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000
FXUS62 KGSP 141421
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1021 AM EDT TUE MAY 14 2013

.SYNOPSIS...
A WARM AND MOIST AIR MASS WILL REMAIN OVER THE REGION THROUGH
WEDNESDAY. A MID LEVEL DISTURBANCE IS EXPECTED TO RIPPLE OVER THE
SOUTHERN APPALACHIANS THURSDAY INTO THURSDAY NIGHT. HIGH PRESSURE
WILL SHIFT OFF THE CAROLINA COAST FOR THE WEEKEND INTO THE EARLY
PART OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF MID MORNING ACROSS THE UPSTATE AND THE NC MOUNTAINS...MOSTLY
CLEAR CONDITIONS CONTINUE TO PREVAIL.  HOWEVER...DUE TO RECENT VISB
SATELLITE TRENDS...BUMPED UP SKY GRIDS ACROSS MAINLY WESTERN NORTH
CAROLINA.  OTHERWISE...FORECAST LOOKS TO BE ON TRACK AND NO OTHER
CHANGES WERE MADE.

REMAINDER OF PREVIOUS DISCUSSION...

OTHERWISE...DEEP LAYER NW FLOW BETWEEN THE DEPARTING E COAST TROUGH
AXIS AND A DEVELOPING RIDGE OVER THE MS RIVER VALLEY WILL CONTINUE
THROUGH THE NEAR TERM PERIOD. MAINLY TRANSIENT MID CLOUDS ARE
EXPECTED IN THE NW FLOW. SFC HIGH PRESSURE WILL MOVE TO THE SE COAST
TODAY...TURNING LOW LEVEL FLOW MORE SOUTHWESTERLY AND INCREASING MAX
TEMPS AT LEAST A COUPLE OF CATEGORIES OVER YESTERDAY.

SLIGHTLY DEEPER MOISTURE WILL PASS NORTH OF THE FORECAST AREA LATER
TODAY THROUGH TONIGHT ALONG A WARM FRONT. HOWEVER...OUR AREA SHOULD
REMAIN DRY THROUGH THE PERIOD UNDER A BUILDING UPPER RIDGE...WITH
MIN TEMPERATURES REBOUNDING MORE THAN 10 DEGREES TONIGHT.
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&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 250 AM TUESDAY...THE AXIS OF A H5 RIDGE IS EXPECTED TO SLIDE
ACROSS THE SOUTHEAST U.S. ON WEDNESDAY. AT THE SFC...HIGH PRESSURE
CENTER OVER THE WESTERN ATLANTIC SHOULD RIDGE WEST ACROSS THE DEEP
SOUTH AS A WARM FRONT REMAINS ACROSS THE MID ATLANTIC STATES. THIS
PATTERN WILL SUPPORT WARM RETURN FLOW ACROSS THE FORECAST
AREA...ALLOWING H85 TEMPS TO REACH AROUND 18C. THE COMBINATION OF
MILD LLVL THICKNESSES...WARM MIXED LAYER TEMPERATURE PROFILES...AND
STRONG INSOLATION SHOULD SUPPORT THE WARMEST TEMPERATURES SO FAR
THIS YEAR WED AFTERNOON. I WILL FORECAST MID 80S WITHIN THE MTN
VALLEYS AND UPPER 80S EAST. FORECAST SOUNDINGS INDICATE WEAK
CONDITIONAL INSTABILITY ACROSS THE REGION DURING THE AFTERNOON...BUT
LLVL CIN LAYER SHOULD PREVENT FREE CONVECTION.

BROAD MID LEVEL RIDGING SHOULD REMAIN ACROSS THE CWA WEDNESDAY
NIGHT. TO THE WEST...H5 TROF WILL DIG ACROSS THE MID AND SOUTHERN
MISSISSIPPI RIVER VALLEY. SKY CONDITIONS WILL TRANSITION FROM NEARLY
CLEAR DURING LATE WEDS EVENING...TO GOSSAMER CIRRUS EARLY THURSDAY
MORNING...BUILDING TO 50 TO 60 PERCENT THICK CIRRUS OVER THE MTNS BY
DAYBREAK. INCREASING HIGH CLOUDS AND LINGERING MILD LLVL THICKNESSES
SHOULD FAVOR MIN TEMPS AROUND 5 DEGREES ABOVE NORMAL.

THURSDAY...SHORT RANGE MODELS AGREE THAT THE MID LEVEL TROUGH WILL
RIPPLE OVER MIDDLE TN AND NRN AL/GA BY THE LATE AFTERNOON. THE
APPROACHING TROUGH SHOULD RESULT IN INCREASING CLOUD COVER ACROSS
THE FORECAST AREA...BECOMING MOSTLY CLOUDY BY LATE AFTERNOON.
DESPITE THE FALLING MID LEVEL HEIGHTS...TEMPERATURES BELOW H5 REMAIN
VERY MILD. THE COMBINATION OF HIGH TEMPERATURES 5 DEGREES ABOVE
NORMAL AND DEWPOINTS IN THE L50S MAY ONLY YIELD CAPE VALUES 500 J/KG
OR LESS. I WILL EXPECT SCT SHRA/TSRA ACROSS THE MTNS AND I-40 WITH
ISO COVERAGE ACROSS THE PIEDMONT.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 310 AM TUESDAY...FRIDAY THROUGH MONDAY...MID LEVEL RIDGE WILL
GRADUALLY DEVELOP OVER BERMUDA AS A L/W TROF DEVELOPS OVER THE GREAT
PLAINS. AT THE SFC...MULTIPLE BOUNDARIES SLIP ACROSS THE CENTRAL
APPALACHIANS AND MID ATLANTIC STATES...BUT REMAIN NORTH OF THE CWA.
GIVEN AN UNSETTLED MID LEVEL FLOW AND SLOW INCREASE IN SFC
DEWPOINTS...CONDITIONS THROUGH THE EXTENDED APPEAR RIPE FOR DIURNAL
CONVECTION...ESPECIALLY OVER THE MTNS. TEMPERATURES WILL AVERAGE
AROUND 5 DEGREES ABOVE NORMAL.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
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AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE THROUGH THE
PERIOD. EXPECT MAINLY FEW TO SCT MID AND HIGH CLOUDS...ESPECIALLY AT
THE NC TAF LOCATIONS...AS A WARM FRONT PASSES NORTH OF THE REGION.
LIGHT NE FLOW EARLY THIS MORNING WILL TURN SW LATE THIS
MORNING...WITH A STEADY 10 KT OR LESS OF S TO SW FLOW LIKELY
THROUGHOUT THE AFTN AS SFC HIGH PRES MOVES OFF THE SE COAST.

OUTLOOK...VFR CONDITIONS ARE GENERALLY EXPECTED THROUGH THE REST OF
THE WEEK. HOWEVER...SCATTERED AFTN AND EVENING THUNDERSTORMS WILL BE
POSSIBLE FROM THURSDAY ONWARD.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-14Z
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
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&&

.GSP WATCHES/WARNINGS/ADVISORIES...
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GA...NONE.
NC...NONE.
SC...NONE.
-- End Changed Discussion --

&&

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