954  
FXUS63 KLSX 141654  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
1154 AM CDT SUN SEP 14 2025  
   
KEY MESSAGES  
 
- HOT WEATHER WILL CONTINUE THROUGH THE MIDDLE OF THIS WEEK.  
 
- THERE IS A SLIGHT CHANCE (15 - 25%) OF SHOWERS AND THUNDERSTORMS  
EACH AFTERNOON FROM TODAY THROUGH TUESDAY. PRECIPITATION  
CHANCES INCREASE TO 30 - 50% MID TO LATE THIS WEEK.  
 
 
   
SHORT TERM  
(THROUGH LATE MONDAY AFTERNOON)  
ISSUED AT 328 AM CDT SUN SEP 14 2025  
 
MID-LEVEL RIDGING WILL CONTINUE TO BE THE PRIMARY INFLUENCE ON OUR  
SENSIBLE WEATHER TODAY THROUGH TUESDAY. EXPECT HIGHS IN THE 90S EACH  
DAY. MONDAY AND TUESDAY WILL BE A FEW DEGREES LESS HOT THAN TODAY AS  
A WEAK BACKDOOR COLD FRONT USHERS SLIGHTLY COOLER AIR INTO THE  
REGION AND AS WE GET INCREASED MID-LEVEL CLOUD COVER FROM A MID-  
LEVEL TROUGH TO THE WEST.  
 
THE MID-LEVEL TROUGH OVER THE CENTRAL AND NORTHERN PLAINS WILL  
PROVIDE LIFT FOR ISOLATED TO WIDELY SCATTERED SHOWERS AND  
THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING. DEEP LAYER SHEAR  
VALUES WILL BE LOWER THAN THOSE OF YESTERDAY, ONLY PEAKING AT 10 -  
15 KTS. SO ALTHOUGH SBCAPE VALUES WILL BE ON THE ORDER OF 1500 -  
2000 J/KG, A LACK OF APPRECIABLE SHEAR WILL FAVOR NON-SEVERE PULSE  
CONVECTION. SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN MONDAY AND  
TUESDAY AFTERNOONS. WITH THE TROUGH KICKING OUT OF THE REGION AND  
THE RIDGE EXPANDING OVER THE AREA, COVERAGE WILL LIKELY BE MORE  
ISOLATED THAN TODAY. OTHERWISE, FAIRLY SIMILAR CAPE AND SHEAR VALUES  
WARRANT MORE PULSE CONVECTION EACH DAY.  
 
JAJA  
 
 
   
LONG TERM  
(MONDAY NIGHT THROUGH SATURDAY)  
ISSUED AT 328 AM CDT SUN SEP 14 2025  
 
THE RIDGE FINALLY ERODES IN THE MIDDLE OF THIS WEEK AS A TROUGH DIPS  
INTO THE CENTRAL CONUS. THIS FEATURE WILL BE RESPONSIBLE FOR A MUCH  
ANTICIPATED COOLDOWN, BUT ITS SLOW-MOVING NATURE WILL DRAG THE  
TRANSITION OUT. BECAUSE OF THIS, ITS ONLY IMPACT ON WEDNESDAY WILL  
BE INCREASED CHANCES OF SHOWERS AND NON-SEVERE THUNDERSTORMS IN  
MISSOURI THAT AFTERNOON. MORE TANGIBLE AND WIDESPREAD RAIN CHANCES  
ARRIVE ON THURSDAY, THOUGH THIS SHOULD BE CHARACTERIZED MORE AS A  
HIGHER CHANCE OF LIGHT RAIN THAN A CHANCE AT DROUGHT RELIEF. LREF  
PROBABILITIES OF RECEIVING 0.25" OF RAIN IN 24 HOURS ENDING AT 00Z  
FRIDAY ARE STILL UNDER 50%.  
 
THURSDAY IS ALSO WHEN COOLER AIR WILL BEGIN TO FILTER INTO THE  
REGION. CONFIDENCE IS INCREASING THAT A SIGNIFICANT PORTION OF THE  
NORTHERN AND WESTERN CWA WILL SEE HIGHS BELOW 90 DEGREES BEGINNING  
THURSDAY WITH THE REST OF OUR COUNTIES FOLLOWING ON FRIDAY. DESPITE  
THE SUB-90 HIGHS, IT LIKELY WON'T BE UNTIL NEXT WEEKEND THAT WE  
RETURN TO NEAR SEASONAL AVERAGE HIGHS REGION-WIDE.  
 
JAJA  
 
 
   
AVIATION  
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)  
ISSUED AT 1151 AM CDT SUN SEP 14 2025  
 
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS TODAY WILL  
GENERALLY BE LIGHT AND VARIABLE. HAVE DECIDED TO KEEP TSRA MENTION  
OUT OF ALL SITES THIS AFTERNOON, ALTHOUGH STILL CANNOT RULE OUT A  
STRAY STORM AFFECTING ESPECIALLY KJEF/KCOU. OTHERWISE, DRY  
CONDITIONS WITH DIURNAL CU AND PASSING HIGH CLOUDS EXPECTED  
THROUGH THE NEXT 24 HOURS.  
 
DEITSCH  
 
 
   
LSX WATCHES/WARNINGS/ADVISORIES  
 
MO...NONE.  
IL...NONE.  
 
 
 
 
WFO LSX  
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