000
FXUS62 KGSP 142335
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
735 PM EDT TUE MAY 14 2013

.SYNOPSIS...
HIGH PRESSURE WILL PUMP WARM MOIST AIR OVER THE REGION THROUGH
WEDNESDAY..AHEAD OF A MID LEVEL DISTURBANCE THAT IS EXPECTED TO
RIPPLE OVER THE SOUTHERN APPALACHIANS ON THURSDAY. HIGH SHIFTS OFF
THE CAROLINA COAST FOR THE WEEKEND AS A COLD FRONT APPROACHES FROM
THE WEST DURING THE EARLY PART OF THE WEEK.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 730 PM...THERE HAS BEEN A BRIEF INCREASE IN MID CLOUD ACROSS
THE MTNS AND MOISTURE ENCOUNTERS SOME MTN WAVE ACTION. THESE MAY
CONTINUE THRU THE EVENING BEFORE DISSIPATING OVERNIGHT. A FEW OF
THESE MAY MOVE OUTSIDE OF THE MTNS...BUT MOSTLY CLEAR CONDITIONS
EXPECTED. WIND GUSTS SHUD END OUTSIDE OF THE MTNS AND IN THE
VALLEYS...BUT WILL CONTINUE ACROSS THE RIDGES. LATEST GUIDANCE IS A
LITTLE COOLER THAN PREV FCST FOR LOWS...AND HAVE TRENDED IN THAT
DIRECTION.

AS OF 425 PM...STRATOCU IS REMAINING WELL NORTH OF THE CWFA THIS
AFTERNOON. SOME MTN CU IS DEVELOPING...BUT WELL UNDER EXPECTATIONS.
HAVE UPDATED SKY COVER TO GO MORE OPTIMISTIC THIS AFTERNOON AND
EVENING. COULD STILL SEE SOME OF THAT NRN STRATOCU SWING ACROSS
OVERNIGHT...BUT SHOULD BE LESS THAN PREVIOUSLY EXPECTED.
OTHERWISE...GOING FCST ON TRACK.

AS OF EARLY AFTERNOON ACROSS THE UPSTATE AND THE NC MOUNTAINS...
CONDITIONS REMAIN RATHER PLEASANT AS ABUNDANT SUNSHINE AND
TEMPERATURES NEAR THE 70 DEGREE MARK PREVAILED ACROSS THE MAJORITY
OF THE REGION.

OVER THE NEXT 24 HOURS...A SURFACE RIDGE OF HIGH PRESSURE CENTERED
OFF THE EAST COAST WILL CONTINUE TO PROMOTE A MODEST WARM AIR
ADVECTION REGION ACROSS THE AREA.  SOUTH TO SOUTHWESTERLY FLOW...AND
MOSTLY SUNNY SKIES WILL ALLOW FOR TEMPERATURES ON WEDNESDAY TO REACH
INTO THE MID TO UPPER 80S ACROSS THE UPSTATE OF SOUTH CAROLINA...AND
LOWER 80S ELSEWHERE.  AS A DEEP UPPER LEVEL TROF CONTINUES TO EJECT
OUT FROM THE EAST COAST...RIDGING WILL STRENGTHEN THUS PROVIDING
SUBSIDENCE...WHICH COMBINED WITH LOW-MID LEVEL CAPPING WILL PREVENT
ANY CONVECTIVE PROCESSES TO TAKE PLACE ON WEDNESDAY.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 215 PM TUESDAY...A FLAT UPPER RIDGE INITIALLY OVER THE AREA
WED NIGHT WILL MOVE EAST ON THU AS A WEAKENING UPPER TROUGH
APPROACHES AND THEN MOVES EAST OF THE AREA THU NIGHT. AS THE TROUGH
REACHES THE AREA THU...THE LOWERING UPPER HEIGHTS SHOULD BE
SUFFICIENT TO ALLOW FOR CONVECTIVE INTIATION DURING THE AFTERNOON
HOURS. THE CONVECTION SHOULD FAVOR THE HIGH TERRAIN OVER WESTERN NC
AND NE GA. EAST OF THE MOUNTAINS...FORECAST SOUNDINGS SHOW QUITE A
BIT OF CIN TO OVERCOME IN THE LOWER LEVELS OF THE COLUMN ON THU.
THIS SHOULD LIMIT ANY CONVECTION OUTSIDE THE MOUNTAINS TO JUST
ISOLATED TO WIDELY SCATTERED COVERAGE. THE CONVECTION IS EXPECTED TO
WANE THU EVENING AS THE TROUGH MOVES EAST AND THE ATMOSPHERE COOLS.
MODEL TIME HEIGHTS SHOW THAT MOISTURE INCREASES SUBSTANTIALLY
THROUGH THE COLUMN ON FRIDAY WHICH WILL RESULT IN MORE CLOUDINESS.
ALSO...WEAK UPSLOPE FLOW WILL PRODUCE SCATTERED AFTERNOON SHOWERS
AND THUNDERSTORMS OVER THE MOUNTAINS...WITH A FEW MOVING OUT OVER THE
FOOHILLS AND PIEDMONT DURING THE LATE AFTEROON HOURS. TEMPS WILL BE
QUITE WARM ON THU WHERE A BLEND OF GUIDANCE PRODUCES MAX TEMPS IN
THE MID TO UPPER 80S OUTSIDE OF THE MOUNTAINS...AND LOW 80S MOUNTAIN
VALLEYS. MORE CLOUDS ON FRIDAY WILL SERVE TO TRIM A FEW DEGREES OFF
MAX TEMPS WITH HIGHS IN THE LOW TO MID 80S OUTSIDE OF THE MOUNTAINS
AND 75 TO 80 MOUNTAIN VALLEYS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 145 PM TUESDAY...A WEAK UPPER RIDGE IS FORECAST TO PREVAIL
FROM THE GULF OF MEX...NE THROUGH THE TN VALLEY SAT THROUGH SUN. THE
RIDGE IS THEN EXPECTED TO MOVE TO THE EAST COAST ON MON AS AN UPPER
TROUGH DEVLOPS OVER THE CENTRAL PORTION OF THE COUNTRY. AT THE
SURFACE...THE WESTERN EXTENSION OF THE WESTERN ATLANTIC SUBTROPICAL
RIDGE WILL DOMINATE THROUGH THE PERIOD. A BACKDOOR COLD FRONT EARLY
IN THE WEEKEND IS EXPECTED TO STALL SOMEWHERE OVER EASTERN NC AND
THEN MOVE NORTH AS A WARM FRONT. THEREFORE...THE FORECAST WILL
FEATURE WARM TEMPERATURES AND MAINLY DIURNAL CONVECTION FAVORING THE
MOUNTAINS. A MCS STILL CAN NOT BE COMPLETELY RULED OUT IN THE SAT
NIGHT TIMEFRAME AS AN UPPER PULSE MOVES OVER THE UPPER RIDGE.
HENCE...HAVE MAINTAINED SOME LOW CHANCE POPS OVER NORTHERN SECTIONS
SAT NIGHT. OTHERWISE...JUST SCATTERED TYPE POPS ARE FORECAST EACH
AFTERNOON AND EVENING. TEMPS ARE FORECAST TO BE ABOUT A CATEGORY
ABOVE AVERAGE EACH DAY.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF
PERIOD. SOUTHWEST WINDS WILL CONTINUE OUTSIDE OF THE MTNS OVERNIGHT
WHILE WINDS BECOME NLY AT KAVL. HAS BEEN AN INCREASE IN MID CLOUD
OVER THE MTNS AS MOISTURE IS AFFECTED BY MTN WAVE ACTION. CANNOT
RULE OUT A BRIEF CIG AT KAVL OR EVEN KHKY. HOWEVER...EXPECT THE BULK
OF THE TAF SITES TO BE CIG FREE. THE CLOUDS SHUD DISSIPATE OVERNIGHT
BUT MAY NOT GO AWAY COMPLETELY. SWLY WINDS PICK BACK UP DURING THE
DAY WED WITH LOW END GUSTS POSSIBLE DURING THE AFTERNOON. SOME LOW
BASED MID CLOUD OR HIGH BASED STRATOCU DEVELOPS FOR WED AFTERNOON.

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...

            23-05Z        05-11Z        11-17Z        17-23Z
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

&&

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

&&

$$
SYNOPSIS...PAT
NEAR TERM...CDG/PM/RWH
SHORT TERM...LG
LONG TERM...LG
AVIATION...RWH