Severe Thunderstorm Warning 91, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
235 PM EDT THU JUN 13 2013

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON THROUGH THIS
EVENING. DRY HIGH PRESSURE WILL BUILD IN FROM THE NORTH BEHIND THE
FRONT FRIDAY...AND SETTLE ACROSS THE REGION THROUGH THE WEEKEND. THE
NEXT COLD FRONT WILL APPROACH FROM THE NORTHWEST BY THE MIDDLE OF
NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
AS OF 225 PM EDT THURSDAY...SEVERE STORMS ARE JUST BEGINNING TO MOVE
INTO THE NC MTNS. WESTERLY WINDS HAVE INCREASED TO AROUND 50 KTS AT
10KFT ACROSS THE REGION...WITH 0-3KM BULK SHEAR VALUES GENERALLY
RANGING BETWEEN 30-40 KTS. DCAPE VALUES ARE HIGH AND THE ATMOSPHERE
IS SUPPORTIVE OF STRONG COLD-POOL GENERATION. THEREFORE I EXPECT THE
LINE TO SURVIVE IT/S TRIP ACROSS THE MOUNTAINS AND DEVELOP QUICKLY
INTO A SQUALL LINE OVER OR JUST EAST OF THE BLUE RIDGE. THIS SHOULD
RESULT IN WIDESPREAD STRAIGHT-LINE WIND DAMAGE ACROSS THE FORECAST
AREA AS IT RAPIDLY MOVES OFF TO THE EAST-SOUTHEAST. THIS FIRST ROUND
OF STORMS MAY MISS THE SOUTHWEST MOUNTAINS AND EXTREME NORTHEAST
GEORGIA TO THE EAST...THOUGH I WOULD EXPECT ADDITION CONVECTION TO
DEVELOP UPSTREAM AND AFFECT THESE AREAS DURING THE EARLY EVENING
HOURS. BY LATE EVENING THINGS WILL QUIET DOWN CONSIDERABLY AS COLD
FRONT CROSSES THE REGION. FOR FRIDAY IT WILL BE SUNNY AND MUCH LESS
HUMID.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AT 230 PM EDT THURSDAY...AN UPPER TROUGH WILL BE ALONG THE EAST
COAST ON FRIDAY EVENING...WHILE AN UPPER RIDGE WILL BE OVER THE
LOWER MS RIVER VALLEY. ON SATURDAY THE TROUGH PROGRESSES FARTHER
OFFSHORE...WHILE THE RIDGE BROADENS ACROSS THE GULF STATES. THE
PATTERN DEAMPLIFIES ON SUNDAY...WITH A FLAT RIDGE ACROSS THE
SOUTHERN TIER OF STATES...AND ZONAL FLOW ACROSS THE NORTHERN TIER.

HIGH PRESSURE WILL BUILD INTO OUR AREA FROM THE NW ON FRIDAY NIGHT
AND SATURDAY. MODEL TIME HEIGHTS SHOW LIMITED LOW LEVEL MOISTURE
LINGERING UNDER A MID LEVEL INVERSION...BUT WITHOUT FORCING OR
BUOYANCY TO SUPPORT CONVECTION.

MOISTURE WILL INCREASE OVER OUR AREA ON SATURDAY NIGHT AND SUNDAY ON
THE BACK SIDE OF THIS HIGH PRESSURE...ESPECIALLY OVER THE MOUNTAINS.
THE MID LEVEL CAP REMAINS...BUT IS WEAKER. SMALL POPS WILL MAINLY
FAVOR MOUNTAINOUS TERRAIN...WHERE AN UPSLOPE FLOW MAY ASSIST IN
OVERCOMING THE WEAK CAPPING INVERSION.

TEMPERATURES WILL RUN A FEW DEGREES BELOW NORMAL ON SATURDAY IN THE
WAKE OF A DEPARTING COLD FRONT AS COOL HIGH PRESSURE ARRIVES.
TEMPERATURES WILL MODERATE UPWARD TOWARD NORMAL VALUES ON SUNDAY AS
HEIGHTS RISE ALOFT AND SOUTHERLY LOW LEVEL FLOW SETS UP.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AT 230 PM EDT THURSDAY...AN UPPER TROUGH BEGINS TO AMPLIFY FROM THE
GREAT LAKES TO THE GULF STATES ON MONDAY. ON TUESDAY THIS TROUGH
REACHES THE CENTRAL AND SOUTHERN APPALACHIANS. ON WEDNESDAY THE
TROUGH REACHES THE EASTERN SEABOARD...AND ON THURSDAY IT MOVES OFF
THE EAST COAST...WHILE AN UPPER RIDGE AMPLIFIES OVER THE PLAINS.

ATLANTIC HIGH PRESSURE WILL EXTEND OVER THE CAROLINAS AND GA ON
MONDAY...WITH A LEE TROUGH EXPECTED EAST OF THE MOUNTAINS. THIS HIGH
PRESSURE WEAKENS ON TUESDAY WHILE A COLD FRONT APPROACHES FORM THE
NW. THE FRONT IS EXPECTED TO CROSS OUR AREA ON TUESDAY NIGHT...
STALLING JUST SOUTH OF OUR AREA ON WEDNESDAY AND THURSDAY.

CONVECTIVE CHANCES WILL IMPROVE AS THE FRONT APPROACHES AND HEIGHTS
FALL ALOFT. ACTIVITY WILL DECREASE BEHIND THE FRONT...BUT WITH THE
BOUNDARY AND ASSOCIATED MOISTURE REMAINING IN THE VICINITY...SOME
ACTIVITY CAN BE EXPECTED TO LINGER IN THE SOUTHERN PORTION OF THE
AREA ON WEDNESDAY AND THURSDAY. TEMPERATURES WILL EXHIBIT A REDUCED
DIURNAL TREND DUE TO CLOUDS AND MOISTURE...WITH HIGHS JUST BELOW
NORMAL...AND LOW A BIT ABOVE NORMAL.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...TIMING THE CONVECTION DEVELOPING OVER ERN TN AT THIS TIME
BRINGS IT ACROSS THE AIRFIELD BETWEEN 20-21 UTC. CONSIDERING THE
SHEAR AND INSTABILITY CHARACTERISTICS OF THE AIRMASS THIS
AFTERNOON...THE STORMS WILL PUT OUT STRONG OUTFLOW BOUNDARIES AND
THEY SHOULD MOVE RAPIDLY TO THE EAST AS THEY EVOLVE. THEREFORE I
THINK THAT TIMING WILL WORK WELL. I DIDN/T ADD GUSTS TO THE TEMPO
GROUP YET...BUT I PROBABLY WILL ONCE I CHAT A LITTLE MORE WITH THE
CWSU AS THERE IS A GOOD CHANCE OF AT LEAST A 40KT GUST WITH THE
LINE...POSSIBLY HIGHER. OTHERWISE WINDS WILL BE GUSTY OUT OF THE
SOUTHWEST AHEAD OF THE LINE...WITH WINDS VEERING AROUND TO WEST AND
THEN NORTHWEST BEHIND THE LINE DURING THE COURSE OF THE EVENING.
GUSTS UP TO 18 KTS OR SO WILL BE POSSIBLE AFTER SUNRISE TOMORROW AS
WE START TO MIX BEHIND A COLD FRONT.

ELSEWHERE...CONDITIONS ELSEWHERE WILL BE THE SAME AS AT KCLT AS A
SQUALL LINE SWEEPS OUT OF THE MOUNTAINS IN A FEW HOUR/S TIME.

OUTLOOK...HIGH PRESSURE WILL BUILD IN THU NITE AND PRODUCE GENERALLY
QUIET WEATHER AND VFR CONDITIONS THROUGH THE WEEKEND.

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  91%     HIGH  96%     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...JAT
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...MCAVOY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
156 PM EDT THU JUN 13 2013

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-141800-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-AVERY-ALEXANDER-
IREDELL-DAVIE-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-CATAWBA-
ROWAN-GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-
HENDERSON-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-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-GREATER OCONEE-
GREATER PICKENS-GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-
ANDERSON-ABBEVILLE-LAURENS-UNION SC-CHESTER-GREENWOOD-
156 PM EDT THU JUN 13 2013

...SEVERE THUNDERSTORM WATCH 307 IN EFFECT UNTIL 8 PM EDT THIS
EVENING...

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   SEVERE THUNDERSTORM WATCH.

A LINE OF THUNDERSTORMS MOVING ACROSS EASTERN TENNESSEE WILL DIVE
TO THE SOUTHEAST THIS AFTERNOON AND MOVE ACROSS THE MOUNTAINS OF
THE CAROLINAS BETWEEN 2 AND 5 PM. THE LINE WILL THEN CROSS THE
REMAINDER OF THE FOOTHILLS AND PIEDMONT DURING THE LATE AFTERNOON
AND EARLY EVENING HOURS. THE ATMOSPHERE OVER THE REGION WILL BE
VERY UNSTABLE THIS AFTERNOON AND THESE STORMS WILL BE CAPABLE OF
PRODUCING LARGE SWATHS OF DAMAGING DOWNBURST WINDS.
ISOLATED...BRIEF TORNADOES ARE ALSO POSSIBLE...ESPECIALLY OVER THE
NORTH CAROLINA FOOTHILLS AND PIEDMONT. A FEW OF THE STORMS WILL
ALSO PRODUCE LARGE HAIL...THOUGH DAMAGING STRAIGHT-LINE WINDS
WILL BE THE MOST SIGNIFICANT THREAT. SEVERE STORMS SHOULD EXIT THE
REGION BY AROUND SUNSET.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTERS ARE REQUESTED TO FORWARD ANY REPORTS OF LARGE
HAIL...DAMAGING WINDS...TORNADOES OR FLASH FLOODING TO OUR OFFICE.
DISPATCHERS...PLEASE FORWARD THIS INFORMATION ON TO EMERGENCY
MANAGERS.

MCAVOY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
149 PM EDT THU JUN 13 2013

NCZ033-048>053-058-059-131900-
AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-
NORTHERN JACKSON-
INCLUDING THE CITIES OF...NEWLAND...SPRUCE PINE...CHEROKEE...
BRYSON CITY...WAYNESVILLE...ASHEVILLE...SYLVA
149 PM EDT THU JUN 13 2013

...INTENSIFYING THUNDERSTORMS APPROACHING WESTERN NORTH CAROLINA...

AT 145 PM EDT...NATIONAL WEATHER SERVICE RADAR INDICATED STRONG TO
SEVERE THUNDERSTORMS ACROSS THE TENNESSEE VALLEY. THESE
THUNDERSTORMS SHOULD CONTINUE TO STRENGTHEN AS THEY APPROACH THE
FAR WESTERN MOUNTAINS AFTER 2 PM. THE THREAT FOR DAMAGING STRAIGHT
LINE WINDS WILL INCREASE...WHILE ISOLATED LARGE HAIL CAN ALSO BE
EXPECTED. A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 8 PM.

STAY TUNED TO NOAA WEATHER RADIO OR LOCAL MEDIA OUTLETS...AS
WARNINGS WILL LIKELY BE ISSUED FOR PORTIONS OF THE AREA BY 230 PM.

LANE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
225 PM EDT THU JUN 13 2013

NCZ051-052-059-131915-
HAYWOOD-NORTHERN JACKSON-SWAIN-
225 PM EDT THU JUN 13 2013

...STRONG THUNDERSTORMS WILL AFFECT NORTHERN HAYWOOD...NORTHWESTERN
JACKSON AND SWAIN COUNTIES THROUGH 315 PM EDT...

AT 218 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM ROUND MOUNTAIN TO 3
MILES SOUTHWEST OF CADES COVE...MOVING EAST AT 35 MPH.

THESE STORMS WILL IMPACT LOCATIONS NEAR...
  CLINGMANS DOME...
  SMOKEMONT...
  CHEROKEE...
  MAGGIE VALLEY...

WIND GUSTS UP TO 40 MPH...AND AREA OF SMALL HAIL ARE EXPECTED WITH
THESE STORMS.

PLEASE REPORT DAMAGING WINDS...HAIL...OR FLOODING TO THE NATIONAL
WEATHER SERVICE GREENVILLE SPARTANBURG BY CALLING TOLL FREE...1...
800...2 6 7...8 1 0 1...OR BY POSTING ON OUR FACEBOOK PAGE...OR TWEET
IT USING HASHTAG NWSGSP. YOUR MESSAGE SHOULD DESCRIBE THE EVENT AND
SPECIFIC LOCATION WHERE IT OCCURRED.

LAT...LON 3550 8390 3558 8365 3557 8349 3560 8347
      3567 8335 3566 8330 3569 8327 3578 8296
      3575 8296 3573 8291 3562 8285 3563 8282
      3556 8276 3540 8325 3547 8391

LANE