799  
FXUS63 KILX 280531  
AFDILX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE LINCOLN IL  
1231 AM CDT MON JUL 28 2025  
   
KEY MESSAGES
 
 
- A HEAT ADVISORY IS IN EFFECT FOR ALL OF CENTRAL AND SOUTHEAST  
ILLINOIS MONDAY AFTERNOON AND EARLY EVENING. DANGEROUS HEAT AND  
HUMIDITY WILL LIKELY CONTINUE TUESDAY FOR THE WHOLE AREA, AND  
WEDNESDAY IN SOUTHEAST IL.  
 
- A SIGNIFICANT PATTERN CHANGE WILL ALLOW A STRONG COLD FRONT TO  
PASS THROUGH THE REGION ON WEDNESDAY, BRINGING A RISK OF STRONG  
STORMS AND HEAVY RAIN.  
 
- COOLER AND MUCH LESS HUMID AIR WILL FOLLOW FOR THE END OF THE  
WEEK AND NEXT WEEKEND.  
 

 
   
DISCUSSION
 
 
ISSUED AT 152 PM CDT SUN JUL 27 2025  
 
18Z SURFACE MAP INDICATED A WEAK STATIONARY BOUNDARY JUST TO OUR  
NORTH, ORIENTED WNW-ESE NEAR THE I-80 CORRIDOR. THIS HAS BEEN THE  
FOCUS FOR SCATTERED STORMS, WITH LARGELY FAILED ATTEMPTS AT  
CONVECTION SOUTH OF THIS BOUNDARY INTO OUR FAR NORTHERN CWA OVER  
THE PAST 1-2 HOURS. RAP/NAM NON- SUPERCELL TORNADO PARAMETER OF  
1-2 ACROSS THE NORTHERN CWA SHOW THE POSSIBILITY OF FUNNELS  
THROUGH LATE AFTERNOON. OTHERWISE FOR THE REMAINDER OF THE AREA  
RICH LOW- MID LEVEL MOISTURE (75-80F DEW POINTS AND 2" PWATS) AND  
UNCAPPED PROFILES SUPPORT ISOLATED CONVECTION (20% POPS) WITH THE  
HIGHEST COVERAGE SOUTH OF I-70 INTO EARLY THIS EVENING BEFORE  
DIMINISHING. NOT LOOKING FOR A SEVERE THREAT BUT COPIOUS MOISTURE  
WILL LEAD TO HEAVY DOWNPOURS AND FREQUENT LIGHTNING IN THE  
LOCATIONS THAT SEE STORMS. A STRATOCU DECK HAS KEPT TEMPS FROM  
SURGING OVER MUCH OF THE AREA WITH 105+ HEAT INDICES SUPPRESSED  
SOUTH OF I-70 THROUGH 1 PM. HOWEVER, RECENT VISIBLE SATELLITE  
TRENDS SHOW LARGER HOLES OPENING UP, THUS MUCH OF THE AREA IS  
STILL EXPECTED TO SEE 100-105 HEAT INDICES LATE THIS AFTERNOON.  
 
CONVECTIVE ALLOWING MODELS SHOW AN MCS DEVELOPING OVER THE UPPER  
MIDWEST THIS EVENING, DROPPING SOUTHEAST INTO EASTERN IA/NORTHWEST  
IL LATE TONIGHT IN A WEAKENING MODE. SOME MODELS SHOW THIS  
COMPLETELY DECAYING BEFORE REACHING OUR NORTHWEST CWA, WHILE A FEW  
SHOW SOME SHOWERS/STORMS PRIMARILY NORTHWEST OF A CANTON TO  
BLOOMINGTON LINE LATE TONIGHT AND EARLY MONDAY MORNING. KEPT LOW  
CHANCE POPS (20-30%) TO ACCOUNT FOR THIS. REGARDLESS OF PRECIP  
COVERAGE, CONVECTIVE DEBRIS CLOUDS WILL LIKELY SLOW DIURNAL  
WARMING OVER THE NORTHERN HALF OF THE CWA THROUGH MONDAY MORNING.  
HOWEVER, TIME/HEIGHT PROGS SHOW CLEARING LIKELY DURING THE  
AFTERNOON WHICH SHOULD ONCE AGAIN PUSH THE ENTIRE AREA INTO HEAT  
ADVISORY CRITERIA, HEAT INDICES PEAKING NEAR 110F.  
 
SHORT RANGE MODELS SUGGEST A REPEAT PERFORMANCE MON NIGHT/TUE  
MORNING WITH ANOTHER UPPER MIDWEST MCS DROPPING SOUTHEAST IN A  
WEAKENING FASHION. THUS WILL CARRY LOW POPS ACROSS THE NORTH, AND  
AFTER DEBRIS CLOUDS DISSIPATE EXPECTING ANOTHER DANGEROUSLY  
HOT/HUMID AFTERNOON WITH WIDESPREAD HEAT INDICES NEAR 110F.  
 
POTENTIALLY ACTIVE WEATHER WEDNESDAY, AS A NORTHERN STREAM  
SHORTWAVE PUSHES A "REAL" COLD FRONT INTO THE AREA. SHEAR AND  
THERMODYNAMIC PROFILES WOULD SUGGEST A LOW END SEVERE RISK, MAINLY  
DAMAGING WIND GUSTS. CSU-MLP SHOWS A 15% SEVERE RISK FOR ALL OF  
CENTRAL/SE IL. WITH THE HIGH PWAT AIRMASS STILL IN PLACE LOCALLY  
HEAVY RAIN ALSO A RISK. DEPENDING ON FRONTAL TIMING, OUR SOUTHEAST  
COUNTIES MAY BE IN LINE FOR ONE MORE DAY OF HEAT HEADLINES.  
 
MEDIUM RANGE GUIDANCE SHOW A WIDE ENVELOPE IN FRONTAL LOCATION  
THU, SO SOME POPS ARE STILL SHOWN BY THE NBM OVER THE SOUTHERN  
HALF OF THE CWA. BUT THE TREND WILL BE FOR DRYING AND COOLER/LESS  
HUMID CONDITIONS ADVECTING ON NORTHEAST LOW LEVEL FLOW, COURTESY  
OF A LARGE CANADIAN RIDGE BUILDING INTO THE GREAT LAKES. THIS IS  
FORECAST TO CONTINUE INTO NEXT WEEKEND, RESULTING IN NBM FORECAST  
HIGHS IN THE UPPER 70S/LOWER 80S, AND LOWS DIPPING INTO THE 50S  
AND LOWER 60S.  
 
25  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)  
ISSUED AT 1231 AM CDT MON JUL 28 2025  
 
AN ORGANIZED THUNDERSTORM COMPLEX OVER NORTHERN IOWA IS FORECAST TO  
CONTINUE DIVING SOUTHEAST THIS MORNING. THE LATEST SUITE OF GUIDANCE  
FAVOR THE COMPLEX TRACKING THROUGH THE AREA BETWEEN ROUGHLY 11-16Z,  
THOUGH IT SHOULD BE IN A DECAYING STATE BY THIS TIME. A TEMPO GROUP  
HAS BEEN ADDED AT KPIA WHERE CONFIDENCE IS HIGHEST FOR THUNDERSTORMS  
AND GUSTY WINDS, WITH PROB30 GROUPS AT THE REMAINING AIRFIELDS.  
CONFIDENCE IS LOW ON PRECIPITATION CHANCES LATER IN THE TAF PERIOD,  
THOUGH DO THINK WE WILL BE MOSTLY DRY THROUGH THE REMAINDER OF THE  
DAY. HOWEVER, THIS MAY CHANGE WITH FUTURE UPDATES.  
 
SOUTH-SOUTHWEST WINDS WILL VEER TO THE WEST LATER TODAY, WITH SPEEDS  
EXPECTED TO BE RELATIVELY LIGHT OUTSIDE OF ANY THUNDERSTORMS.  
 
NMA  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR  
ILZ027>031-036>038-040>057-061>063-066>068-071>073.  
 

 
 

 
 
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