086  
FXUS63 KLSX 231544  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
1044 AM CDT FRI JUN 23 2017  
   
UPDATE
 
 
ISSUED AT 1043 AM CDT FRI JUN 23 2017  
 
COLD FRONT HAS MOVED SOUTHEAST THROUGH ABOUT HALFWAY ACROSS THE  
CWA LATE THIS MORNING. THE HEAVIEST SHOWERS AND ISOLATED  
THUNDERSTORMS ASSOCIATED WITH THE REMNANTS OF CINDY ARE JUST SOUTH  
OF THE CWA OVER FAR SOUTHEAST MISSOURI INTO SOUTHERN ILLINOIS.  
WILL KEEP WITH A CHANCE OF SHOWERS AND A FEW THUNDERSTORMS AHEAD  
OF THE FRONT THE REST OF THE MORNING INTO THE EARLY AFTERNOON.  
THE CHANCE WILL DIMINISH OVER THE SOUTHEAST MISSOURI AND SOUTHWEST  
ILLINOIS COUNTIES BY LATE AFTERNOON AS FRONT PUSHES SOUTH OF THE  
AREA. THE CLOUDS WILL ALSO SHOW SOME SLOW CLEARING AS UPPER CLOUDS  
PUSHES OFF TO THE EAST AND DRIER AIR MOVES IN BEHIND THE COLD  
FRONT. GOING HIGHS STILL LOOK GOOD FOR TODAY.  
 
BRITT  
 

 
   
SHORT TERM
 
(THROUGH LATE TONIGHT)  
ISSUED AT 330 AM CDT FRI JUN 23 2017  
 
COLD FRONT EXTENDING FROM EAST CENTRAL IA SOUTHWESTWARD TO  
NORTHWESTERN MO TO SINK SLOWLY TO THE SOUTHEAST TODAY. IN THE  
MEANTIME, TROPICAL DEPRESSION CINDY, WHICH IS OVER CENTRAL ARKANSAS,  
WILL LIFT NORTHEASTWARD INTO FAR SOUTHERN PORTIONS OF MO BOOTHEEL  
LATE THIS MORNING, THEN TRACK EASTWARD ALONG TN/KY BORDER. SO  
DEALING WITH TWO AREAS OF ACTIVITY, SHOWERS AND STORMS ALONG COLD  
FRONT THAT WILL CONTINUE TO TRACK SOUTHEAST INTO NORTHEAST MO/WEST  
CENTRAL IL BY 4-5 AM TIMEFRAME AND ISOLATED/SCATTERED STORMS OVER  
REMAINDER OF FORECAST AREA DUE TO T.D. CINDY. COVERAGE OF ACTIVITY  
FROM BOTH SYSTEMS HARD TO PIN DOWN, BUT BEST CHANCES WILL BE OVER  
EAST CENTRAL AND SOUTHEAST MO, AS WELL AS SOUTHERN IL THROUGH  
MIDDAY, THEN TAPER OFF QUICKLY DURING THE AFTERNOON HOURS AS COLD  
FRONT EXITS REGION. BECAUSE OF CLOUDS AND PRECIPITATION, HIGHS TODAY  
WILL BE A BIT BELOW NORMAL, IN THE LOW TO MID 80S.  
 
DRY AND LESS HUMID AIR TO MAKE IT'S WAY INTO REGION BEHIND COLD  
FRONT AS SKIES CLEAR OUT. SO LOWS TONIGHT WILL BE IN THE MID 50S TO  
LOW 60S.  
 
BYRD  
   
LONG TERM
 
(SATURDAY THROUGH THURSDAY)  
ISSUED AT 330 AM CDT FRI JUN 23 2017  
 
MAIN FOCUS THRU THE FORECAST PERIOD WILL BE TEMPS.  
 
THE CDFNT, CURRENTLY APPROACHING THE CWA FROM THE NORTH, WILL BE  
SOUTH OF THE AREA BY 12Z SAT. WITH A DEEP UPPER TROF SETTLING ACROSS  
THE EASTERN TWO-THIRDS OF THE U.S. WITH NW FLOW ACROSS THE REGION,  
EXPECT MOSTLY DRY CONDITIONS WITH WELL BELOW SEASONAL AVERAGE TEMPS.  
A REINFORCING CDFNT WILL BRING ANOTHER SHOT OF COOLER TEMPS ON SAT.  
HOWEVER, THIS FNT WILL LINGER ACROSS SRN PORTIONS OF THE CWA. A S/W  
DROPPING INTO THE REGION LATE SUN NIGHT INTO MON WILL GENERATE SHRA  
ALONG THIS FNT.  
 
AS THE UPPER TROF DIGS INTO THE REGION, ANOTHER REINFORCING CDFNT  
WILL DROP THRU THE AREA. AS THE SFC RIDGE BUILDS INTO THE REGION,  
EXPECT MON TO BE THE COOLEST DAY OF THE FORECAST PERIOD. TEMPS SHUD  
BEGIN TO REBOUND BY TUES AS SFC WINDS BECOME SLY AND THE THERMAL  
RIDGE BEGINS TO BUILD INTO THE AREA. HOWEVER, STILL EXPECTING BELOW  
SEASONAL AVERAGE TEMPS THRU AT LEAST MID WEEK.  
 
AS SLY FLOW RETURNS, THE CHANCE FOR TSRA INCREASES, MAINLY LATE IN  
THE WEEK. HOWEVER, TIMING REMAINS UNCERTAIN AND HAVE KEPT POPS  
FAIRLY LOW ATTM.  
 
TILLY  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)  
ISSUED AT 1142 PM CDT THU JUN 22 2017  
 
AN ARE OF IFR CEILINGS DEVELOPED OVER ILLINOIS EARLIER IN THE  
EVENING AND IS TRYING TO SPREAD VERY SLOWLY WESTWARD. THIS AREA OF  
IFR CEILINGS MAY GET INTO THE STL METRO AREA LATER TONIGHT, BUT  
CURRENT MODEL GUIDANCE IS NOT VERY EXCITED ABOUT THIS POSSIBILITY.  
ANOTHER AREA OF MVFR CEILINGS DEVELOPED OVER THE EASTERN OZARKS  
AND IS EXPECTED TO SPREAD SLOWLY NORTH THROUGH THE REMAINDER OF  
THE NIGHT. A COLD FRONT OVER CENTRAL IOWA WILL DROP SOUTHEAST  
ACROSS THE AREA FROM AROUND 11Z THROUGH 17Z. EXPECT SHOWERS AND  
THUNDERSTORMS ALONG AND AHEAD OF THE FRONT THROUGH THE MORNING  
HOURS. ALSO EXPECT MVFR CEILINGS TO MOVE THROUGH WITH THE  
FRONT...LIFTING AND SCATTERING OUT DURING THE LATE MORNING AND  
AFTERNOON FROM NORTHWEST TO SOUTHEAST.  
 
SPECIFICS FOR KSTL:  
 
IFR CEILINGS OVER CENTRAL ILLINOIS WILL TRY TO BUILD WESTWARD  
TOWARD THE TERMINAL...BUT MODEL GUIDANCE IS NOT SHOWING THAT THE  
LOW CEILINGS WILL MAKE IT TO LAMBERT. OTHERWISE, EXPECT VFR  
CONDITIONS TO PREVAIL UNTIL THE COLD FRONT MOVES INTO THE VICINITY  
OF THE TERMINAL. WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL  
LIKELY BE IN THE VICINITY OF THE TERMINAL AS THE FRONT MOVES  
THROUGH. EXPECT AN MVFR CEILING TO MOVE IN WITH THE FRONT AND  
STICK AROUND THROUGH MOST OF THE MORNING BEFORE LIFTING AND  
SCATTERING AS DRIER AIR MOVES IN BEHIND THE FRONT.  
 
CARNEY  
 

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

 
 

 
 
WFO LSX  
 
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