Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 041805
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
205 PM EDT SAT JUL 4 2015

.SYNOPSIS...
A BROAD UPPER LEVEL TROUGH WILL REMAIN OVER THE SOUTHEAST THROUGH
MONDAY...PROVIDING LIFT AND MAINTAINING ELEVATED RAIN AND
THUNDERSTORM CHANCES EACH DAY. SLIGHTLY DRIER CONDITIONS RETURN
TUESDAY AND WEDNESDAY...BEFORE ANOTHER FRONT PUSHES ACROSS THE
SOUTHERN APPALACHIANS BY THE END OF THE WORK WEEK.

&&

.NEAR TERM /THROUGH SUNDAY/...
AS OF 145 PM EDT...NEARLY THE ENTIRE FORECAST AREA REMAINS FAIRLY
STABLE THIS AFTERNOON UNDER ABUNDANT MID CLOUDS WITH PATCHY LIGHT
SHRA FALLING INTERMITTENTLY. THE MOUNTAIN SHOWERS ARE STARTING TO
SHOW SOME VERTICAL DEVELOPMENT...AND A FEW BREAKS OVER THE NC
FOOTHILLS AND THE ERN FRINGE HOLD OUT SOME CHANCE FOR ISOLD TSTMS TO
REDEVELOP IN LINE WITH THE HRRR. OTHERWISE...500 MB HEIGHTS CONTINUE
TO FALL ACROSS THE MS RIVER VALLEY THIS AFTERNOON...AND HEIGHT FALLS
WILL CONTINUE EASTWARD ACROSS TN TONIGHT THROUGH SUNDAY.
INTERMITTENT SHORTWAVES WILL PIVOT EAST THROUGH THE FORECAST AREA
AROUND THE UPPER TROUGH DURING THIS PERIOD. THE ENTRANCE REGION OF
AN UPPER JETLET WILL ALSO REMAIN PARKED JUST WEST OF THE SRN
APPALACHIANS THROUGH THE NEAR TERM...ALTHOUGH THE JETLET LOOKS A BIT
WEAKER THAN IN PREVIOUS MODEL RUNS. AT THE SURFACE...A STALLED FRONT
REMAINS DRAPED NORTH AND WEST OF THE AREA THIS AFTN...WITH A
LINGERING SFC TROUGH AXIS STRETCHED OUT TO THE SOUTH IN THE BETTER
INSTABILITY...AND THESE FEATURES WILL MOVE LITTLE. GIVEN ALL OF
THESE VARIOUS FORCING MECHANISMS...CONTINUED WSW UPSLOPE INTO THE SW
MTNS...AND PRECIPITABLE WATER VALUES RUNNING 1.5 TO 1.75 INCHES OVER
THE AREA...ANTICIPATE THE PRECIPITATION COVERAGE TO MAKE A COMEBACK
FROM THE WEST TONIGHT THROUGH SUNDAY. OTHER THAN ANY LINGERING
DIURNAL SHRA/TSRA...A FAIRLY SHARP W TO E GRADIENT WILL BE FEATURED
ON POPS...WITH THE SW MOUNTAINS THE CLEAR FOCUS FOR ANY HIGHER END
UPSLOPE QPF. NO CHANGES ARE NEEDED AT PRESENT TO THE FFA. WILL
CONTINUE A SMALLER THAN CLIMO RANGE ON MIN/MAX TEMPS.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 315 AM INDEPENDENCE DAY...ON SUNDAY THE KEY FEATURES WILL
CONTINUE TO BE A BROAD UPPER SHORTWAVE CENTERED OVER THE UPPER TENN
VALLEY...AND A WEAK LOW LEVEL BOUNDARY OVER THE CAROLINAS.
DIFFERENCES IN THE PATTERN ARE MINOR COMPARED TO SATURDAY. DEEP
MOISTURE WILL ACTUALLY BE SLIGHTLY BETTER...CHARACTERIZED BY PWAT
VALUES ABOVE THE 90TH PERCENTILE PER SPC RAOB CLIMO. THIS IS IN PART
DUE TO A BETTER GULF CONNECTION...ON ACCOUNT OF LOW LEVEL WINDS
BACKING TO SOUTHWEST IMMEDIATELY AHEAD OF THE UPPER TROUGH. THIS WILL
ENHANCE UPSLOPE FORCING INTO THE SW PORTION OF THE CWFA AS WELL.
FURTHERMORE WIND PROFILES WILL FEATURE WEAK AND NEARLY UNIDIRECTIONAL
SHEAR. THE CONCERN ACCORDINGLY WILL CONTINUE TO BE FOR THUNDERSTORMS
PRODUCING HEAVY RAIN AND POTENTIALLY TRAINING. WITH THE INGREDIENTS
CONTINUING TO BE IN PLACE FOR A FLOOD THREAT...WE HAVE EXTENDED THE
FLASH FLOOD WATCH ANOTHER 24 HOURS...NOW ENDING AT 00Z MONDAY. ALSO
THE AREA HAS EXPANDED TO ALL OF JACKSON CO...OCONEE CO...AND THE
REMAINDER OF OUR NE GA COUNTIES. THESE AREAS HAVE THE LOWEST FFG
VALUES AS WELL AS GREATER POTENTIAL FOR UPSLOPE ENHANCEMENT. MAX
TEMPS WILL CONTINUE TO BE BELOW CLIMO...SIMILAR TO SATURDAY.

ON MONDAY THE TROUGH WILL LIFT NEWD ACRS THE AREA...AND BEGIN TO
MERGE WITH A LARGER SCALE SHORTWAVE ENTERING THE UPPER MISSISSIPPI
VALLEY. THE INFLUENCE OF THE TROUGH ON LIFT WILL BE LESSER...AND
PROFILES ARE LESS CONDUCIVE TO HEAVY RAIN PRODUCTION. HOWEVER
ISOLATED FLOODING CANNOT BE RULED OUT. POPS IN GENERAL WILL BE LOWER
PARTICULARLY OVER THE SRN HALF OF THE CWFA. DESPITE LESS CLOUD COVER
AND PRECIP...TEMPS MAY BE SLIGHTLY COOLER DUE TO LOWER THICKNESSES
BENEATH THE TROUGH. SO VALUES STILL TOP OUT A CATEGORY OR TWO BELOW
CLIMO.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 130 AM INDEPENDENCE DAY...HEIGHTS START TO RISE TUESDAY AS
UPPER LOW IS ABSORBED INTO THE NRN STREAM AND SUBTROPICAL RIDGE
REGAINS STRENGTH OVER THE SOUTHEAST. MIDLEVEL LAPSE RATES ACCORDINGLY
WEAKEN FROM DAY TO DAY...SO DIURNAL CONVECTIVE POTENTIAL WILL RETURN
TO NEAR CLIMO...WITH MAINLY JUST SHOWERS MENTIONED. AS A SHORTWAVE
MOVES ACRS ONTARIO/QUEBEC A COLD FRONT WILL SAG INTO THE OHIO VALLEY
WED...WITH HIGH PRESSURE BUILDING EWD BEHIND IT. THE PRESENCE OF THIS
FEATURE LIMITS OUR CONFIDENCE GOING FORWARD. IT IS A SEASONABLY WEAK
BOUNDARY...HOWEVER GLOBAL MODELS HINT THAT A WAVE WILL DEVELOP ALONG
IT SOMEWHERE TO OUR WEST...THOUGH THEY DIFFER IN THE DETAILS. GFS/GEM
DEPICT THE WAVE TRACKING ALONG OR N OF THE OHIO RIVER...MAINLY
KEEPING THE FRONT ON OUR NWRN FRINGE. THE EC ON THE OTHER HAND
DEVELOPS A STRONGER WAVE OVER THE SRN PLAINS...LEADING IT TO DELAY
ITS PUSH ACRS THE MTNS UNTIL FRI. HOWEVER THIS ALSO IMPLIES A MORE
BULLISH FRONT. WILL BRING POPS BACK UP SLIGHTLY THU AND THU NIGHT.
TEMPS WILL WARM BACK TO NEAR NORMAL BY WED.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT...VFR CLOUDS AND LIGHT SHRA HAVE KEPT THE PIEDMONT FAIRLY
STABLE THIS AFTERNOON...AND MAINLY INTERMITTENT -SHRA ARE EXPECTED
THROUGH LATE AFTERNOON. THE COVERAGE OF PRECIPITATION SHOULD SHIFT
BACK TOWARD THE MOUNTAINS TONIGHT INTO SUNDAY AS THE UPPER TROUGH
SHARPENS UP WEST OF THE MTN CHAIN. WILL ONCE AGAIN HINT AT FEW TO
SCT LOW STRATUS BUT NONE OF THE MODEL PROFILES OR MOS HAVE ANY CIG
RESTRICTIONS TOWARD DAYBREAK SUNDAY. EXPECT OCNL SW GUSTS TO
CONTINUE UNTIL EARLY EVENING...WITH STEADIER SW FLOW LESS THAN 10 KT
THEREAFTER.

ELSEWHERE...SHOWER COVERAGE WILL STEADILY INCREASE IN THE MTNS AS
HEIGHTS FALL TO THE WEST OF THE APPALACHIANS...BUT COVERAGE REMAINS
MORE UNCERTAIN OVER THE FOOTHILLS WHERE PROFILES ARE FAIRLY STABLE.
ANTICIPATE VFR CONDITIONS INITIALLY...WITH TEMPO MVFR UNDER AT SHRA
AT KAVL. LOWER CIG RESTRICTIONS WILL BE POSSIBLE ONCE AGAIN TOWARD
DAYBREAK...BUT MORE CERTAIN AT KAVL WHERE MORE QPF IS EXPECTED. WILL
JUST HINT AT MVFR CIGS OVERNIGHT AT THE FOOTHILL SITES. SW WINDS
WILL GUST AT THE UPSTATE TAF SITES THROUGH LATE AFTN BEFORE SETTLING
DOWN TO STEADY SW LESS THAN 10 KT FOR THE REMAINDER OF THE PERIOD.
ANOTHER ROUND OF SHOWERS MAY MOVE UP THE MTNS/FOOTHILLS SUNDAY
MORNING...WITH MAINLY VCSH AT THE FOOTHILL SITES...AND MORE SOLID
SHRA WITH VCTS AT KAVL AFTER 15Z SUNDAY.

OUTLOOK...PRECIPITATION COVERAGE WILL REMAIN FAIRLY HIGH INTO SUNDAY
NIGHT BEFORE THE PATTERN GRADUALLY TRANSITIONS TO MORE DIURNAL
TIMING AND COVERAGE MONDAY THROUGH THURSDAY. WITH CONTINUED MOISTURE
IN THE AREA...RESTRICTIONS WILL BE POSSIBLE UNDER ANY HEAVIER
SHOWERS AND ALSO AROUND DAYBREAK.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH  98%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH  98%     HIGH  98%
KAVL       HIGH  92%     HIGH  86%     MED   63%     HIGH  84%
KHKY       HIGH 100%     HIGH 100%     HIGH  90%     HIGH  86%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH  97%     HIGH  98%

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...FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR GAZ010-017-018-
     026-028-029.
NC...FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR NCZ048-051-052-
     058-059-062-063.
SC...FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR SCZ001-004.

&&

$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...HG



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