020  
FXUS63 KLSX 260954  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
454 AM CDT SAT APR 26 2025  
   
KEY MESSAGES  
 
- THERE IS A CHANCE (30-60%) OF SHOWERS AND THUNDERSTORMS LATE  
TONIGHT INTO SUNDAY, MAINLY ALONG AND SOUTH OF I-70.  
 
- MONDAY WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS IN THE  
80S.  
 
- THERE IS A 15-30% CHANCE FOR SEVERE THUNDERSTORMS ON MONDAY  
NIGHT AND TUESDAY.  
 
 
   
SHORT TERM  
(THROUGH LATE SUNDAY AFTERNOON)  
ISSUED AT 347 AM CDT SAT APR 26 2025  
 
LATEST SATELLITE IMAGERY IS SHOWING AN EXTENSIVE AREA OF LOW CLOUDS  
MOVING SLOWLY SOUTH ACROSS MISSOURI AND ILLINOIS. LATEST HREF  
GUIDANCE SUGGESTS THAT THESE CLOUDS WILL PERSIST OVER THE AREA INTO  
THE AFTERNOON. COMBINED WITH THE PERSISTENT COLD AIR ADVECTION VIA  
THE NORTH TO NORTHEAST WINDS, I AM KEEPING HIGHS ONLY IN THE MID TO  
UPPER 60S TODAY.  
 
IT STILL LOOKS DRY THROUGH THIS EVENING BEFORE A WEAK MID-LEVEL VORT  
MOVES INTO THE AREA UNDER THE UPPER LEVEL RIDGE. THIS WILL BE  
ENOUGH LIFT COMBINED WITH INCREASING LOW-MID LEVEL WARM AIR  
ADVECTION TO BRING A CHANCE (30-60%) OF SHOWERS AND THUNDERSTORMS  
LATE SATURDAY NIGHT INTO SUNDAY MORNING WITH THE GREATEST CHANCE  
ALONG AND SOUTH OF I-70 WHERE THE CURRENT TRACK OF THE VORT IS.  
WHILE CHANCES WILL LINGER INTO THE AFTERNOON OVER SOUTHEAST MISSOURI  
AND SOUTHWEST ILLINOIS, THEY ARE NOT EXPECTED TO BE AS HIGH AS THE  
UPPER RIDGE BUILDS INTO THE AREA. HIGHS ON SUNDAY WILL BE SIMILAR  
TO SATURDAY'S WITH SOUTHEAST WINDS AND CLOUDY SKIES.  
 
BRITT  
 
 
   
LONG TERM  
(SUNDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 347 AM CDT SAT APR 26 2025  
 
MONDAY STILL LOOKS LIKE THE WARMEST DAY OF THE WEEK AS WINDS WILL  
TURN OUT OF THE SOUTH AND 850MB TEMPERATURES WARM TO AROUND 15C  
SUPPORTING HIGHS IN THE MIDDLE TO UPPER 80S. WE WILL ENTER AN  
ACTIVE PATTERN FOR SHOWERS AND THUNDERSTORMS NEXT WEEK AS THE LREF  
IS SHOWING TWO NOTABLE TROUGHS. CLUSTER ANALYSIS DOES SHOW SOME  
SLIGHT TIMING DIFFERENCES WITH THE FIRST TROUGH AS IT MOVES FROM THE  
PLAINS INTO THE GREAT LAKES MONDAY INTO TUESDAY WHICH WILL LIKELY  
BRING A COLD FRONT SOUTH THROUGH THE AREA ON TUESDAY. LREF AND NSSL  
MACHINE LEARNING PROBABILITIES ARE STILL SUPPORTING THE POTENTIAL  
FOR SEVERE STORMS OVER NORTHWEST HALF OF THE CWA ON MONDAY NIGHT,  
LIKELY FROM THE REMAINING LINE OF ANY SEVERE STORMS THAT DEVELOP  
ALONG THE COLD FRONT DURING THE DAY ON MONDAY. ADDITIONAL SEVERE  
STORMS WILL BE POSSIBLE ON TUESDAY, MORE LIKELY ACROSS THE  
SOUTHERN HALF OF THE CWA AHEAD OF THE COLD FRONT. THESE SCENARIOS  
ARE STILL 3-4 DAYS OUT, SO THERE IS STILL QUESTIONS ABOUT IF, WHEN  
AND WHERE SEVERE WEATHER WILL DEVELOP GIVEN THE COMPLEX  
INTERACTION OF RESIDUAL OUTFLOW BOUNDARIES, THE COLD FRONT, AND  
CLOUD COVER. EVEN WITH THESE QUESTIONS, ALL HAZARDS (E.G. DAMAGING  
WINDS, LARGE HAIL, TORNADOES) LOOK POSSIBLE WITH SEVERE STORMS  
BOTH ON MONDAY NIGHT AND TUESDAY.  
 
THE CHANCE FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE TUESDAY NIGHT  
INTO FRIDAY AS THE FRONT WILL GET STALLED UNDER QUASI-STATIONARY  
FLOW ALOFT AHEAD OF THE AFOREMENTIONED SECOND NOTABLE TROUGH THAT  
THE LREF WILL MOVE THROUGH THE AREA ON THURSDAY. MOST OF THE LREF  
MEMBER ARE PRODUCING PRECIPITATION DURING THIS PERIOD WITH THE  
GREATEST NUMBER OF ENSEMBLE MEMBERS (70-80%) ON WEDNESDAY NIGHT AND  
THURSDAY ASSOCIATED WITH THE TROUGH. IT SHOULD ALSO BE NOTED THAT  
CHANCE OF SEEING ANOTHER 2" OF RAINFALL IN THE NEXT WEEK ALONG AND  
SOUTH OF I-70 IS 30-40% ACCORDING TO THE LREF GIVEN THE REPEATED  
WAVES OF SHOWERS AND THUNDERSTORMS.  
 
BRITT  
 
 
   
AVIATION  
(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)  
ISSUED AT 447 AM CDT SAT APR 26 2025  
 
MVFR CEILINGS AS LOW AS 1500 FEET AGL ARE EXPECTED TO IMPROVE TO  
VFR BY 19Z. THEN DRY AND VFR CONDITIONS ARE EXPECTED THROUGH 06Z  
WHEN THERE WILL BE A CHANCE FOR SHOWERS (PROB30) TO MOVE INTO THE  
ALL OF THE TERMINALS EXCEPT FOR UIN. THESE SHOWERS WILL HAVE THE  
POTENTIAL TO REDUCE CEILING AND VISIBILITIES TO MVFR. OTHERWISE,  
CURRENT NORTHERLY WINDS WILL VEER TO THE EAST-SOUTHEAST BY 06Z.  
 
BRITT  
 
 
   
CLIMATE  
 
ISSUED AT 218 AM CDT WED APR 23 2025  
 
UNSEASONABLY WARM TEMPERATURES ARE EXPECTED ON MONDAY, NEARING  
DAILY RECORDS FOR LATE APRIL. HERE ARE THE DAILY RECORD HIGHS  
FOR APRIL 28.  
 
LOCATION RECORD  
ST LOUIS 92 SET IN 1970  
COLUMBIA 88 SET IN 1970  
QUINCY 88 SET IN 1970  
 
 
   
LSX WATCHES/WARNINGS/ADVISORIES  
 
MO...NONE.  
IL...NONE.  
 
 
 
 
WFO LSX  
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