Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 030824
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
324 AM CDT MON AUG 3 2015

.SHORT TERM:  (THROUGH LATE THIS AFTERNOON)
ISSUED AT 316 AM CDT MON AUG 3 2015

SURFACE FRONT EXTENDS FROM NORTHERN ILLINOIS THROUGH SOUTHERN
IOWA INTO FAR NORTHWESTERN MISSOURI AT THIS HOUR. THIS FRONT WILL
MOVE SOUTH TODAY AND BEGIN TO REALIGN ITSELF UNDER THE
NORTHWESTERLYUPPER FLOW ALOFT SO THAT IT WILL EXTEND FROM
CENTRAL MISSOURI INTO SOUTHEAST MISSOURI BY LATER THIS AFTERNOON.
WHILE THERE WILL NOT BE ANY SIGNIFICANT SHORTWAVE TROUGHS MOVING
THROUGH THE AREA TODAY TO PROVIDE ENHANCED ASCENT ALONG THE
FRONT...THERE WILL BE ENOUGH LOW LEVEL CONVERGENCE ALONG IT TO
SUPPORT GOING SLIGHT CHANCES. MLCAPES BY LATER THIS AFTERNOON WILL
BE IN THE 2000-3000 J/KG RANGE.

TEMPERATURES WILL STILL BE WARM AHEAD OF THE FRONT IN THE SOUTHERN
CWA WHERE MIXING WILL BE ABOVE 850MB.  TEMPERATURES WILL STILL
LIKELY BE IN THE LOWER TO MIDDLE 90S ALONG AND SOUTH OF I-70 AHEAD
OF THE COLD FRONT WHERE MIXING WILL BE ABOVE 850MB.

BRITT

.LONG TERM:  (TONIGHT THROUGH SUNDAY)
ISSUED AT 316 AM CDT MON AUG 3 2015

(TONIGHT THROUGH WEDNESDAY)

THE SURFACE FRONT WILL MOVE SOUTH OF THE AREA BY TUESDAY MORNING AND
REMAIN SOUTH OF THE AREA THROUGH WEDNESDAY.  RAIN CHANCES WILL BE
GREATER TONIGHT INTO TUESDAY AS BOTH THE NAM AND GFS ARE SHOWING AN
INCREASE IN LOW LEVEL MOISTURE CONVERGENCE OVERNIGHT OVER NORTHEAST
AND EAST CENTRAL MISSOURI OVERNIGHT.  BY TUESDAY AND WEDNESDAY...TWO
SIGNIFICANT SHORTWAVE TROUGHS WILL MOVE ACROSS MISSOURI AND
ILLINOIS WITH A CORRESPONDING INCREASE IN LOW LEVEL MOISTURE
CONVERGENCE. THIS JUSTIFIES THE GOING HIGH CHANCE OR LIKELY
CHANCES FOR THUNDERSTORMS.

(THURSDAY THROUGH SUNDAY)

WAVY FRONT WILL REMAIN OVER THE AREA AT LEAST THROUGH FRIDAY
KEEPING THUNDERSTORM CHANCES IN THE FORECAST. HEIGHTS WILL
INCREASE OVER THE AREA BY THE WEEKEND WITH 850MB TEMPERATURES NEAR
20C. THIS SHOULD CAUSE TEMPERATURES TO CLIMB BACK ABOVE NORMAL.

BRITT

&&

.AVIATION:  (FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1149 PM CDT SUN AUG 2 2015

I`VE INCLUDED A SHORT TEMPO GROUP AT THE BEGINNING OF THE TAF
PERIOD FOR KCOU DUE TO WEAKENING CLUSTER OF STORMS TRACKING
SOUTHEAST TOWARDS THE TERMINAL. OTHERWISE I EXPECT A DRY NIGHT
WITH VFR FLIGHT CONDITIONS. A COLD FRONT WILL MOVE ACROSS THE AREA
ON MONDAY. THERE WILL PROBABLY BE ISOLATED-SCATTERED STORMS
(20-30% PROBABILITY) WITH THE FRONT IN THE AFTERNOON. HOWEVER
GIVEN THE LOW COVERAGE AND UNCERTAINTY WITH LOCATION AND TERMINAL
IMPACTS, I HAVE OPTED TO NOT MENTION ANY THUNDER IN THE TAFS AT
THIS TIME.

SPECIFICS FOR KSTL:

VFR FLIGHT CONDITIONS ARE EXPECTED TO DOMINATE THE TAF PERIOD. A
COLD FRONT WILL MOVE ACROSS THE AREA ON MONDAY. THERE WILL
PROBABLY BE ISOLATED-SCATTERED STORMS (20-30% PROBABILITY) WITH
THE FRONT IN THE AFTERNOON. HOWEVER GIVEN THE LOW COVERAGE AND
UNCERTAINTY WITH LOCATION AND TERMINAL IMPACTS, I HAVE OPTED TO
NOT MENTION ANY THUNDER IN THE KSTL TAF AT THIS TIME.

GLASS

&&

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

$$

WFO LSX



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