Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 182306
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
606 PM CDT TUE JUN 18 2013

.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 243 PM CDT TUE JUN 18 2013

FOCUS TONIGHT WILL BE POPS...AGAIN.

THIS PORTION OF THE AFD IS BEGINNING TO SOUND LIKE A BROKEN RECORD.
HAVE INCREASED POPS THRU EARLY THIS EVENING. EXPECT ONGOING TSRA TO
DISSIPATE AND/OR MOVE SEWD OUT OF THE AREA BY MID TO LATE THIS
EVENING.

MDLS DO DEPICT AN AREA OF 850H CONVERGENCE ACROSS PORTIONS OF N
CENTRAL MO LATE TONIGHT INTO WED MORNING. THE NAM IS...SO FAR...THE
ONLY MDL THAT PRODUCES PRECIP WITH THIS FEATURE. OTHER MDLS SUGGEST
MID LEVEL TEMPS WILL BE TOO WARM TO ALLOW FOR CONVECTION. WILL
THEREFORE KEEP THE PERIOD AFTER MIDNIGHT DRY FOR NOW.

VERY MINOR ADJUSTMENTS MADE TO THE PREV FORECAST. CAN NOT RULE OUT
SOME FG DEVELOPMENT LATE TONIGHT...ESP ACROSS CENTRAL MO WHERE DRIER
AIR WILL STRUGGLE TO ADVECT INTO THE REGION.

TILLY

.LONG TERM...(WEDNESDAY THROUGH NEXT TUESDAY)
ISSUED AT 243 PM CDT TUE JUN 18 2013

WEDNESDAY THROUGH FRIDAY...
DRY AND SEASONAL WEATHER IS EXPECTED FOR WEDNESDAY WITH LIGHT WINDS
FROM THE EAST AS THE SURFACE RIDGE DOMINATES THE REGION. WEDNESDAY
NIGHT A 50KT LOW LEVEL JET WILL INTENSIFY ACROSS THE PLAINS AND
INTERACT WITH A SHORTWAVE TOPPING THE UPPER LEVEL RIDGE. THE GFS
DEPICTS A DEEPER SHORTWAVE WHEN COMPARED TO THE NAM AND THEREFORE
DEVELOPS SHOWERS AND THUNDERSTORMS ACROSS CENTRAL NEBRASKA AND EAST
CENTRAL KANSAS. THE QUESTION IS HOW FAR EAST WILL THE CONVECTION
TRAVEL WEDNESDAY NIGHT INTO THURSDAY MORNING AS THE LOW LEVEL JET
VEERS. FOR NOW HAVE MAINTAINED SLIGHT CHANCE POPS ACROSS CENTRAL AND
NORTHEAST MISSOURI LATE WEDNESDAY NIGHT...BUT FEEL THE BETTER
CHANCES WILL REMAIN WEST OF THE CWA.

MEANWHILE...AT THE SURFACE A WARM FRONT WILL BE PUSHING NORTHEAST
ACROSS THE REGION ON THURSDAY. INSTABILITY WILL INCREASE THROUGHOUT
THE DAY BRINGING A GREATER CHANCE FOR THUNDERSTORMS TO THE AREA.

THE WARM FRONT SHOULD MOVE NORTHEAST OF THE REGION AS THE UPPER
RIDGE BUILDS OVER THE CWA. DEEP MIXING AND A SOUTHERLY SURFACE WIND
WILL ALLOW TEMPERATURES TO RISE ABOVE NORMAL INTO THE LOWER 90S.

SATURDAY THROUGH TUESDAY...
SOUTHWEST TO NORTHEAST ORIENTATED UPPER LEVEL RIDGE TO DOMINATE THE
CENTER OF THE NATION THIS WEEKEND...WITH ABOVE NORMAL TEMPERATURES
AND LIMITED CHANCES OF PRECIPITATION. THE PATTERN WILL BEGIN TO
BREAK DOWN BY EARLY NEXT WEEK AS THE FLOW BECOMES MORE ZONAL AND THE
UPPER LEVEL RIDGE REESTABLISHES ITSELF TO OUR WEST.

GRANA

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 559 PM CDT TUE JUN 18 2013

ISOLATED THUNDERSTORMS CONTINUE TO PERCOLATE ACROSS THE REGION
HOWEVER THE COVERAGE WAS TOO LOW TO INCLUDE A MENTION OF TSRA IN
THE 00Z TAFS. THUNDERSTORMS WILL DIMINISH WITH THE LOSS OF DAYTIME
HEATING TONIGHT. DRIER AIR WILL BE SLOWER TO REACH KCOU THEREFORE
A PD OF MVFR FOG OR STRATUS IS POSSIBLE TOWARDS DAYBREAK.

SPECIFICS FOR KSTL...COVERAGE OF ISOLATED THUNDERSTORMS IS TOO LOW
TO INCLUDE IN THE TAF ATTM. OTHERWISE VFR WITH LIGHT WINDS
BECOMING SELY TOMORROW.

KANOFSKY

&&

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

$$

WFO LSX






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