Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 030535
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
135 AM EDT MON AUG 3 2015

.SYNOPSIS...
DRY HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE AREA TODAY. LOW
LEVEL MOISTURE WILL GRADUALLY RETURN THROUGH THE WORK WEEK AS A COLD
FRONT APPROACHES FROM THE AREA FROM THE NORTHWEST.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 135 AM...SEA BREEZE BOUNDARY CONTINUES ITS SLOW MARCH
NORTHWARD WITH DEW POINTS RISING ALONG THE WAY. THIS COULD HELP LOW
STRATUS DEVELOP OR MOVE INTO THE AREA BY DAYBREAK. THAT SAID...IT
SHOULD REMAIN WELL SOUTH OF THE I-85 CORRIDOR. PATCHY FOG ALSO MORE
LIKELY. OTHERWISE...GOING FCST ON TRACK WITH UPDATES MAINLY FOR
CURRENT CONDITIONS.

1015 PM UPDATE...SEA BREEZE BOUNDARY HAS NOW MARCHED UP TO ABOUT
I-85. DEWPOINTS HAVE JUMPED 10 DEGREES IN SPOTS WITH THE ARRIVAL OF
THE MARINE AIRMASS. GIVEN THIS OBSERVATION...IT NOW APPEARS THAT AS
FAR AS LOW CLOUD AND FOG DEVELOPMENT IN THE PIEDMONT LATE
TONIGHT...THE EARLIER SUGGESTIONS OF THE NAM AND ITS FAMILY MEMBERS
ARE NOW MUCH MORE PLAUSIBLE. I EXPANDED THE FOG MENTION ACROSS MOST
OF THIS AREA...BUT STILL DID NOT BITE ON THE PRECIP THE NAM IS
SUGGESTING WILL DEVELOP OVER THE ERN ESCARPMENT. I HAVE ALSO BUMPED
UP MIN TEMPS IN THE PIEDMONT A COUPLE OF DEGREES.

AS OF 230 PM EDT SUNDAY...SYNOPTIC PATTERN REMAINS RELATIVELY
UNCHANGED WITH LONGWAVE TROUGH DOMINATING THE EASTERN SEABOARD.
SHORTWAVE SHOULD PUSH THROUGH THE AREA TONIGHT INTO EARLY
TOMORROW...BUT SOME DISCREPANCIES ON HOW STRONG THE SHORTWAVE IS.
NAM IS THE STRONGEST WITH MORE SIGNIFICANT VORTLOBE PUSHING INTO
NORTH CAROLINA. THIS RESULTS IN MORE CONVECTIVE ACTIVITY THAN OTHER
GUIDANCE...AND QUITE A BIT MORE SURFACE MOISTURE AND OVERNIGHT FOG
POTENTIAL. NAM IS A BIT OF AN OUTLIER WITH THIS...SO LEANED MORE
TOWARD THE GFS/ECMWF.

OTHER ITEM OF NOTE IS SURFACE WAVE/LOW NEAR THE FLORIDA BIG BEND
THIS AFTERNOON. THIS LOW WILL RIDE NORTHEAST ALONG THE STALLED
BOUNDARY OVERNIGHT AND GENERALLY ALONG THE SOUTH CAROLINA COAST BY
MONDAY AFTERNOON. GUIDANCE IN FAIRLY DECENT AGREEMENT THOUGH THE GFS
IS DEFINITELY ON THE STRONGER SIDE WITH THIS LOW. FOR NOW...LOOKS
LIKE ANY SENSIBLE WEATHER IMPACTS WILL REMAIN OUT OF OUR FORECAST
AREA AND CLOSER TO THE COAST...BUT WILL CONTINUE TO MONITOR. FOR NOW
THE LOW LOOKS UNLIKELY TO DEVELOP TROPICAL CHARACTERISTICS...REFER
TO NHC TROPICAL WEATHER OUTLOOK.

TEMPS WILL REMAIN NEAR TO JUST ABOVE NORMAL VALUES THROUGH THE NEAR
TERM BUT WITH A TREND UPWARDS AS SURFACE WINDS SWING AROUND TO THE
SOUTH ALLOWING RETURN MOIST FLOW TO BEGIN SETTING UP TOWARD THE END
OF THE PERIOD. HOWEVER...AS THE SURFACE LOW TRACKS TO THE
SOUTHEAST...WILL LIKELY SEE A BRIEF PERIOD OF NORTHWEST SURFACE FLOW
BEFORE THE WINDS RESPOND AGAIN TO THE LARGER SYNOPTIC PATTERN AS WE
TRANSITION INTO THE SHORT TERM.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
AS OF 205 PM SUNDAY...THE MIDDLE PART OF THE WEEK LOOKS LIKE A
GRADUAL RETURN TO MORE TYPICAL SUMMERTIME HUMIDITY...AND MORE
TYPICAL DIURNAL THUNDERSTORM CHANCES. THE MODELS STILL SHOW THE
EASTERN UPPER TROF GRADUALLY LOSING AMPLITUDE THRU WEDNESDAY AS A
SHORT WAVE COMES OUT OVER THE PLAINS AND MIDWEST. THE APPROACH OF
THIS FEATURE ALLOWS SOME WEAK MOISTURE TRANSPORT BACK INTO THE AREA
THAT SHOULD IMPROVE OUR POTENTIAL FOR INSTABILITY WITH SOME
AFTERNOON HEATING...WHICH SHOULD BE SUBSTANTIAL...AT LEAST ON
TUESDAY WHICH LOOKS LIKE THE HOTTEST DAY. WHAT REMAINS TO BE SEEN IS
HOW THE DETAILS WORK OUT. THE MODELS HAVE A SHORT WAVE MOVING PAST
TO THE NORTH LATE MONDAY THAT LEAVES A SURFACE BOUNDARY STRETCHED
OUT TO THE NORTH ON TUESDAY...WHICH SHOULD PROVIDE SOME FOCUS FOR
SHOWERS AND STORMS. THE GFS SEEMS UNDERDONE WITH ITS LACK OF PRECIP.
THE NAM MIGHT BE WRONG ON SOME OF THE DETAILS BUT THINK IT IS RIGHT
WITH DEVELOPING SOME AFTERNOON STORMS SOUTH OF THE BOUNDARY. FOR
THAT REASON...HAVE KEPT AT LEAST A SLIGHT CHC ACROSS THE NC PART OF
THE FCST AREA INTO THE EARLY EVE. WEDNESDAY SHOULD BE MORE FAVORABLE
WITH SLIGHTLY BETTER MOISTURE AS THE WAVE APPROACHES FROM THE
WEST... BUT ONCE AGAIN THE GFS IS UNIMPRESSED. THINK THE PATTERN
FAVORS POTENTIAL A BIT ABOVE CLIMATOLOGY...SO WILL SHADE ON THE HIGH
SIDE OF GUIDANCE WITH A CHANCE ACROSS JUST ABOUT THE WHOLE FCST AREA
IN THE AFTERNOON. A BIT MORE CONVECTION SHOULD MEAN A BIT LOWER HIGH
TEMPS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM SUNDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
THURSDAY WITH BROAD UPPER TROFFING CENTERED OVER NEW ENGLAND
AND PERSISTENT UPPER RIDGING OVER THE WESTERN CONUS. OVER THE NEXT
COUPLE OF DAYS...THE UPPER TROF LIFTS TO THE NE AND ANOTHER NORTHERN
STREAM UPPER TROF HELPS TO FLATTEN THE RIDGE OVER THE WEST. SIMULTANEOUSLY
A SERIES OF EMBEDDED UPPER SHORTWAVES APPROACH THE FCST AREA FROM THE
NORTHWEST ON BOTH THURS AND FRI. TOWARDS THE END OF THE PERIOD NEXT
SUN...THE UPPER RIDGE TRIES TO BUILD EASTWARD AND HEIGHTS COULD BEGIN
TO RISE AGAIN OVER THE SOUTHEAST. AT THE SFC...THE SUBTROPICAL
BERMUDA HIGH WILL MAINTAIN ITS INFLUENCE OVER THE SE REGION THRU
MOST OF THE PERIOD WITH GENERALLY LIGHT SLY FLOW. THE LONG RANGE
MODELS REMAIN IN POOR AGREEMENT WRT THE SFC PATTERN EVOLUTION FOR
MOST OF THE MEDIUM RANGE. THEY ATTEMPT TO SPIN UP MULTIPLE LOWS
OVER THE SE REGION AND THEN MOVE THEM OFFSHORE ON FRI AND SAT YET
THE PLACEMENT AND TIMING STILL DIFFER QUITE A BIT...ALTHOUGH THE ECMWF
AND CANADIAN MODELS HAVE COME INTO BETTER AGREEMENT WITH EACH OTHER.
AS SUCH...I LEANED MORE TOWARDS AN ECMWF/CMC TYPE SOLUTION. I KEPT
POPS AT A HIGH END SOLID CHANCE FOR MOST OF THURS AND FRI AND TAPER THEM
BACK FOR THE WEEKEND. THE LATER INTO THE WEEKEND WE MOVE...THE DRIER IT IS
LIKELY TO BE. TEMPS START OUT NEAR NORMAL AND THEN COOL A FEW DEGREES
THRU THE PERIOD.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR MOST LIKELY WILL PREVAIL THRU 06Z TUE. AS AN UPPER
TROF DIGS TOWARD THE SOUTH ATLANTIC COAST THIS MORNING...A WEAK SFC
LOW WILL SPIN UP OVER SRN GA. NAM AND SOME OF THE OTHER WRF BASED
GUIDANCE ADVECT STALLED FRONTAL BOUNDARY NWD FROM SC...AND BRING
MVFR STRATUS OVER THE FIELD IN THE MRNG. IT CURRENTLY APPEARS THESE
MODELS ARE OVERDOING THIS. HOWEVER SUCH A DECK WILL LIKELY BE NOT
TOO FAR AWAY. TO HINT AT THE POTENTIAL A SCT MVFR LEVEL DECK WAS
MENTIONED NEAR DAYBREAK. WINDS START OUT SSE THEN GO SW FOR THE
AFTERNOON...BACK TO SSE FOR THE EVENING. LOW VFR CU SHOULD BREAK OUT
BY AFTN....BUT WILL LIKELY START BEFORE NOON THEN RISE THRU THE DAY.
HIGH BASED CU CONTINUE INTO THE EVENING.

ELSEWHERE...SOME RESTRICTED VSBYS ARE EXPECTED BRIEFLY NEAR DAYBREAK
AT KAVL...WITH MOISTURE IMPROVING SOMEWHAT COMPARED TO RECENT
MORNINGS. ENOUGH MOISTURE IS ALSO EXPECTED TO ADVECT INTO THE LOWER
PIEDMONT FOR SOME PATCHY FOG AT KAND. OTHERWISE VFR THRU THE PERIOD
WITH FAIR WEATHER CU DEVELOPING EARLY ACROSS THE AREA. EXCEPT FOR
NNW WINDS AT KAVL THRU THE PERIOD...VERY LIGHT S TO SW SELY WINDS
WILL PREVAIL THRU THE PERIOD.

OUTLOOK...GRADUALLY INCREASING PRECIPITATION/RESTRICTION CHANCES
THROUGH MID WEEK AS MOIST SOUTHERLY FLOW RETURNS AHEAD OF THE NEXT
COLD FRONT.

CONFIDENCE TABLE...

            05-11Z        11-17Z        17-23Z        23-00Z
KCLT       HIGH 100%     HIGH  94%     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  94%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH  94%     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...JPT
NEAR TERM...RWH/TDP/WIMBERLEY
SHORT TERM...PM
LONG TERM...JPT
AVIATION...RWH



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