Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 270847
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
347 AM CDT THU AUG 27 2015

.SHORT TERM:  (THROUGH LATE THIS AFTERNOON)
ISSUED AT 345 AM CDT THU AUG 27 2015

EARLY THIS MORNING...OUR REGION REMAINS SANDWICHED BETWEEN A TROF
OVER THE EAST COAST AND A RIDGE DOMINATING THE ROCKIES AND HIGH
PLAINS AT THE UPPER LEVELS...RESULTING IN N-NW FLOW ALOFT FOR OUR
REGION.  AN AREA OF HIGH PRESSURE AT THE SURFACE WAS CENTERED OVER
THE WESTERN GREAT LAKES BUT STILL EXERTED STRONG INFLUENCE OVER OUR
REGION...PROVIDING A VERY LIGHT EASTERLY FLOW.  SATELLITE DATA SHOWS
CLEAR SKIES FOR OUR REGION.  TEMPERATURES AT MOST LOCALES WERE IN
THE 50S.

N-NW FLOW ALOFT ABSENT OF UPPER LEVEL DISTURBANCES WILL PERSIST
TODAY...AS THE AREA OF HIGH PRESSURE AT THE SURFACE CONTINUES TO
SLOWLY MOVE AWAY BUT SHOULD RETAIN A DOMINANT INFLUENCE THROUGH THE
AFTERNOON.  THIS SHOULD ALSO CONTINUE THE CURRENT DRY ATMOSPHERIC
COLUMN...WITH MINIMAL ANTICIPATED CLOUD COVER...AND LEAVE US WITH
ANOTHER DRY DAY.

THE SLOW BUT INEXORABLE DECLINE IN THE SURFACE HIGH PRESSURE`S
INFLUENCE WILL BEGIN TO BE FELT A BIT IN TEMPS THIS AFTERNOON...
WITH A FORECAST ABOUT 1-2F HIGHER THAN PERSISTENCE FAVORED WHICH
LEANS TOWARDS THE MAV MOS NUMBERS:  AROUND 80 IN IL AND LOWER 80S IN
MO.

TES

.LONG TERM:  (TONIGHT THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU AUG 27 2015

TONIGHT THE SURFACE RIDGE CONTINUES TO MOVE OFF TO THE EAST WITH LOW
LEVEL MOISTURE ON THE INCREASE AS NEXT SYSTEM APPROACHES FROM THE
NORTHWEST.  THERE IS A LOT OF DRY AIR TO OVERCOME SO THINK IT WILL
BE DRY WITH JUST AN INCREASE IN MID AND HIGH CLOUDS. LOWS WILL BE
IN THE UPPER 50S TO LOW 60S.

WITH COLD FRONT, UPPER LEVEL SHORTWAVE AND DECENT LOW LEVEL JET
APPROACHING THE REGION ON FRIDAY, WILL SEE PRECIPITATION CHANCES ON
THE INCREASE. BEST CHANCES WILL BE FRIDAY NIGHT THROUGH SATURDAY AS
COLD FRONT SLIDES THROUGH REGION, THOUGH DO NOT EXPECT WIDESPREAD
COVERAGE AS MOISTURE WILL BE LIMITED. HIGHS WILL BE IN THE LOW TO
MID 80S FRIDAY AND SATURDAY WITH OVERNIGHT LOWS IN THE 60S.

FRONT TO WEAKEN AS IT EXITS REGION, WASHING OUT TO OUR SOUTHEAST.
ALSO, SURFACE RIDGE BEHIND FRONT IS RATHER WEAK WITH UPPER LEVEL
RIDGE BUILDING INTO THE CENTRAL PLAINS THROUGH EARLY NEXT WEEK. SO
IT LEAVES OUR AREA IN LIMBO, WITH TEMPERATURES ACTUALLY A BIT WARMER
WITH FRONTAL PASSAGE THROUGH MID WEEK NEXT WEEK. ALSO, WITH WEAK
FLOW OVERHEAD AND WEAK SHORTWAVES SLIDING THROUGH REGION, COULD SEE
ISOLATED/SCATTERED ACTIVITY THROUGH THE REST OF THE FORECAST PERIOD.
FOR NOW WILL KEEP FORECAST DRY UNTIL EXTENDED MODELS GET A BETTER
GRASP ON THE PATTERN THAT WILL EVOLVE OVER REGION. ANOTHER FLY IN
OINTMENT IS WHAT WILL HAPPEN WITH "ERIKA" AS IT APPROACHES THE
SOUTHEASTERN US EARLY NEXT WEEK AND ITS AFFECTS ON THE WEATHER
PATTERN ACROSS OUR REGION.

BYRD
&&

.AVIATION: (FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 950 PM CDT WED AUG 26 2015

LITTLE CHANGE IN THINKING SINCE PREVIOUS DISCUSSION. VFR FLIGHT
CONDITIONS WILL PREVAIL ACROSS THE AREA WITH SOME PATCHY RIVER
FOG. NOTICED RELATIVE HUMIDITY LEVELS WERE A LITTLE HIGHER AT
KCPS THIS EVENING AND MOS GUIDANCE IS GIVING THEM SOME FOG, SO
WILL TEMPO MVFR FOG IN THE 06Z UPDATE. OTHERWISE...VFR CONDITIONS
WILL CONTINUE TO PREVAIL ON THURSDAY WITH WIND BECOMING
SOUTHEASTERLY.

SPECIFICS FOR KSTL:

VFR FLIGHT CONDITIONS WILL PREVAIL WITH LIGHT WIND...BECOMING
SOUTHEASTERLY ON THURSDAY.

CARNEY
&&

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

$$
WFO LSX



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