Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 241831
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
231 PM EDT SUN APR 24 2016

.SYNOPSIS...
DRY HIGH PRESSURE WILL LINGER OVER THE REGION TONIGHT AND MOVE
OFFSHORE ON MONDAY AND TUESDAY ALLOWING MORE MOIST SOUTHWESTERLY
FLOW TO GRADUALLY RETURN ACROSS THE SOUTHERN APPALACHIANS. A BACK
DOOR COLD FRONT WILL APPROACH FROM THE NORTH EARLY WEDNESDAY AND
STALL OVER THE AREA BEFORE RETURNING NORTH AS A WARM FRONT ON
THURSDAY. ANOTHER WEAK COLD FRONT WILL APPROACH FROM THE NORTHWEST
EARLY FRIDAY.

&&

.NEAR TERM /THROUGH MONDAY/...
AT 230 PM SUNDAY...AN UPPER RIDGE WILL PROGRESS FROM THE GULF STATES
AND UPPER MS RIVER VALLEY TO THE SOUTHERN APPALACHIANS AND GREAT
LAKES OVERNIGHT WHILE DEAMPLIFYING SOMEWHAT. ON MONDAY AMPLIFICATION
OF ANOTHER TROUGH UPSTREAM OVER THE PLAINS RESULTS IN NEARLY ZONAL
FLOW FROM THE MID MS RIVER VALLEY TO THE CAROLINA COAST.

AT THE SURFACE...DRY HIGH PRESSURE WILL MOVE OFF THE EAST COAST
OVERNIGHT...WHILE GULF MOISTURE SPREADS NORTH AHEAD OF A COLD FRONT
IN THE PLAINS. ALTHOUGH THE BULK OF THIS MOISTURE WILL MOVE UP THE
MS RIVER VALLEY ON MONDAY...ENOUGH MOISTURE MIGHT REACH OUR AREA TO
SUPPORT SOME ISOLATED LIGHT RAIN IN THE NC MOUNTAINS DURING THE DAY.
LOW TEMPERATURES TONIGHT WILL RUN AROUND 6 DEGREES ABOVE NORMAL...
AND HIGH TEMPERATURES ON MONDAY WILL RUN AROUND 3 DEGREE ABOVE
NORMAL.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 215 PM EDT SUNDAY...BROAD...FLATTENING UPPER RIDGE WILL
DOMINATE THE SOUTHEAST AS WE START THE SHORT TERM...WITH SOME
LOW-LEVEL MOISTURE ACROSS THE AREA AS A WEAKNESS TRAVERSES THE
NORTHERN GULF. A WARM MOIST...SUMMER-LIKE AIRMASS WILL BE IN PLACE
WITH SURFACE HIGH OFF THE WESTERN ATLANTIC WITH CONTINUING LOW-LEVEL
WAA INTO THE SOUTHEAST. TUESDAY SHOULD BE MAINLY DRY BUT WITH
INTERMITTENT CLOUDINESS ACROSS THE AREA FROM THE UPPER WEAKNESS. AN
UPPER LOW WILL DEEPEN OVER THE HIGH PLAINS...INCREASING THE
AMPLITUDE OF THE DOWNSTREAM RIDGE...AS AN UPPER LOW OVER THE HUDSON
BAY SLOWLY SPINS SOUTH. THIS WILL PUSH A BACKDOOR FRONT DOWN THE
EASTERN SEABOARD...STALLING JUST TO OUR NORTH...BUT CLOSE ENOUGH FOR
POPS TO INCREASE ACROSS OUR NORTHERN ZONES TUESDAY NIGHT INTO
WEDNESDAY. INCREASING INSTABILITY WITH SBCAPES CLIMBING TO OVER 1000
J/KG WILL WARRANT CONTINUED THUNDER WORDING.

MEANWHILE...THE HIGH PLAINS UPPER LOW WILL SHIFT INTO THE CENTRAL
PORTION OF THE COUNTRY...NEGATIVELY TILTED BUT BEGINNING TO FILL AS
IT DOES SO...SWEEPING A COLD FRONT ACROSS THE PLAINS AND MISSISSIPPI
VALLEY. THIS FRONT WILL BE ON OUR DOORSTEP AT THE END OF THE SHORT
TERM. EXPECT HIGHS WEDNESDAY...SOLIDLY IN THE WARM SECTOR TO BE A
GOOD 8-10 DEGREES ABOVE SEASONAL NORMALS...EVEN WITH THE CLOUDS AND
INCREASING POPS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 230 PM EDT SUNDAY...WHAT IS LEFT OF THE APPROACHING FRONT WILL
PUSH INTO THE AREA ON THURSDAY. DEEP LAYER SHEAR IS ALMOST
NONEXISTENT AS THE UPPER FORCING HAS SPLIT OFF FROM THE ROCKIES LOW
AND BY THE TIME IT APPROACHES OUR AREA IT HAS SERIOUSLY DAMPED.
SBCAPES HOWEVER EVEN ON THE LESS ROBUST GFS APPROACH 1500 J/KG SO
CONDITIONAL THUNDER CHANCES ARE PRETTY HIGH. AS THE COLD FRONT
CONTINUES TO WASH OUT...THE ECMWF IS A TAD FASTER THAN THE GFS SO
DEFINITELY SOME UNCERTAINTY IN WHEN POPS WILL END.

SHOULD SEE A BIT OF A BREAK TOWARD THE END OF THE WORK WEEK AND THE
START OF THE WEEKEND AS UPPER RIDGING BUILDS IN AGAIN. OVERALL VERY
LITTLE CHANGE TO TEMPERATURE TRENDS WITH HIGHS CONTINUING TO HOVER
8-10 DEGREES ABOVE SEASONAL NORMALS. ANOTHER PIECE OF ENERGY FROM
THE ROCKIES LOW BREAKS OFF...INDUCING SURFACE CYCLOGENESIS THAT
SWEEPS ACROSS THE PLAINS FRIDAY INTO SATURDAY. SHOULD SEE SOME
UPSLOPE/WARM FRONTAL PRECIPITATION ON SATURDAY...WITH BOTH MODELS
BRINGING MORE WIDESPREAD PRECIPITATION TO THE AREA AT THE END OF THE
PERIOD...THOUGH THE GFS INDICATES MORE ACTIVITY WITH HIGHER QPF
VALUES. HAVE BROUGHT IN MID-RANGE POPS.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...SSE WINDS WILL VEER SW LATE TONIGHT WEST OF
KCLT...AND SW AT KCLT AFTER DAWN. GUSTS ARE EXPECTED OT BE MODEST.
MODEL TIME HEIGHTS SHOW THE PRIMARY CLOUD BASE TO BE AROUND 4000 FT
EAST OF THE MOUNTAINS...AND AROUND 3000 FT AT KAVL...BUT CLOUD COVER
SHOULD BE TOO LIMITED TO PRODUCE CIGS. GUIDANCE SUPPORTS BRIEF LOW
VFR VSBY BEFORE DAWN AT KAVL AND KAND.

OUTLOOK...HIGH PRESSURE AND MOSTLY VFR CONDITIONS WILL PERSIST INTO
MONDAY. PRECIPITATION CHANCES WILL INCREASE FROM ON TUESDAY THROUGH
THURSDAY.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       LOW   55%     LOW   55%     LOW   56%     LOW   59%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  97%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY.  COMPLET HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK:

WWW.WEATHER.GOV/GSP/AVIATION

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...JPT
NEAR TERM...JAT
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...JAT



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