Severe Thunderstorm Warning 137, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1047 PM EDT TUE MAY 10 2011

.SYNOPSIS...
AN UPPER LEVEL RIDGE WILL CONTINUE TO STRENGTHEN ACROSS THE EASTERN
HALF OF THE COUNTRY THROUGH WEDNESDAY. A WEAK BOUNDARY THROUGH
WESTERN NORTH CAROLINA INTO SOUTH CAROLINA WILL GRADUALLY MOVE
WESTWARD AND THEN DISSIPATE. A CLOSED UPPER LOW WILL SLOWLY APPROACH
THE AREA FROM THE WEST THIS WEEKEND.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
0300 UTC UPDATE...A NEW SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED
FOR BOWING THUNDERSTORMS MOVING SOUTH TOWARD INTO THE NORTHERN NC
MOUNTAINS. WEATHER GRIDS HAVE BEEN UPDATED TO MENTION DAMAGING WINDS
AND LARGE HAIL IN THE WATCH AREA.

PREVIOUS DISCUSSION...AN UPPER RIDGE AXIS EXTENDED FROM THE GULF
COAST TO THE GREAT LAKES THIS EVENING. A LOW MOVING WARM FRONT WAS
LOCATED FROM THE NORTHERN NC MOUNTAINS TO THE NORTHERN SC COAST. A
FIRST ROUND OF CONVECTION HAS WEAKENED AND MOVED SOUTHEAST OF OUR
AREA...BUT ADDITIONAL CONVECTION IN EASTERN KY IS MOVING THIS WAY
WITH A SECOND AND MORE VIGOROUS UPPER LEVEL IMPULSE. ALTHOUGH
INSTABILITY WILL BE DECREASING AS THE UPPER SYSTEM APPROACHES...BUT
ENOUGH SURVIVES TO WARRANT LIKELY POPS IN THE NORTHERN PORTION OF
THE AREA. IT REMAINS TO BE SEEN WHETHER A SECOND SEVERE THUNDERSTORM
WATCH WILL BE ISSUED FOR THIS SECOND ROUND OF CONVECTION LATE THIS
EVENING. MINIMUM TEMPERATURES WILL REMAIN RATHER MILD TONIGHT...
AROUND 10 DEGREES ABOVE NORMAL. FOG IS SUPPORTED BY GUIDANCE ACROSS
MUCH OF THE AREA BY DAYBREAK...MAINLY IN WESTERN NC AND THE SAVANNAH
RIVER VALLEY.

UPPER RIDGE AXIS OFF TO OUR WEST POKES A BIT FURTHER EASTWARD ON
WEDNESDAY AND DIURNAL DESTABILIZATION EXPECTED TO BE AT LEAST
MODERATE...ESPECIALLY WHERE TEMPERATURES WARM WELL INTO THE 80S ACRS
THE SW HALF OF THE CWFA. ALTHOUGH EFFECTIVE BULK SHEAR WILL BE
EXPECTEDLY LESS THAN WHAT WE ARE SEEING TODAY...ISOLATED...DIURNALLY
ENHANCED SVR STORMS WILL BE PROBABLE.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 120 PM TUESDAY...A HIGH AMPLITUDE RIDGE WILL BREAK DOWN DURING
THIS SHORT TERM PERIOD OF THE FORECAST. SOME LEFT OVER CONVECTION
CARRYING INTO WEDNESDAY EVENING WITH THE NW FLOW AND THEN A DECREASE
THROUGH THURSDAY MORNING WITH THE RIDGE AXIS PASSING OVERHEAD.
GREATEST INSTABILITY SHOULD BE OVER NE GA AND THE WESTERN UPSTATE
WITH FAIRLY LIGHT WIND FIELDS.  NOT A BIG CONCERN AS OF THIS TIME.
HOWEVER...CONCERN PICKS UP AGAIN ON FRIDAY WITH LOW TO MID LEVEL
WIND FIELDS INCREASING LATE IN THE DAY AS COLD FRONT APPROACHES FROM
THE WEST.  CAPE VALUES VARY DEPENDING OF THE MODEL BUT MAINLY 1000
TO 1500 IN THE GA TO CAROLINA PIEDMONT. EXPECT INCREASING COVERAGE
OF SHOWERS AND STORMS LATE FRIDAY. HIGHS THURSDAY IN THE MID 80S
UPPER SAVANNAH TO THE LOWER TO MID 70S NEAR THE TRIAD. HIGHS FRIDAY
FROM LOWER 80S UPPER SAVANNAH TO UPPER 70S NW NC PIEDMONT.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 200 PM TUESDAY...NEW GUIDANCE CONTINUES TO SUPPORT AN
UNSETTLED WEATHER PATTERN FOR THE WEEKEND INTO THE FIRST PORTION OF
NEXT WEEK. BY EARLY IN THE WEEKEND...THE UPPER RIDGE WILL SHIFT EAST
OF THE AREA AS A CLOSED UPPER LOW MOVES SOUTHEAST FROM THE MIDWEST
INTO THE DEEP SOUTH BY MONDAY. LEANED HEAVILY ON HPC GUIDANCE WHICH
UTILIZED THE ECM/ECM ENSEMBLE MEAN EARLY ON THEN THE ECM/GFS
ENSEMBLE MEANS FOR THE LATE IN THE FORECAST PERIOD. WITH THE
SOUTHERN APPALACHIANS AND WESTERN CAROLINAS COMING UNDER INCREASING
UPPER DIVERGENCE DURING THE WEEKEND...THE LIKELY POPS SEEM
REASONABLE...WITH DAILY SOLID COVERAGE A GOOD BET THROUGH MON. A
GENERAL COOLING TREND IN TEMPERATURES IS ALSO EXPECTED DUE TO
WIDESPREAD CLOUDS/PRECIP AND LOWERING HEIGHTS.

&&

.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...CONVECTION AND ASSOCIATED RESTRICTIONS ARE STILL POSSIBLE
THIS EVENING AS UPPER SYSTEM INTERACTS WITH FRONT JUST NORTH OF THE
AIR FIELD...BUT WITH NO IMMEDIATE TREAT UPSTREAM...ONLY CB WILL BE
CARRIED IN THE TAF. GUIDANCE SHOWS WINDS TAKING ON A MORE
NORTHEASTERLY DIRECTION OVERNIGHT. SOME GUIDANCE SUPPORT FOR FOG BY
DAWN...BUT GUIDANCE HAS BEEN OVERLY AGGRESSIVE WITH FOG THE LAST FEW
NIGHT...AND VFR WILL BE MAINTAINED IN TAF...AS WILL A LOW VFR CIG.
CONVECTION WEDNESDAY AFTERNOON WILL BE TOO SCATTERED TO MENTION IN
THE TAF. LIGHT WINDS VEER TO ESE IN THE AFTERNOON.

ELSEWHERE...CONVECTIVE CHANCES WILL BE GREATEST FROM KAVL TO
KGSP/KGMU THIS EVENING...WHERE BETTER INSTABILITY EXISTS IN
PROXIMITY TO THE FRONT AND THE TRACK OF THE UPPER SYSTEM. WINDS ARE
EXPECTED TO TAKE ON A NORTHEASTERLY DIRECTION OVERNIGHT. GUIDANCE
SUPPORTS MVFR IN MUCH OF THE AREA AROUND DAWN...BUT RESTRICTIONS
WILL BE RESERVED FOR THE MOST PRONE AREAS OF WESTERN NC AND KAND.
TEMPORARY IFR VSBY WILL BE POSSIBLE AT KAVL. AFTERNOON CONVECTION ON
WEDNESDAY WILL BE ISOLATED TO SCATTERED...WITH CONFIDENCE TOO LOW TO
MENTION IN THE TAFS. LIGHT WINDS VEER TO SE IN THE
AFTERNOON...BECOMING S AT KAVL.

OUTLOOK...SCATTERED CEILING AND VISIBILITY RESTRICTIONS IN
THUNDERSTORMS MOST NUMEROUS OVER MOUNTAINS AND DURING AFTERNOONS AND
EVENINGS THROUGH END OF WEEK. MORNING MVFR FOG POSSIBLE WHERE RAIN
FELL THE NIGHT BEFORE.

&&

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

&&

SYNOPSIS...LG
NEAR TERM...CSH/JAT
SHORT TERM...DEO
LONG TERM...LG
AVIATION...JAT

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
341 PM EDT TUE MAY 10 2011

GAZ010-017-018-026-028-029-NCZ051-058-059-062>064-SCZ001-002-004-005-
010-011-019-110300-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-SWAIN-GRAHAM-
NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-
OCONEE MOUNTAINS-PICKENS MOUNTAINS-GREATER OCONEE-GREATER PICKENS-
ANDERSON-ABBEVILLE-GREENWOOD-
341 PM EDT TUE MAY 10 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

UPPER LEVEL ENERGY WILL MOVE ACROSS THE REGION INTO TONIGHT...AIDING
IN THUNDERSTORM DEVELOPMENT AND ORGANIZATION. SOME OF THESE STORMS
WILL HAVE THE POTENTIAL TO BECOME SEVERE...PRODUCING LARGE HAIL...
DAMAGING WIND GUSTS AND POSSIBLY EVEN A TORNADO.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

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.

NCZ033-035>037-048>050-052-053-056-057-065-068>072-082-501>510-
SCZ003-006>009-012>014-110300-
AVERY-ALEXANDER-IREDELL-DAVIE-MADISON-YANCEY-MITCHELL-HAYWOOD-
BUNCOMBE-CATAWBA-ROWAN-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-
GREENVILLE MOUNTAINS-GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-
LAURENS-UNION SC-CHESTER-
341 PM EDT TUE MAY 10 2011

...SEVERE THUNDERSTORM WATCH 269 IN EFFECT UNTIL 11 PM EDT THIS
EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR 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.

UPPER LEVEL ENERGY WILL MOVE ACROSS THE REGION INTO TONIGHT...AIDING
IN THUNDERSTORM DEVELOPMENT AND ORGANIZATION. SOME OF THESE STORMS
WILL HAVE THE POTENTIAL TO BECOME SEVERE...PRODUCING LARGE HAIL...
DAMAGING WIND GUSTS AND POSSIBLY EVEN A TORNADO.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

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.

DEO

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
836 PM EDT TUE MAY 10 2011

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

0700 PM     HAIL             4 NE GREENVILLE         34.88N 82.32W
05/10/2011  E1.50 INCH       GREENVILLE         SC   PUBLIC

            COCORAHS OBSERVER REPORTS QUARTER TO PING PONG BALL SIZED
            HAIL.

&&

BSH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
843 PM EDT TUE MAY 10 2011

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

0805 PM     HAIL             2 NW GRAY COURT         34.63N 82.14W
05/10/2011  E1.00 INCH       LAURENS            SC   PUBLIC

            HW-14 QUICK STOP RERPORTED HAIL UP TO THE SIZE OF
            QUARTERS.

0812 PM     HAIL             GRAY COURT              34.61N 82.11W
05/10/2011  E0.75 INCH       LAURENS            SC   FIRE DEPT/RESCUE

&&

BSH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1107 PM EDT TUE MAY 10 2011

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

1058 PM     HAIL             6 WNW STATESVILLE       35.82N 80.99W
05/10/2011  E0.75 INCH       IREDELL            NC   AMATEUR RADIO

&&

BSH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1131 PM EDT TUE MAY 10 2011

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

1055 PM     TSTM WND DMG     ELK PARK                36.16N 81.98W
05/10/2011                   AVERY              NC   COUNTY OFFICIAL

            TREE IN THE ROADWAY ON HW-19E. COUNTY ALSO REPORTS
            NUMEROUS OTHER TREES DOWN IN THE COUNTY.

1057 PM     TSTM WND DMG     5 WNW NEWLAND           36.11N 82.01W
05/10/2011                   AVERY              NC   COUNTY OFFICIAL

            TREE IN THE ROADWAY ON BIRCHFIELD CREEK ROAD. COUNTY
            COMMS ALSO REPORTS NUMEROUS TREES DOWN IN OTHER PARTS OF
            THE COUNTY.

1108 PM     TSTM WND DMG     3 ENE SPRUCE PINE       35.93N 82.02W
05/10/2011                   AVERY              NC   COUNTY OFFICIAL

            TREE IN THE ROADWAY ON RED BUD LANE. COUNTY COMMS ALSO

            REPORTS NUMEROUS TREES DOWN IN OTHER PARTS OF THE COUNTY.

&&

BSH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1146 PM EDT TUE MAY 10 2011

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

1132 PM     TSTM WND DMG     4 WNW LENOIR            35.93N 81.60W
05/10/2011                   CALDWELL           NC   AMATEUR RADIO

            MULTIPLE TREES DOWN IN THE ROADWAY ALONG ABINGTON ROAD
            NEAR ANGEL LANE. ONE OF THE TREES IS ON A HOUSE.

&&

BSH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1149 PM EDT TUE MAY 10 2011

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

1141 PM     TSTM WND DMG     LENOIR                  35.91N 81.53W
05/10/2011                   CALDWELL           NC   COUNTY OFFICIAL

            ROOF COLLAPSED.

&&

07