Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 191829
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
229 PM EDT SUN OCT 19 2014

.SYNOPSIS...
DRY AND COOL CANADIAN HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS
THE REGION THROUGH MONDAY. A WEAK COLD FRONT WILL CROSS THE AREA
TUESDAY...BRINGING WITH IT SMALL CHANCES OF RAIN. DRY AND MOSTLY
SUNNY WEATHER WILL PREVAIL THE REST OF THE WEEK WITH TEMPERATURES
TYPICAL FOR THE SEASON.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 230 PM...THE FCST LOOKS LIKE IT IS ON TRACK. TEMP/DEWPT TRENDS
LOOK GOOD. SATELLITE IMAGERY SHOWS ONLY A FEW WISPS OF CIRRUS MOVING
ACROSS MAINLY THE SRN PART OF THE FCST AREA. NO CHANGES.

A SHORT WAVE RIDGE WILL MOVE OVERHEAD TONIGHT WHICH SHOULD CARRY
SURFACE HIGH PRESSURE OVERHEAD TONIGHT. SKY WILL START OUT CLEAR AND
WIND SHOULD BECOME LIGHT AND VARIABLE THIS EVENING...WHICH SHOULD
LEAD TO GOOD RADIATIONAL COOLING CONDITIONS AT LEAST THROUGH THE
EARLY MORNING HOURS...AT WHICH POINT SOME INCREASE IN HIGH CLOUDS IS
LIKELY. MIN TEMPS WILL BE SOMEWHERE IN THE NEIGHBORHOOD OF 5-10
DEGREES BELOW NORMAL...PROBABLY NOT COOL ENOUGH FOR FROST ACROSS ALL
BUT THE MOST SHELTERED AREAS OF THE NC PIEDMONT. THERE IS MORE
CONCERN FOR THE MTNS. HOWEVER...LOW LEVEL MOISTURE IS ALSO EXPECTED
TO INCREASE AFTER MIDNIGHT. OBJECTIVELY SPEAKING...THE INCREASE IN
MOISTURE SHOULD KEEP TEMPS JUST WARM ENOUGH TO KEEP FROST FROM
BECOMING WIDESPREAD ENOUGH TO REQUIRE A FROST ADVISORY. IF THE MIN
TEMPS DROP LOWER THAN EXPECTED...THIS COULD REQUIRE A FROST ADVISORY
ACROSS PARTS OF THE NC MTNS.

HIGH PRESSURE WILL DRIFT OFF THE EAST COAST ON MONDAY AS THE NEXT
UPPER SHORT WAVE DROPS DOWN THROUGH THE MIDWEST TO THE TN VALLEY BY
THE END OF THE DAY. MOISTURE WILL INCREASE FROM THE NW AHEAD OF THE
MID/UPPER FORCING LATE IN THE DAY...THAT COULD RESULT IN A FEW
SHOWERS MAINLY ALONG THE TN BORDER OF THE NC MTNS. WILL INCLUDE A
SLIGHT CHANCE POP AFTER 21Z. TEMPS WILL REBOUND A FEW DEGREES WITH
WEAK WARM ADVECTION DEVELOPING.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM EDT SUNDAY...AN UPPER TROUGH CONTINUES TO DIG INTO THE
SOUTHEAST WITH ITS AXIS CROSSING THE FORECAST AREA MON NIGHT INTO
EARLY TUE. THIS OPEN TROUGH IS PROGGED TO CLOSE OFF AS AN UPPER LOW
JUST TO OUR NORTHEAST BY TUE NIGHT AND SLOWLY MOVES OFF THE MID
ATLANTIC COAST THROUGH WED WEDNESDAY...LEAVING OUR CWA UNDER N/NNW
FLOW ALOFT DURING THIS PERIOD.

AT THE SURFACE...A SURFACE LOW OVER THE EASTERN GREAT LAKES REGION
MON NIGHT WILL MOVE EASTWARD INTO THE NE COAST BY TUE NIGHT. THIS
WILL PUSH AN ASSOCIATED WEAK COLD FRONT THROUGH THE FORECAST AREA
DURING THE DAY ON TUESDAY WITH SW WINDS VEERING TO THE NW IN ITS
WAKE. MODEL CROSS SECTION SHOWS NEARLY SATURATED MOISTURE LAYER
DEVELOPING UP TO 800MB ALONG THE TN BORDER AS LLVL MOISTURE WRAPPING
AROUND THE LOW REACHES THE SOUTHERN APPALACHIANS IN PREVAILING NW
FLOW. WITH THE COMBINATION OF UPSLOPE NW FLOW AND LLVL
MOISTURE...MODELS SHOW LIGHT QPF RESPONSE ALONG THE TN BORDER LINE.
THEREFORE...HAVE CARRIED SLIGHT CHANCE TO LOW END CHANCE FOR LIGHT
SHOWERS MAINLY OVER THE NORTHERN NC MTNS TUE INTO EARLY WED. COOL
AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN FROM THE NW BEHIND THE
FRONT...YIELDING DRY CONDITIONS FOR MOST LOCATIONS ON WED.
TEMPERATURES WILL BE NEAR NORMAL ON TUE AND DROP BY 8-10 DEGREES ON
WED. MIN TEMPS DURING THE SHORT RANGE PERIOD APPEARS TOO WARM FOR
FORST CONCERNS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
AS OF 100 PM EDT SUNDAY...AN UPPER LEVEL LOW SPINNING OFF THE
MID-ATLANTIC COAST WED NIGHT WILL LIFT OFF TOWARD THE NE WHILE AN
UPPER SHORTWAVE DIGS INTO THE REGION BY LATE FRI...OFF THE SE COAST
BY SAT. HEIGHTS WILL THEN RISE OVER THE FORECAST AREA SAT INTO SUN
AS AN UPPER RIDGE BUILDS IN FROM THE CENTRAL CONUS.

AT THE SURFACE...DRY AND COOL CANADIAN HIGH PRESSURE WILL CONTINUE
TO BUILD IN FROM THE NW WED NIGHT INTO FRI AND BECOMES CENTERED OVER
THE REGION SAT INTO SUN. THIS WILL RESULT IN A PROLONGED PERIOD OF
DRY WEATHER THROUGHOUT THE MEDIUM RANGE PERIOD. TEMPERATURES WILL
START OUT AROUND 5-10 DEGREES BELOW NORMAL ON THU...AND A GRADUAL
WARMING TREND IS EXPECTED FRI THRU SUN.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE (EXCEPT KAVL)...VFR THROUGH THE PERIOD...AND
ESSENTIALLY A WIND FORECAST-ONLY DURING THE NEXT 24 HOURS. LIGHT NW
WIND SHOULD BECOME LIGHT AND VARIABLE WITH SUNSET AS HIGH PRESSURE
MOVES OVERHEAD...AND THEN LIGHT S TO SW AFTER SUNRISE ON MONDAY AS
THE HIGH SHIFTS TO THE EAST. THERE IS SOME INDICATION THAT A RETURN
FLOW OF MOISTURE BEGINNING MONDAY MORNING COULD BRING A FEW LOW
CLOUDS BACK INTO THE REGION AFTER SUNRISE.

AT KAVL...NW/UP-VALLEY WINDS AT 8-12 KTS WILL CONTINUE THROUGH THE
DAY...WITH OCCL GUSTS IN THE TEENS LIKELY THROUGH MID TO LATE
AFTERNOON. THE GUSTS SHOULD ABATE BY EARLY EVENING AS THE HIGH MOVES
IN. THE MODELS SUGGEST LOW LEVEL MOISTURE WILL MOVE IN FROM THE SW
DURING THE EARLY MORNING HOURS...WHICH SOME OF THE GUIDANCE USES TO
DEVELOP LOW CLOUDS AND FOG ACROSS THE MTNS. WE COULD EASILY SEE SOME
DEVELOPMENT IN THE LITTLE TN VALLEY...BUT PREFER TO KEEP IT OUT OF
THE FR BROAD VALLEY/KAVL AT THIS TIME BECAUSE OF GREAT UNCERTAINTY.
IF ANY FOG DEVELOPS IT WOULD DISSIPATE BY 14Z.

OUTLOOK...DRY HIGH PRES WILL GENERALLY DOMINATE THROUGH TUESDAY.
ANOTHER ROUND OF GUSTY NW WINDS AND MOUNTAIN STRATOCU WILL BE
POSSIBLE BEHIND ANOTHER (MOSTLY DRY) COLD FRONT LATE TUE INTO EARLY
WED. OTHERWISE...VFR CONDITIONS SHOULD PREDOMINATE INTO LATE WEEK.

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       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
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 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...JOH
NEAR TERM...PM
SHORT TERM...JOH
LONG TERM...JOH
AVIATION...PM





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