707  
FXUS63 KLSX 082333  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
633 PM CDT WED MAY 8 2024  
   
KEY MESSAGES
 
 
- SCATTERED STRONG TO SEVERE THUNDERSTORMS WILL PERSIST THROUGH  
EARLY THIS EVENING. ALL HAZARDS ARE EXPECTED: LARGE HAIL,  
DAMAGING WINDS, ISOLATED TORNADOES, AS WELL AS FLASH FLOODING.  
 
- A PERIOD OF MUCH NEEDED CALMER WEATHER AND COOLER TEMPERATURES IS  
EXPECTED TO END THE WEEK AND CONTINUE THROUGH THE WEEKEND.  
 

 
   
SHORT TERM
 
(THROUGH LATE THURSDAY NIGHT)  
ISSUED AT 344 PM CDT WED MAY 8 2024  
 
(LATE THIS AFTERNOON THROUGH TONIGHT)  
 
AS OF 3 PM, OUTFLOW FROM THE ACTIVITY CONTINUES TO SINK SOUTH AND  
EXTENDS FROM JUST NORTH OF SPRINGFIELD, MO TO JUST SOUTH OF  
CARBONDALE, IL. THE WARM SECTOR ALONG AND SOUTH OF THE BOUNDARY  
REMAINS QUITE UNSTABLE WITH MU CAPES IN EXCESS OF 3000 J/KG, ML  
LAPSE RATES OF 7-8C/KM AND 0-6KM BULK SHEAR 50-60KTS. ALSO, THE  
ONGOING ACTIVITY, OVER FAR SOUTHEASTERN SECTIONS OF CWA, HAS  
CONGEALED INTO A LINE WITH EMBEDDED SUPERCELLS, WHILE FURTHER WEST,  
IN NWS SPRINGFIELD'S AREA, DISCRETE SUPERCELLS ARE FORMING ALONG  
THE OUTFLOW BOUNDARY. THESE STORMS WILL SLIDE EAST NORTHEAST  
MOVING INTO THE SOUTHERN PORTIONS OF THE CWA BY 21Z. THEREFORE,  
THERE REMAINS A TORNADO THREAT AS WELL AS LARGE HAIL POSSIBLE.  
NORTH OF THE OUTFLOW BOUNDARY, COULD SEE SCATTERED STRONG TO  
SEVERE STORMS WITH THE MAIN THREAT BEING LARGE HAIL.  
 
OTHERWISE, AS THE SURFACE LOW OVER NE OK LIFTS NORTHEASTWARD IT WILL  
DRAG A COLD FRONT EASTWARD THROUGH THE FORECAST AREA, WITH THE  
PRECIPITATION TAPERING OFF FROM WEST TO EAST. THE FRONT WILL EXIT  
THE REGION BY 05Z THURSDAY.  
 
STILL SOME CONCERN FOR ISOLATED FLASH FLOODING AS SOME STORMS MAY  
TRAIN OVER THE AREA, ESPECIALLY SOUTH OF I-70. SO WILL NOT MAKE ANY  
ADJUSTMENTS TO THE FLASH FLOOD WATCH AT THIS TIME.  
 
LOWS TONIGHT WILL BE IN THE LOW 50S TO LOW 60S.  
 
(THURSDAY THROUGH THURSDAY NIGHT)  
 
ON THURSDAY, A SECONDARY SHORTWAVE/COLD FRONT ON THE BACKSIDE OF THE  
SYSTEM WILL SLIDE SOUTHEAST THROUGH THE REGION. SO EXPECT INCREASING  
CLOUDS, ESPECIALLY NORTH OF I-70. OTHERWISE, THERE WILL BE ENOUGH  
MOISTURE AND WEAK INSTABILITY TO GENERATE SCATTERED SHOWERS AND A  
FEW THUNDERSTORMS OVER PORTIONS OF NORTHEAST MISSOURI AND WEST  
CENTRAL ILLINOIS LATE MORNING THROUGH EARLY EVENING. OTHERWISE,  
HIGHS ON THURSDAY WILL BE NEAR NORMAL IN THE UPPER 60S TO UPPER 70S.  
LOWS THURSDAY NIGHT WILL BE IN THE UPPER 40S TO LOW 50S.  
 
BYRD  

 
   
LONG TERM
 
(FRIDAY THROUGH NEXT WEDNESDAY)  
ISSUED AT 344 PM CDT WED MAY 8 2024  
 
COOLER AND DRIER WEATHER THROUGH THE REST OF THE WORK WEEK AND  
INTO THE WEEKEND. BEYOND THAT, UPPER LEVEL TROUGH OVER THE WESTERN  
CONUS WILL BEGIN TO LIFT OUT TOWARDS THE REGION WITH CHANCES OF  
SHOWERS AND STORMS LATE ON SUNDAY THROUGH MID WEEK. STILL A LOT OF  
TIMING, STRENGTH AND LOCATION DIFFERENCES AMONG THE ENSEMBLES AND  
DETERMINISTIC MODELS, SO STUCK WITH THE LATEST NBM SOLUTION.  
TEMPERATURES WILL MODERATE THROUGH THE PERIOD WITH HIGHS IN THE  
MID 70S TO LOW 80S.  
 
BYRD  

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)  
ISSUED AT 631 PM CDT WED MAY 8 2024  
 
MAIN AREA OF SHOWERS AND STORMS HAVE EXITED TAF SITES, THOUGH SOME  
ISOLATED ACTIVITY STILL POSSIBLE. KEPT VICINITY THUNDERSTORM  
MENTION AT KUIN AND ST. LOUIS METRO TAF SITES THROUGH 03Z-04Z  
THURSDAY, WHILE BETTER CHANCES AT KCOU AND KJEF SO ADDED TEMPO  
MENTION FROM 00Z TO 01Z. OTHERWISE, COLD FRONT WILL MOVE THROUGH  
THIS EVENING WITH SOUTH WINDS VEERING TO THE WEST TO NORTHWEST.  
WILL SEE GUSTS UP TO 25KTS AT TIMES THURSDAY AFTERNOON.  
 
STILL EXPECTING SOME WRAP AROUND SC DECK ON BACK SIDE OF SYSTEM  
WITH SOME SCATTERED SHOWERS POSSIBLE THURSDAY AFTERNOON,  
ESPECIALLY AT KUIN, SO KEPT MVFR CEILINGS FROM 04Z THURSDAY  
THROUGH REMAINDER OF FORECAST PERIOD. COULD SEE THE MVFR CEILINGS  
AS FAR SOUTH AS ST. LOUIS METRO AREA BETWEEN 09Z AND 12Z THURSDAY.  
 
BYRD  

 
   
LSX WATCHES/WARNINGS/ADVISORIES
 
 
MO...FLOOD WATCH UNTIL MIDNIGHT CDT TONIGHT FOR COLE MO-CRAWFORD MO-  
FRANKLIN MO-GASCONADE MO-IRON MO-JEFFERSON MO-MADISON MO-  
MONITEAU MO-OSAGE MO-REYNOLDS MO-SAINT FRANCOIS MO-SAINT  
LOUIS CITY MO-SAINT LOUIS MO-SAINTE GENEVIEVE MO-WASHINGTON  
MO.  
 
IL...FLOOD WATCH UNTIL MIDNIGHT CDT TONIGHT FOR MONROE IL-RANDOLPH IL-  
SAINT CLAIR IL.  
 

 
 

 
WFO LSX  
 
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