Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 190855
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
455 AM EDT SAT APR 19 2014

.SYNOPSIS...
A MOIST LOW PRESSURE SYSTEM WILL MOVE SLOWLY ACROSS SOUTHERN GEORGIA
TODAY...AND CONTINUE TRACKING EAST OFF THE SOUTH CAROLINA COAST
TONIGHT THROUGH SUNDAY. HIGH PRESSURE WILL BRIEFLY BUILD IN
MONDAY...BEFORE A COLD FRONT PUSHES ACROSS THE REGION ON TUESDAY. A
BROAD AND DRY AREA OF HIGH PRESSURE WILL THEN BUILD IN FROM THE
NORTH WEDNESDAY AND LINGER THROUGH THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 440 AM EDT...WATER VAPOR IMAGERY SHOWS A TONGUE OF MID AND
UPPER LEVEL DRY AIR WRAPPING INTO THE UPPER SAVANNAH RIVER AREA THIS
MORNING. PRECIPITATION HAS LARGELY TRANSITIONED TO DRIZZLE IN THESE
AREAS...AND POPS WILL BE PARED BACK FROM THE SW WITH AREAS OF
DRIZZLE ADDED TO THE FORECAST. OTHERWISE...THE INCREASINGLY STACKED
SE LOW PRES SYSTEM WILL CONTINUE DRIFTING EWD TOWARD THE COAST.
STILL ANTICIPATE A BRIEF RESURGENCE IN FORCING 12Z TO 18Z AS DEEP
LAYER QG FORCING CROSSES THE REGION AND AN AXIS OF FRONTOGENESIS
PERSISTS ACROSS THE HEART OF THE FORECAST AREA THROUGH EARLY AFTN
BEFORE WEAKENING LATE TODAY INTO TONIGHT. THE GREATEST QPF SHOULD
IMPACT THE CHARLOTTE METRO AREA...BUT GIVEN THE WEAK RAINFALL
RATES OBSERVED THUS FAR...AS WELL AS THE FFG AND HEADWATER GUIDANCE
VALUES...IT APPEARS THAT ANY HYDRO PROBLEMS WILL BE QUITE ISOLATED.

IN ADDITION...THE TIGHTENING PRES GRADIENT WILL CAUSE NE WINDS TO
PICK UP...WITH GUSTS WELL INTO THE 20S AND POSSIBLY ABOVE 30 MPH AT
TIMES THIS AFTN ACROSS THE PIEDMONT. SFC CAD REMAINING IN PLACE
THROUGH TONIGHT WILL KEEP THE DIURNAL TEMP RANGE FAIRLY SMALL.
PRECIPITATION SHOULD GRADUALLY END FROM THE WEST TONIGHT AS THE
MOISTURE AND FORCING DIMINISH.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 AM SATURDAY...THE STACKED LOW PRES SYSTEM WILL CONTINUE TO
SLOWLY DRIFT EAST AWAY FROM THE CAROLINA COASTS ON SUNDAY...WITH
WRAP-AROUND CLOUD COVER AND DECENT NELY LLVL FLOW LINGERING ATOP THE
CWFA. IT DOES LOOK LIKE POPS SHUD PRETTY MUCH BE OVER ACRS THE AREA
BY DAYBREAK SUNDAY...BUT A SLGT CHC DOES LINGER IN THE SE ZONES THRU
MIDDAY. WITH THE COOL NE FLOW AND LINGERING CLOUDS...I UNDERCUT MOS
TEMPS...ESP IN THE EAST.

SUNDAY NIGHT THRU MONDAY...SHORTWAVE RIDGING RIPPLES ACRS THE AREA
BEHIND THE DEPARTING LOW. TEMPS REBOUND TO NEAR NORMAL READINGS
UNDER MOSTLY CLEAR SKIES.

MONDAY NIGHT...THE NEXT SHORTWAVE TROF APPROACHES FROM THE WEST.
HEIGHT FALLS ALOFT AND LLVL MOISTURE ARRIVING WITHIN INCREASING WLY
FLOW MAY SUPPORT A FEW SHWRS ALONG THE NC/TN BORDER OVERNIGHT. BUT
OTHERWISE...JUST AN INCREASE IN CLOUDS AND TEMPS A COUPLE CATEGORIES
ABOVE NORMAL.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 AM SATURDAY...MODELS STILL IN GOOD AGREEMENT ON TIMING A
COLD FROPA ACRS THE CWFA ON TUESDAY. THE FRONT WILL BE RELATIVELY
WEAKLY FORCED. BUT THERE SHUD BE ENUF Q-VECTOR CONVERGENCE COUPLED
WITH LLVL FRONTAL CONVERGENCE AND MOISTURE TO SUPPORT AT LEAST
SCATTERED SHWRS WITH THE FRONT. THE TIMING LOOKS GOOD FOR ABOUT
MAXIMUM DAYTIME HEATING INSTBY...WITH THE GFS MOST BULLISH WITH UP
TO 1000 J/KG OF SBCAPE BY 18Z TUESDAY. HOWEVER...I THINK THE
DOWNSLOPE W/NW LLVL FLOW WILL LIMIT COVERAGE AND OVERALL INSTBY. THE
GFS HODOGRAPHS ALSO DON/T SHOW MUCH SHEAR FOR ORGANIZED
CONVECTION...WITH UNIDIRECTIONAL W/NW FLOW ONLY INCREASING TO ABOUT
30 KTS IN THE MID LVLS. TEMPS WILL BE ABOVE NORMAL...UPR 70S TO LWR
80S EAST OF THE MTNS...ASSUMING FRONT PUSHES THRU LATE AFTN/EVE.

TUESDAY NIGHT THRU END OF THE WEEK...UPR FLOW CONTINUES TO BE QUITE
PROGRESSIVE...WITH ANOTHER UPR RIDGE BUILDING IN FOR WEDNESDAY AND
THURSDAY...FOLLOWED BY ANOTHER LATITUDINAL TROF APPROACHING THE AREA
FRIDAY. TEMPS REMAIN NEAR OR SLIGHTLY ABOVE NORMAL...WITH THE SFC
HIGH PRES CENTER TRANSLATING EAST ACRS THE GREAT LAKES. A COLD FRONT
WILL PUSH INTO THE OHIO VALLEY FRIDAY...WITH SLGT CHC TO LOW-END CHC
POPS CREEPING BACK IN BY FRIDAY EVENING.

&&

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...CONTINUING STEADY RAINFALL WILL KEEP MVFR TO TEMPO IFR
LEVEL CLOUDS IN PLACE AROUND KCLT THROUGH THE MORNING HOURS.
ANTICIPATE MAINLY MVFR CIGS THROUGH THE REST OF THE DAY WITH PERIODS
OF MODERATE RAINFALL AS THE FRONTOGENESIS MAX PIVOTS OVERHEAD.
ADDITIONAL TEMPO IFR CIGS MAY LIKELY BE NEEDED IN LATER ISSUANCES.
THE TIGHTENING PRES GRADIENT SHOULD EASILY PRODUCE GUSTS INTO THE
20S THROUGH MOST OF THE TAF PERIOD.

AT KAVL AND KHKY...THE WESTERN NC TAF SITES WILL BE THE FARTHEST
FROM THE DEEPER MOISTURE WITH THE SE LOW...AND THE LEAST LIKELY TO
EXPERIENCE ANY EXTENDED PERIODS OF IFR CIGS. IFR CIGS ARE
POSSIBLE...BUT FOLLOWING A MOS CONSENSUS OF MAINLY MVFR TO LOWERING
VFR SEEMS REASONABLE. BRIEF N TO NE WIND GUSTS ARE LIKELY AS
WELL...BUT WITH LESS MAGNITUDE THAN TAF LOCATIONS FARTHER SE.

AT THE UPSTATE TAF SITES...TEMPO IFR CIGS WILL CONTINUE TO MAKE A
RUN AT THE AIRFIELDS THROUGHOUT THE MORNING HOURS...ALONG WITH RAIN
AND DRIZZLE AT TIMES. WILL FEATURE MAINLY MVFR CIGS THROUGH THE
COURSE OF THE DAY. NE FLOW WILL STEADILY INCREASE AS THE PRES
GRADIENT TIGHTENS...AND GUSTS TO BETTER THAN 25 KT WILL BE LIKELY
TODAY THROUGH THIS EVENING. RAIN SHOULD TAPER OFF FROM THE WEST LATE
IN THE PERIOD.

OUTLOOK...CEILING RESTRICTIONS MAY WELL LINGER INTO SUNDAY MORNING
BEFORE MOISTURE PULLS AWAY WITH THE SLOWLY DEPARTING OFFSHORE LOW
PRESSURE SYSTEM. DRY HIGH PRES WILL THEN DEVELOP THROUGH
MONDAY...WITH A FAIRLY WET FRONTAL SYSTEM EXPECTED ON TUE.

CONFIDENCE TABLE...

            09-15Z        15-21Z        21-03Z        03-09Z
KCLT       HIGH  96%     HIGH  90%     MED   75%     HIGH  84%
KGSP       HIGH  85%     HIGH  90%     MED   75%     HIGH  80%
KAVL       HIGH  98%     MED   77%     MED   64%     HIGH  94%
KHKY       HIGH 100%     MED   64%     MED   76%     HIGH  98%
KGMU       HIGH  82%     HIGH  90%     MED   71%     HIGH  80%
KAND       HIGH  90%     HIGH  91%     HIGH  86%     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...ARK
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...HG






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