Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 201341
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
941 AM EDT SUN APR 20 2014

.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS IN TODAY THROUGH MONDAY BEHIND...AS LOW
PRESSURE DRIFTS EAST OF THE AREA. A COLD FRONT WILL CROSS THE REGION
ON TUESDAY...FOLLOWED BY DRY HIGH PRESSURE FOR WEDNESDAY AND
THURSDAY. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE REGION ON
FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT SUNDAY....9 AM TEMPERATURES WERE RUNNING A GOOD 5
DEGREES WARMER THAN PROGGED. CONSIDERING THE CLEARING SKIES AND THE
WARM START...I POPULATED MAX TEMPS WITH THE MAV MOS GUIDANCE WHICH
RAISES THE MAX TEMPS 3 TO 5 DEGREES TODAY...WITH THE GREATEST
INCREASE OVER THE NC MOUNTAINS.

AS OF 645 AM EDT...ALL LINGERING DEFORMATION ZONE LIGHT RAIN HAS
DISSIPATED SOUTHEAST OF CHARLOTTE...SO POPS HAVE BEEN REMOVED ON THE
LATEST UPDATE. OTHERWISE...WATER VAPOR IMAGERY SHOWS THE SWIRLING
UPPER LOW MOVING OVER THE OFFSHORE WATERS EAST OF SAVANNAH THIS
MORNING. AS THIS UPPER VORTEX MOVES FARTHER OFFSHORE TODAY...RIDGING
WILL BUILD IN FROM THE WEST. GRADUAL SCATTERING OF THE CLOUDS WILL
ALLOW TEMPS TO REBOUND DESPITE THE LINGERING SFC HIGH PRES RIDGE
REMAINING IN PLACE. THE NAM HAS MORE EASTERLY FLOW MOISTURE AT 850
MB TONIGHT...BUT THE PREFERRED GFS/ECM CAMP KEEP THE MOISTURE
CONFINED MORE TO THE COASTAL PLAIN. EXPECT MAXES IN THE 60S THIS
AFTN AND MINS IN THE 40S TONIGHT.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM EDT SUNDAY...THE SHALLOW UPPER RIDGE WILL MOVE MORE
SQUARELY OVER THE REGION ON MONDAY...WHILE SFC HIGH PRESSURE SLOWLY
WEAKENS. ANTICIPATE MAXES TO REBOUND TO NEAR OR SLIGHTLY ABOVE
CLIMO. THE NEXT UPSTREAM TROUGH AXIS EJECTING EASTWARD FROM THE
PLAINS WILL APPROACH THE APPALACHIANS MON NIGHT AND CROSS THE
FORECAST AREA ON TUE ALONG WITH AN ATTENDANT COLD FRONT. INSTABILITY
WILL BUBBLE UP IN PIEDMONT SECTIONS TO SUPPORT PRE/FRONTAL AFTN TSRA
TUE...BUT SHEAR PROFILES APPEAR TOO WEAK FOR MUCH OF A SEVERE
THREAT. SHOWER CHANCES WILL END QUICKLY TUE EVENING...WITH MIN TEMPS
FALLING INTO THE UPPER 30S AT SOME HIGHER RIDGE TOPS EARLY WED
MORNING. HOWEVER...NO FROST OR FREEZE IS EXPECTED.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...A SHARP UPR RIDGE AXIS WILL CROSS THE AREA
THURSDAY....FOLLOWED BY ANOTHER POTENT SHORTWAVE TROF...WHICH WILL
LIFT NE INTO THE GREAT LAKES ON FRIDAY. AT THE SFC...DRY HIGH PRES
BUILDS IN FROM THE NORTH WEDNESDAY AND THURSDAY...GRADUALLY SHIFTING
SOUTHEAST OF THE AREA TO ALLOW AN INCREASING RETURN FLOW ATOP THE
CWFA BY FRIDAY. LOW PRES DEEPENS OVER THE WESTERN GREAT LAKES
THURSDAY INTO FRIDAY...WITH A TRAILING COLD FRONT PUSHING ACRS THE
OH/TN VLYS. MODELS ARE IN GOOD AGREEMENT ON THE FRONT PUSHING THRU
THE CWFA ON FRIDAY WITH A LITTLE MORE INSTBY/SHEAR AND FORCING TO
WORK WITH COMPARED TO THE FRONT THAT IS EXPECTED TO CROSS ON
TUESDAY. STILL...IT DOES LOOK LIKE MOISTURE WILL STILL BE SOMEWHAT
LIMITED...AND THAT FAR OUT IN THE EXTENDED...THE SEVERE WX THREAT IS
STILL UNCERTAIN. THE FRONT SHUD PUSH THRU THE AREA BY EARLY
SATURDAY...WITH DRY WX. TEMPS LOOK TO BE A CATEGORY OR TWO COOLER
THAN TUESDAY FOR BOTH WEDNESDAY AND THURSDAY...WHICH IS NEAR NORMAL.
THEN TEMPS WARM BACK ABOVE NORMAL FOR FRIDAY AND SATURDAY.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
AT KCLT...WITH ALL DEFORMATION ZONE LIGHT RAIN SAFELY SE OF THE
TERMINAL AREA AT ISSUANCE TIME...ONLY ISSUE WILL BE ANY LINGERING
VFR CIGS. EXPECT STEADY N TO NE FLOW THIS MORNING...BUT WITH
INCREASING GUSTS ABOVE 20 KT WITH MIXING THROUGH THE COURSE OF THE
DAY. ANY MORNING VFR CIGS WILL SCATTER BEFORE AFTN. WILL CONTINUE TO
LEAN TOWARD DRIER GFS/ECM VERSUS NAM SHOWING 850 MB MOISTURE ON
EASTERLY FLOW TONIGHT. IF NO STRATOCUMULUS ARRIVE ON THE EASTERLY
FLOW...THERE IS A SMALL CHANCE OF VSBY RESTRICTIONS IN FOG TOWARD
DAYBREAK MONDAY.

ELSEWHERE...PESKY STRATOCUMULUS LAYER AT 6 TO 8 KT WILL STEADILY
THIN AND SCATTER THIS MORNING...WITH MAINLY HIGHER CLOUDS LEFT
THROUGH THE REST OF THE DAY. EXPECT OCCASIONAL GUSTS ON NE FLOW AT
THE UPSTATE TAF SITES TODAY...ESPECIALLY PICKING UP WITH MIXING BY
LATE MORNING. THE NAM IS MORE AGGRESSIVE WITH VFR STRATOCUMULUS
ADVECTING BACK INTO THE REGION ON EASTERLY FLOW TONIGHT...BUT THE
DRIER GFS/ECM SOLUTIONS ARE PREFERRED.

OUTLOOK...DRY HIGH PRES WILL DEVELOP THROUGH MONDAY. A FAIRLY WET
FRONTAL SYSTEM...WITH PIEDMONT THUNDERSTORMS...IS EXPECTED ON
TUE...WITH DRYING RETURNING MID WEEK.

CONFIDENCE TABLE...

            13-19Z        19-01Z        01-07Z        07-13Z
KCLT       HIGH 100%     HIGH 100%     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 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     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...ARK
NEAR TERM...HG/MCAVOY
SHORT TERM...HG
LONG TERM...ARK
AVIATION...HG






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