Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 201847
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
247 PM EDT MON OCT 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE EASTERN SEABOARD TONIGHT. A WEAK
COLD FRONT WILL CROSS THE REGION FROM THE NORTHWEST ON TUESDAY. DRY
HIGH PRESSURE WILL GRADUALLY RETURN MID TO LATE WEEK AND LINGER INTO
THE WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 245 PM EDT...WATER VAPOR IMAGERY SHOWS UPPER LOW SPINNING
ACROSS LOWER MICHIGAN...WITH THE FIRST S/W BEING PUSHED INTO EASTERN
KY. THE FIRST WAVE IS ACCOMPANIED BY A BAND OF CIGS CONSISTING OF
MID LEVEL CLOUDS. THE MODEL PLANE SECTION RH DATA...POINT RH DATA
AND BUFKIT INFORMATION ALL SHOW THIS SLUG OF MOISTURE CROSSING OUR
FORECAST AREA TONIGHT. THE MODELS INSIST THAT OUR NRN MOUNTAINS
COULD STILL SQUEEZE OUT A FEW SPRINKLES...AND WE WILL FOLLOW THAT
COURSE.

MEANWHILE ONCE THAT FIRST BAND OF CLOUDS PASS...AND BEFORE THE NEXT
SURFACE FRONT MAKES IT INTO OUR REGION...THERE APPEARS TO BE A
WINDOW OF OPPORTUNITY WITH LIGHT WINDS AND POTENTIAL FOG DEVELOPMENT
FOR A FEW HOURS LATE TONIGHT/VERY EARLY TUESDAY MORNING...IN PARTS
OF THE CENTRAL AND SRN NC RIVER VALLEYS...NE GA AND THE NW PORTIONS OF
UPSTATE SC. WE WILL ADD FOG TO THIS FORECAST. TEMPERATURES SHOULD BE
ABOVE READINGS OF LAST NIGHT WITH THE PERIOD OF CLOUDS MOVING
THROUGH.

THE COLD FRONT WILL CROSS OUR REGION TUESDAY MORNING. NICE
PERPENDICULAR LOOK OF THE H85 HEIGHT CONTOURS...RELATIVE TO THE H85
THERMAL PATTERN...SUGGESTS VERY GOOD CROSS CONTOURING...YIELDING
GUSTY WINDS. UPSLOPE FLOW...ALONG WITH A STRONG 2DRY S/W TUESDAY
AFTERNOON...WILL HELP WITH THE GENERATION OF SCATTERED SHOWERS.

THE MODELS ON NOT TO KEEN ON COLD AIR CU ELSEWHERE...BUT WOULD BE
SURPRISED IF THEY WERE ABSENT. WE HAVE FOLLOWED AN AVERAGE
TEMPERATURE FORECAST BASED ON OUR MOST RELIABLE MODEL GUIDE SET.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 205 PM EDT MONDAY...A STRONG UPPER LOW WILL MOVE OFF THE
MID-ATLANTIC COAST TUESDAY NIGHT. A SHORT WAVE RIDGE IS FORECAST TO
BUILD OVER THE SE STATES IN ITS WAKE WED INTO THU. DEEP LAYER N/NW
FLOW WILL PERSIST THROUGH WED ALONG WITH ASSOCIATED COLD ADVECTION.
THICKNESSES WILL REBOUND SOME ON THU AS UPPER HEIGHTS INCREASE. DRY
WEATHER IS EXPECTED THROUGH THU AS THE LOW TO THE NE PULLS AWAY AND
SURFACE HIGH PRESSURE TO THE NW SLOWLY BUILDS TOWARD THE AREA. THE
EXCEPTION TO THE TOTALLY DRY FORECAST MAY BE A FEW SPRINKLES IN THE
NORTHERN MOUNTAINS TUE NIGHT DUE TO UPSLOPE NWLY FLOW. MODEL TIME
HEIGHTS INDICATE GENERALLY CLEAR CONDITIONS WILL PERSIST EAST OF THE
MOUNTAINS IN THE DOWNSLOPE FLOW. HOWEVER OVER THE MOUNTAINS TUE
NIGHT...SOME STRATO CUMULUS CEILINGS ARE LIKELY. MODEL SOUNDINGS
OVER THE MOUNTAINS INDICATE THAT ENOUGH LOW LEVEL MOISTURE WILL
PERSIST INTO THU FOR PATCHY CLOUDS.

WINDS WILL BE GUSTY IN THE MOUNTAINS TUE NIGHT AND WED IN THE COLD
ADVECTION REGIME. COOL AUTUMN TEMPS ARE EXPECTED WITH MAX TEMPS
5-10 DEGREES BELOW CLIMO ON WEDNESDAY. DESPITE THE COOL REGIME...CURRENT
INDICATIONS ARE THAT CLOUDS AND/OR WIND WILL PRECLUDE MUCH OF A
FROST FREEZE CONCERN IN THE MTNS TUE NIGHT...EXCEPT PERHAPS IN THE
SHELTERED VALLEYS OF THE SOUTHWEST MTNS (WHERE THE FROST/FREEZE
PROGRAM HAS ALREADY ENDED FOR THE SEASON). WITH WINDS DIMINISHING
WED NIGHT...A BETTER CASE CAN BE MADE FOR FROST AND AREAS
OF FREEZING TEMPS. HOWEVER....IT APPEARS THE SW MOUNTAINS WILL BE
THE COLDEST AGAIN WHILE AREAS ACROSS THE CENTRAL MOUNTAINS WHERE THE
FROST/FREEZE PROGRAM HAS NOT ENDED MAY STAY MIXED ENOUGH TO PRECLUDE
ANY FREEZE ISSUES. TEMPS WILL MODEERATE ON THU...BUT REMAIN BELOW
CLIMO.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 215 PM MONDAY...EVEN THOUGH THE 12Z GFS DEPICTS A RATHER
VIGOROUS LOOKING UPPER TROUGH MOVING SE THROUGH THE AREA THU NIGHT
INTO FRI...IT APPEARS THAT THE SYSTEM WILL BE MOISTURE STARVED AND
HENCE NO PRECIP ASSOCIATED WITH IT. MODEL TIME HEIGHTS INDICATE
PERHAPS SOME HIGH LEVEL CLOUDINESS ONLY. BEYOND THAT...AN UPPER
RIDGE IS FORECAST TO MOVE EASTWWARD FROM THE 4-CORNERS AREA TO OVER
THE EASTERN U.S. BY SUN NIGHT AND THEN OFF THE EAST COAST ON MONDAY.
SURFACE HIGH PRESSURE WILL DOMINATE THE WEATHER REGIME AS IT
EVENTUALLY MIGRATES TO OFF THE SE COAST ON MONDAY. DOWNSLOPE FLOW ON
FRIDAY LOOKS TO OVERCOME THE WEAK COLD ADVECTION ASSOCIATED WITH THE
UPPER TROUGH AND ALLOW FOR NEAR CLIMO MAX TEMPS. TEMPS WILL THEN
SLOWLY WARM TO ABOVE CLIMO THE REMAINDER OF THE PERIOD.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AT KCLT AND ELSEWHERE...ANY LEFT OVER CU WILL DISSIPATE AT SUNDOWN
AROUND THE CLT AIRFIELD. MEANWHILE...THE FIRST S/W IN A DEVELOPING
NWLY FLOW ALOFT...WILL PIVOT ACROSS THE REGION TONIGHT. A BAND OF
BOTH MID AND HIGH LEVEL CLOUDS SHOULD BE NOTED. ONCE THEY PASS...
THERE WILL BE A PAUSE BEFORE THE FRONTAL PATTERN (SURFACE FRONT)
CROSSES THE FIELD TUESDAY MORNING. THIS SHOULD YIELD SOME SCT COLD
AIR STRATO CU CLOUDS...AROUND 3K...AND AN UPTICK IN THE WINDS. WE
WOULD EXPECT FOR THE LATER HALF OF TUESDAY FOR SOME GUSTY NWLY WINDS
TO MATERIALIZE. THE FRONT...AND ASSOCIATED PACKETS OF ENERGY...
SHOULD BE RATHER MOISTURE STARVED THEREFORE NO PRECIPITATION IS
EXPECTED.

ELSEHWERE NOT MUCH CHANGE IN THE PHILOSOPHY OF THE AFOREMENTIONED
DISCUSSION ABOVE. THE FRONT WILL COME THROUGH THE MOUNTAINS A FEW
HOURS EARLIER...AND PERHAPS A LITTLE LATER TUESDAY MORNING IN PARTS
OF THE SOUTHERN UPSTATE OF SC. WE DO CARRY A BRIEF VISIBILITY
RESTRICTION AT AVL FOR A FEW PREDAWN HOURS TUESDAY. THIS IS BEFORE
THE CAA KICKS IN...AND AFTER THE FIRST WAVE OF CLOUDS MOVE BY. IT
APPEARS POINTS TO THE SOUTH HAVE A BETTER OPPORTUNITY FOR FOG
CONDITIONS.

OUTLOOK...BLUSTERY AND COOLER FOR THE MIDDLE PART OF THE WEEK...THEN
WARMING THE LATER PORTIONS. GUSTY MOUNTAIN WINDS TUESDAY NIGHT SEEM
TO BE THE ONLY AVIATION CONCERN APPARENT AT THIS TIME.

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  91%     HIGH  91%
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...HG
NEAR TERM...TS
SHORT TERM...LG
LONG TERM...LG
AVIATION...TS






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