEBRASKA. SW WINDS AND INCREASING CLOUDS GIVING MILD TEMPS IN  
THE LOW TO MID 70S (WARMEST FROM I-55 WEST). DEWPOINTS WERE IN  
THE LOWER TO MID 60S IN EAST CENTRAL AND SOUTHEAST IL AND UPPER  
60S TO NEAR 70F FROM HIGHWAY 51 WEST.  
 
THE 06Z AND 07Z HRRR SHOW SCATTERED CONVECTION NORTH OF PEORIA  
AND LIFTING THROUGH EARLY THIS MORNING AND MOSTLY EXISTING CWA  
BY MID MORNING AS LOW LEVEL JETS PUSHES FURTHER NE OF CENTRAL IL.  
A FEW STRONG CELLS WITH GUSTY WINDS ALONG WITH LOCALLY HEAVY  
RAINFALL POSSIBLE EARLY THIS MORNING WITH THIS CONVECTION MAINLY  
NORTH OF PIA AND BMI NEXT FEW HOURS. OTHERWISE AN OUTFLOW  
BOUNDARY LINGERING OVER NORTHERN CWA TO SEE SCATTERED CONVECTION  
DEVELOP NEAR IT DURING THIS AFTERNOON IN UNSTABLE AIR MASS (BUT  
WEAK WIND SHEAR), ESPECIALLY DURING MID TO LATE AFTERNOON  
INITIALLY NORTH OF A RUSHVILLE TO LINCOLN TO PARIS LINE. BUT  
CONVECTION CHANCES TO SHIFT FURTHER SOUTH INTO CENTRAL IL DURING  
THIS EVENING BUT GENERALLY STAYING NORTH OF I-70 INTO TONIGHT.  
SPC DAY1 OUTLOOK HAS MARGINAL RISK OF SEVERE STORMS THIS  
AFTERNOON/EVENING NORTH OF AN EFFINGHAM TO ROBINSON LINE FOR  
DAMAGING WINDS AND LARGE HAIL. THE HREF LPMM ALSO SHOWS A FEW  
POCKETS OF 1-2 INCHES NORTH OF I-74 EARLY THIS MORNING AND NORTH  
OF HIGHWAY 36 THIS AFTERNOON/EVENING. MUGGY TODAY WITH VERY  
WARM HIGHS IN THE UPPER 80S WITH AFTERNOON HEAT INDICES IN THE  
LOWER 90S. LOWS OVERNIGHT IN THE UPPER 60S, WITH SE IL AROUND  
70F.  
 
THE MAIN SYNOPTIC FRONT WILL MOVE INTO NORTHERN IL THIS  
AFTERNOON/EVENING, AND REMAIN NORTH OF CENTRAL IL ON SUNDAY.  
BEST CONVECTION CHANCES TONIGHT INTO SUNDAY WILL BE OVER  
NORTHERN CWA CLOSER TO THIS FRONT AND OVER THE MS RIVER VALLEY  
LATE SUNDAY AFTERNOON AS SYSTEM WX SYSTEM APPROACHES FROM WEST  
TEXAS. THE WEAK CUTOFF 500 MB LOW OVER WEST TEXAS TO OPEN UP  
INTO A MID LEVEL TROF AS IT MOVES OVER IA/MO OVERNIGHT SUNDAY  
NIGHT AND INTO IL MONDAY AFTERNOON. DEEPER TROPICAL MOISTURE TO  
LIFT INTO IL AHEAD OF THIS SYSTEM SUNDAY NIGHT AND MONDAY, WITH  
MORE WIDESPREAD CONVECTION MOVING EASTWARD OVER IL DURING SUNDAY  
NIGHT AND CONTINUES MONDAY BEFORE DIMINISHING FROM THE WEST  
OVERNIGHT MONDAY NIGHT INTO TUE MORNING. NBM HAS 70-90% CHANCE  
OF OVER 1 INCH OF RAIN OVER CWA SUNDAY NIGHT THRU MONDAY NIGHT.  
HIGHS SUNDAY MID TO UPPER 80S AND LOW TO MID 80S MONDAY. CHANCES  
OF SHOWERS AND THUNDERSTORMS LINGERS ON TUE AND TUE NIGHT ESPECIALLY  
IN EASTERN IL.  
 
UPPER LEVEL RIDGING INTO IL TUE/WED TO RETURN HIGHER HEAT AND  
HUMIDITY TO THE AREA DURING MID/LATE WEEK. HIGHS TUE IN THE  
UPPER 80S TO AROUND 90F AND 90-95F WED-FRI (WARMEST OVER THE IL  
RIVER VALLEY). DEWPOINTS IN THE LOW TO MID 70S TO GIVE AFTERNOON  
HEAT INDICES OF 95-105F FROM TUE THRU FRIDAY. THIS WILL BE OUR  
LONGEST HEAT WAVE SO FAR THIS SEASON AND BE WEATHER AWARE OF  
THIS HIGH HEAT AND HUMIDITY. THE ECMWF AND GFS MODELS SHOWING A  
FRONTAL BOUNDARY PUSHING SE INTO IL THU NIGHT AND TO BRING MORE  
CHANCES OF CONVECTION. THOUGH MOST DAYS UPCOMING WEEK WE HAVE AT  
LEAST SLIGHT CHANCES OF CONVECTION IN TROPICAL AIRMASS.  
 
 
   
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/  
 
ISSUED AT 614 AM CDT SAT JUN 6 2026  
 
CLUSTER OF THUNDERSTORMS HAS BEEN SLIDING JUST NORTH OF THE  
KPIA-KCMI CORRIDOR EARLY THIS MORNING. AN ASSOCIATED OUTFLOW  
SHOULD HELP TRIGGER ADDITIONAL STORMS LATER TODAY, BUT TIMING  
AND PLACEMENT IS STILL IN FLUX. THUS, PROB30 MENTIONS ARE THE  
BEST OPTION UNTIL TRENDS BECOME MORE OBVIOUS LATER TODAY.  
 
SOUTHWEST WINDS WILL AVERAGE ABOUT 10 KNOTS MUCH OF THE DAY,  
BEFORE DROPPING TO LESS THAN 5 KNOTS EARLY IN THE EVENING.  
 
 
   
ILX WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
 
KEY MESSAGES...07  
DISCUSSION...07  
AVIATION...GEELHART  
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