Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 020016
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
816 PM EDT FRI AUG 1 2014

.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN WEDGED OVER THE CAROLINAS
THROUGH SATURDAY AS AN UPPER TROUGH REMAINS CENTERED TO OUR WEST. TO
THE EAST...A FRONT WILL REMAIN NEARLY STATIONARY ALONG THE COAST
ALLOWING DEEP ATLANTIC MOISTURE TO CONTINUE TO SPREAD OVER THE AREA.
CONDITIONS ARE EXPECTED TO RETURN TO MORE TYPICAL LATE SUMMER
CONDITIONS BY THE MIDDLE OF NEXT WEEK AS THE BERMUDA STRENGTHENS TO
OUR EAST.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 745 PM...STRATIFORM WEDGE PRECIP HAS DISSIPATED OVER THE ERN
HALF OF THE CWFA OVER THE PAST FEW HRS AS DRIER AIR WORKS IN ALOFT
IN THE WAKE OF A SHORTWAVE. CLEAR SKIES IN THE LATE AFTN ALLOWED
DESTABILIZATION OVER THE SW NC MTNS...PRODUCING A FEW SHRA WHICH
CONTINUE ATTM. THESE SHOULD GRADUALLY DIMINISH GOING INTO THE
EVENING. A LOW STRATUS DECK NOW COVERS MOST OF THE CWFA WHICH
REPLACED THE THICKER DECK THAT PRODUCED THE PRECIP EARLIER...A
RESULT OF VERY SHALLOW EAST TO NORTHEAST FLOW AND JUICY LLVL
PROFILES. THOUGH UPGLIDE IS STILL EXPECTED TO WEAKEN
OVERNIGHT...THERE WILL BE NOTHING TO ERODE THIS LOW DECK SO THEY
SHOULD STAY IN PLACE INTO SATURDAY MRNG. THERE IS SUFFICIENT
ISENTROPIC LIFT REMAINING ON MODEL PROGS THAT SCHC TO CHC POPS HAVE
BEEN RETAINED OVERNIGHT...VERY SIMILAR TO WHAT WAS IN THE LAST
UPDATE...BUT QPF HAS BEEN CUT BACK. BETTER CHANCES ARE STILL
EXPECTED TO RETURN TOMORROW AFTN WITH THE CLOUD DECK LIFTING AND
ALLOWING MORE SFC HEATING AND DESTABILIZATION. ANOTHER SHORTWAVE
ROUNDING THE UPPER TROUGH WILL ALSO ENHANCE LIFT. TEMPS WILL RETURN
INTO THE U70S IN THE MTN VALLEYS AND L80S ACRS THE PIEDMONT SATURDAY
AFTN...STILL NEAR 10 DEG BELOW CLIMO.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM FRIDAY...A POSITIVELY-TILTED UPPER TROF WILL LINGER
OVER THE GREAT LAKES TO THE LWR MS VALLEY INTO EARLY NEXT WEEK. A
SERIES OF EMBEDDED SHORTWAVES WILL ROUND THE BASE OF THE TROF AND
LIFT NE ACRS THE CWFA SUNDAY AND MONDAY. HOWEVER...OVERALL FORCING
WILL REMAIN FAIRLY WEAK. AN UPPER JET STREAK WILL ALSO EXIST BETWEEN
THE TROF AND A LARGE SUBTROPICAL RIDGE ACRS THE NORTH ATLANTIC. THE
OP MODELS ALL PLACE THE BEST RIGHT ENTRANCE REGION OF THE JET STREAK
TO THE EAST OF THE CWFA ALONG THE CAROLINA COASTS. AT THE SFC...A
QUASI-STATIONARY FRONT/INVERTED TROF WILL LINGER PARALLEL TO THE
UPPER JET...EXTENDING FROM FL NE TO NEW ENGLAND. GUIDANCE DIFFERS ON
EXACT PLACEMENT AND SHARPNESS OF THE TROF AXIS...WITH THE NAM STRONG
OUTLIER...CLOSING OFF A SFC LOW EAST OF FL AND LIFTING IT NORTH
TOWARD SC. MEANWHILE...THE GFS IS THE WEAKEST...ALLOWING MORE
MOISTURE AND INSTBY TO BE TRANSPORTED NW FROM THE COAST TO THE BLUE
RIDGE. I LIKE THE ECMWF REPRESENTATION...WHICH IS IN BETWEEN. THE
RESULT IS FOR A SLIGHT WARMING TREND (BUT STILL SLIGHTLY BELOW
NORMAL) AND GENERALLY DIURNAL SHOTGUN CHC POPS BOTH SUNDAY AND
MONDAY. INSTBY AND SHEAR WILL BE MODEST...SO SEVERE THREAT SHUD BE
LOW. ALSO...CONVECTION ALONG/EAST OF SFC TROF AXIS SHUD LIMIT THE
ANOMALOUSLY HIGH PWATS FROM REACHING THE AREA FROM THE EAST. AND
WITH LACK OF LLVL TRIGGERING AND WEAK UPPER FORCING...I DON/T EXPECT
MUCH OF A HEAVY RAIN THREAT.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 215 PM FRIDAY...THE MEDIUM RANGE STARTS AT 00Z TUESDAY. THE
MODELS IN OKAY AGREEMENT ON THE UPPER FLOW FLATTENING OUT
SOMEWHAT...BUT A GENERAL EAST COAST TROFINESS WILL LINGER INTO LATE
NEXT WEEK. THE COASTAL INVERTED TROF/STATIONARY FRONT FINALLY WASHES
OUT AND IS REPLACED BY DRIER AIR WORKING IN FROM THE WEST. TUESDAY
AND WEDNESDAY LOOK TO HAVE ONLY ISOLD TO WIDELY SCATTERED DIURNALLY
DRIVEN CONVECTION. TEMPS RETURN TO AROUND NORMAL.

THURSDAY AND FRIDAY...MODELS ARE TRENDING DEEPER WITH ANOTHER TROF
DIGGING ACRS THE GREAT LAKES TO THE MID SOUTH. THIS USHERS IN A WEAK
BACKDOOR COLD FRONT...WHICH THEN STALLS ACRS THE REGION. POPS
INCREASE TO MID TO HIGH CHC...AND TEMPS TREND A CATEGORY OR TWO
COOLER.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...LOW MVFR CIGS ALREADY OVER THE FIELD ARE UNLIKELY TO BUDGE
OVERNIGHT EVEN AS WARM UPGLIDE WANES ATOP COOL WEDGE AT THE SFC. IN
FACT MAJORITY OF GUID SHOWS CIGS LOWERING TO IFR BEFORE THE FIRST
MRNG PUSH. THESE CIGS WILL SLOWLY LIFT TO VFR BY EARLY AFTN.
SATURDAY IS A SOMEWHAT MORE TYPICAL DAY WITH MAIN DRIVER FOR PRECIP
BEING DIURNAL BUOYANCY...HOWEVER WEAK. PROB30 THUS INCLUDED FOR AFTN
TSRA. WITH CLOUDY CONDITIONS CONTINUING...WEDGE IS UNLIKELY TO ERODE
AS NAM SEEMS TO SUGGEST /WITH SOUTHERLY WINDS/. FAVORED GFS BASED
GUID WHICH HAS WINDS PREVAILING NELY THRU THE END OF THE PERIOD.

ELSEWHERE...MUCH LIKE KCLT WITH ALL SITES UNDER THE INFLUENCE OF
COOL WEDGE OF HIGH PRESSURE. LOWERING TO IFR IS ANTICIPATED AFTER
MIDNIGHT. KHKY IS AN EXCEPTION WITH CONTINUED RAINFALL THIS AFTN
LOCKING THEM IN AT LIFR WHICH IS UNLIKELY TO IMPROVE. CANNOT RULE
OUT A FEW AREAS OF LIGHT PRECIP OVERNIGHT BUT IMPACT IS MINIMAL
BEYOND THE ALREADY POOR CONDITIONS. AREAS OF MVFR TO IFR FOG WILL
LIKELY OCCUR ESP WHERE NO RAIN IS FALLING. AFTER BOTTOMING OUT NEAR
DAYBREAK...CIGS WILL LIFT SLOWLY THRU THE MRNG...BUT ENOUGH SO TO
ALLOW BETTER SFC HEATING FOR THE AFTN. THUS PROB30 FOR TSRA IS
MENTIONED AT ALL SITES. NELY WINDS CONTINUE THRU THE PERIOD AT ALL
SITES...EXCEPT CHANNELED N AT KAVL.

OUTLOOK...UNSETTLED WEATHER WITH ENHANCED PRECIPITATION CHANCES
ALONG WITH MORNING FOG/STRATUS ARE EXPECTED THROUGH THE WEEKEND.
TEMPERATURES WILL BEGIN TO MODERATE EARLY NEXT WEEK AS A MORE
SUMMERLIKE PATTERN GRADUALLY TAKES HOLD AGAIN...BUT PERIODIC
RESTRICTIONS FROM CLOUDS AND PRECIP ARE STILL LIKELY AT THAT TIME.

CONFIDENCE TABLE...

            00-06Z        06-12Z        12-18Z        18-24Z
KCLT       HIGH  88%     LOW   57%     MED   77%     HIGH  98%
KGSP       HIGH  82%     MED   66%     MED   70%     HIGH  90%
KAVL       HIGH  85%     MED   73%     HIGH  80%     HIGH 100%
KHKY       MED   64%     MED   70%     MED   65%     HIGH  88%
KGMU       MED   75%     MED   78%     MED   69%     HIGH 100%
KAND       HIGH  91%     MED   72%     MED   66%     HIGH  95%

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...ARK
NEAR TERM...WIMBERLEY
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...WIMBERLEY





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