948  
FXUS63 KLSX 161753  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
1253 PM CDT THU OCT 16 2025  
   
KEY MESSAGES
 
 
-WARM AND DRY CONDITIONS CONTINUE THROUGH FRIDAY.  
 
-WIDESPREAD SHOWERS AND THUNDERSTORMS WILL IMPACT THE AREA  
SATURDAY, WITH A LOW AND CONDITIONAL RISK FOR SEVERE  
THUNDERSTORMS.  
 

 
   
SHORT TERM
 
(THROUGH LATE FRIDAY AFTERNOON)  
ISSUED AT 400 AM CDT THU OCT 16 2025  
 
MORNING MID-LEVEL WATER VAPOR IMAGERY SHOWS THE RIDGE OVER THE MID-  
MISSISSIPPI VALLEY, WHICH IS KEEPING THE AREA DRY AND LARGELY CLOUD  
FREE. OVER THE COURSE OF THE DAY THE RIDGE WILL START TO WEAKEN AND  
SHIFT EASTWARD. DESPITE THIS, CONFIDENCE IS HIGH THAT ANOTHER DRY  
AND WARM DAY IS ON TAP. TEMPERATURES WILL PEAK IN THE LOW TO MID  
80S, SIMILAR TO YESTERDAY.  
 
WHILE THE MID-LEVEL RIDGE WEAKENS AND SHIFTS EASTWARD, A MID-LEVEL  
TROUGH WILL PUSH INTO THE REGION IN ITS WAKE. THE CENTER OF THIS  
TROUGH WILL SLIDE NORTHEAST FROM THE CENTRAL PLAINS INTO THE UPPER  
MISSISSIPPI VALLEY OVERNIGHT THURSDAY INTO FRIDAY, BUT ANOTHER  
SHORTWAVE WILL SURGE SOUTH WITHIN THE BROADER TROUGH FROM THE  
PACIFIC NORTHWEST DURING THE DAY. IT IS THIS FEATURE THAT WILL  
PROGRESS THE BROADER TROUGH EASTWARD INTO THE WEEKEND AND GENERATE  
THIS WEEKEND'S RAINFALL. AHEAD OF THIS SYSTEM HOWEVER, SOUTHERLY  
FLOW WILL PREVAIL ON FRIDAY AND TEMPERATURES WILL ONCE AGAIN PEAK IN  
THE LOW TO MID 80S.  
 
DELIA  
 

 
   
LONG TERM
 
(FRIDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 400 AM CDT THU OCT 16 2025  
 
FOCUS NOW TURNS TO SATURDAY AND THE LOW RISK FOR SEVERE  
THUNDERSTORMS. AS THE MID-LEVEL TROUGH STRENGTHENS AND PUSHES  
EASTWARD INTO SATURDAY A SURFACE LOW WILL FORM IN RESPONSE ALONG THE  
US-CANADA BORDER. THE ASSOCIATED COLD FRONT WILL DRAPE THROUGH THE  
CENTRAL PLAINS AND SLOWLY APPROACH THE MID-MISSISSIPPI VALLEY  
SATURDAY. GUIDANCE HAS COME INTO BETTER AGREEMENT OVER THE LAST 24  
HOURS THAT THIS FRONT WILL MOVE THROUGH THE FORECAST AREA MUCH  
SLOWER THAN PREVIOUS SOLUTIONS WERE SUGGESTING. AHEAD OF THE FRONT A  
STRONG LOW-LEVEL JET WILL PUMP WARM, MOIST AIR TO THE REGION. THE  
LOW-LEVEL JET WILL COMBINE WITH THE UPPER LEVEL JET EXIT TO SUPPORT  
SHOWERS AND THUNDERSTORMS DEVELOPING AHEAD OF THE FRONT SATURDAY  
ALONG LOW-LEVEL MOISTURE CONVERGENCE. COOLING ALOFT ASSOCIATED WITH  
THE APPROACH OF THIS SYSTEM WILL HELP TO GENERATE SOME INSTABILITY  
ACROSS THE REGION, WITH DETERMINISTIC MODELS GENERATING 600-1500  
J/KG OF MLCAPE. THE HIGHER END OF THIS RANGE COULD BE REALIZED IF  
BREAKS IN THE CLOUDS AND ONGOING SHOWERS AND THUNDERSTORMS CAN  
PRODUCE ADEQUATE SURFACE HEATING AND BOUNDARY LAYER MIXING. IF THIS  
WERE TO HAPPEN, THUNDERSTORMS WILL BE ABLE TO TAKE ADVANTAGE OF THE  
40-60 KTS OF 0-6KM SHEAR AND BECOME SEVERE DURING THE AFTERNOON AND  
EVENING. DEEP MIXING IN THIS SCENARIO WILL RESULT IN HIGH LCLS AND  
INVERTED V SOUNDINGS THAT WOULD FAVOR HAIL AND DAMAGING WINDS. THE  
BEST LOCATION FOR SEVERE THUNDERSTORMS DEVELOPMENT IN THIS SCENARIO  
IS ACROSS SOUTHEASTERN MISSOURI AND SOUTHERN ILLINOIS, FURTHER AWAY  
FROM THE BEST MOISTURE CONVERGENCE.  
 
HOWEVER, IF INSTABILITY IS LOWER FROM WIDESPREAD CLOUD COVER AND  
RAIN, THE SHEAR WILL BE TOO STRONG FOR THUNDERSTORM MAINTENANCE AND  
STRONG TO SEVERE THUNDERSTORMS WOULD BE SIGNIFICANTLY LESS  
LIKELY. WHILE THE SLOWER FRONT DOES OPEN THE REGION UP TO A  
SLIGHTLY HIGHER POTENTIAL FOR SEVERE WEATHER, WIDESPREAD RAIN AND  
LIMITED SEVERE THREAT IS STILL FAVORED. THIS IS STILL THE MOST  
LIKELY SCENARIO AS THE UPPER-LEVEL JET AND MID-LEVEL VORTICITY  
ADVECTION ARE ANTICIPATED TO PRODUCE WIDESPREAD SHOWERS AND  
THUNDERSTORMS ADMITS THE ABUNDANT MOISTURE ACROSS THE FORECAST  
AREA. THE LACK OF SURFACE HEATING WOULD KEEP INSTABILITY ELEVATED  
AND LIMIT THE SEVERE POTENTIAL SIGNIFICANTLY. THIS WOULD SHUNT THE  
RISK FOR SEVERE WEATHER TO OUR SOUTH WHERE MORE HEATING AND  
INSTABILITY WOULD GENERATE A MORE FAVORABLE ENVIRONMENT.  
 
REGARDLESS OF THE SEVERE POTENTIAL, THIS SYSTEM WILL BRING MUCH  
NEEDED RAIN TO THE ENTIRE FORECAST AREA. STRONG MOISTURE RETURN  
AHEAD OF THE SYSTEM RESULT IN PWAT VALUES BETWEEN 1.3-1.6". GLOBAL  
ENSEMBLES INDICATE A 65% CHANCE FOR AT LEAST 0.50" OF RAIN AREA  
WIDE, AND A 20-30% CHANCE FOR AT LEAST 1.00" OF RAIN. WHILE THIS  
WON'T BE ENOUGH TO COMPLETELY RELIEVE THE ONGOING DROUGHT  
CONDITIONS, IT WILL CERTAINLY BENEFIT OUR MOST DROUGHT IMPACTED  
AREAS, INCLUDING SOUTHEAST MISSOURI AND SOUTHERN ILLINOIS.  
 
THE COLD FRONT WILL PUSH THROUGH THE AREA SATURDAY EVENING, BRINGING  
AN END TO SHOWERS AND THUNDERSTORMS. COOL, DRY AIR WILL FLOW INTO  
THE REGION OVERNIGHT AS THE 850 MB FRONT PASSES OVERHEAD AND THE MID-  
LEVEL TROUGH EXITS THE REGION. TEMPERATURES ON SUNDAY WILL BE NEARLY  
20 DEGREES COOLER THAN RECENT DAYS WITH HIGHS REACHING ONLY THE MID  
TO UPPER 60S DESPITE THE CLEAR SKY. A MID-LEVEL SHORTWAVE RIDGE WILL  
PASS OVER THE MID-MISSISSIPPI VALLEY MONDAY, ALLOWING FOR A BRIEF  
AND RELATIVE WARM UP INTO THE 70S BEFORE ANOTHER MID-LEVEL TROUGH  
AND SURFACE COLD FRONT PUSH THROUGH THE REGION MONDAY INTO TUESDAY.  
TEMPERATURES IN THE WAKE OF THIS SYSTEM ARE EXPECTED TO COOL TO NEAR  
NORMAL, THOUGH THERE IS DISAGREEMENT IN THE MID-LEVEL PATTERN BEYOND  
TUESDAY.  
 
DELIA  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)  
ISSUED AT 1230 PM CDT THU OCT 16 2025  
 
VFR FLIGHT CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE PERIOD.  
WINDS WILL GRADUALLY VEER TO THE SOUTHEAST AND THEN TO THE SOUTH  
BY BY FRIDAY MORNING.  
 
CARNEY  
 

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

 
 

 
 
WFO LSX  
 
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