925  
FXUS63 KLSX 151056  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
556 AM CDT MON SEP 15 2025  
   
KEY MESSAGES
 
 
- HOT WEATHER IS EXPECTED THROUGH THURSDAY WITH SOME RELIEF LIKELY  
BY THE END OF THE WEEK.  
 
- THERE IS A CHANCE OF THUNDERSTORMS OVER PARTS OF THE AREA EACH  
DAY, WITH THE BEST CHANCE (30-60%) ACROSS MUCH OF THE AREA  
THURSDAY NIGHT INTO SATURDAY.  
 

 
   
SHORT TERM
 
(THROUGH LATE TUESDAY AFTERNOON)  
ISSUED AT 331 AM CDT MON SEP 15 2025  
 
SCATTERED THUNDERSTORMS CURRENTLY DRIFTING OVER CENTRAL AND  
SOUTHEAST MISSOURI WILL LIKELY DISSIPATE IN THE NEXT FEW HOURS AS  
THE RAP IS SHOWING LOW LEVEL CONVERGENCE WEAKENING. THE REST OF THE  
MORNING IS EXPECTED TO BE MAINLY DRY BEFORE ADDITIONAL SCATTERED  
SHOWERS AND THUNDERSTORMS (20-30% CHANCE) DEVELOP BY EARLY AFTERNOON  
ACROSS THE WESTERN HALF OF THE CWA. THESE STORMS WILL OCCUR ON THE  
WESTERN PERIPHERY OF THE UPPER RIDGE WHERE THE RAP IS SHOWING SOME  
SURFACE CONVERGENCE THIS AFTERNOON. LIKE YESTERDAY, I COULD NOT  
RULE OUT ONE OR TWO STRONGER WIND GUSTS THIS AFTERNOON (>45 MPH)  
WITH THESE STORMS GIVEN MLCAPES IN THE 2000-3000+ J/KG RANGE AND  
INVERTED-V SOUNDINGS SEEN IN THE RAP. THE STORMS WILL DIE OUT BY  
EARLY THIS EVENING WITH THE LOSS OF DAYTIME HEATING LEAVING THE REST  
OF TONIGHT DRY.  
 
WITH CURRENT TEMPERATURES IN THE 70S, HIGHS TODAY WILL STILL CLIMB  
INTO THE LOW TO MID 90S. LOWS TONIGHT WILL DROP INTO THE 60S.  
 
BRITT  
 

 
   
LONG TERM
 
(TUESDAY NIGHT THROUGH SUNDAY)  
ISSUED AT 331 AM CDT MON SEP 15 2025  
 
THE LREF IS SHOWING THAT THE UPPER HIGH ASSOCIATED WITH THE OMEGA  
BLOCK WILL STAY IN PLACE THROUGH THURSDAY WHICH WILL CONTINUE TO  
KEEP FORCING FOR DAILY SCATTERED SHOWERS AND THUNDERSTORMS CONFINED  
OVER THE WESTERN PART OF THE CWA. THE OMEGA BLOCK WILL BEGIN TO  
BREAK DOWN LATER THIS WEEK AS THE WESTERN UPPER TROUGH MOVES EAST  
ACROSS THE MIDWEST INCREASING THE CHANCE OF SHOWERS AND  
THUNDERSTORMS AREAWIDE. 30-60% OF THE LREF MEMBERS ARE PRODUCING  
PRECIPITATION ACROSS CWA THURSDAY NIGHT INTO SATURDAY SUPPORTING  
THIS TREND.  
 
WITH THE OMEGA BLOCK STAYING IN PLACE, STILL EXPECT HIGHS TO BE  
MAINLY IN THE 90S THROUGH THURSDAY BEFORE DROPPING BACK INTO THE 80S  
AND UPPER 70S AS 850MB TEMPERATURES FALL FROM 20C TO 15C.  
TEMPERATURES WILL ALSO BE AFFECTED BY MORE CLOUDS AND THE POTENTIAL  
FOR CLOUDS AND RAIN. THIS IS REFLECTED IN THE NBM IQR AT STL WHICH  
IS ONLY 2-4 DEGREES THROUGH THURSDAY BUT THEN INCREASES TO 7 DEGREES  
FROM FRIDAY ON.  
 
BRITT  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 546 AM CDT MON SEP 15 2025  
 
THERE WILL BE SCATTERED THUNDERSTORMS THAT MAY AFFECT UIN/COU/JEF  
THIS AFTERNOON AND HAVE ADDED PROB30 GROUPS AT COU/JEF BETWEEN  
21-24Z WHERE I THINK THE LOCATION AND TIMING IS MOST LIKELY. IF  
THUNDERSTORMS DO AFFECT A TERMINAL, MVFR/POSSIBLE IFR CEILINGS AND  
VISIBILITES ARE POSSIBLE IN BRIEF DOWNPOURS. OTHERWISE DRY AND  
VFR CONDITIONS ARE EXPECTED WITH LIGHT WINDS OUTSIDE OF  
THUNDERSTORMS.  
 
BRITT  
 

 
   
LSX WATCHES/WARNINGS/ADVISORIES
 
 
MO...NONE.  
IL...NONE.  

 
 

 
 
WFO LSX  
 
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