Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
331 PM EDT FRI AUG 3 2012

.SYNOPSIS...
CIRCULATION AROUND HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC
WILL KEEP THE SOUTHERN APPALACHIAN REGION WARM AND HUMID THROUGH THE
WEEKEND. A COLD FRONT IS EXPECTED TO SLOWLY SWEEP ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA EARLY NEXT WEEK...POSSIBLY BECOMING
STATIONARY AND LINGERING INTO LATE IN THE WORK WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
1930 UTC UPDATE...POPS WERE INCREASED ALONG THE TN BORDER IN THE
CENTRAL AND SOUTHERN NC MOUNTAINS PER RADAR TRENDS. SKY COVER WAS
UPDATED FORM THE LATEST VISIBLE IMAGERY.

PREVIOUS DISCUSSION...CONVECTION HAS BEGUN TO DEVELOP OVER THE
SOUTHWEST AND CENTRAL NC MTNS. LAYER RH VALUES ARE THE HIGHEST IN
THIS PART OF THE FORECAST AREA...AND IT/S CLOSET TO THE APPROACHING
SHORTWAVE TROUGH WHICH CURRENTLY EXTENDS FROM CENTRAL KY TO ERN TN.
THE FEATURE ITSELF IS QUITE WEAK AND THE EFFECTIVE BULK SHEAR ACROSS
THE REGION IS WELL UNDER 20 KTS. THEREFORE DIFFERENTIAL HEATING AND
LLVL MASS CONVERGENCE SHOULD BE THE MAIN DRIVERS FOR CONVECTION THIS
EVENING. THE LATEST HI-RES NUMERICAL MODEL RUNS ARE MORE VARIED THAN
WHAT I SAW THIS MORNING. THE WRF-ARW AND THE HRRR BOTH DEVELOP
CONVECTION OVER PARTS OF THE FA...BUT IT/S NOT LOOKING AS ORGANIZED
AS EARLIER. THE 12 UTC 4KM SPC WRF ON THE OTHER HAND HAS A LARGE
AREA OF CONVECTION OVER THE WESTERN UPSTATE AND NE GA THIS EVENING.
THE 12 UTC NAM HAS STRONG LLVL CONVERGENCE THIS EVENING AND ALSO
DEVELOPS INTENSE SLOW MOVING CONVECTION OVER THE UPSTATE.
OVERALL...THE IDEA OF LIKELY POPS SLOWLY SPREADING FROM WEST TO EAST
ACROSS THE FA THE REST OF THE AFN AND EVENING STILL LOOKS GOOD.
DCAPE VALUES ARE WELL OVER 1000 J/KG ACROSS THE UPSTATE AND NE
GA...AND PULSE SEVERE STORMS ARE A GOOD BET AGAIN THIS EVENING.
PULSE SEVERE WON/T BE LIKELY OVER THE NC MTNS AND FOOTHILLS...BUT
EVEN THOUGH CURRENT DCAPE VALUES AREN/T THAT GREAT...I STILL SUSPECT
WE/LL SEE A FEW SEVERE STORMS ALONG THE I-77 URBAN CORRIDOR. VERY
HEAVY RAIN IS ALSO POSSIBLE IS SPOTS AND ISOLATED FLASH FLOODING IS
POSSIBLE. LATER TONIGHT WIDESPREAD LOW CLOUDS SHOULD DEVELOP ACROSS
MOST OF THE FA.

ON SATURDAY THE UPPER TROUGH WEAKENS QUICKLY AS THE ATLANTIC RIDGE
STARTS TO BUILD BACK INTO THE REGION. THE WEAKENING OF THE TROUGH IS
A LITTLE FASTER THAN WHAT WE/D BEEN EXPECTING. LAYER RH/S WILL
REMAIN HIGH AND EVEN WITH VERY WEAK FORCING...THERE SHOULD BE PLENTY
OF CONVECTION OVER THE HIGH TERRAIN AND A LITTLE LESS OUT ACROSS THE
FOOTHILLS AND PIEDMONT. THE SEVERE AND FLOODING RISK DON/T LOOK AS
GREAT TOMORROW. INTERESTINGLY...THE STRONGEST FORCING OF THE DAY
COULD COME IN THE FORM OF THE SEA-BREEZE FRONT WHICH THE NAM BRINGS
INTO THE SE ZONES EARLY IN THE EVENING.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 145 PM EDT...EXPECT SOME ONGOING SCATTERED CONVECTION SATURDAY
EVENING TO WANE RATHER QUICKLY AS SUBTROPICAL RIDGE BUILDS WESTWARD
INTO THE AREA SAT NIGHT. HENCE...THE SAT OVERNIGHT THROUGH SUNDAY
MORNING IS EXPECTED TO BE TRANQUIL. ON SUNDAY AFTERNOON...UPSLOPE
FLOW AND THE APPROACH OF A WEAK COLD FRONT FROM THE NW SHOULD
TRIGGER SCATTERED TO NUMEROUS SHOWERS/THUDNERSTORMS ACROSS THE
MOUNTAINS. ONLY ISOLATED TO WIDELY SCATTERED ACTIVITY IS EXPECTED
ELSEWHERE. THE MODELS BRING THE FRONTAL BOUNDARY INTO THE MOUNTAINS
SUNDAY NIGHT WHICH NECESSITATES MAINTAINING AT LEAST SCATTERED POPS
THERE. ON MONDAY...THE FRONT IS FORECAST TO LAY OUT ACROSS THE
WESTERN CAROLINAS INTO NE GA WHICH SHOULD BE A FOCAL POINT FOR
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MAXIMUM
TEMPERATURES ARE EXPECTED TO BE NEAR CLIMO WITH MIN TEMPERATURES
ABOUT A CATEGORY ABOVE AVERAGE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 1 PM EDT FRIDAY...THE MEDIUM RANGE IS EXPECTED TO FEATURE
SOME DEGREE OF BROAD UPPER TROFFING OVER THE EASTERN U.S. WITH
PERHAPS SOME AMPLIFICATION IN THE TROUGH TOWARD THE END OF THE
PERIOD. THE PERSISTENT TROUGH AND THE APPROACH OF A WEAK COLD FRONT
WILL CONTINUE TO TRIGGER SHOWERS AND THUNDERSTORMS THROUGH
TUE...WITH AN UPTICK DURING THE FAVORED AFTERNOON AND EVENING TIME
PERIOD. THERE IS SOME DIVERGENCE IN THE GUIDANCE IN REGARD TO HOW
FAR SOUTH THE AFOREMENTIONED FRONT GOES. THE ECM CAMP TAKES THE
FRONTAL BOUNDARY JUST SOUTH OF THE AREA ON WED AND BRINGS SOMEWHAT
DRYER INTO THE REGION FOR WED INTO THU. THIS WOULD PRODUCE A
DECREASE IN SHOWER/THUNDERSTORM ACTIVITY FOR WED INTO THU. ON THE
OTHER HAND... THE GFS HANGS UP THE BOUNDARY OVER THE AREA THROUGH
THE PERIOD WITH A CONTINUATION OF ENHANCED SHOWER AND THUDNERSTORM
ACTIVITY THROUGH THE END OF THE WEEK. HPC SIDED WITH THE ECM FRONTAL
POSITION. WE GENERALLY STAYED CLOSE TO HPC GUIDANCE WITH HIGHER THAN
CLIMO POPS FOR TUE AND THEN SOMEWHAT LOWER THAN CLIMO...ESPECIALLY
ACROSS THE MOUNTAINS FOR WED. BASICALLY CLIMO POPS RETURN FOR THE
END OF THE WEEK. USED A BLEND OF HPC/GMOS FOR TEMPS WHICH
ESSENTIALLY IS CLOSE TO CLIMO.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...SHOWERS ARE BEGINNING TO DEVELOP OVER THE FOOTHILLS ABOUT
80 MI WEST OF THE AIRFIELD. WHILE CONVECTION IS EXPECTED TO BUILD
OVER THE FOOTHILLS THE REST OF THE AFTN...IT WILL TAKE A WHILE FOR
STORMS TO DEVELOP OUT ACROSS THE PIEDMONT. HOWEVER...MANY NUMERICAL
MODELS ARE BULLISH ON DEVELOPING CONVECTION...AND I THINK THAT BY 22
UTC TSTMS ARE LIKELY TO DEVELOP IN PLACE OVER THE REGION. THE TEMPO
GROUP FOR CONVECTION FROM 22-02 UTC STILL LOOKS GOOD FOR THIS
REASON. THE MODEL GUIDANCE ALSO IS STRONGLY SUGGESTING THAT STRATUS
WILL DEVELOP OVERNIGHT. WITH DEWPOINTS GETTING UP INTO THE LOW 70S
AND EXPECTED WIDESPREAD UPSTREAM PRECIPITATION THIS LOOKS REASONABLE
AND AN 800 FOOT CIG HAS BEEN INTRODUCED INTO THE TAF VERY LATE
TONIGHT THROUGH MID MORNING ON SATURDAY.

AND ELSEWHERE...SHRA/TSTMS ARE BEGINNING TO DEVELOP IN THE VCNTY OF
THE KAVL AIRFIELD. VCTS HAS BEEN ADDED FOR THE NEXT FEW HOURS WITH
PREVAILING THUNDER FROM LATE AFTN INTO THE EARLY EVENING AS IT LOOKS
TO BE A STORMY EVENING IN THE MTNS AHEAD OF AN APPROACHING UPPER
LOW. ONCE CONVECTION ENDS LATER TONIGHT LOW CLOUDS AND VALLEY FOG
SHOULD DEVELOP. THE TIMING WILL DEPEND UPON HOW MUCH RAIN FALLS AT
THE AIRFIELD AND HOW QUICKLY MID AND HIGH CLOUDS THIN. THE SAME
APPLIES TO THE REST OF THE REGION...THOUGH IT WILL TAKE TSTMS A FEW
HOURS YET TO BEGIN TO DEVELOP OUTSIDE THE MTNS. TEMPO OR PREVAILING
GROUPS WILL PROBABLY BE NEEDED AT MOST AIRFIELDS...BUT CONFIDENCE
ISN/T HIGH ENOUGH TO DO THAT YET OUTSIDE THE MTNS. WITH LOW 70S
DEWPOINTS...15 KTS OF SLY LLVL FLOW AND MORE RAIN THIS
EVENING...STRATUS IS A GOOD BET TONIGHT. BASED ON THE AMOUNT OF
MIXING AND 800 FOOT DECK SEEMS REASONABLE.

OUTLOOK...ISO/SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS
WILL SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG.

AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...

WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM

&&

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

&&

SYNOPSIS...NED
NEAR TERM...JAT/MCAVOY
SHORT TERM...LG
LONG TERM...LG
AVIATION...MCAVOY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
247 PM EDT FRI AUG 3 2012

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-041900-
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-
247 PM EDT FRI AUG 3 2012

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

NUMEROUS THUNDERSTORMS WILL DEVELOP ACROSS THE MOUNTAINS AND
FOOTHILLS THIS AFTERNOON AND SLOWLY MOVE EASTWARD INTO THE EVENING
HOURS. SOME OF THE STORMS ARE EXPECTED TO BECOME SEVERE WITH SMALL
AREAS OF DAMAGING WIND AND HAIL UP TO THE SIZE OF QUARTERS
POSSIBLE. THE BEST CHANCE FOR WIND DAMAGE WILL BE OVER THE
UPSTATE...NORTHEAST GEORGIA AND THE SOUTHERN PIEDMONT OF NORTH
CAROLINA.

THUNDERSTORMS THIS EVENING WILL ALSO BE SLOW MOVING...AND A FEW
LOCATIONS WILL SEE SEVERAL INCHES OF RAIN IN A SHORT PERIOD OF
TIME. ISOLATED FLASH FLOODING IS POSSIBLE...PARTICULARLY IF HEAVY
RAIN AFFECTS URBAN AREAS OR A LOCATION THAT HAS SEEN HEAVY RAIN
IN RECENT DAYS. IN ADDITION...NEARLY CONTINUOUS CLOUD TO GROUND
LIGHTING WILL ACCOMPANY THE STRONGER STORMS THIS EVENING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTERS ARE REQUESTED TO FORWARD ANY REPORTS OF LARGE
HAIL...DAMAGING WINDS OR FLASH FLOODING TO OUR OFFICE.

MCAVOY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1255 PM EDT FRI AUG 03 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0904 PM     TSTM WND DMG     TOCCOA                  34.58N 83.32W
08/02/2012                   STEPHENS           GA   911 CALL CENTER

            SEVERAL TREES AND POWERLINES DOWN ON THE NORTH SIDE OF
            TOCCOA...GA. TIME DETERMINED BY RADAR.

&&

NED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
107 PM EDT FRI AUG 03 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0914 PM     HAIL             5 E TOCCOA              34.59N 83.24W
08/02/2012  E1.00 INCH       STEPHENS           GA   PUBLIC

            SMALL BRANCHES DOWN.

&&

NED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
136 PM EDT FRI AUG 03 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0620 PM     HAIL             5 SW NEW SALEM          35.07N 80.43W
08/02/2012  E1.25 INCH       UNION              NC   TRAINED SPOTTER

0620 PM     TSTM WND DMG     5 SW NEW SALEM          35.07N 80.43W
08/02/2012                   UNION              NC   TRAINED SPOTTER

            TREES DOWN ALONG NEW SALEM ROAD...NEAR THE INTERSECTION
            OF NC200 AND TARTON MILL ROAD AT THE POLK MOUNTAIN
            MARKET.

&&

NED

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
241 PM EDT FRI AUG 3 2012

NCZ051-062-031915-
MACON-SWAIN-
241 PM EDT FRI AUG 3 2012

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN MACON AND SOUTHERN
SWAIN COUNTIES THROUGH 315 PM EDT...

AT 238 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR WESSER...OR 11 MILES EAST OF ROBBINSVILLE...
MOVING NORTHEAST AT 15 MPH.

PEOPLE IN NORTHWESTERN MACON AND SOUTHERN SWAIN COUNTIES...INCLUDING
THE FOLLOWING LOCATION...

ALARKA...

SHOULD MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE
WARNINGS AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE
WEATHER THREATEN.

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

LAT...LON 3533 8368 3541 8345 3525 8330 3522 8365
      3532 8369

NED

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
245 PM EDT FRI AUG 3 2012

NCZ048-052-031915-
HAYWOOD-MADISON-
245 PM EDT FRI AUG 3 2012

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN HAYWOOD AND
SOUTHWESTERN MADISON COUNTIES THROUGH 315 PM EDT...

AT 241 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 5 MILES WEST OF LUCK...OR 16 MILES NORTH OF
WAYNESVILLE...MOVING NORTHEAST AT 15 MPH.

PEOPLE IN NORTHERN HAYWOOD AND SOUTHWESTERN MADISON COUNTIES...

SHOULD MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE
WARNINGS AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE
WEATHER THREATEN.

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

LAT...LON 3572 8278 3563 8299 3574 8309 3584 8287

NED

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
339 PM EDT FRI AUG 3 2012

NCZ048-052-053-032030-
BUNCOMBE-HAYWOOD-MADISON-
339 PM EDT FRI AUG 3 2012

...STRONG THUNDERSTORMS WILL AFFECT MADISON...NORTHEASTERN HAYWOOD
AND NORTHWESTERN BUNCOMBE COUNTIES THROUGH 430 PM EDT...

AT 336 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 3 MILES NORTHWEST OF
SPRING CREEK TO 3 MILES NORTH OF CANTON...MOVING NORTHEAST AT 15 MPH.

THESE STORMS WILL IMPACT LOCATIONS NEAR...
  HOT SPRINGS...
  LEICESTER...
  LEICESTER...
  MARSHALL...
  WEAVERVILLE...

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

HEAVY RAINS MAY FLOOD AREAS WITH POOR DRAINAGE...SUCH AS DITCHES AND
UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS. WATER
LEVELS OF SMALL STREAMS AND RIVERS MAY ALSO RISE RAPIDLY. SEEK HIGHER
GROUND IF THREATENED BY FLOOD WATERS.

LAT...LON 3604 8259 3597 8260 3597 8257 3570 8255
      3553 8294 3580 8297 3584 8292 3591 8291
      3594 8284 3593 8281 3596 8279 3605 8261

KRENTZ