-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KGSP 151051
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
651 AM EDT WED MAY 15 2013

.SYNOPSIS...
A WARM AIR MASS WILL REMAIN OVER THE REGION THROUGH THE REST OF THE
WEEK. LIGHT SOUTHWEST WINDS WILL SUPPLY HIGHER HUMIDITY VALUES EACH
DAY THIS PERIOD. A MID LEVEL DISTURBANCE WILL ARRIVE OVER THE REGION
ON THURSDAY AND WILL REMAIN INTO FRIDAY. AN UNSETTLED PATTERN WILL
CONTINUE ACROSS THE REGION THIS WEEKEND THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF 645 AM EDT...DAYBREAK OBSERVATIONS FROM THE HIGH ELEVATIONS OF
THE NORTHERN NORTH CAROLINA MOUNTAINS CONTINUE TO SHOW SOME GUSTS IN
THE 30 TO 40 MPH RANGE. THE ASSOCIATED 850 MB JET RIDING OVER THE
RIDGE IN A WARM ADVECTION PATTERN SHOULD PULL EAST OF THE
APPALACHIANS THROUGH THE LATER MORNING HOURS. WILL KEEP THE CURRENT
SPS FOR 40+ GUSTS ABOVE 4500 FEET IN PLACE ACROSS THE NRN MTNS
THROUGH 12Z.

OTHERWISE...THE FLAT UPPER RIDGE WILL PERSIST OVER THE AREA TODAY AS
A CLOSED LOW PRES SYSTEM MOVES SLOWLY E ACROSS THE SOUTHERN PLAINS.
THE RESULTANT WESTERLY LOW LEVEL FLOW WILL PRODUCE DOWNSLOPE WARMING
EAST OF THE MTNS TODAY...WITH A LEE TROUGH LIKELY STRENGTHENING. A
FEW SREF MEMBERS AS WELL AS THE OPERATIONAL GFS HAVE ISOLATED
SHOWERS LATE TODAY IN THE LEE TROUGH AXIS. MODEL PROFILES INDICATE
FAIRLY DECENT SFC BASED CAPE VALUES AROUND 1000 J/KG. HOWEVER...LOW
LEVEL CONVERGENCE IN THE LEE TROUGH SHOULD BE TOO WEAK TO PROVIDE
MUCH TRIGGERING GIVEN THE RELATIVELY HIGH LFC HEIGHTS. MAX TEMPS
WILL SURGE TO 7 TO 10 DEGREES ABOVE NORMAL IN MOST LOCATIONS THIS
AFTN.

THE H5 LOW WILL MEANDER INTO THE MID MS RIVER VALLEY TONIGHT...WITH
ALL ATTENDANT SHORTWAVE ENERGY STAYING W OF THE FORECAST AREA
THROUGH THE PERIOD. EXPECT MAINLY AN INCREASE IN HIGH CLOUDS FROM
THE W OVERNIGHT...WITH MIN TEMPERATURES 1 TO 2 CATEGORIES ABOVE
NORMAL.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 225 AM WEDNESDAY...BROAD MID LEVEL RIDGING WILL REMAIN OVER
THE FORECAST AREA BY SUNRISE THURSDAY. DURING THE AFTERNOON AND
EVENING...THE H5 TROUGH WILL RIPPLE ACROSS THE SOUTHERN MISSISSIPPI
RIVER VALLEY...RESULTING IN FALLING HEIGHTS ACROSS THE SOUTHERN
APPALACHIANS. AT THE SFC...A WEST TO EAST FRONT WILL BECOMING
STATIONARY ACROSS THE MID APPALACHIANS AND MID ATLANTIC STATES...WITH
HIGH PRESSURE ACROSS THE SOUTHEAST. FORECAST SOUNDINGS INDICATE
FAIRLY MILD TEMPERATURES BELOW H5 WITH DEEP WEST WINDS. A CONSENSUS
OF MOS GUIDANCE SUPPORTS HIGHS WITHIN THE MTN VALLEYS IN THE LOW 80S
WITH MID TO UPPER 80S EAST...DEWPOINTS IN THE LOW TO MID 50S.
FORECAST SOUNDINGS ALSO INDICATES CIN VALUES BETWEEN 50-100 J/KG
EAST OF THE MTNS. I WILL FORECAST CHC POPS ACROSS THE MTNS FOR
SHRA/TSRA...FAVORING THE TN LINE FOR THE GREATEST COVERAGE. EAST OF
THE MTNS...INHIBITION SHOULD KEEP DEEP CONVECTION LIMITED TO ISO
COVERAGE. CONVECTION IS FORECAST TO SLOWLY ASHE OUT DURING THE
EVENING HOURS. CLOUD COVER AND MILE LLVL THICKNESSES WILL FAVOR MIN
TEMPERATURES AROUND 3 TO 5 DEGREES ABOVE NORMAL.

FRIDAY...THE H5 TROF OR CLOSED LOW IS EXPECTED TO SLIDE OVER THE
FORECAST AREA DURING THE AFTERNOON. SHORT RANGE MODELS SHOW VERY
LITTLE CHANGE IN THE SFC FEATURES FROM THURSDAY.
HOWEVER...INCREASING MOISTURE AND GRADUALLY RISING DEWPOINTS SHOULD
PROVIDE SLIGHT INCREASE IN CONDITIONAL INSTABILITY WITH SHALLOW CIN
LAYER. I WILL FORECAST CHC POPS ACROSS THE NC AND MTN ZONES...SCHC
ELSEWHERE. HIGH TEMPERATURES WILL LIKELY RANGE VERY CLOSE TO
THURSDAY VALUES.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...MEDIUM RANGE GUIDANCE INDICATES THAT
UNSETTLED ZONAL FLOW WILL REMAIN OVER THE CWA DURING THE
WEEKEND...SHALLOW RIDGING EXPECTED EARLY NEXT WEEK. THE GFS APPEARS
VERY CHAOTIC WITH A FEW PASSAGES OF MCS FEATURES ACROSS KY/TN/NC.
THE ECMWF APPEARS LESS ACTIVE WITH MCS/S...BUT DOES INDICATE A RIPE
ENVIRONMENT FOR DIURNAL CONVECTION. I WILL USE A BLEND OF BOTH
SOLUTIONS...FORECASTING CHC POPS PEAKING DURING THE HEAT OF THE
AFTERNOON...ONLY FADING TO SCHC AT NIGHT...COVERAGE GREATEST OVER
THE MTNS. TEMPERATURES WILL FEATURE LITTLE CHANGE FROM DAY TO
DAY...REMAINING 3 TO 5 DEGREES ABOVE NORMAL.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE THROUGH THE TAF
PERIOD. WESTERLY FLOW OVER THE MTNS WILL MAINTAIN A LEE TROUGH E OF
THE BLUE RIDGE TODAY...WITH WINDS ADJUSTING TO SW AT THE FOOTHILLS
TAF SITES AS WELL AS KCLT. LOW END GUSTS OF 17 TO 19 KT ARE EXPECTED
WITH PEAK MIXING THIS AFTN. MAINLY FEW TO SCT MID AND HIGH CLOUDS
ARE ANTICIPATED...BUT HIGH BASED CONVECTIVE CUMULUS MAY DEVELOP IN
THE LEE TROUGH CONVERGENCE AXIS THIS AFTERNOON...ESPECIALLY FROM
KGSP TO KCLT. ALTHOUGH THERE IS SOME CAPE IN PROFILES AROUND THE
REGION...FORCING FROM LEE TROUGH CONVERGENCE SHOULD BE TOO WEAK TO
OVERCOME THE NEGATIVE ENERGY AREA IN SOUNDINGS TODAY. EXPECT LIGHT
SW FLOW TONIGHT...WITH HIGH CLOUDS INCREASING FROM THE W.

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

CONFIDENCE TABLE...

            11-17Z        17-23Z        23-05Z        05-11Z
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
-- End Changed Discussion --

&&

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

&&

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