Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 191040
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
640 AM EDT FRI SEP 19 2014

.SYNOPSIS...
A WEAK RIDGE OF HIGH PRESSURE WILL LINGER ATOP THE REGION INTO
SATURDAY. COOL TEMPERATURES WILL RETURN TO NORMAL READINGS OVER THE
WEEKEND AHEAD OF A COLD FRONT WHICH IS FORECAST TO PASS THROUGH
SUNDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
1030 UTC UPDATE...POPS AND QPF HAVE BEEN ADJUSTED PER RADAR
TRENDS...FAVORING THE SC SIDE OF THE UPPER SAVANNA RIVER VALLEY.

AT 300 AM EDT FRIDAY...CONVECTION IN THE CHARLOTTE AREA SHOWS LIMITED
SIGNS OF DIMINISHING EARLY THIS MORNING...AND HIGH POPS AND QPF WILL
BE CARRIED THERE EARLY TODAY.

AN UPPER TROUGH WILL DEAMPLIFY ALONG THE EAST COAST TODAY...LAVING
BEHIND AN UPPER LOW OFF THE GA COAST. A SURFACE HIGH WILL MOVE
ACROSS NEW ENGLAND TODAY...AND WILL PASS SOUTH OF NOVA SCOTIA
TONIGHT. AS THE SURFACE HIGH BUILDS DOWN THE EAST COAST..THE MODELS
SHOW SLIGHT RELATIVE DRYING EARLY TODAY...BUT ENOUGH MOISTURE WILL
REMAIN FOR PRECIPIATION WITH HEATING THIS AFTERNOON. LIGHT SURFACE
FLOW IS EXPECTED TO VEER FROM NE TO SE TODAY...IMPROVING MOIST
UPSLOPE FLOW INTO THE SOUTHERN APPALACHIANS...WHERE THE HIGHEST POPS
WILL BE CARRIED TODAY. MAXIMUM TEMPERATURES WILL RUN SLIGHTLY BELOW
NORMAL UNDER CLOUD COVER.

SURFACE WINDS WILL BACK TO NE THIS EVENING AS A SURFACE LOW DEVELOPS
OFF THE FL COAST...AND THE MODEL SHOW ADDITIONAL DRYING EAST OF THE
MOUNTAINS TONIGHT. POPS WILL BE ALLOWED TO FALL OFF THIS EVENING
WITH THE LOSS OF HEATING. MINIMUM TEMPERATURES WILL BE NEAR NORMAL.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 230 AM EDT FRIDAY...THIS FORECAST BEGINS 12Z SATURDAY WITH LOW
LEVEL FLOW BECOMING NE AND PARALLEL TO THE RIDGE LINE. COOL HIGH
PRESSURE WILL BE CENTERED TO THE EAST OF NOVA SCOTIA AT THAT TIME
AND MOVING FARTHER TO THE EAST. A LOW WILL BECOME BETTER ORGANIZED
TO THE EAST OF JACKSONVILLE FL ON SATURDAY AND BEGIN MOVING NE OFF
THE CAROLINA COAST FROM LATE SATURDAY INTO SUNDAY. WE WILL BE DRY
SATURDAY THROUGH SUNDAY MORNING. SOME MOISTURE AHEAD OF THE
APPROACHING COLD FRONT WILL SERVE TO FORM SHOWERS OVER THE NC MTNS
LATE SUNDAY AND SUNDAY NIGHT. THERE ARE SMALL DIFFERENCES IN THE
TIMING OF THE PASSAGE OF THE FRONT AMONG THE MODELS BUT THE ONGOING
FORECAST FROM THE PREVIOUS PACKAGE LOOKS GOOD. AT 18Z SUNDAY ON THE
GFS...CAPE VALUES JUST AHEAD OF THE FRONT IN THE CROSSVILLE TO
NASHVILLE AREA. THIS INSTABILITY WEAKENS CONSIDERABLY BY 00Z MONDAY
UPON REACHING THE NC MTNS. THE ROUGHLY 500 CAPE VALUES IN GRAHAM AND
SWAIN AT 00Z MONDAY IS ENOUGH TO SHOW BRIEF THUNDER FOR THAT AREA
BUT ALL OTHER LOCATIONS ONLY INDICATE SHOWERS. TEMPS ARE RAISED A
DEGREE OR TWO OVER THE WEEKEND AHEAD OF THE FRONT.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRI...ONCE THE MINIMAL INSTABILITY FADES SUNDAY EVENING
OVER THE NC MTNS...THERE IS NO RETURN OF INSTABILITY FOR THE WESTERN
CAROLINAS AND NE GA WITH THE LATE NIGHT PASSAGE OF THE COLD FRONT.
WE HAVE LOW SLIGHT CHANCE POPS ON MONDAY IN THE FORM OF ONLY
SHOWERS. DRY AND COOLER HIGH PRESSURE WILL PREVAIL MONDAY NIGHT
THROUGH AT LEAST WED NIGHT. THE COMBINATION OF A DEVELOPING COASTAL
LOW NEAR THE FLORIDA AND GEORGIA COAST AND THE 1035MB HIGH OVER NEW
ENGLAND ON THURSDAY WILL CREATE A STRONG EASTERLY LOW LEVEL FLOW OFF
THE ATLANTIC LATE THURSDAY AND THURS NIGHT. MODELS SHOW A BATCH OF
MOISTURE MOVING IN FROM THE EAST BUT SINCE THAT IS THE END OF THE
CURRENT FORECAST CYCLE IT IS BEST TO LEAVE POPS QUIT LOW UNTIL THE
GET CLOSER TO THAT TIME FRAME. AFTER THE FRONT PASSES EXPECT TEMPS 5
TO 7 DEGREES BELOW NORMAL THROUGH MID WEEK.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR. GUIDANCE HAS BEEN TOO PESSIMISTIC WITH CIG AND VSBY
RESTRICTIONS...AND THE FORECAST THIS MORNING WILL LARGELY FOLLOW
OBSERVATIONAL TRENDS. WINDS ARE EXPECTED TO VEER FORM NW TO SE
TODAY...THEN BACK TO NE TONIGHT. CONVECTIVE CHANCES ARE TOO LOW TO
MENTION THIS AFTERNOON. GUIDANCE BACKS WINDS TO THE NE TONIGHT...
WHICH ALIGNS WELL WITH A SURFACE RIDGE BUILDING DOWN THE EAST COAST.
THE GUIDANCE BLEND VSBY FOR SATURDAY MORNING HAS BEEN ADJUSTED UP
DUE TO LIMITED CONFIDENCE.

ELSEWHERE...RESTRICIONS THIS MORNING WILL BE LIMITED TO KAVL AND
KHKY PER OBSERVATIONS...DESPITE PESSIMISTIC GUIDANCE. NE WINDS ARE
EXPECTED TO VEER SE TODAY...THEN BACK TO NE TONIGHT. CONVECTIVE
CHANCES WILL BE BEST ALONG THE BLUE RIDGE IN MOIST UPSLOPE
FLOW...BUT TOO LIMITED TO MENTION AT TAF SITES. VSBY RESTRICIONS
HAVE BEEN ADJUSTED UP ON SATURDAY MORNING DUE TO LOW CONFIDENCE...
YIELDING IFR AT KAVL AND MVFR AT KHKY.

OUTLOOK...CONDITIONS MAY FINALLY DRY OUT FOR THE LATTER PART OF THE
WEEKEND. A COLD FRONT MAY BRING INCREASING CHANCES FOR SHOWERS/TSTMS
EARLY NEXT WEEK.

CONFIDENCE TABLE...

            10-16Z        16-22Z        22-04Z        04-10Z
KCLT       HIGH  98%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH  88%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       MED   74%     HIGH  95%     HIGH 100%     HIGH  97%
KHKY       HIGH  95%     HIGH  98%     HIGH 100%     HIGH 100%
KGMU       HIGH  89%     HIGH  98%     HIGH 100%     HIGH 100%
KAND       HIGH  96%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

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

&&

$$
SYNOPSIS...DEO
NEAR TERM...JAT
SHORT TERM...DEO
LONG TERM...DEO
AVIATION...JAT






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