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000
FXUS62 KGSP 140711
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
311 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/...
AS OF 225 AM EDT...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. HIGH CLOUDS HAVE DEVELOPED IN
THE NW FLOW ACROSS THE REGION EARLY THIS MORNING...WITH IR SATELLITE
IMAGERY SHOWING ADDITIONAL MID AND HIGH CLOUDS MOVING SE THROUGH THE
OH VALLEY TOWARD THE SRN APPALACHIANS. ANY THICKER MID/HIGH CLOUDS
SHOULD BE SUFFICIENTLY DELAYED TO ALLOW AT LEAST SCATTERED FROST TO
FORM IN MTN VALLEY SECTIONS OF THE CURRENT FROST ADVISORY AREA.
OTHERWISE...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 REGION
SHOULD REMAIN DRY THROUGH THE PERIOD UNDER A BUILDING UPPER
RIDGE...WITH MIN TEMPERATURES REBOUNDING MORE THAN 10 DEGREES
TONIGHT.

&&

.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 /07Z TUESDAY THROUGH SATURDAY/...
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 NRLY 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...

            07-13Z        13-19Z        19-01Z        01-07Z
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

&&

.CLIMATE...
RECORD LOW TEMPERATURES THIS MORNING...

AVL...30 1895
CLT...41 1917
GSP...41 1960

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR NCZ033-048>053-
     058-059-062-063.
SC...NONE.

&&

$$
SYNOPSIS...NED
NEAR TERM...HG
SHORT TERM...NED
LONG TERM...NED
AVIATION...HG
CLIMATE...HG