859  
FXUS63 KLSX 230008  
AFDLSX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE SAINT LOUIS MO  
708 PM CDT THU JUN 22 2017  
   
SHORT TERM
 
(THROUGH LATE FRIDAY AFTERNOON)  
ISSUED AT 349 PM CDT THU JUN 22 2017  
 
JUST A FEW SHOWERS ARE CURRENTLY MOVING ACROSS SOUTHEAST MISSOURI  
INTO SOUTH CENTRAL ILLINOIS. THESE ARE OCCURRING ON THE NORTHERN  
PERIPHERY OF TROPICAL DEPRESSION CINDY. MOISTURE AND SHOWERS  
ASSOCIATED WITH CINDY WILL BE CONFINED TO THE SOUTHEASTERN PART OF  
THE CWA WHILE AN SHORTWAVE TROUGH MOVES ACROSS IOWA INTO ILLINOIS IN  
THE MID-LEVEL FLOW. THIS WILL IN TURN CAUSE THE COLD FRONT THAT IS  
CURRENTLY OVER THE UPPER MIDWEST TO DROP SOUTH ACROSS THE REGION  
LATE TONIGHT AND ON FRIDAY AT THE SAME TIME THE REMNANTS FROM CINDY  
MOVES NORTHEAST ACROSS ARKANSAS AND KENTUCKY. HAVE KEPT HIGH  
CHANCE/LOW LIKELY POPS FOR SHOWERS AND THUNDERSTORMS LATE TONIGHT  
THROUGH EARLY AFTERNOON ON FRIDAY BEFORE THE RAIN MOVES SOUTHEAST OF  
THE AREA BY LATE IN THE AFTERNOON.  
 
AGREEABLE MOS GUIDANCE LOOKS GOOD FOR LOWS TONIGHT. HIGHS TOMORROW  
WILL BE CLOSER TO THE SREF MEAN MOS TEMPERATURES.  
 
BRITT  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH NEXT THURSDAY)  
ISSUED AT 349 PM CDT THU JUN 22 2017  
 
MUCH COOLER AND DRIER WEATHER WILL BE THE RULE BEGINNING FRIDAY  
NIGHT AND LASTING THROUGH THE WEEKEND AND AT LEAST THROUGH EARLY  
NEXT WEEK.  
 
LONGWAVE TROUGH WILL CARVE OUT ACROSS THE EASTERN 2/3 OF THE CONUS  
THIS WEEKEND AND EARLY NEXT WEEK WITH NORTHWEST FLOW ALOFT ACROSS  
THE MID-MISSISSIPPI VALLEY. THERE LOOKS TO BE AT LEAST A FEW  
REINFORCING SHOTS OF COOLER AIR BEHIND INDIVIDUAL SHORTWAVE TROUGHS  
AND ASSOCIATED COLD FRONTS. THE END RESULT SHOULD BE 4 DAYS OF WELL  
BELOW NORMAL TEMPERATURES ALONG WITH DRY WEATHER. WHILE THE  
POSSIBILITY OF ISOLATED INSTABILITY SHOWERS CANNOT TOTALLY BE  
RULED OUT DURING THE AFTERNOON HOURS SUNDAY OR MONDAY, BETTER  
CHANCE OF THIS ACTIVITY WILL BE FURTHER TO THE NORTHEAST WHERE  
STRONGER MID/UPPER LEVEL FORCING WILL RESIDE.  
 
VERY STRONG SURFACE HIGH (~1025 HPA) WILL SETTLE INTO THE BI-STATE  
AREA EARLY NEXT WEEK. THIS HIGH WILL SLOWLY SLIDE TO THE EAST  
TUESDAY INTO WEDNESDAY. RETURN FLOW AROUND THIS HIGH WILL BRING  
WARM/MOIST ADVECTION WHICH WILL BRING AN INCREASING THREAT FOR  
SHOWERS AND THUNDERSTORMS, MAINLY FOCUSED ON THE WEDNESDAY/THURSDAY  
TIMEFRAME.  
 
GOSSELIN  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)  
ISSUED AT 631 PM CDT THU JUN 22 2017  
 
A COLD FRONT OVER NORTHWEST IOWA WILL MOVE SOUTHEAST INTO MISSOURI  
OVERNIGHT. MEANWHILE, MOISTURE FROM TROPICAL DEPRESSION CINDY WILL  
CONTINUE TO STREAM UP INTO THE MID MISSISSIPPI VALLEY AHEAD OF THE  
FRONT. WHILE VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS MOST OF  
THE AREA THROUGH THE EVENING, THERE ARE A FEW SHOWERS MOVING INTO  
SOUTHERN PORTIONS OF THE AREA WHICH COULD PRODUCE SOME MVFR  
CIGS/VSBYS AS THE MOVE NORTH. GUIDANCE CONTINUES TO DEVELOP  
SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT AS IT MOVES  
SOUTHEAST INTO OUR AREA OVERNIGHT. ADDITIONALLY, EXPECT MVFR  
CEILINGS TO DEVELOP ALONG AND BEHIND THE FRONT AS IT INTERACTS  
WITH THE RICH LOW LEVEL MOISTURE OVERNIGHT. MVFR CEILINGS WILL  
LIKELY PERSIST THROUGH MOST OF, IF NOT ALL MORNING BUT SHOULD LIFT  
AND SCATTER DURING THE AFTERNOON AS DRIER AIR POURS INTO THE AREA  
FROM THE NORTHWEST.  
 
SPECIFICS FOR KSTL:  
 
EXPECT VFR CONDITIONS TO PREVAIL AT LAMBERT THIS EVENING AND  
PROBABLY FOR A GOOD PORTION OF THE OVERNIGHT HOURS TOO. HOWEVER, A  
COLD FRONT CURRENTLY OVER IOWA WILL MOVE SOUTHEAST INTO THE  
VICINITY OF THE TERMINAL BETWEEN 10-12Z. EXPECT SHOWERS AND  
THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE FRONT...ALONG WITH  
MVFR CEILINGS AS THE FRONT INTERACTS WITH RICH LOW LEVEL MOISTURE  
FROM TROPICAL DEPRESSION CINDY. CURRENT THINKING IS THAT THE FRONT  
WILL BE THROUGH THE TERMINAL BY 14-15Z FRIDAY BUT MVFR CEILINGS  
WILL LIKELY PERSIST FOR A FEW HOURS AFTER THE FRONT MOVES  
THROUGH...PROBABLY THROUGH THE ENTIRE MORNING AND FOR A FEW HOURS  
OF THE AFTERNOON. EXPECT VFR CONDITIONS TO PREVAIL THEREAFTER AS  
COOLER AND DRIER AIR FILTERS INTO THE REGION.  
 
CARNEY  
 

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

 
 

 
 
WFO LSX  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab MO Page
The Nexlab IL Page Main Text Page