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000
FXUS62 KGSP 161826
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
226 PM EDT SUN JUN 16 2013

.SYNOPSIS...
A COLD FRONT WILL SLOWLY CROSS THE OHIO VALLEY TO START THE WEEK AS
A SOUTHWESTERLY FLOW BRINGS MOISTURE FROM THE GULF. EXPECT THE FRONT
TO STALL FROM WEST TO EAST JUST SOUTH OF OUR REGION AND SLOWLY
DISSIPATE IN THE SECOND HALF OF THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 220 PM EDT...WATER VAPOR IMAGERY SHOWS A SHORTWAVE BACK ACROSS
AR/MO WITH MORE OF A CHANNELED SPEED MAX ACROSS MIDDLE TN. THE NAM
AND GFS BOTH BRING THIS ENERGY ACROSS THE MOUNTAINS A LITTLE AFTER
00 UTC. MORNING SOUNDINGS STILL HAD A RESPECTABLE INVERSION BETWEN
700-800 MB...AND IT/S NO SURPRISE THAT CONVECTION HASN/T INITIATED
YET. BUT WE SHOULD SEE SHOWERS AND STORMS BEGIN TO POP OVER THE
MOUNTAINS OVER THE NEXT COUPLE HOURS AS HEIGHTS FALL. IT WILL
PROBABLY TAKE UNTIL SOMETIME BETWEEN 8 PM AND MIDNIGHT BEFORE SCT
CONVECTION REALLY BEGINS TO MAKE AN EASTWARD PUSH. THE CONVECTION
ALLOWING MODELS AREN/T IN GREAT AGREEMENT IN HOW CONVECTION EVOLVES
OVERNIGHT...OFTEN A SIGN THAT WE WON/T SEE A GREAT DEAL OF COVERAGE.
HOWEVER...THE MOS IS GENERALLY IN THE LIKELY RANGE OVER THE MTNS AND
FOOTHILLS...AND I/VE FOLLOWED THAT TREND. POPS OVER THE ERN ZONES
WILL HOLD BETWEEN 30 AND 40 PERCENT OVERNIGHT...THOUGH I DOUBT
ANYTHING WILL DEVELOP THERE UNTIL AFTER SUNSET.

MONDAY IS ALSO NOT A HIGH CONFIDENCE FORECAST. WE WILL CERTAINLY SEE
SCT SHRA/TSTMS...BUT THE GFS HAS THE REGION UNDER WEAK NVA AS THE
WAVE THAT CROSSES THE FA TONIGHT MOVES OFF THE COAST. WE WILL BE
UNDER CYCLONIC CURVATURE AND BY LATE DAY SOME WEAK PVA DOES DEVELOP
AGAIN. BUT EXACTLY HOW AND WHERE CONVECTION EVOLVES ISN/T ALL THAT
CLEAR ATTM. REGARDLESS...WITH WEAK LAPSE RATES...A MOIST ATMOSPHERE
AND ONLY ABOUT 10 KTS OF SPEED SHEAR...SEVERE CHANCES WILL BE LOW
BOTH TONIGHT AND MONDAY.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AT 230 PM EDT SUNDAY...A SLOWLY PROGRESSIVE MEAN UPPER TROUGH AXIS
WILL BE OVER THE EASTERN HALF OF THE NATION FROM MONDAY NIGHT
THROUGH WEDNESDAY. A SHORTWAVE WILL CROSS THE SOUTHERN APPALACHIANS
ON TUESDAY...FOLLOWED BY ANOTHER ON WEDNESDAY.

A NEARLY STATIONARY BAND OF MOISTURE EXTENDING FROM THE COAST TO THE
MOUNTAINS WILL BE OVER OUR AREA ON MONDAY NIGHT THROUGH TUESDAY NIGHT
A SURFACE WAVE ORGANIZES IN THE MID MS RIVER VALLEY MONDAY NIGHT...
THEN MOVES INTO THE SOUTHERN APPALACHIANS ON TUESDAY...AND OFF THE
COAST WEDNESDAY.

MODEL TIME HEIGHTS SHOW DEEP MOISTURE OVER OUR AREA AHEAD OF THE
WAVE...BUT WITH LITTLE TO NO ISENTROPIC UPGLIDE. A LIGHT LOW LEVEL
FLOW VEERS FROM SW TO W...SHIFTING WEAK UPSLOPE FLOW FROM THE SOUTH
FACING BLUE RIDGE ESCARPMENT...TO THE TN BORER. MODEST AMOUNTS OF
CAPE AND SHEAR WILL BE PRESENT. LOW LEVEL MOISTURE MAY LINGER
THROUGH WEDNESDAY...AS A BACK DOOR FRONT MOVES IN FROM THE NORTH ON
THE HEELS OF THE DEPARTING SURFACE WAVE.

TEMPERATURES WILL EXHIBIT A LOWER THEN NORMAL DIURNAL RANGE DUE TO
CLOUD COVER.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 215 PM EDT SUNDAY...THE MEDIUM RANGE FORECAST PERIOD WILL HAVE
TYPICAL PM CONVECTION FOR THIS TIME OF YEAR BUT TEMPERATURES A BIT
ON THE COOL SIDE. THE COLD FRONT WILL BE TO OUR SOUTH AS SURFACE
HIGH PRESSURE TRANSITS FROM WESTERN PA WEDNESDAY NIGHT TO OFF THE
JERSEY COAST THURSDAY NIGHT. DURING THIS TIME A LIGHT NORTHEAST FLOW
WILL USHER IN COOLER THAN NORMAL TEMPERATURES WITH HIGHS ON THURSDAY
ABOUT 3 CATEGORIES BELOW NORMAL. MINOR SHORTWAVES WILL BE ROUNDING
THE TOP OF THE UPPER RIDGE CENTERED NEAR TEXAS COMBINED WITH
AFTERNOON HEATING BRINGS CONVECTION. LOOKING VERTICALLY...THE WIND
WILL GENERALLY BE 10 KNOTS OR LESS IN THE SECOND HALF OF THE WEEK
UNTIL YOU GET TO AROUND 500MB. THE ATMOSPHERE WILL BE RATHER STABLE
THURSDAY AND FRIDAY WITH GREATEST INSTABILITY OVER UPPER SAVANNAH
VALLEY WILL RANGE FROM 800 TO 1100 ON THURSDAY. AFTERNOON CAPES A
LITTLE HIGHER SATURDAY AND SUNDAY. THE LOW AMPLITUDE UPPER TROUGH
WHICH HAD AXIS ALONG THE EAST COAST BACK IN MID WEEK WILL BE
TRANSITIONING OFF THE EAST COAST FOR NEXT WEEKEND WITH THE UPPER
RIDGE ONLY PROGRESSING EAST FROM TEXAS TO PERHAPS ARKANSAS BY THE
END OF THIS CURRENT FORECAST PERIOD SUNDAY NIGHT. BY THAT TIME
TEMPERATURES WILL BE GETTING CLOSE TO NORMAL.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
AT KCLT...CU FIELD HAS DEVELOPED AGAIN THIS AFTN. EXPECTING IT TO
RISE TO AROUND 5KFT OVER THE NEXT COUPLE HOURS BUT PERSIST THROUGH
SUNSET. SHRA/TSTMS WILL DEVELOP OVER THE MTNS LATE DAY AND SLOWLY
MOVE EAST. THINK BEST CHANCES AT AIRFIELD WON/T DEVELOP TIL LATE
TONIGHT. SOME GUIDANCE HINTS AT LOW CLOUDS...BUT NON OF THE RAW
GUIDANCE...SAVE THE NAM...HAVE ANYTHING LOW. I TOOK CIGS DOWN TO
3000 FEET...BUT THAT/S ALL. WITH SHOWERS IN THE AREA AND MOIST
AIR...CIGS WILL BE SLOW TO RISE ON MONDAY. WINDS WILL BE OUT THE
SOUTHWEST FOR THE MOST PART THROUGH THE PERIOD.

ELSEWHERE...SIMILAR CONDITIONS TO KCLT ELSEWHERE THIS AFTN. KAVL
COULD SEE TSTMS IN THE VICINITY BY AROUND 20-22 UTC...WITH COVERAGE
INCREASING THROUGH THE EVENING. NOT EXPECTING ANYTHING OVER THE
UPSTATE UNTIL AFTER 00 UTC WITH BEST COVERAGE STARTING CLOSER TO
MIDNIGHT AS AN UPPER TROUGH MOVES THROUGH THE REGION. I HAVE CIGS
GOING DOWN TO 3KFT LATE TONIGHT. DOESN/T LOOK LIKE A FAVORABLE
SITUATION FOR ANYTHING LOWER THAN THAT.

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...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH 100%     HIGH 100%     HIGH  91%     HIGH  83%
KGSP       HIGH 100%     HIGH 100%     HIGH  88%     MED   75%
KAVL       HIGH 100%     HIGH 100%     HIGH  86%     MED   67%
KHKY       HIGH 100%     HIGH 100%     HIGH  82%     MED   72%
KGMU       HIGH 100%     HIGH 100%     HIGH  88%     MED   75%
KAND       HIGH 100%     HIGH 100%     HIGH  82%     MED   66%

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...DEO
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...DEO
AVIATION...MCAVOY