Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 282223
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
523 PM CDT FRI AUG 28 2015

.SHORT TERM:  (THROUGH LATE TONIGHT)
ISSUED AT 315 PM CDT FRI AUG 28 2015

WATER VAPOR IMAGERY SHOWS THAT A SHORTWAVE TROUGH IS MOVING SLOWLY
EAST ACROSS MISSOURI AT THIS HOUR.  LATEST RUNS OF THE RAP SUGGEST
THAT IT WILL TAKE ALL EVENING FOR THIS FIRST SHORTWAVE TO REACH
HALFWAY ACROSS THE CWA WHILE A SECOND SHORTWAVE WILL ENTER WESTERN
MISSOURI BEHIND IT LATER TONIGHT.  LOW LEVEL MOISTURE CONVERGENCE
WILL INCREASE ACROSS EASTERN MISSOURI BY LATER THIS EVENING AS LOW
LEVEL JET VEERS AND INCREASES IN SPEED SLIGHTLY.  THIS SHOULD CAUSE
AN INCREASE IN COVERAGE IN SCATTERED SHOWERS AND THUNDERSTORMS BY
LATE EVENING AND OVERNIGHT OVER THE REGION BECAUSE OF THE FORCING
FROM THE SHORTWAVES AND THE MOISTURE CONVERGENCE.  THE 1KM
REFLECTIVITY FROM THE CAMS DEPICTS THIS PRETTY WELL.

MOS LOWS TONIGHT LOOK REASONABLE GIVEN THE INCREASING DEWPOINTS
AHEAD OF THE COLD FRONT CURRENTLY OVER THE CENTRAL PLAINS.

BRITT

.LONG TERM:  (SATURDAY THROUGH NEXT FRIDAY)
ISSUED AT 316 PM CDT FRI AUG 28 2015

AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED ON
SATURDAY AND SATURDAY EVENING AS AN UPPER LEVEL TROUGH MOVES
SLOWLY SOUTHEASTWARD THROUGH OUR AREA. IT NOW APPEARS THAT THE
COLD FRONT WILL ONLY MAKE IT INTO NORTHEAST MO AND WEST CENTRAL IL
BEFORE GRADUALLY DISSIPATING. ONLY SLIGHT COOLING IS EXPECTED
ACROSS NORTHEAST MO AND WEST CENTRAL IL SATURDAY AND SATURDAY
NIGHT WITH THE REST OF THE AREA SLIGHTLY WARMER AND MORE HUMID
DESPITE THE CLOUD COVER ON SATURDAY WITH MAINLY A WEAK SOUTHERLY
FLOW. ALTHOUGH THE CHANCE OF PRECIPITATION WILL LESSEN BY LATE
SATURDAY NIGHT AND SUNDAY...THERE MAY STILL BE AT LEAST ISOLATED
SHOWERS/STORMS ACROSS MAINLY SOUTHEAST MO AND SOUTHWEST IL AS THE
WEAKENING UPPER LEVEL TROUGH...SHEAR AXIS MOVES ONLY SLOWLY
SOUTHEASTWARD. A WAMER PERIOD OF WEATHER IS FORECAST FOR THE NEXT
WORK WEEK DUE TO PERSISTENT SOUTHERLY SURFACE/LOW LEVEL FLOW WITH
THE SURFACE/850 MB RIDGE EAST/SOUTHEAST OF OUR AREA...AND AT
LEAST UPPER LEVEL RIDGING ACROSS NORTHWEST MO. WILL KEEP THE
REMAINDER OF THE FORECAST DRY FOR NOW...ALTHOUGH COULD NOT RULE
OUT A FEW SHOWERS/STORMS MAINLY DURING THE AFTERNOON AND EARLY
EVENING HOURS AS THE MODELS CONTINUE TO DEPICT SOME WEAK MID-UPPER
LEVEL TROUGHING...SHEAR AXIS ACROSS MAINLY SOUTHEAST MO AND
SOUTHWEST IL.

GKS

&&

.AVIATION:  (FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 519 PM CDT FRI AUG 28 2015

SLOW MOVING TROF OF LOW PRESSURE AND SEVERAL UPPER AIR
DISTURBANCES WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE
REGION TONIGHT THROUGH SATURDAY NIGHT. EXPECT VFR CONDITIONS
OUTSIDE OF ANY HEAVIER SHOWERS THAT COULD TEMPORARILY REDUCE
THE VISIBILITY AND CEILING AT A TERMINAL. LIGHT SOUTHEAST/SOUTH
WIND EXPECTED TO CONTINUE THROUGH THE PERIOD.

SPECIFICS FOR KSTL:

SCATTERED SHOWERS SHOULD ARRIVE NEAR THE TERMINAL COMPLEX AROUND
12Z WITH THE THREAT OF SCATTERED THUNDERSTORMS DEVELOPING DURING
THE HEAT OF THE DAY...OR AFTERNOON. CONFIDENCE IN COVERAGE OF RAIN
IS NOT HIGH ENOUGH TO INCLUDE IN THE FORECAST OUTSIDE OF VICINITY
AT THIS TIME. LIGHT SOUTHEAST TO SOUTH WIND EXPECTED TO CONTINUE
THROUGH THE PERIOD.

CVKING

&&

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

$$

WFO LSX


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