000
FXUS62 KGSP 160601
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
201 AM EDT THU MAY 16 2013

.SYNOPSIS...
HIGH PRESSURE SITUATED OFF THE CAROLINA COAST WILL DRIVE
SOUTHWESTERLY FLOW FOR THE WESTERN CAROLINAS AND NORTHEAST
GEORGIA...MAINTAINING A WARM AND MOIST AIRMASS THROUGHOUT THE
PERIOD. AN UPPER LEVEL DISTURBANCE WILL APPROACH ON THURSDAY AND
KEEP THE PATTERN UNSETTLED THROUGH EARLY NEXT WEEK...WITH A COLD
FRONT EXPECTED TO CROSS THE REGION BY LATE TUESDAY OR EARLY
WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM EDT...WATER VAPOR IMAGERY SHOWS A 500 MB LOW CENTER
MEANDERING E ACROSS OK EARLY THIS MORNING. THIS FEATURE WILL
GRADUALLY OPEN UP AND CONTINUE MOVING EAST...STEADILY BREAKING DOWN
THE RIDGE OVER THE APPALACHIANS AND SPREADING MID AND HIGH LEVEL
CLOUD INTO THE FORECAST AREA. SCATTERED CONVECTION SHOULD DEVELOP
FIRST TODAY OVER THE SW MTNS OF NC WHERE A LOW LEVEL SW UPSLOPE FLOW
AND WEAK VORT MAXIMA ALOFT WILL PROVIDE SOME TRIGGERING. SOME
CONVECTIVE INHIBITION WILL REMAIN IN MODEL PROFILES TODAY...BUT THIS
SHOULD BE OVERCOME IN THE MTNS WITH THE WEAK FORCING...WITH A FEW
STRONG TSTMS THEN POSSIBLE IN THE FAIRLY STEEP LAPSE RATES ALOFT.
WESTERLY STEERING FLOW WILL CARRY SCATTERED MTN CONVECTION INTO THE
FOOTHILLS THIS AFTERNOON...AND ISOLD COVERAGE MAY SURVIVE EAST INTO
THE PIEDMONT LATE IN THE DAY. DESPITE THE INCREASING CLOUDS...EXPECT
MAXES 5 DEGREES OR MORE ABOVE NORMAL.

ALTHOUGH THE CONVECTION WILL WANE WITH THE LOSS OF DAYTIME HEATING
TONIGHT...ISOLATED SHOWERS COULD LINGER OVERNIGHT OVER THE NC MTNS
AS WEAK ENERGY AHEAD OF THE OPENING UPPER LOW PUSHES INTO THE
APPALACHIANS. EXPECT WARM MINS UNDER THE CLOUD COVER...WITH MAINLY
50S MTNS AND LOWER 60S PIEDMONT.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 215 PM WEDNESDAY...THE SHORT TERM WILL FEATURE DIURNALLY
DRIVEN CONVECTION ALONG WITH A WEAK ZONAL UPPER FLOW THROUGH SAT.
THE MODELS FORECAST A COUPLE WEAK IMPULSES MOVING ACROSS THE AREA AS
WELL. PARTLY CLOUDY CONDITIONS SHOULD PREVAIL THROUGH
FRIDAY...WITH SCATTERED SHOWERS/THUDNERSTORMS DEVELOPING OVER THE
MOUNTAINS BY EARLY AFTERNOON...AND IN THE FOOTHILLS AND PIEDMONT
AREAS DURING THE MID TO LATE AFTERNOON HOURS. CONVECTION SHOULD
WANE AGAIN FRI NIGHT...THEN SCATTERED SHOWERS/STORMS SHOULD FIRE
BACK UP SAT AFTERNOON ACROSS THE FORECAST AREA. WARM LOW LEVEL
THICKNESS VALUES WILL SUPPORT ABOVE AVERAGE TEMPS ON FRI AND SAT.
USED A BLEND OF GUIDANCE SOURCES TO GENERATE TEMP FIELDS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 140 PM WEDNESDAY...WPC FAVORED A BLEND OF THE 06Z GFS/00Z ECM
ENSEMBLES FOR THE MEDIUM RANGE. THE EXPECTATION IS FOR AN AMPLIFYING
UPPER RIDGE TO DEVELOP OVER THE EASTERN U.S. THE FIRST PART OF NEXT
WEEK AS A SIGNIFICANT UPPER TROUGH DEVELOPS OVER THE CENTRAL PART OF
THE COUNTRY. THE WEEKEND LOOKS LIKE IT WILL BE QUITE UNSETTLED AS A
REMNANT VORT MAX MOVES ACROSS THE AREA SAT NIGHT INTO SUNDAY...AND A
BACKDOOR COLD FRONT APPROACHES. THE LATEST GUIDANCE DOES KEEP THE
FRONT JUST TO THE NE OF THE AREA SAT NIGHT INTO SUN. HENCE...WILL
HAVE FAIRLY ROBUST POPS IN THE SAT NIGHT/SUN TIMEFRAME WITH THE
HIGHEST VALUES OVER THE NORTHERN REACHES OF THE FORECAST AREA. AS
THE UPPER RIDGE BUILDS NEXT WEEK...THE PRECIP SHOULD BECOME MORE
DIURNAL IN NATURE WITH THE HIGHEST COVERAGE OF SHOWERS/STORMS OVER
THE CLIMATOLOGICAL FAVORED MOUNTAINS. WITH MORE IN THE WAY OF
CLOUDINESS EXPECTED...MAX TEMPS SHOULD AVERAGE NEAR NORMAL SUN AND
MON...BUT RISE TO ABOUT A CATEGORY ABOVE AVERAGE FOR TUE AND WED.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...MID AND HIGH CLOUDS WILL INCREASE THROUGH THE PERIOD AS AN
UPPER LEVEL LOW PRESSURE SYSTEM BREAKS DOWN THE RIDGE FROM THE WEST.
SCATTERED MOUNTAIN CONVECTION TODAY COULD MAKE A RUN EASTWARD IN THE
WESTERLY STEERING FLOW...BUT THERE IS ONLY A SLIGHT CHANCE OF IT
SURVIVING EAST TO KCLT LATE DAY. IF IT DID...IT WOULD PROBABLY
IMPACT THE AIRFIELD 22Z TO 00Z. SW WINDS WILL INCREASE WITH MIXING
TODAY BUT REMAIN GENERALLY 10 KT OR LESS WITH ONLY LIMITED GUSTS.

ELSEWHERE...MID AND HIGH CLOUD CEILINGS WILL DEVELOP AND PERSIST
THROUGH THE PERIOD AS A 500 MB LOW CENTER OPENS UP TO THE W.
SCATTERED CONVECTION SHOULD DEVELOP OVER THE SW NC MTNS BY MIDDAY
AND STEER E...WITH THE BEST CHANCE OF THUNDER AT KAVL. SCT ACTIVITY
WILL LIKELY SPILL OUT INTO THE FOOTHILLS DURING THE AFTN...WITH
PROB30 FEATURED FOR TSRA FROM KGMU TO KGSP...AND MAINLY VCSH NEAR
KHKY. ANTICIPATE STEADY SW FLOW THROUGH THE PERIOD AT MAINLY 5 TO 10
KT...WITH ISOLATED LOW END GUSTS POSSIBLE DURING AFTERNOON MIXING.

OUTLOOK...SHOWER AND THUNDERSTORM COVERAGE...AND ASSOCIATED
RESTRICTIONS...WILL GRADUALLY INCREASE FRIDAY THROUGH MONDAY.

CONFIDENCE TABLE...

            06-12Z        12-18Z        18-24Z        00-06Z
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...LEV
NEAR TERM...HG
SHORT TERM...LG
LONG TERM...LG
AVIATION...HG