931  
FXUS63 KILX 041918  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
218 PM CDT THU JUN 4 2026  
   
KEY MESSAGES
 
 
- A MARGINAL RISK FOR SEVERE THUNDERSTORMS ON DECK FOR TOMORROW,  
WITH ISOLATED DAMAGING WIND GUSTS SERVING AS THE PRIMARY  
RISK.  
 
- AN UNSETTLED WEATHER PATTERN WILL BRING DAILY CHANCES OF  
SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE OF NEXT WEEK.  
 
- HUMIDITY BUILDS OVER CENTRAL AND SOUTHEAST ILLINOIS THIS  
WEEKEND AND LINGERS INTO NEXT WEEK, DRIVING PEAK HEAT INDEX  
VALUES INTO THE LOW TO MID 90S. A NONZERO (10- 20%) CHANCE FOR  
HEAT INDICES ABOVE 100 DEGREES EXISTS FOR LATE NEXT WEEK.  
 

 
   
DISCUSSION
 
 
ISSUED AT 218 PM CDT THU JUN 4 2026  
 
THE HIGH PRESSURE CENTER DRIFTED OFF TO THE SOUTHEAST OF CENTRAL IL,  
SHIFTING THE FLOW TO A MORE SOUTHERLY DIRECTION TODAY. THIS WILL  
SUPPORT INCREASING MOISTURE AS WE GO INTO THE WEEKEND, STARTING  
TODAY. HIGHS WILL INCREASE TO THE UPPER 80S TO LOW 90S, WITH  
DEWPOINTS IN THE MID 60S TO LOW 70S FOR FRIDAY INTO MONDAY. HEAT  
INDICES COULD BUMP NORTH OF 90 DEGREES BY SATURDAY AND LOOKS TO  
POTENTIALLY CONTINUE INTO THE NEW WEEK. THE LREF SHOWS A NONZERO (10-  
20%) CHANCE FOR APPARENT TEMPS ABOVE 100 DEGREES LATE NEXT WEEK. IN  
CONCLUSION... SUMMER HAS ARRIVED.  
 
A SHORTWAVE WILL PULSE THROUGH THE REGION TOMORROW, BRINGING RAIN  
CHANCES INTO THE FORECAST. THE SHOWERS AND THUNDERSTORMS TOMORROW  
INTO SATURDAY COULD BE EFFICIENT RAIN PRODUCERS WITH PWATS AROUND  
1.7-2.0 INCHES. THE CONVECTIVE COMPLEX MOVING IN FROM IOWA WILL BE  
DECAYING AS IT ENTERS OUR WESTERN CWA. SPC HAS OUTLINED A MARGINAL  
RISK (LEVEL 1/5) OF SEVERE WEATHER NORTH OF A MOUNT STERLING TO  
GIBSON CITY LINE. THE PRIMARY THREAT WILL BE ISOLATED DAMAGING WIND  
GUSTS AS A PULSE OR MULTICELL STORM COLLAPSES. THE HIGHER RAINFALL  
AMOUNTS WILL BE LOCALIZED WHERE MULTIPLE SHOWERS OR THUNDERSTORMS  
PASS OVER THE SAME AREA DURING THIS TIME. OUTSIDE OF CONVECTIVE  
ACTIVITY, A TIGHTENING PRESSURE GRADIENT WILL CAUSE SOUTHWESTERLY  
WIND GUSTS TO EXCEED 25 MPH AT TIMES.  
 
THERE DOES APPEAR TO BE THE POSSIBILITY OF A FEW MORE WEAK ROUNDS OF  
CONVECTION INTO WEDNESDAY. THE TIMING AND RAINFALL AMOUNT FORECAST  
REMAINS UNCERTAIN AT THIS TIME, DUE TO WEAK FORCING. A CUTOFF UPPER-  
LEVEL LOW OR SLOW-MOVING TROUGH IS FORECAST TO DEVELOP AND LINGER  
AROUND THE MIDWEST, WHILE A WEAK FRONTAL BOUNDARY DRIFTS AROUND THE  
AREA. THE EXTENDED FORECAST RELIES HEAVILY ON THE NBM DUE TO THAT  
UNCERTAINTY. LOOKING BEYOND THE SEVEN-DAY WINDOW, THE CPC 6-10 DAY  
OUTLOOK HIGHLIGHTS A STRONG SIGNAL FOR A PERSISTENCE OF ABOVE-NORMAL  
TEMPERATURES ACROSS THE CENTRAL U.S.  
 

 
   
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
 
 
ISSUED AT 1230 PM CDT THU JUN 4 2026  
 
VFR CONDITIONS REIGN OVER THE MAJORITY OF THE 18Z TAF PERIOD.  
HOWEVER, TOMORROW MORNING (AFTER 14Z TOMORROW), SHOWERS AND  
THUNDERSTORMS WILL MOVE INTO THE CENTRAL IL AREA, BRINGING MVFR  
CEILINGS WITH IT. PIA WILL SEE THE <3000KFT CEILINGS FIRST. THE  
COMPLEX OF SHOWERS AND THUNDERSTORMS WILL BE DECAYING AS IT  
ARRIVES, THEREFORE THE PROB30 GROUPS WERE USED. CMI WILL BE THE  
LAST SITE TO SEE PRECIPITATION NEARING THE END OF THE PERIOD.  
 
WINDS WILL BE PREDOMINATELY OUT OF THE SOUTH-SOUTHWEST GUSTING  
TO 20 KNOTS. THEY WILL RELAX BRIEFLY OVERNIGHT BEFORE INCREASING  
AGAIN AS THE SUN STARTS TO RISE AHEAD OF THE PRECIPITATION  
MOVING IN.  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
KEY MESSAGES...COPPLE  
DISCUSSION...COPPLE  
AVIATION...COPPLE  
 
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