Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
247 PM EDT THU AUG 7 2014

.SYNOPSIS...
A WEAK STATIONARY FRONT WILL REMAIN MAINLY JUST SOUTH OF OUR REGION
OVER CENTRAL GEORGIA AND THE SOUTHERN TIP OF SOUTH CAROLINA INTO THE
FIRST PART OF NEXT WEEK. A SERIES OF LOW PRESSURE CENTERS WILL
MOVE EAST ALONG THE FRONT...INCREASING THE CHANCE OF SHOWERS AND
THUNDERSTORMS THIS WEEKEND WITH CONTINUED RAINFALL THROUGH EARLY
NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
AS OF MID AFTERNOON...SATELLITE IMAGERY SHOWS SOME ENHANCED CU ON
THE RIDGETOPS OVER THE BALSAMS AND SMOKIES...SO THE FCST DEVELOPMENT
OF ISOLATED SHOWERS/STORMS STILL LOOKS LIKE A DISTINCT POSSIBILITY.
WILL KEEP THE LOW POP GOING INTO THE EARLY PART OF THE EVENING
MAINLY OVER THE SRN MOUNTAINS OF NC.

THE BALANCE OF THE OVERNIGHT HOURS SHOULD BE RELATIVELY QUIET ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...AT HIGH AND MID LEVEL
MOISTURE INCREASES FROM THE WEST. THE MODELS SUGGEST A WARM-FRONTAL
LIKE FEATURE APPROACHING FROM THE WEST AND REACHING THE MTNS BEFORE
DAYBREAK...AS INDICATED BY A RIBBON OF LOW LEVEL CONVERGENCE. THIS
MAY BRING SOME PRECIP INTO THE SW MOUNTAINS BY 12Z FRIDAY...BUT
THINK PRECIP WILL NOT DEVELOP AS FAR E AS THE BLUE RIDGE IN NC AS
LOW LEVEL FLOW REMAINS MORE NE AND WEAK...AND FLOW AT 850 IS LIGHT
FROM THE S...OR NOT PARTICULARLY FAVORABLE TO DEVELOPING PRECIP THAT
FAR EAST THAT EARLY. TEMPS WERE NUDGED UP A BIT WITH INCREASING
CLOUD COVER.

FOR FRIDAY...MOST OF THE UPPER FORCING APPEARS TO BE CONCENTRATED IN
THE OHIO VALLEY IN THE MORNING AND INTO THE MID ATLANTIC REGION IN
THE AFTERNOON. THE WARM FRONTAL FEATURE LIFTS ACROSS THE MTNS AND IS
ESTABLISHED MORE TO OUR N BY THE END OF THE DAY. THE MODELS GIVE THE
APPEARANCE OF A MATURE CYCLONE WRAPPED UP OVER THE MID MS VALLEY
WITH THE WESTERN CAROLINAS IN A WARM SECTOR IN THE AFTERNOON.
INCREASING MOISTURE FLUX IN THE AFTERNOON...DEEPER MOISTURE...AND AN
IMPROVEMENT OF FORCING SUGGEST THAT CONVECTIVE PRECIP COVERAGE WILL
INCREASE FROM THE WEST THROUGH THE DAY. THE PRECIP PROBABILITY FROM
THE OLD FCST WAS HIGHER THAN THE LATEST GUIDANCE BUT SEE NO REASON
TO LOWER IT FOR NOW. EXPECT THAT A CATEGORICAL POP MIGHT BE NEEDED
FOR THE MTNS IF THE MODEL TREND CONTINUES. HIGH TEMPS LOOK A BIT
TRICKY AND DEPEND ON DEVELOPMENT OF CLOUDS AND PRECIP TO KEEP THEM
SUPPRESSED ACROSS THE NC FOOTHILLS AND NW PIEDMONT...BECAUSE THE
SURFACE HIGH IS NOT IN A FAVORABLE SPOT TO LOCK IN ANY COLD AIR
DAMMING.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 2 PM THURS...FRIDAY NIGHT...THE LARGE SHIELD OF RAINFALL THAT
DEVELOPED DURING THE DAY ON FRIDAY WILL LIKELY CONTINUE THROUGH MOST
OF FRIDAY NIGHT...SUPPORTED BY A LAYER OF WEAK INSTABILITY AND
SOUTHEAST UPSLOPE FLOW. RAINFALL RATES MAY INCREASE DURING THE
PREDAWN HOURS...AS THE NAM INDICATES THAT A BAND OF CONVECTION MAY
ARRIVE OVER THE NC MOUNTAINS AROUND SUNRISE SATURDAY. ON
SATURDAY...A BROAD SURFACE LOW PRESSURE SYSTEM WILL REMAIN OVER THE
WESTERN OHIO RIVER VALLEY. CIRCULATION AROUND THE LOW WILL RESULT IN
DEEP GULF AND ATLANTIC MOISTURE ACROSS THE SOUTHERN APPALACHIAN
REGION. FORECASTS SOUNDINGS FROM THE GFS INDICATE THE PRECIPITABLE
WATER VALUES WILL EXCEED 2 INCHES WITH K INDEX RANGING FROM 35 TO
37. HOWEVER...BOTH THE NAM AND GFS INDICATE THAT THE BEST OVERLAP
MOISTURE AND FORCING WILL REMAIN NORTHEAST OF THE FORECAST
AREA...GENERATING 2 INCHES OF QPF FOR 6 HOURS. BASED ON THE NAM AND
GFS...QPF ACROSS THE NC MOUNTAINS AND EAST FACING SLOPES MAY
GENERALLY RANGE FROM ONE QUARTER TO THREE QUARTERS OF AN INCH EVERY
3 HOURS. WILL POPULATE THE QPF USING WPC GUIDANCE...YIELDING A TOTAL
QPF FOR SATURDAY RANGING FROM ONE INCH ACROSS THE UPPER SAVANNAH
RIVER VALLEY TO AN INCH AND THREE QUARTERS ALONG AND EAST OF I-77.
ONE CHALLENGE OF SATURDAY/S FORECAST IS TEMPS. I WILL FAVOR THE
COOLER MEMBERS OF PREFERRED MOS GUIDANCE...INDICATING A RANGE IN
HIGHS FROM THE LOW 70S ACROSS THE MTNS TO THE LOW TO MID 80S ACROSS
THE LAKELANDS.

ON SUNDAY...A VERY INTERESTING SURFACE PATTERN EMERGES DURING THE
DAYLIGHT HOURS. SHORT RANGE MODELS INDICATE THAT A COASTAL LOW WILL
DEVELOP IN THE MORNING...POSSIBLY STRENGTHENING THROUGH THE
AFTERNOON. IN ADDITION...WEAK HIGH PRESSURE COULD RIDGE SOUTHEAST
ACROSS THE NC FOOTHILLS DURING THE AFTERNOON HOURS. THIS SURFACE
PATTERN WILL FAVOR LIGHTER QPF...RESULTING FROM LOW LEVEL WEST WINDS
ACROSS THE NC/SC STATE LINE. HOWEVER...CLOUDS AND RAINFALL WILL
LIKELY PERSIST ACROSS THE NC FOOTHILLS RESULTING FROM LOW LEVEL
ISENTROPIC LIFT. IN ADDITION...FORECAST SOUNDINGS SHOW AFTERNOON
CAPE VALUES WILL RANGE FROM 500 TO 800 J/KG. WILL FORECAST HIGH
CHANCE TO LIKELY POPS DURING THE PERIOD OF ISENTROPIC LIFT AND
PASSAGE OF MID LEVEL SHORT WAVE. THE WEAK CAD PATTERN COULD RESULT
IN HIGH TEMPS 1 OR 2 DEGREES COOLER THAN SATURDAY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 205 PM THURSDAY...AN UPPER RIDGE WILL BE IN PLACE OVER THE
EAST COASTAL STATES TO START THE EXTENDED AT 00Z MONDAY IN A SPLIT
FLOW PATTERN WITH SHORTWAVES RIDING ACROSS THE CAROLINAS. A SURFACE
HIGH PRESSURE WILL RESIDE AT THAT TIME OVER THE NE STATES RIDGING
SOUTH THROUGH THE MID ATLANTIC. THE UPPER RIDGE SLOWLY MOVES EAST
WITH AXIS OVER THE CANADIAN MARITIMES MONDAY AS AN UPPER TROUGH
PUSHES SOUTH FROM CENTRAL CANADA. THE STATIONARY FRONT WHICH HAS
BEEN ROUGHLY WEST TO EAST ACROSS OUR REGION FOR DAYS AT THIS POINT
SHOULD SLOWLY DISSIPATE IN THE FIRST HALF OF NEXT WEEK.  AS THIS
HAPPENS...THE COLD FRONT MOVING FROM THE NW WHICH WILL BE THE
LEADING EDGE OF SOME COOLER AND DRIER AIR APPROACHES THE CAROLINAS
AND NE GA IN MID WEEK. THE GFS AND ECMWF BOTH HAVE THE COLD FRONT
ARRIVING WEDNESDAY NIGHT WITH DRIER WEATHER ON THURSDAY.

A STRONG WAVE OF LOW PRESSURE WILL LINGER ALONG THE CAROLINA COAST
SUNDAY NIGHT THROUGH AT LEAST MONDAY EVENING WITH STRONG LOW LEVEL
NE FLOW AROUND THE LOW ACROSS THE CAROLINA PIEDMONT AND FOOTHILLS.
AS THE LOW MOVES MORE OFFSHORE ON TUES...THE NE FLOW WILL BE
REPLACED BY A SW TO W LOW LEVEL FLOW WITH WEAK HIGH PRESSURE OVER
THE EASTERN GULF. SMALL LOW PRESSURE CENTERS CONTINUE TO MOVE WEST
TO EAST ACROSS THE SE STATES AHEAD OF THE APPROACHING COLD FRONT.
THE BEST INSTABILITY ACCORDING TO THE GFS WILL BE LATE TUESDAY AND
NEAR I-85 IN THE CAROLINAS LATE WED WITH CAPES ABOVE 1500. THE FRONT
SLOWS AND STALLS SOUTH OF OUR REGION LATE THURS AND THERE WILL BE
SLIGHT TO SMALL CHANCE POPS SOUTH OF I-85 WITH WAVES OF LOW PRESSURE
PASSING WEST TO EAST TO THE SOUTH OF OUR FORECAST AREA.

HIGH TEMPERATURES WILL BE AROUND 8 DEGREES BELOW NORMAL
MONDAY...ONLY ABOUT A CATEGORY BELOW NORMAL...JUST BELOW ON WED THEN
8 TO 10 BELOW FOR HIGHS THURS ALONG AND NORTH OF I-85. LOWS WILL BE
CLOSER IN LINE TO NORMAL TEMPS.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...VFR THROUGH THE PERIOD. A DEEPENING BOUNDARY LAYER SHOULD
LIFT FEW/SCT STRATOCU UP TO 060 BY MID AFTERNOON SO THAT IS WHERE
THE TAF BEGINS. MOISTURE SHOULD INCREASE...MAINLY AT MID LEVELS
DURING THE OVERNIGHT HOURS...SO AN ALTOCU CEILING IS INTRODUCED
AROUND DAYBREAK ON FRIDAY. THE MOVEMENT OF A WEAK SURFACE HIGH
SHOULD BRING A LIGHT WIND AROUND FROM THE N OR NE THIS AFTERNOON...
GRADUALLY TO THE EAST OVERNIGHT...WITH A SHIFT TO ESE AROUND SUNRISE
FRIDAY. LAMP GUIDANCE SUGGESTS THAT SOME FOG MAY DEVELOP AROUND
DAYBREAK ACROSS THE NC PIEDMONT...BUT NOT CONFIDENT ENOUGH TO
INCLUDE THAT IN THE TAF. FAIRLY CONFIDENT THAT DEEP CONVECTION AND
LOWER CLOUDS WILL NOT REACH THE TERMINAL UNTIL AFTER THE END OF THE
TAF PERIOD.

ELSEWHERE...SIMILAR TO KCLT INTO THE OVERNIGHT HOURS. A FEW SHOWERS
COULD DEVELOP ALONG THE RIDGETOPS TO THE W/SW OF KAVL...BUT WILL
KEEP THIS OUT OF THE TAF AT KAVL/KAND. THE LAMP GUIDANCE MIGHT YET
AGAIN BE OVERDOING THE AMOUNT/THICKNESS OF FOG ACROSS THE MTNS. KEPT
THE MVFR PREVAILING AT KAVL LATE TONIGHT AND THEN INCLUDED SOME IFR
VSBY/CIG AT DAYBREAK WITH THE EXPECTATION THAT CROSSOVER TEMP WILL
BE REACHED. OTHERWISE...MOISTURE WILL INCREASE AT MID LEVELS
OVERNIGHT REQUIRING A MID LEVEL CEILING. THE MODELS SUGGEST A WARM
FRONT OF SORTS DEVELOPING AND MOVING ACROSS THE MTNS IN THE
MORNING...AND THE MODELS RESPOND TO LOW LEVEL FORCING AND THE
PASSAGE OF A WEAK LEAD SHORT WAVE BY DEVELOPING PRECIP MAINLY OVER
THE MTNS AND EASTERLY UPSLOPE PARTS NEAR THE BLUE RIDGE BY LATE
MORNING. TIMING IS NOT CERTAIN...SO THIS WILL BE HANDLED WITH A
PROB30 AFTER 15Z.

OUTLOOK...MOISTURE RETURNS FROM LOW PRES TO THE WEST ON FRIDAY
AFTERNOON. EXPECT NUMEROUS SHOWERS AND STORMS TO DEVELOP ACROSS THE
AREA BY FRIDAY EVENING...WITH ASSOCIATED RESTRICTIONS. A PERSISTENT
MOIST PATTERN WILL SET UP FRI THROUGH THE WEEKEND TO GENERATE
WIDESPREAD RESTRICTIONS WITH LOW CLOUDS AND RAIN. THESE CONDITIONS
MAY BE VERY SLOW TO CLEAR INTO EARLY NEXT WEEK.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH  95%     HIGH  87%     HIGH  90%
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...DEO
NEAR TERM...PM
SHORT TERM...NED/STAARMANN
LONG TERM...DEO
AVIATION...PM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
402 PM EDT THU AUG 7 2014

GAZ018-026-028-029-NCZ033-035>037-048>053-056>059-068>072-082-
501>510-SCZ004>014-019-082015-
STEPHENS-FRANKLIN-HART-ELBERT-AVERY-ALEXANDER-IREDELL-DAVIE-MADISON-
YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-CATAWBA-ROWAN-GRAHAM-
NORTHERN JACKSON-CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-
UNION NC-CALDWELL MOUNTAINS-GREATER CALDWELL-BURKE MOUNTAINS-
GREATER BURKE-MCDOWELL MOUNTAINS-EASTERN MCDOWELL-
RUTHERFORD MOUNTAINS-GREATER RUTHERFORD-POLK MOUNTAINS-EASTERN POLK-
GREATER OCONEE-GREATER PICKENS-GREATER GREENVILLE-SPARTANBURG-
CHEROKEE-YORK-ANDERSON-ABBEVILLE-LAURENS-UNION SC-CHESTER-GREENWOOD-
402 PM EDT THU AUG 7 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST GEORGIA...PIEDMONT
NORTH CAROLINA...WESTERN NORTH CAROLINA AND UPSTATE SOUTH CAROLINA.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

..FRIDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SATURDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SUNDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..MONDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..TUESDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..WEDNESDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

GAZ010-017-NCZ062>065-SCZ001>003-082015-
RABUN-HABERSHAM-MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-
OCONEE MOUNTAINS-PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-
402 PM EDT THU AUG 7 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST GEORGIA...WESTERN
NORTH CAROLINA AND UPSTATE SOUTH CAROLINA.

.DAY ONE...TONIGHT.

ISOLATED THUNDERSTORMS WILL DEVELOP ACROSS THE SOUTHWEST MOUNTAINS
OF NORTH CAROLINA AND THE MOUNTAINS OF NORTHEAST GEORGIA AND SOUTH
CAROLINA. CLOUD TO GROUND LIGHTNING WILL BE THE MAIN THREAT WITH
ANY OF THESE STORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

..FRIDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SATURDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SUNDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..MONDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..TUESDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..WEDNESDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
411 PM EDT THU AUG 7 2014

GAZ010-017-018-SCZ001-004-072100-
GREATER OCONEE-HABERSHAM-OCONEE MOUNTAINS-RABUN-STEPHENS-
411 PM EDT THU AUG 7 2014

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN OCONEE...EAST
CENTRAL HABERSHAM...SOUTH CENTRAL RABUN AND STEPHENS COUNTIES THROUGH
500 PM EDT...

AT 407 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR LAKEMONT...OR 7 MILES SOUTH OF CLAYTON...
MOVING SOUTHEAST AT 20 MPH.

THIS STORM WILL IMPACT LOCATIONS NEAR...
  TALLULAH FALLS...
  TOCCOA...
  EASTANOLEE...

PEA SIZE HAIL...AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS
STORM.

LAT...LON 3478 8356 3489 8338 3455 8302 3451 8308
      3453 8309 3453 8311 3448 8318 3447 8332

ARK