Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 011800
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
100 PM CDT WED JUL 1 2015

.SHORT TERM:  (THROUGH LATE THIS AFTERNOON)
ISSUED AT 113 AM CDT WED JUL 1 2015

CONVECTION CONTINUES TO DEVELOP EARLY THIS MORNING ACROSS
NORTHWEST MO AHEAD OF A NORTHWEST FLOW SHORTWAVE, AND IN A REGION
OF STRONG LOW LEVEL WARM AIR ADVECTION AND MOISTURE CONVERGENCE
ON THE NOSE OF A SOUTHWESTERLY LOW LEVEL JET. MODELS ALSO RAMP UP
UPPER LEVEL DIVERGENCE OVER CENTRAL MO BY 12Z THIS MORNING. HIGH
RESOLUTION MODELS HAVE THE STRONGEST AND MOST WIDEPREAD CONVECTION
ACROSS CENTRAL AND SOUTHEAST MO THIS MORNING. THE FIRST WAVE OF
SHOWERS/STORMS MAY SHIFT SOUTHEAST OF OUR FORECAST AREA BY NOON,
BUT MORE CONVECTION SHOULD DEVELOP ACROSS SOUTHERN IA AND DROP
SOUTHEASTWARD INTO NORTHEAST MO LATE THIS AFTERNOON, WITH ANOTHER
AREA OF CONVECTION DEVELOPING OVER WEST CENTRAL MO AND DROPPING
SOUTHEASTWARD INTO SOUTHEAST MO. THIS SECOND, MORE SOUTHERN AREA
OF CONVECTION MAY BE SEVERE AND ALSO PRODUCE HEAVY RAINFALL AND
POSSIBLE FLASH FLOODING. HIGH TEMPERATURES WILL NOT BE AS WARM
TODAY COMPARED TO TUESDAY DUE TO THE CLOUD COVER AND
PRECIPITATION.

GKS

.LONG TERM:  (TONIGHT THROUGH MONDAY)
ISSUED AT 113 AM CDT WED JUL 1 2015

ANOTHER MCS IS EXPECTED TONIGHT, MAINLY ALONG AND SOUTH OF I-70
ACROSS CENTRAL AND SOUTHEAST MO INTO SOUTHWEST IL. THIS ACTIVITY
WILL BE AHEAD OF A SURFACE LOW MOVING EASTWARD INTO SOUTHWEST MO
ALONG A STATIONARY FRONT. HEAVY RAINFALL IS EXPECTED WITH THE
POTENTIAL FOR FLASH FLOODING. WILL CONTINUE THE FLASH FLOOD WATCH
ACROSS CENTRAL AND SOUTHEAST MO UNTIL 12Z THURSDAY. THE STRONGER
AND MORE WIDESPREAD CONVECTION SHOULD BEGIN TO SHIFT SOUTH AND
SOUTHEAST OF OUR FORECAST AREA ON THURSDAY AS THE FRONT SAGS
FURTHER SOUTH AS THE SURFACE WAVE SHIFTS SOUTHEAST OF THE REGION.
MOST OF THE SHOWERS/STORMS WILL BE ACROSS SOUTHEAST MO AND
SOUTHWEST IL ON THURSDAY, AND MAINLY DURING THE MORNING. ALTHOUGH
THERE WILL BE LESS OF A THREAT FOR SEVERE WEATHER OR HEAVY
RAINFALL THURSDAY NIGHT AND FRIDAY, THE CHANCE FOR CONVECTION WILL
CONTINUE AS AN UPPER LEVEL TROUGH DROPS SOUTHEASTWARD THROUGH THE
REGION. THE WEEKEND LOOKS DRIER ALTHOUGH THERE WILL STILL BE THE
CHANCE FOR PRECIPITATION, MAINLY ACROSS SOUTHEAST MO AND
SOUTHWEST IL, PARTICULARLY DURING THE AFTERNOON AND EVENING HOURS.
THE CHANCE FOR CONVECTION SHOULD RAMP UP AGAIN MONDAY NIGHT AND
CONTINUE THROUGH TUESDAY NIGHT AS A COLD FRONT MOVES SLOWLY
SOUTHEASTWARD THROUGH OUR REGION. THE PROGRESSION OF THE FRONT
SHOULD BE SLOW WITH ONLY A GRADUAL SOUTHWARD SHIFT OF THE UPPER
LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS FORECAST.

GKS

&&

.AVIATION:  (FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1246 PM CDT WED JUL 1 2015

DIFFICULT AVIATION FORECAST THIS AFTERNOON. LATEST GUIDANCE
SUGGESTS THERE SHOULD BE AN INCREASE IN THUNDERSTORM ACTIVITY
LATER THIS AFTERNOON OR EARLY THIS EVENING. THE PROBLEM IS THAT NO
ONE MODEL AGREES WITH ANOTHER ON TIMING, COVERAGE, OR WHAT PARTS
OF THE AREA WILL SEE THE THUNDERSTORMS. THINK THE HIGHEST THREAT
FOR STORMS WILL BE AFTER 22Z ALONG AND SOUTH OF THE I-70 CORRIDOR.
UNTIL THEN, SCATTERED SHOWERS WILL CONTINUE TO MOVE SOUTHEAST
ACROSS THE AREA...WITH OCCASIONAL MVFR CEILINGS AT OR BELOW 2500
FT. EXPECT THUNDERSTORMS TO CONTINUE AT LEAST INTO THE MID TO LATE
EVENING PRODUCING OCCASIONAL IFR CONDITIONS IN HEAVY RAIN. STORMS
SHOULD WEAKEN AND AT LEAST PARTIALLY DISSIPATE BEFORE SUNRISE
THURSDAY. LOW END MVFR/IFR CEILINGS ARE LIKELY TO PERSIST EVEN
AFTER THE RAIN ENDS.

SPECIFICS FOR KSTL:

SCATTERED SHOWERS WILL MOVE FROM CENTRAL MO INTO THE VICINITY OF
THE TERMINAL LATER THIS AFTERNOON. ADDITIONAL THUNDERSTORM
DEVELOPMENT IS LIKELY LATE THIS AFTERNOON INTO THE EVENING, BUT
TIMING AND AREAL COVERAGE OF THE STORMS IS UNCERTAIN. SOME STORMS
WILL LIKELY PRODUCE IFR CONDITIONS IN HEAVY RAIN, BUT AM NOT
CONFIDENT ENOUGH YET TO TRY TO TIME THAT IN THE TAF. STORMS SHOULD
DISSIPATE OVERNIGHT BUT LINGERING LOW CEILINGS AND FOG WILL LIKELY
PREVAIL WELL INTO THURSDAY MORNING.

CARNEY

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...FLASH FLOOD WATCH THROUGH THURSDAY MORNING 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-ST. FRANCOIS MO-STE. GENEVIEVE MO-WARREN MO-
     WASHINGTON MO.

IL...NONE.
&&

$$

WFO LSX



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