Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 191106
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
706 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 700 AM EDT...WATER VAPOR IMAGERY CONTINUES TO SHOW A TONGUE OF
MID AND UPPER LEVEL DRY AIR WRAPPING INTO THE SW HALF OF THE
FORECAST AREA THIS MORNING. PRECIPITATION HAS LARGELY TRANSITIONED
TO DRIZZLE IN THESE AREAS...AND POPS HAVE BEEN 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 /11Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...DEFORMATION ZONE PRECIPITATION OVER OR NEAR THE AIRFIELD
WILL LIKELY KEEP IFR CIGS IN PLACE THROUGH 15Z...WITH MAINLY MVFR
CIGS CONTINUING THROUGH THE DAY. THE TIGHTENING PRES GRADIENT SHOULD
EASILY PRODUCE GUSTS INTO THE 20S THROUGH MOST OF THE TAF PERIOD.
SLOW IMPROVEMENT TO VFR IS POSSIBLE TONIGHT AS THE DEFORMATION ZONE
MOVES EAST AND WEAKENS AND THE MOISTURE BECOMES SHALLOWER.

AT KAVL AND KHKY...PRECIPITATION RATES IN AND NEAR THE DEFORMATION
ZONE SHOULD BE LIGHT ENOUGH TO ALLOW CIGS TO STAY MAINLY VFR TEMPO
MVFR THROUGH THE DAY...WITH IMPROVEMENT TO MORE SOLID VFR TONIGHT.
BRIEF N TO NE WIND GUSTS ARE LIKELY AS WELL...BUT WITH LESS
MAGNITUDE THAN TAF LOCATIONS FARTHER SE.

AT THE UPSTATE TAF SITES...A MID AND UPPER LEVEL DRY SLOT HAS WORKED
IN OVER THE SC TAFS. THIS HAS LESSENED THE PRECIPITATION TO DRIZZLE
OR VERY LIGHT RAIN...AND ALLOWED CIGS TO DIP INTO THE IFR RANGE AT
TIMES. MAINLY IFR IS EXPECTED THROUGH LATE MORNING...WITH MVFR CIGS
THE REST OF THE DAY...IMPROVING TO VFR TONIGHT. NE FLOW WILL
STEADILY INCREASE AS THE PRES GRADIENT TIGHTENS...AND GUSTS TO 25 KT
WILL BE LIKELY TODAY THROUGH THIS EVENING.

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...

            11-17Z        17-23Z        23-05Z        05-11Z
KCLT       HIGH  84%     HIGH  85%     HIGH  82%     HIGH  94%
KGSP       HIGH  91%     HIGH  87%     HIGH  89%     HIGH  93%
KAVL       HIGH  85%     HIGH  81%     HIGH  98%     HIGH 100%
KHKY       HIGH  89%     HIGH  84%     HIGH 100%     HIGH 100%
KGMU       HIGH  91%     HIGH  86%     HIGH  89%     HIGH  93%
KAND       HIGH  95%     HIGH  92%     HIGH  86%     HIGH  86%

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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