Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 060731
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
331 AM EDT MON JUL 6 2015

.SYNOPSIS...
AS AN UPPER LEVEL LOW PRESSURE SYSTEM DEPARTS THE REGION...SLIGHTLY
DRIER AIR ARRIVES FROM THE WEST TODAY. A BROAD UPPER RIDGE WILL
STRENGTHEN AND MIGRATE OVER THE SOUTHEAST THROUGH THE REMAINDER OF
THE WEEK AND INTO THE WEEKEND.  AS A RESULT...SHOWER AND
THUNDERSTORM CHANCE WILL BECOME INCREASINGLY DIURNAL IN NATURE.
TEMPERATURES ARE ALSO EXPECTED TO MODERATE TO ABOVE NORMAL LEVELS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM...THE UPPER TROUGH THAT HAS LINGERED OVER THE CWFA THE
PAST COUPLE OF DAYS IS STARTING TO LOSE INFLUENCE AS IT DRIFTS
NEWD...EVENTUALLY GETTING ABSORBED BACK INTO THE NRN STREAM FLOW AS
A BROADER SHORTWAVE ENTERS THE UPPER MISSISSIPPI VALLEY. THE BEST
DPVA IS ALREADY OFF TO OUR NORTHEAST. SHOWER ACTIVITY HAS WANED OVER
THE WRN CAROLINAS...WITH RADAR RETURNS EVEN DIMINISHING OVER THE NC
MTNS. MESO MODELS GENERALLY FEATURE NO NEW DEVELOPMENT UNTIL AFTER
DAWN. SO FOR THE EARLY MORNING HOURS ANY CHANCE OF SHOWERS PRODUCING
ACCUMULATION WILL BE CONFINED TO THE MTNS WHERE SLIGHT UPSLOPING
WILL PROVIDE A LITTLE EXTRA FORCING. HOWEVER A FEW SPRINKLES CANNOT
BE RULED OUT ELSEWHERE IN THE AREA.

CYCLONIC MID-UPPER FLOW WILL REMAIN OVERHEAD THRU MOST OF THE DAY.
THOUGH EMBEDDED VORTICES MIGHT PROVIDE MESOSCALE ENHANCEMENT TO
LIFT...THE UPPER PATTERN IS EXPECTED TO HAVE LITTLE IMPACT ON POPS.
THE MAJOR MODELS INCLUDING THE CONVECTION ALLOWING SPC AND NSSL WRF
RUNS MAINLY KICK OFF ACTIVITY ALONG THE SRN END OF THE BLUE RIDGE AT
MIDDAY...PROPAGATING IT EWD AND FEATURING THE BEST COVERAGE OVER THE
PIEDMONT BY MID-AFTN. SOME DIFFERENCES CONTINUE TO BE SEEN BETWEEN
NAM AND GFS IN TERMS OF INSTABILITY...MORESO THAN USUAL. GFS SHOWS
POORER LAPSE RATES PERHAPS ON ACCOUNT OF SUBSIDENCE IN THE WAKE OF
THE TROUGH. NONETHELESS BOTH MODELS SUPPORT SCATTERED ACTIVITY.
TSTMS ARE EXPECTED TO REMAIN MORE ISOLATED THAN SHOWERS WITH
BUOYANCY IN QUESTION. PROFILES WILL BE QUITE A BIT DRIER IN THE
UPPER LEVELS WHICH MIGHT ALLOW TSTMS TO PRODUCE ROBUST
OUTFLOWS...PARTICULARLY IF THE HIGHER NAM CAPES VERIFY. HOWEVER I
WILL NOT VENTURE TO SAY THAT DAMAGING WINDS CAN BE EXPECTED. MAX
TEMPS WILL BE CLOSE TO NORMAL...MAYBE A DEGREE OR TWO BELOW.

TONIGHT POPS DIMINISH WITH NOCTURNAL STABILIZATION AND CONTINUED
DEPARTURE OF THE TROUGH. HOWEVER WITH WARM ADVECTION RAMPING UP OVER
THE TENN VALLEY IN SW FLOW AHEAD OF THE MIDWEST TROUGH...I KEPT AN
ISOLD SHOWER MENTION AND MCLDY SKIES OVER THE MTNS. MIN TEMPS WILL
BE SIMILAR TO THOSE THIS MORNING...ABOUT NORMAL.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM EDT MONDAY...THE SHORT TERM FCST PERIOD INITIALIZES
TUESDAY MORNING AMIDST BUILDING UPPER RIDGING OVER THE WESTERN
ATLANTIC...WHILE A LOW AMPLITUDE TROF DIGS ACROSS THE UPPER MIDWEST
AND GREAT LAKES STATES.  AT THE SURFACE...A COLD FRONT TIED TO SAID
UPPER TROFFING WILL EXTENDED FROM THE UPPER PENINSULA OF
MICHIGAN...SOUTHWARD THROUGH THE MID MISSISSIPPI RIVER VALLEY INTO
THE SOUTHERN PLAINS.  FURTHER EAST...BERMUDA HIGH PRESSURE WILL
STRENGTHEN LEADING TO IMPROVING/PREVAILING SOUTHERLY FLOW OVER THE
SOUTHEAST.  IN RESPONSE...MODELS INDICATE MODEST DESTABILIZATION ON
TUESDAY WITH UPWARDS OF 1K-2K SBCAPE ACROSS THE AREA.  THUS...THE
FCST FOR TUESDAY WILL FEATURE DIURNALLY FAVORED POPS WITH MID/HIGH
CHANCE POPS OVER THE MTNS WHERE UPPER HEIGHTS ARE LOWEST.  POPS OVER
THE LOW TERRAIN REMAIN AT SLIGHT CHANCE LEVELS DUE TO WEAK
SUBSIDENCE...DESPITE SOME FOCUSING POSSIBLE ALONG PIEDMONT
TROFFING.  DUE TO WEAK SHEAR...ANY STORMS THAT DO DEVELOP WILL
LIKELY BE PULSE IN NATURE AND COULD REACH STRONG/SEVERE LIMITS WITH
DAMAGING WINDS AND HAIL BEING THE PRIMARY THREATS THANKS TO INVERTED
V PROFILES AMONGST DEEP MIXED LAYER.  TEMPERATURES ON TUESDAY WILL
RETURN TO CLIMO LEVELS.

POPS WILL TAPER TO NON MENTIONABLE LEVELS OVERNIGHT INTO WEDNESDAY
MORNING WITH HEATING LOSS.  MEANWHILE...THE ABOVE MENTIONED UPPER
RIDGE WILL ELONGATE AND BEGIN A MULTIDAY JOURNEY OF WESTWARD
RETROGRESSION WHILE THE COLD FRONT SLIDES INTO THE OH VALLEY...ALL
THE WHILE REMAINING NORTH OF THE CWFA.  IN RESPONSE...TEMPERATURES WILL
FINALLY RETURN TO ABOVE CLIMO LEVELS ON WEDNESDAY AS HEIGHTS RISE
ALOFT.  PROFILES WILL ONCE AGAIN EXHIBIT A DEEP/DRY MIXED
LAYER...AND WEAK SHEAR LEADING TO PULSE STORMS WITH MICROBURSTS/HAIL
BEING THE PRIMARY THREATS.  AS FOR THE FCST...POPS REMAIN AT CHANCE
LEVELS OVER THE HIGH TERRAIN WITH SLIGHT CHANCES FEATURED OVER THE
PIEDMONT REGIONS.  OVERALL...EXPECTING COVERAGE TO BE SOMEWHAT
DIMINISHED ON WEDNESDAY AS SUBSIDENCE IMPROVES LEADING TO AT LEAST
MODEST CAPPING.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 330 AM EDT MONDAY...THE MEDIUM RANGE FCST PERIOD INITIALIZES
THURSDAY MORNING AS A 593DM H5 RIDGE CONTINUES TO SLOWLY RETROGRADE
WESTWARD...WHILE A BERMUDA HIGH PREVAILS AT THE SURFACE.  THE
PATTERN WILL SLOWLY EVOLVE THROUGH THE MEDIUM RANGE WHICH IS
HIGHLIGHTED BY THE UPPER RIDGE CENTER SHIFTING WESTWARD.
MEANWHILE...A SERIES OF UPPER IMPULSES WILL SLIDE ATOP THE RIDGE
AXIS AMONGST THE QUASIZONAL FLOW ACROSS THE OHIO AND MID MISSISSIPPI
RIVER VALLEYS.  THIS WILL LIKELY BE OF NO CONSEQUENCE TO NORTHEAST GA
AND THE WESTERN CAROLINAS THROUGH AT LEAST THE START OF THE
WEEKEND.  THUS...THE FCST FEATURES ONLY DIURNALLY FAVORED SHOWERS
AND THUNDERSTORMS THURSDAY/FRIDAY WITH POPS AROUND OR JUST BELOW
CLIMO LEVELS DUE TO DEEP LAYER SUBSIDENCE.

PRECIPITATION CHANCES WILL SLOWLY INCREASE THROUGH THE WEEKEND AND
INTO THE START OF NEXT WEEK AS THE UPPER RIDGE CENTER SHIFTS FURTHER
WEST PLACING THE SOUTHERN APPS ON THE DESCENDING BRANCH.  ON TOP OF
INCREASING DIURNAL CHANCES DUE TO WEAKENING SUBSIDENCE...THIS
PATTERN WILL ALSO LEND ITSELF TO INCREASED EVENING/OVERNIGHT MCS
PROPAGATION.  THUS...POPS WILL RETURN TO CLIMO LEVELS SATURDAY AND
SUNDAY.  TEMPERATURES THROUGH THE MEDIUM RANGE ARE EXPECTED TO
CONTINUALLY CLIMB TO AROUND 3-5 DEGREES ABOVE CLIMO BY
SUNDAY...WHICH COMBINED WITH UPPER 60S DEWPOINTS COULD YIELD
INCREASED HEAT THREATS.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...UPPER LOW IS BEGINNING TO LIFT OUT OF THE
REGION...BUT THE CYCLONIC FLOW AND ELEVATED MOISTURE ARE CONTINUING
TO RESULT IN ABUNDANT MID-HIGH CLOUD DECKS. THESE WILL BECOME LESS
WIDESPREAD THRU THE MRNG. BETWEEN NOW AND DAYBREAK...A FEW SPRINKLES
ARE POSSIBLE HERE AND THERE AS WELL. GUIDANCE SUGGESTS CIGS WILL
REMAIN VFR EXCEPT OVER THE HIGHER ELEVATIONS OF THE MTNS. SPOTTY
FEW-SCT IFR LEVEL CLOUD REPORTS ARE COMING IN FROM SOME AREA OBS
SITES...POSSIBLY FORMING OVER AREAS THAT SAW RAINFALL ON SUNDAY
AND/OR IN UPSLOPE SWLY LOW LEVEL FLOW. SOME MODELS INDICATE A BAND
OF IFR CIGS AND/OR FOG DEVELOPING OVER THE SC MIDLANDS AND ADVECTING
NWD...BUT THE CHC SEEMS LOW IN LIGHT OF RATHER DRY CONDITIONS.
NONETHELESS AT KCLT I HAVE INCLUDED A TEMPO FOR A 1000 FT CIG NEAR
DAYBREAK. SOME MVFR FOG IS EXPECTED TO FORM OVER THE USUALLY FOGGY
SITES AROUND THE AREA...INCLUDING KAVL/KAND/KHKY. DURING THE
DAY...FLOW WILL CONTINUE TO BE GENERALLY SW EAST OF THE MTNS.
DIURNALLY DRIVEN TSRA MAY FORM INVOF THE BLUE RIDGE ESCARPMENT AND
PROPAGATE EWD THRU THE AFTN. PROB30 MENTION AT ALL SITES WITH TIMING
FOLLOWING CONSENSUS OF CONVECTION ALLOWING MODELS AND THE NAM.

OUTLOOK...THE WEATHER REGIME WILL RETURN TO A MORE TYPICAL DIURNAL
SUMMERTIME PATTERN THROUGH THE WEEK. THIS WILL MEAN SCATTERED
AFTN/EVENING THUNDERSTORMS OVER THE AREA...MAINLY IN THE MTNS...WITH
ASSOCIATED RESTRICTIONS UNDER THE HEAVIEST SHOWERS...AND SPOTTY LOW
CLOUDS AND FOG THE FOLLOWING MORNING.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       HIGH  98%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH  96%     HIGH  97%     HIGH 100%     HIGH 100%
KHKY       HIGH  96%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH  91%     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...CDG/WIMBERLEY
NEAR TERM...WIMBERLEY
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...WIMBERLEY



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