468  
FXUS63 KLSX 100843  
AFDLSX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
343 AM CDT THU JUL 10 2025  
   
KEY MESSAGES  
 
- THERE ARE MULTIPLE CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE  
MIDDLE OF NEXT WEEK. A FEW SEVERE THUNDERSTORMS ARE POSSIBLE  
FRIDAY AFTERNOON AND EVENING OVER NORTHEAST MISSOURI AND WEST  
CENTRAL ILLINOIS.  
 
- FRIDAY WILL BE THE WARMEST DAY OF THE WEEK AS HEAT INDEX VALUES  
CLIMB TO AROUND 100 DEGREES FOR MOST. THE ST. LOUIS METRO AREA  
WILL SEE VALUES CLOSER TO 105 DEGREES.  
 
 
   
SHORT TERM  
(THROUGH LATE FRIDAY AFTERNOON)  
ISSUED AT 342 AM CDT THU JUL 10 2025  
 
THE SKY WAS MAINLY CLEAR ACROSS THE AREA THIS MORNING, THOUGH THERE  
WERE SOME HIGH CLOUDS BEGINNING TO FILTER IN FROM THE NORTHWEST  
AHEAD OF A LARGE MCS OVER NEBRASKA AND IOWA. WINDS WERE LIGHT  
THANKS TO HIGH PRESSURE CENTERED OVER KENTUCKY AND TENNESSEE. THE  
LATEST SURFACE OBSERVATIONS ARE SHOWING SOME FOG OVER THE SOUTHERN  
PARTS OF ILLINOIS AND MISSOURI, BUT I DO NOT EXPECT AS MUCH FOG AS  
YESTERDAY MORNING CONSIDERING THE AMOUNT OF MIXING THAT WE SAW  
DURING THE AFTERNOON. THE LATEST CAMS ARE SHOWING THAT THE MOST  
ACTIVE PART OF THE QLCS OVER THE MIDDLE MISSOURI VALLEY WILL  
CONTINUE TO MOVE EAST AND STAY NORTH OF THE CWA. THE OUTFLOW FROM  
THE QLCS WILL MOVE INTO THE NORTHERN PART OF THE CWA TODAY WHERE THE  
RAP SOUNDINGS ARE SHOWING SOME UNCAPPED SOUNDINGS THIS AFTERNOON.  
THE HREF IS FOCUSING ISOLATED DEVELOPMENT OVER THE NORTHERN AND  
EASTERN PART OF THE CWA THIS AFTERNOON, SO THAT IS WHERE I HAVE  
MAINTAINED SLIGHT CHANCE POPS.  
 
A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL OCCUR ON FRIDAY  
AFTERNOON AND FRIDAY NIGHT WHEN AN UPPER TROUGH WILL APPROACH THE  
AREA FROM THE WEST. THERE WILL BE SEVERAL BOUNDARIES ASSOCIATED  
WITH THE TROUGH INCLUDING A WARM FRONT OVER IOWA AND NORTHERN  
ILLINOIS AND AN ATTENDANT COLD FRONT THAT WILL BE ENTERING WESTERN  
MISSOURI ON FRIDAY NIGHT. SHOWERS AND THUNDERSTORMS MAY DEVELOP  
OVER THE NORTHERN CWA AS SOON AS FRIDAY AFTERNOON ASSOCIATED WITH A  
RESIDUAL OUTFLOW BOUNDARY FROM CONVECTION THAT WILL MOVE THROUGH  
IOWA TONIGHT. MOST OF THE CAMS KEEP THUNDERSTORMS OUT OF THE CWA  
TOMORROW AFTERNOON EXCEPT FOR THE FV3 AND ARW. A BETTER CHANCE WILL  
WAIT UNTIL TOMORROW EVENING ASSOCIATED WITH THE COLD FRONT WHEN  
MLCAPES OF 2000-3000+ J/KG AND DEEP LAYER SHEAR OF 20-30 KTS WILL  
SUPPORT A FEW ORGANIZED SEVERE MULTICELL STORMS ACROSS THE NORTHERN  
CWA PER THE LATEST SWODY2. LARGE HAIL AND DAMAGING WIND GUSTS WILL  
BE THE PRIMARY THREAT FROM ANY SEVERE THUNDERSTORMS.  
 
HIGHS THE NEXT TWO DAYS WILL BE IN THE LOWER TO MID 90S WITH FRIDAY  
SLIGHTLY WARMER. DEWPOINTS WILL CLIMB INTO THE 70S ON FRIDAY  
SUPPORTING HEAT INDEXES FROM THE MID 90S TO NEAR 105 DEGREES.  
 
BRITT  
 
 
   
LONG TERM  
(FRIDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 342 AM CDT THU JUL 10 2025  
 
THE LREF IS STILL SUPPORTING AN ACTIVE PATTERN OVER THE WEEKEND  
THROUGH THE MIDDLE OF NEXT WEEK WITH SEVERAL CHANCES FOR SHOWERS AND  
THUNDERSTORMS AS SEVERAL UPPER TROUGHS WILL MOVE THROUGH MISSOURI  
AND ILLINOIS. THE LREF MEMBERS ARE STILL PRODUCING THE BEST CHANCE  
OF RAIN (40-60%) ON FRIDAY NIGHT AND SATURDAY WITH A LINGERING  
CHANCE (30-50%) ACROSS THE SOUTHERN HALF OF THE CWA AS A FRONT GETS  
STALLED ACROSS THE CWA AND A SECOND TROUGH MOVES ACROSS THE MISSOURI  
AND ILLINOIS. HERE AGAIN, IT SHOULD BE POINTED OUT THAT WHILE THE  
WEEKEND WILL NOT BE A WASHOUT, SOME LOCALLY HEAVY RAINFALL COULD BE  
POSSIBLE AS BOTH THE GFS/NAM HAVE PWATS AOA 2" ALONG THE FRONT.  
ADDITIONAL CHANCES FOR THUNDERSTORMS WILL BE POSSIBLE BY EARLY-MID  
NEXT WEEK AS ALL OF THE GLOBAL MODELS ARE SHOWING YET ANOTHER TROUGH  
AND ATTENDANT FRONT MOVING ACROSS THE MIDWEST.  
 
TEMPERATURES THROUGH THE WEEKEND INTO NEXT WEEK WILL BE CLOSE TO  
JULY NORMALS RANGING FROM THE MID 80S TO AROUND 90 DEGREES.  
CONFIDENCE IN TEMPERATURES REMAINS FAIRLY HIGH AS THE NBM IQR IS  
ONLY 4-6 DEGREES.  
 
BRITT  
 
 
   
AVIATION  
(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)  
ISSUED AT 1045 PM CDT WED JUL 9 2025  
 
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR A MAJORITY OF THE 06Z  
TAF CYCLE. CLEARING SKIES AND LIGHT WINDS TONIGHT MAY ALLOW FOR  
SOME PATCHY RIVER VALLEY FOG FORMATION. WHILE DENSE FOG DID OCCUR  
YESTERDAY IN A FEW LOCATIONS, MUCH OF THIS WAS LIKELY CAUSED BY  
RAIN EARLIER IN THE DAY, WHICH DID NOT OCCUR TODAY. AFTER A DAY OF  
FULL SUN AND DEEP MIXING, WE DON'T EXPECT THAT COVERAGE WILL BE AS  
WIDESPREAD, AND CONFIDENCE IS LOW THAT LOCAL TERMINALS WILL BE  
IMPACTED AGAIN TONIGHT. OTHERWISE, THERE IS A LOW CHANCE FOR  
SHOWERS AND WEAK THUNDERSTORMS DURING THE DAY, WITH HIGHEST  
CHANCES (~40%) AT UIN LATE IN THE AFTERNOON. AT OTHER SITES, LOWER  
PROBABILITIES (20% OR LESS) EXIST, AND THIS REMAINS TOO LOW TO  
INCLUDED IN THE TAF AT THIS TIME. LIGHT SOUTHERLY WINDS ARE ALSO  
EXPECTED TO PREVAIL FROM TOMORROW MORNING ONWARD.  
 
BRC  
 
 
   
LSX WATCHES/WARNINGS/ADVISORIES  
 
MO...NONE.  
IL...NONE.  
 
 
 
 
WFO LSX  
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