860  
FXUS63 KLSX 051110  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
610 AM CDT TUE JUL 5 2022  
   
SHORT TERM
 
(THROUGH LATE WEDNESDAY NIGHT)  
ISSUED AT 417 AM CDT TUE JUL 5 2022  
 
AN UPPER LEVEL RIDGE WILL REMAIN ANCHORED OVER THE REGION TODAY  
BEFORE BEGINNING TO WEAKEN/RETROGRADE ON WEDNESDAY. SO WITH STRONG  
SOUTHERLY FLOW OVER THE AREA CONTINUING TO USHER IN STRONG WAA  
AND LOW LEVEL MOISTURE, HEAT INDEX VALUES WILL TOP OUT BETWEEN 105  
AND 110 THIS AFTERNOON. BEYOND TODAY STRONG WAA IS EXPECTED  
THROUGH THURSDAY AND DESPITE SOME UNCERTAINTY ON ANY SHOWERS AND  
STORMS EACH DAY, WILL EXTEND THE EXCESSIVE HEAT WARNING IN TIME  
AND LOCATION, ALONG AND SOUTH OF I-70 THROUGH 11 PM THURSDAY.  
NORTH OF THIS AREA I WILL KEEP HEAT ADVISORY GOING TIL 11 PM  
WEDNESDAY AS THIS AREA COULD BE AFFECTED BY INCREASING CHANCES OF  
SHOWERS AND STORMS.  
 
IN THE MEANTIME, DRY WEATHER IS EXPECTED TODAY DESPITE INCREASING  
LOW LEVEL MOISTURE AND MU CAPES BETWEEN 2000 AND 3000 J/KG, AS  
DEEP LAYER SHEAR WILL REMAIN RATHER WEAK, BETWEEN 20 AND 30KTS  
WITH LITTLE TO NO FORCING ACROSS THE REGION. HOWEVER, A STRAY  
SHOWER OR STORM IS NOT OUT OF THE QUESTION ACROSS PORTIONS OF  
SOUTHEAST MISSOURI THIS AFTERNOON.  
 
BY TONIGHT, UPPER LEVEL RIDGE WILL BEGIN TO WEAKEN AND RETROGRADE  
ALLOWING THE FRONTAL BOUNDARY DRAPED ACROSS THE UPPER MIDWEST TO  
BEGIN SLOWLY SINKING SOUTH INTO NORTHERN MISSOURI. HOWEVER, THE  
LATEST DETERMINISTIC AND CAMS HAVE DIFFERENCES IN TIMING AND  
LOCATION OF THE BOUNDARY THROUGH WEDNESDAY. FOR NOW WILL STICK WITH  
THE LATEST NBM SOLUTION WITH THE ACTIVITY SKIMMING ACROSS NORTHERN  
PORTIONS OF THE FORECAST AREA BEGINNING LATE THIS EVENING THROUGH  
THE OVERNIGHT HOURS. ON WEDNESDAY, IT LOOKS LIKE A WEAKENING COMPLEX  
OF STORMS WILL APPROACH PORTIONS OF NORTHEASTERN MO/WEST CENTRAL IL  
DURING THE MORNING HOURS. THEN DEPENDING ON WHERE ANY OUTFLOW  
BOUNDARIES END UP, AFTERNOON ACTIVITY IS HARD TO PIN DOWN, THUS  
HAVE LOW CONFIDENCE OF ANY STRONG TO SEVERE STORMS DUE TO WEAK  
DEEP LAYER SHEAR. THEREFORE, WILL NOT MESSAGE ANY RISK OF SEVERE  
STORMS AT THIS TIME FOR WEDNESDAY/WEDNESDAY NIGHT.  
 
BYRD  
   
LONG TERM
 
(THURSDAY THROUGH MONDAY)  
ISSUED AT 417 AM CDT TUE JUL 5 2022  
 
THERE IS GOOD AGREEMENT AMONG THE MODELS ON THE LATEST CLUSTER  
ANALYSIS PAGE THAT THE UPPER LEVEL RIDGE WILL RETROGRADE BACK TO THE  
WEST WITH FLOW ALOFT BECOMING NORTHWESTERLY ACROSS THE REGION BY  
THIS WEEKEND. HOWEVER, THERE REMAINS SOME TIMING/LOCATION  
DIFFERENCES AMONG THE DETERMINISTIC AND ENSEMBLES OF EXACTLY WHERE  
THE SURFACE FRONT WILL BE ESPECIALLY ON THURSDAY AND FRIDAY. FOR NOW  
CONFIDENCE IS HIGH THAT THE BOUNDARY WILL REMAIN NORTH OF THE I-70  
CORRIDOR ON THURSDAY, SO EXTENDED/EXPANDED THE EXCESSIVE HEAT  
WARNING IN THIS AREA.  
 
OTHERWISE, EXPECT INCREASING CHANCES OF SHOWERS AND STORMS THURSDAY  
NIGHT THROUGH SATURDAY AS THE FRONT SLOWLY SINKS SOUTH THROUGH THE  
FORECAST AREA. WITH THE FLOW ALOFT BECOMING MORE NORTHWESTERLY THIS  
WILL PUSH THE FRONT SOUTH OF THE AREA BY SATURDAY MORNING WITH  
SHOWERS AND STORMS TAPERING OFF. OTHERWISE, DRY AND NEAR NORMAL  
TEMPERATURES ARE EXPECTED FOR THE REST OF THE WEEKEND AND INTO EARLY  
NEXT WEEK.  
 
BYRD  

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 610 AM CDT TUE JUL 5 2022  
 
VFR FLIGHT CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD.  
OTHERWISE, SOUTHWEST WINDS WILL BECOME LIGHT AND VARIABLE AFTER  
SUNSET THIS EVENING.  
 
BYRD  

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SAINT LOUIS 101 81 101 80 / 5 10 20 20  
QUINCY 97 77 96 76 / 10 20 30 40  
COLUMBIA 100 77 100 76 / 5 10 10 20  
JEFFERSON CITY 101 77 102 77 / 5 5 10 10  
SALEM 98 77 98 76 / 10 10 30 20  
FARMINGTON 98 76 100 75 / 10 5 10 5  
 

 
   
LSX WATCHES/WARNINGS/ADVISORIES
 
 
MO...EXCESSIVE HEAT WARNING UNTIL 11 PM CDT THURSDAY FOR BOONE MO-  
CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-GASCONADE MO-  
IRON MO-JEFFERSON MO-MADISON MO-MONITEAU MO-MONTGOMERY MO-  
OSAGE MO-REYNOLDS MO-SAINT CHARLES MO-SAINT FRANCOIS MO-  
SAINT LOUIS CITY MO-SAINT LOUIS MO-SAINTE GENEVIEVE MO-  
WARREN MO-WASHINGTON MO.  
 
HEAT ADVISORY UNTIL 11 PM CDT WEDNESDAY FOR AUDRAIN MO-KNOX MO-  
LEWIS MO-LINCOLN MO-MARION MO-MONROE MO-PIKE MO-RALLS MO-  
SHELBY MO.  
 
IL...EXCESSIVE HEAT WARNING UNTIL 11 PM CDT THURSDAY FOR BOND IL-  
CLINTON IL-FAYETTE IL-MADISON IL-MARION IL-MONROE IL-  
RANDOLPH IL-SAINT CLAIR-WASHINGTON IL.  
 
HEAT ADVISORY UNTIL 11 PM CDT WEDNESDAY FOR ADAMS IL-BROWN IL-  
CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MONTGOMERY IL-  
PIKE IL.  
 

 
 

 
 
WFO LSX  
 
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