Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 232344
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
744 PM EDT WED JUL 23 2014

.SYNOPSIS...
WEAK HIGH PRESSURE ATOP THE REGION WILL GIVE WAY TO A SURFACE FRONT
APPROACHING FROM THE NORTHWEST TONIGHT. THE FRONT IS EXPECTED TO
MOVE ACROSS THE CAROLINAS AND NORTH GEORGIA THURSDAY AFTERNOON AND
EVENING. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR FRIDAY AND
THE WEEKEND. ANOTHER FRONT IS EXPECTED TO PASS ON MONDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
AS OF 730 PM EDT...EVENING SHOWER AND THUNDERSTORM COVERAGE IS
SLOWLY STARTING TO WANE WITH THE LOSS OF DAYTIME HEATING.
HOWEVER...LIGHT SW UPSLOPE FLOW INTO THE MOUNTAINS...ALONG WITH
LINGERING TRIGGERING ALONG OLD OUTFLOW BOUNDARIES NEAR INTERSTATE 85
MAY WELL KEEP AT LEAST SCT TSTM COVERAGE GOING NEAR THE NC/SC BORDER
THROUGH MID EVENING. HEAVY RAIN WILL BE THE MAIN ISSUE WITH THESE
THUNDERSTORMS AS THE UPDRAFT STRENGTHS HAVE DIMINISHED. ANTICIPATE
SOME LOW CLOUDS AND FOG THROUGH THE EARLY MORNING HOURS WHERE HEAVY
RAIN FELL...AND ALSO THROUGHOUT THE MTN VALLEYS.

MORE WIDESPREAD CONVECTIVE COVERAGE ALONG THE APPROACHING COLD FRONT
STRETCHES FROM NASHVILLE TO CHARLESTON WV THIS EVENING. PRE/FRONTAL
SHRA/TSRA COULD REACH THE SRN APPALACHIANS BY DAYBREAK...BUT
COVERAGE WILL LIKELY INCREASE ACROSS THE MTNS LATER IN THE MORNING
AND THEN THROUGHOUT THE AREA THU AFTN. THE FRONTAL ZONE FORCING...A
DIGGING UPPER TROUGH...AND SBCAPES CAPES POOLING TO BETWEEN
1000-2000J DURING THE AFTERNOON WILL WARRANT CONTINUED LIKELY POPS
THROUGHOUT. SPC IS STILL JUST HIGHLIGHTING THE I-77 CORRIDOR
EASTWARD WITH A 5 PERCENT SEVERE THREAT ON THURSDAY. WITH SLIGHTLY
IMPROVING SHEAR...WOULD NOT BE SURPRISED TO SEE A FEW SEVERE STORMS
THURSDAY AFTERNOON. MAX TEMPS ON THU WILL BE TEMPERED BY CLOUDS AND
CONVECTION SO THEY SHOULD BE A COUPLE DEGREES LOWER THAN TODAY.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM WED...COLD FRONT WILL CONTINUE TO PUSH THRU THE PIEDMONT
THURSDAY EVENING...WITH AXIS OF DEEP UPPER TROUGH MOVING THRU EARLY
FRI. POPS WILL DECLINE EAST OF THE MTNS FOLLOWING THE END OF
HEATING...WITH LLVL CONVERGENCE UNLIKELY TO OVERCOME THE INHIBITION
RESULTING FROM POOR LAPSE RATES ABOVE THE PBL. PROFILES FROM THE
HIGHER TERRAIN HOWEVER DO SHOW THE EFFECTS OF MIDLEVEL CAA FOLLOWING
THE FRONT...THUS A SCHC POP IS KEPT INTO EARLY FRI MRNG. GOING
FORWARD HOWEVER...HIGH PRESSURE EXPANDS OUT OF THE MIDWEST WHICH
SHOULD PROVIDE AT LEAST A WEAK SUBSIDENCE INVERSION TO CAP OFF MOST
DEEP CONVECTION FRI AND SAT. THE NAM AND A PORTION OF THE SREF
MEMBERS DO NOT SHOW THE INVERSION BEING STRONG ENOUGH TO KEEP THE
ENTIRE CWFA DRY DURING THIS TIME. WILL ADVERTISE SCHC POPS OVER THE
BLUE RIDGE FRI AS WELL AS IN THE LOWER PIEDMONT...WELL SE OF
I-85...WHERE THE HIGH WILL HAVE THE LEAST INFLUENCE. THERE IS BETTER
CONSENSUS FOR A DRY FCST SATURDAY...THOUGH BY THAT TIME THE HIGH HAS
BECOME INDISTINCT DUE TO THE UPPER FLOW BECOMING NEARLY ZONAL. POPS
THUS COULD BE EASILY REINTRODUCED FOR SAT IN SUBSEQUENT FCST
PACKAGES. TEMPS DURING THE SHORT RANGE WILL RETURN TO NEAR NORMAL AS
THICKNESS VALUES INCREASE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1215 PM WEDNESDAY...DURING THE LATTER HALF OF THE UPCOMING
WEEKEND...DIURNALLY ENHANCED TSTM ACTIVITY HAS THE OPPORTUNITY TO
BECOME CONSIDERABLE ON SUNDAY WITHIN DEVELOPING LLVL RETURN FLOW
REGIME UNDERNEATH PROGRESSIVELY LOWERING UPPER HEIGHTS. L/WV TROUGH
AXIS IS PROGGED TO CONTINUE TO DIG INTO THE SE CONUS THROUGH
MONDAY...EVENTUALLY FORCING A COLD FRONT ACRS THE REGION BY MONDAY
NIGHT. WITH PRONOUNCED UPPER LEVEL TROUGH ACRS THE ERN CONUS AND
A CONTINENTAL AIRMASS OVERSPREADING THE REGION...A NOTABLY DRY AND
COOLER FCST IS ON TAP FOR TUESDAY AND WEDNESDAY.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AT KCLT...TWO OUTFLOWS HAVE CONVERGED ON THE AIRFIELD THIS
EVENING...ONE FROM THE NW AND ONE FROM THE S. THE ONE FROM THE NW
APPEARS TO HAVE ARRIVED FIRST AND SHOULD WIN OUT FOR A SHORT WHILE
AS CONVECTION SOUTH OF THE TERMINAL HAS DIMINISHED. SHOWERS TRAINING
NE TOWARD THE AIRFIELD WILL LIKELY BRING -SHRA AT TIMES THROUGH 02Z
AND TURN WINDS BACK SW. WINDS WILL PREVAIL SW THROUGH THE LATER
EVENING HOURS...WITH SHRA COVERAGE WANING ACROSS THE REGION. MAINLY
SCT TO BKN VFR LEVEL CLOUDS ARE EXPECTED OVERNIGHT WELL AHEAD OF THE
COLD FRONT APPROACHING FROM THE WEST. MOISTURE AND FORCING WILL RAMP
BACK UP THROUGH THU...WITH VCSH WARRANTED AFTER 15Z AND THEN MORE
WIDESPREAD SHRA WITH SCT TSTMS THROUGH THE AFTN HOURS. RESTRICTIONS
WILL BE POSSIBLE UNDER ANY TSRA THROUGH THU AFTN.

ELSEWHERE...MID EVENING CONVECTION REMAINS LINED UP ALONG THE SRN
ESCARPMENT AREA...OCCASIONALLY ADVECTING OUT CLOSE TO KGMU AND
KGSP...WHERE ADDITIONAL CONVERAGE IS FORMING ALONG OLD OUTFLOWS.
WILL FEATURE VCTS FOR BOTH KGMU AND KGSP THROUGH 02Z...WITH MAINLY
JUST VCSH FROM KAVL TO KHKY...AND DRY CONDITIONS AT KAND. EXPECT
MAINLY VFR CIGS OVERNIGHT...EXCEPT FOR IFR LIKELY IN THE MTN VALLEYS
AFTER 06Z AND LIFR CIGS QUITE POSSIBLE AT KAVL AFTER 09Z.
PRECIPITATION COVERAGE WILL RAMP UP FROM THE WEST WITH THE ARRIVING
FRONT THROUGH THU...WITH COVERAGE FEATURED MAINLY DURING THE AFTN
HOURS. ANTICIPATE SW WINDS BECOMING MORE WESTERLY WITH TIME...EXCEPT
PERSISTENT NW FLOW AT KAVL.

OUTLOOK... SHOWERS AND THUNDERSTORMS WILL END THU EVENING AS A COLD
FRONT MOVES SOUTHEAST OF THE AREA. FRI AND SAT SHOULD BE QUIET AND
VFR...THE EXCEPTION WILL BE THE MOUNTAIN VALLEYS WHERE EARLY MORNING
FOG MAY OCCUR. THUNDERSTORMS WILL RETURN TO THE FORECAST FOR SUNDAY
AFTERNOON THROUGH MON AS ANOTHER COLD FRONT APPROACHES AND THEN
MOVES THROUGH THE AREA ON MON.

CONFIDENCE TABLE...

            23-05Z        05-11Z        11-17Z        17-23Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH  83%     HIGH  83%     HIGH  97%
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...CSH
NEAR TERM...HG/LG
SHORT TERM...WIMBERLEY
LONG TERM...CSH
AVIATION...HG/LG






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