Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 262330
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
630 PM CDT WED AUG 26 2015

.SHORT TERM:  (THROUGH LATE TONIGHT)
ISSUED AT 246 PM CDT WED AUG 26 2015

COOL AND DRY CONDITIONS CAN BE EXPECTED AGAIN TONIGHT. THE
PERSISTENT SURFACE RIDGE EXTENDING FROM MN SOUTH THROUGH MO WILL
MOVE VERY SLOWLY EASTWARD TONIGHT. THE DIURNAL CUMULUS CLOUDS
ACROSS IL MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER FROM STL
SOUTH SHOULD DISSIPATE EARLY THIS EVENING DUE TO THE LOSS OF DAYTIME
HEATING. GOOD RADIATIONAL COOLING CAN BE EXPECTED AGAIN TONIGHT
DUE TO A CLEAR SKY...LIGHT SURFACE WIND NEAR THE SURFACE RIDGE
AXIS...AND SURFACE DEW POINTS ONLY IN THE 50S. LOW TEMPERATURES
WILL BE SIMILAR TO THE PREVIOUS NIGHT MAY BE A COUPLE OF DEGREES
WARMER BUT STILL ABOUT 10 DEGREES BELOW NORMAL FOR LATE AUGUST.

GKS

.LONG TERM:  (THURSDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 246 PM CDT WED AUG 26 2015

A GRADUAL WARMING TREND WILL BEGIN THURSDAY AS THE SURFACE RIDGE
SHIFTS EAST OF THE AREA WITH THE SURFACE WIND BECOMING SOUTHEASTERLY
AND THE 850 MB WIND BECOMING SOUTH SOUTHWESTERLY. TEMPERATURES BY
FRIDAY SHOULD BE UP TO SEASONAL NORMALS. SHOWERS AND STORMS MAY
MOVE INTO NORTHEAST MO AS EARLY AS LATE THURSDAY NIGHT...BUT MORE
LIKELY NOT UNTIL FRIDAY AS AN UPPER LEVEL TROUGH IN THE NORTHERN
PLAINS WITH ITS ASSOCIATED SURFACE LOW AND TRAILING COLD FRONT
APPROACHES OUR AREA WITH A SOUTHWESTERLY LOW LEVEL JET BRINGING
INCEASING LOW LEVEL MOISTURE INTO THE REGION AHEAD OF THE LOW AND
TRAILNG COLD FRONT. THE THREAT FOR CONVECTION WILL SHIFT
SOUTHEASTWARD INTO CENTRAL MO AND WEST CENTRAL IL FRIDAY NIGHT...
ALTHOUGH THE BEST COVERAGE OF PRECIPITATION SHOULD CONTINUE TO BE
ACROSS THE NORTHERN PORTION OF THE FORECAST AREA CLOSER TO THE
UPPER LEVEL TROUGH...VORT MAX AND SURFACE LOW. THE COLD FRONT WILL
WEAKEN AS IT DROPS SOUTHEASTWARD THROUGH OUR FORECAST AREA ON
SATURDAY WITH THE UPPER LEVEL TROUGH SHIFTING EASTWARD INTO THE
GREAT LAKES REGION. THERE WILL LIKELY BE AT LEAST ISOLATED TO
WIDELY SCATTERED SHOWERS/STORMS ALONG THIS WEAKENING FRONT ON
SATURDAY INTO SATURDAY EVENING. WARMER BUT MAINLY DRY WEATHER IS
EXPECTED FOR SUNDAY THROUGH THE REMAINDER OF THE EXTENDED FORECAST
AS THE ECMWF MODEL TRIES TO BUILD THE UPPER LEVEL RIDGE
NORTHEASTWARD INTO OUR AREA FROM THE SOUTHWESTERN US WITH
PERSISTENT SOUTHERLY SURFACE WINDS. THE GFS IS NOT AS WARM AND
DOES HAVE SOME LIGHT QPF ACROSS PARTS OF OUR AREA DO TO AN UPPER
LEVEL LOW WHICH MEANDERS INTO THE AREA FROM THE GULF COAST REGION.
FOR NOW WILL KEEP MOST OF THE AREA DRY FROM SUNDAY THROUGH
WEDNESDAY AS THE MODELS DO NOT USUALLY DO A GOOD JOB WITH THE
INTENSITY AND TRACK OF UPPER LEVEL LOWS COMING UP FROM THE GULF
REGION.

GKS

&&

.AVIATION:  (FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 625 PM CDT WED AUG 26 2015

VFR FLIGHT CONDITIONS AND LIGHT WIND WILL PREVAIL THROUGH
THURSDAY. WIND WILL GRADUALLY BECOME MORE SOUTHEASTERLY THROUGH
TONIGHT AND THURSDAY MORNING. THERE MAY BE SOME RIVER FOG BEFORE
SUNRISE THURSDAY...BUT IT WILL PROBABLY BE VERY LOCALIZED SO HAVE
NOT INCLUDED MENTION OF FOG IN THE TERMINALS AT THIS TIME.

SPECIFICS FOR KSTL:

VFR FLIGHT CONDITIONS AND LIGHT WIND WILL PREVAIL THROUGH
THURSDAY. WIND WILL GRADUALLY BECOME MORE SOUTHEASTERLY THROUGH
TONIGHT AND THURSDAY MORNING.

CARNEY

&&

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

$$

WFO LSX



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