Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 011606
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1206 PM EDT WED APR 1 2015

.SYNOPSIS...
SURFACE RIDGING WILL PREVAIL ON WEDNESDAY AHEAD OF INCREASING
PRECIPITATION CHANCES ON THURSDAY AS MOIST SOUTHERLY FLOW RETURNS.
ANOTHER COLD FRONT WILL PUSH THROUGH NORTHEAST GEORGIA AND THE
WESTERN CAROLINAS ON FRIDAY EVENING AHEAD OF DRIER HIGH PRESSURE FOR
THE WEEKEND.  MOISTURE WILL RETURN FOR THE START OF THE NEXT WORK
WEAK AS SOUTHERLY FLOW ONCE AGAIN COMMENCES OVER THE REGION
THEREFORE INCREASING PRECIPITATION CHANCES.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1205 PM...CLEAR CONDITIONS PREVAIL ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GA AS OF MIDDAY. TEMPS WILL MAX OUT A LITTLE
ABOVE CLIMO THIS AFTERNOON MAINLY OVER THE WESTERN PORTION OF THE
FORECAST AREA. CURRENT GRIDS ARE IN GOOD SHAPE BUT MADE SOME MINOR
ADJUSTMENTS TO WINDS/DEWPOINTS PRIMARILY FOR FIRE WX.

AS OF 915 AM...MADE SOME ADJUSTMENTS TO TEMP TRENDS. OTHERWISE...THE
CURRENT FORECAST LOOKS ON TARGET.

AS OF 630 AM...AFTER A NEAR MISS FROM THE NRN EXTENT OF THE DECAYING
PRECIP ASSOCIATED WITH THE CONVECTION MOVING ACROSS GEORGIA...WE
SHOULD REMAIN DRY THIS MORNING. STILL A VERY SMALL CHC OF A SHOWER
DEVELOPING OVER THE LAKELANDS/SAVANNAH RIVER BASIN WITH THE FRONT
DRIFTING S ACROSS THAT REGION...BUT IT WILL NOT BE INCLUDED IN THE
FCST. TEMPS CONTINUE TO RUN WARMER THAN FCST...GIVING US A BIT OF A
MILDER START TO THE DAY.

OVER THE NEXT 24 HOURS...A PROGRESSIVE UPPER PATTERN WILL SEE THE
UPPER TROF AXIS MOVE EASTWARD OUT OVER THE WRN ATLANTIC...AND AN
UPPER RIDGE BUILDING EASTWARD OVER THE APPALACHIANS/WRN CAROLINAS.
WEAK HIGH PRESSURE WILL BUILD IN FROM THE MID-ATLANTIC REGION BEHIND
THE FRONT THIS MORNING. HIGH TEMPS SHOULD BE ON THE ORDER OF FIVE
DEGREES COOLER THAN YESTERDAY WITH THE SUBTLE AIR MASS CHANGE. THE
UPPER RIDGE AXIS WILL MOVE EAST ACROSS THE REGION LATE TONIGHT AND
THAT SHOULD PUSH THE SURFACE HIGH OFFSHORE...SETTING THE STAGE FOR
MOISTURE RETURN AFTER MIDNIGHT. A DAMPENING SHORT WAVE RIDING UP THE
RIDGE WILL APPROACH FROM THE WEST AFTER 06Z THURSDAY AND WILL BRING
SOME GULF MOISTURE WITH IT...WHILE THE FLOW AROUND THE DEPARTED
SURFACE HIGH WILL ALLOW SOME ATLANTIC MOISTURE TO RETURN AS WELL.
PREFER THE SLIGHTLY LESS ENTHUSIASTIC PRECIP DEVELOPMENT OF THE GFS
NEAR THE BLUE RIDGE W OF I-26 AROUND DAYBREAK THURSDAY...AS IT SEEMS
THE MODEL GUIDANCE DEVELOPS THE UPSLOPE PRECIP A BIT TOO FAST. WILL
CUT DOWN THE PRECIP CHANCES A BIT. MIN TEMPS SHOULD BE AT OR ABOVE
NORMAL.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM EDT WEDNESDAY...THE SHORT TERM FCST PERIOD INITIALIZES
THURSDAY MORNING AMIDST SHORT WAVE RIDGING ALOFT OVER THE SOUTHEAST
ATLANTIC COAST...WHILE REGION OF HEIGHT FALLS APPROACHES FROM THE
WEST.  AT THE SURFACE...HIGH PRESSURE WILL BE IN CONTROL OF THE
PATTERN ACROSS NORTHEAST GA AND THE WESTERN CAROLINAS...HOWEVER
QUICKLY RETREATING OUT TO SEA AS A WARM FRONT APPROACHES FROM THE
SOUTHWEST DRIVEN BY POTENT SOUTHERN STREAM UPPER WAVE AND ASSOCIATED
SFC CYCLONE OVER THE CENTRAL PLAINS.  A NORTHERN STREAM UPPER WAVE
WILL BE SLIDING THROUGH THE NORTHERN GREAT LAKES WITH A SURFACE
TROF/FRONT STRETCHED TO THE SOUTH ALONG THE MISSISSIPPI RIVER
VALLEY.  MODELS CONTINUE TO AGREE ON IMPROVING WAA REGIME WITH
DEWPOINTS SURGING ACROSS THE SOUTHERN APPS THROUGH THE DAY ON
THURSDAY.  THEREFORE THE FCST FEATURES INCREASING POPS THROUGH
MORNING ACROSS NORTHEAST GA...SOUTHWEST NC...AND THE WESTERN UPSTATE
AS UPSLOPE/UPGLIDE FORCED PRECIPITATION PREVAILS EARLY ON AHEAD OF
MAX HEATING/INSTABILITY.  POPS WILL THEN SPREAD OUT FURTHER EAST AS
MODEL SOUNDINGS INDICATE MODEST/IMPROVING LAPSE RATES ALOFT AS THE
UPPER RIDGE SHIFTS EAST...WITH STEEPENING LLV LAPSE RATES WITH
HEATING AND MOISTURE INFLUX.  SOUNDINGS ALSO INDICATE SOME
DIRECTIONAL SHEER IN THE PROFILE THURSDAY AFTERNOON/EVENING ACROSS
THESE ZONES WITH APPROX 30KM BULK SHEAR PRESENT...HOWEVER SPEED
SHEAR LOOKS TO BE LACKING AS NO PRIMARY LLJ/MLJ IS PRESENT.  ALL
SAID...WOULD NOT BE SURPRISED AT ALL TO SEE A FEW DEEP/ORGANIZED
THUNDERSTORMS WITH HAIL/DAMAGING WINDS BEING THE PRIMARY THREATS AS
FZ LEVELS REMAIN BELOW 10KFT.

BEYOND THAT...SOUTHERLY UPSLOPE FLOW WILL VEER SOUTHWESTERLY
SOMEWHAT AND WEAKEN INTO THE OVERNIGHT HOURS.  THIS COMBINED WITH
HEATING LOSS WARRANTS LOWERED POPS DUE TO LACK OF ANY FORCING IN THE
RETURN.  ON FRIDAY SOUTHERLY FLOW WILL CONTINUE...HOWEVER ACCORDING
TO MODEL GUIDANCE...LLV DRY AIR FROM REMNANT H85 RIDGE OVER THE GULF
WILL BE ENTRAINED IN THE MEAN FLOW THUS ADVECTING A REGION OF LOWER
DEWPOINTS NORTHWARD.  THIS DRIER AIR AT THE SURFACE ON FRIDAY WOULD
BE A SUBSTANTIAL LIMITING FACTOR FOR ANY CONVECTION AHEAD OF THE
FROPA FRIDAY NIGHT.  THUS...POPS ACTUALLY LOWER TO SLIGHT CHANCE
LEVELS ACROSS THE NC/SC PIEDMONT AS SOUNDINGS LOOK RATHER
UNIMPRESSIVE.  MODELS CONTINUED TO FAVOR AT LEAST HIGH END CHANCE
POPS OVER THE HIGH TERRAIN THUS THAT WAS ACCEPTED IN THE FCST.
MEANWHILE...A LINE OF CONVECTION JUST AHEAD OF THE FRONT WILL LIKELY
BE MARCHING EAST THROUGH THE TN VALLEY...EVENTUALLY ARRIVING INTO
THE WESTERN NC AND NORTHEAST GA MTNS BY THE 00Z TIMEFRAME.
EXPECTING THIS LINE TO MOVE THROUGH THE REGION OVERNIGHT...THEREFORE
LIKELY POPS ARE FEATURE OVER MOST OF THE FCST AREA WITH THUNDER
MENTIONED.  DUE TO THE ABOVE MENTIONED STABLE AIRMASS OVER THE
SOUTHERN APPS...WOULD NOT BE SURPRISED TO SEE ANY STRONG/SEVERE
CONVECTION ALONG THIS LINE TO WEAKEN AS IT ENTERS THE FCST AREA.  BY
PERIODS END SATURDAY MORNING...THE PRIMARY UPPER TROF AXIS WILL
SWING THROUGH THEREBY MOTIVATING THE FRONT ALONG OR JUST EAST OF THE
INTERSTATE 77 CORRIDOR.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 345 AM EDT WEDNESDAY...THE MEDIUM RANGE FCST PERIOD
INITIALIZES SATURDAY MORNING AMIDST A DEPARTING COLD FRONT AND
INTRUDING HIGH PRESSURE BENEATH QUASI ZONAL FLOW ALOFT.  MENTIONABLE
POPS WILL BE IN THE FCST INITIALLY...HOWEVER WILL LOWER QUICKLY TO
NON MENTIONABLE LEVELS BY MID AFTERNOON.  SKIES WILL CLEAR OUT AS
THE HIGH BUILDS IN THUS ALLOWING FOR ABUNDANT SUNSHINE AMONGST
FALLING THICKNESSES.  TEMPERATURES ON SATURDAY WILL BE A FEW DEGREES
UNDER CLIMO...WITH SLIGHTLY COOLER TEMPERATURES PREVAILING ON SUNDAY
WHERE FROST CONDITIONS ARE POSSIBLE OVER THE MTNS DURING THE EARLY
MORNING HOURS.  THE SURFACE RIDGE WILL MIGRATE EAST INTO MONDAY ALLOWING
FOR THE RETURN OF SOUTHERLY WAA BENEATH CONTINUED ZONAL FLOW ALOFT.
MODEST BAROCLINIC ZONE ACROSS THE ARKLATEX...EAST INTO THE MIDSOUTH
WILL BUILD AHEAD OF ANOTHER POTENT COLD FRONT.  INCREASING MOISTURE
OVER THE SOUTHERN APPS MONDAY INTO TUESDAY WILL YIELD REINTRODUCTION
OF CHANCE POPS BY MONDAY EVENING AS UPGLIDE MAXIMA REGION ADVECTS
OVERHEAD ALONG THE WESTERN PERIPHERY OF THE DEPARTING SURFACE
RIDGE.  POPS WILL REMAIN AT LOW END CHANCE LEVELS ON TUESDAY AS
IMPROVING WAA REGIME YIELDS DEWPOINTS IN THE UPPER 50S TO LOWER 60S
THUS PROVIDING AMPLE MOISTURE FOR CONVECTION.  TEMPERATURES ON
MONDAY WILL RETURN TO NORMAL LEVELS...WITH WARMER TEMPERATURES FCST
ON TUESDAY.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR THRU THE PERIOD. SOME THICKER CIRRUS/CONVECTIVE DEBRIS
CLOUDINESS WILL MOVE OVERHEAD THRU MID MORNING. N WIND EARLY THIS
MORNING COURTESY OF HIGH PRESSURE OVER THE MID ATLANTIC REGION WILL
COME AROUND MORE TO THE NE THRU MIDDAY...THEN EVENTUALLY SHIFT TO SE
LATE IN THE AFTERNOON/EARLY EVENING AS THE HIGH CENTER MOVES
OFFSHORE. WENT WITH A WIND SHIFT AT 22Z...WHEN SOME SCATTERED LOW
CLOUDS WERE INTRODUCED. IMPROVING MOIST UPSLOPE WILL BRING MORE LOW
CLOUDS INTO THE REGION...BUT AT THIS TIME IT APPEARS ANY
RESTRICTIONS WILL BE CLOSER TO THE BLUE RIDGE.

ELSEWHERE...A WEAK FRONT WILL SLIP S ACROSS UPSTATE SC THIS
MORNING...WHICH SHOULD BRING THE WIND DIRECTION AROUND TO N BY MID
MORNING...THEN NE DURING THE AFTERNOON. CONDITIONS SHOULD REMAIN VFR
THROUGH THE EVENING HOURS. SIMILAR TO KCLT...THE WIND SHOULD COME
AROUND TO SE DURING THE EARLY EVENING HOURS. MOISTURE RETURN FROM
THE GULF/ATLANTIC WILL HELP THE DEVELOPMENT OF LOW CLOUDS NEAR THE
BLUE RIDGE BY THE EARLY MORNING HOURS ON THURSDAY...PERHAPS NEAR
KAND BY LATE IN THE TAF PERIOD. THINK ANY LIGHT PRECIP WILL NOT
RESTRICT VSBY AND WILL BE CONFINED TO THE BLUE RIDGE THRU 12Z
THURSDAY.

OUTLOOK...AN APPROACHING WARM FRONT AND RESULTANT MOISTURE RETURN
WILL BRING BETTER CHANCES FOR PRECIP/RESTRICTIONS ACROSS THE AREA
BEGINNING ON THURSDAY MORNING. EXPECT LOW CLOUDS TO DEVELOP WITH A
SOUTHEAST UPSLOPE FLOW THURSDAY NIGHT AND FRIDAY MORNING. A COLD
FRONT WILL AFFECT THE AREA FRIDAY INTO EARLY SATURDAY...BRINGING
ANOTHER ROUND OF RAIN/POSSIBLE THUNDERSTORMS AND RESTRICTIONS. VFR
WILL RETURN FOR THE REST OF THE WEEKEND.

CONFIDENCE TABLE...

            16-22Z        22-04Z        04-10Z        10-12Z
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  83%
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  88%

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...CDG
NEAR TERM...LG
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...PM


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