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000
FXUS62 KGSP 170726
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
326 AM EDT MON JUN 17 2013

.SYNOPSIS...
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WEAK UPPER LEVEL DISTURBANCES WILL CROSS THE AREA FROM THE WEST
THROUGH MID WEEK AS A ZONE OF RELATIVELY ABUNDANT MOISTURE LAYS
DRAPED ACROSS THE AREA. SLIGHTLY DRIER HIGH PRESSURE WILL BUILD INTO
THE REGION THROUGH FRIDAY...WITH WARMER BERMUDA HIGH PRESSURE
DOMINATING THROUGH THE WEEKEND.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF 250 AM EDT MONDAY...CURRENT RADAR TRENDS INDICATE A LARGE
SHIELD OF STRATIFORM PRECIPITATION LOCATED ACROSS NORTHEAST GEORGIA
AND THE WESTERN UPSTATE REGION OF SOUTH CAROLINA.  OTHERWISE...BROAD
CYCLONIC FLOW WILL PROMOTE CONTINUED SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE PERIOD.  SHORT RANGE MODEL GUIDANCE INDICATES A
SERIES OF MID-UPPER LEVEL VORTICITY MAXIMA PASSING THROUGH THE
REGION OVER THE NEXT 18-24 HOURS.  IN RESPONSE...A MILDLY UNSTABLE
AIRMASS AT THE SURFACE WILL PROVIDE ENOUGH LOW LEVEL LIFTING
POTENTIAL FOR SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT MONDAY
MORNING. SOUNDINGS INDICATE SBCAPE VALUES GENERALLY RANGING FROM
500-1000 J/KG WITH THE HIGHEST VALUES LYING ACROSS WESTERN NORTH
CAROLINA DUE TO CURRENT SHOWER ACTIVITY WORKING OVER THE ATMOSPHERE
ACROSS THE UPSTATE AND NORTHEAST GEORGIA.  BY LATE MORNING TO EARLY
AFTERNOON...EXPECTING SKY COVER TO INCREASE AS THE COLUMN MOISTENS
THEREBY DECREASING SURFACE HEATING.  WITH THAT...MOST IF NOT ALL
ISOLATED THUNDERSTORM DEVELOPMENT WILL CEASE LEADING TO MORE OF A
STRATIFORM PRECIPITATION REGIME WITH EMBEDDED CLUSTERS OF HEAVIER
RAINFALL.  SHOWER ACTIVITY WILL DECREASE FROM NORTH TO SOUTH AS
UPPER LEVEL IMPULSES EXIT THE REGION ON MONDAY EVENING.  THE
OVERNIGHT HOURS OF TUESDAY MORNING SHOULD REMAIN MOSTLY DRY AS MODEL
GUIDANCE INDICATES A LULL IN THE SHOWER ACTIVITY.  TEMPERATURES
THROUGH THIS PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL FOR
HIGHS...AND SLIGHTLY ABOVE NORMAL FOR LOWS.
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&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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AT 315 AM EDT MON...A CLIPPER WAVE MOVING SE THROUGH THE MIDWEST ON
TUE WILL SHARPEN UP AN ERN TROUGH AXIS OVER THE APPALACHIANS TUE
NIGHT THROUGH WED. THE NUMERICAL MODELS ALL FEATURE WEAK SFC WAVES
AHEAD OF THE UPPER CLIPPER MOVING EAST ALONG THE LINGERING WEAK
BOUNDARY IN PLACE OVER THE FORECAST AREA. IN ADDITION...THE
STRONGEST RIGHT ENTRANCE REGION UPPER JET DIVERGENCE WILL CROSS THE
FORECAST AREA MAINLY TUE NIGHT INTO WED. THESE VARIOUS FORCING
MECHANISMS WILL COINCIDE WITH A ZONE OF RELATIVELY DEEP MOISTURE
ORIENTED W TO E ACROSS THE AREA TUE THROUGH MUCH OF WED. THIS WILL
REQUIRE SOLID CHC TO LOW END LIKELY POPS THROUGHOUT. THERE IS VERY
LIMITED SHEAR IN THE MODEL PROFILES TUE THROUGH WED...AND SFC BASED
INSTABILITY MAY ALSO BE LIMITED DESPITE THE HIGH DEWPOINTS BECAUSE
OF CLOUD COVER. LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREAT.
WILL CONTINUE TO FEATURE A SMALLER THAN CLIMO DIURNAL RANGE OF WARM
MIN TEMPS AND COOLER THAN NORMAL MAX TEMPS TUE THROUGH WED NIGHT
GIVEN THE CLOUD COVER AND PRECIP CHANCES.
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&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
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AS OF 320 AM EDT MONDAY...HEIGHTS WILL BUILD FROM THE W THU THROUGH
FRI AS A LARGE ANTICYCLONE TAKES UP RESIDENCE OVER THE SRN PLAINS.
HOWEVER...ENERGY TOPPING THE RIDGE COULD SPARK MCS ACITIVTY THAT MAY
MAKE A RUN TOWARD THE SRN APPALACHIANS LATE FRI/FRI NIGHT. THIS IS
QUITE UNCERTAIN AT PRESENT...SO WILL KEEP THE THUNDERSTORM FORECAST
ON A MORE TYPICAL SCATTERED DIURNAL PATTERN THU AND FRI AFTNS.

UPPER RIDGING WILL BECOME MORE DOMINANT THROUGH THE WEEKEND.
HOWEVER...LINGERING LOW LEVEL MOISTURE AND A SE ATLANTIC FETCH COULD
LEAD TO MORNING STRATUS EACH DAY. THERE WILL PERSIST A MAINLY
DIURNAL ISOLD TO SCT THUNDERSTORM THREAT...ESPECIALLY OVER THE MTNS.
MAXES WILL STEADILY RISE TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES BY
SUNDAY AFTN.
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&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
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AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH
THE ONLY EXCEPTIONS BEING LOWERING VISB ADJACENT TO ANY THUNDERSTORM
DEVELOPMENT ON MONDAY AFTERNOON.  IN THE NEAR TERM...DECIDED TO PULL
THE PREVIOUS SHRA TEMPO AS LATEST RADAR TRENDS SHOW A GRADUAL DECAY
IN ACTIVITY WELL TO THE WEST.  EXPECTING CIGS TO LOWER TO AROUND
10KFT AS UPPER SHORTWAVE TROF PASSES THROUGH TOMORROW MORNING.
LIKEWISE...A GRADUAL INCREASE IN COVERAGE OF SHOWER ACTIVITY IS
EXPECTED THUS PROMPTING MENTION OF -SHRA AROUND 15Z.  AS SOME
HEATING OCCURS DURING THE EARLY AFTERNOON HOURS...THERE WILL BE A
CHANCE FOR SOME RATHER DISORGANIZED CONVECTION LEADING TO PROB30 FOR
TSRA THROUGH THE AFTERNOON.  SOME LOWER BKN CIGS ARE POSSIBLE LATE
IN THE PERIOD DUE TO OVERSPREADING CONVECTIVE DEBRIS.  WINDS WILL
GENERALLY BE LIGHT AND SOUTHERLY.

ELSEWHERE...LOOK FOR VFR CONDITIONS TO PERSIST THROUGH THE TAF
PERIOD ASIDE FOR VISB RESTRICTIONS DUE TO THUNDERSTORM DEVELOPMENT
MONDAY AFTERNOON.  AS WITH KCLT ABOVE...EXPECTING COVERAGE OF
SHOWERS TO INCREASE THROUGH THE MORNING HOURS IN RESPONSE TO UPPER
TROF.  MODELS INDICATE THE BEST INSTABILITY TO BE AROUND THE 15-18Z
TIMEFRAME ACROSS THE FOOTHILLS OF NORTH CAROLINA...AND THE
UPSTATE/PIEDMONT REGIONS OF SOUTH CAROLINA.  THUS...WENT WITH TEMPO
GROUPS FOR TSRA AT ALL CORRESPONDING SITES FOR THIS PERIOD.  BEYOND
THAT... EXPECTING LESS THUNDERSTORM PERSISTENCE THUS REVERTED TO
-SHRA WITH VCTS MENTION IN THE TAFS.  SHOWER ACTIVITY WILL TAPER OFF
FROM NORTH TO SOUTH MONDAY EVENING THEREFORE KEPT VCSH AT ALL SOUTH
CAROLINA SITES.

OUTLOOK...THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED FLIGHT
RESTRICTIONS WILL INCREASE THROUGH TUE WITH THE ARRIVAL OF A FRONT.
CONDITIONS WILL REMAIN UNSETTLED THROUGH MUCH OF THE WEEK.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-07Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     MED   69%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     MED   69%
KAVL       HIGH  94%     HIGH  97%     HIGH 100%     MED   78%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     MED   69%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     MED   69%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     MED   69%

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
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&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

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