Severe Thunderstorm Warning 368, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
305 PM EDT THU AUG 23 2007

.SYNOPSIS...
AN UPPER RIDGE WILL REMAIN OVER THE SOUTHEAST THROUGH THE END
OF THE WEEK...BEFORE A COLD FRONT APPROACHES THE WESTERN CAROLINAS
LATE IN THE WEEKEND. THE FRONT WILL BECOME STATIONARY OVER THE
REGION AND SLOWLY DISSIPATE EARLY NEXT WEEK AS THE UPPER RIDGE
BUILDS BACK OVER THE REGION ONCE AGAIN.

&&

.NEAR TERM /THROUGH FRIDAY/...
SHOWER AND TSTM ACTIVITY WILL GRADUALLY DIMINISH THIS EVENING AND
SOME DEBRIS CLOUDS LINGER UNTIL AROUND MIDNIGHT. WITH UPSLOPE FLOW
OVERNIGHT...THE NAM/GFS/SREF ALL HAVE SLIGHT CHC TO CHC POP IN
VARIOUS BULLSEYES ACROSS THE CWFA. DECIDED THAT THERE MAY BE A STRAY
SHOWER POSSIBLE ACROSS THE AREA AND KEPT SLIGHT CHC WITH THE HIGHEST
OVER THE UPSLOPE AREAS ALONG THE BLUE RIDGE ESCARPMENT. THE NAM IS
SHOWING SOME STRATUS ADVANCING FROM THE NORTHEAST...WITH INCREASING
LOW LEVEL CLOUDINESS ACROSS THE NORTHWESTERN PIEDMONT OF NC (MAINLY
THE TRIAD TO KHKY). HENCE...HAVE BUMPED UP SKY COVER GRIDS AND MIN
TEMPS A COUPLE DEGREES ABOVE MAV. IN ANY CASE MIN TEMPS SHOULD BE IN
THE LOWER TO MIDDLE 70S.

FRIDAY...LITTLE CHANGE IN AIR MASS...WITH CONTINUED SELY LOW LVL
FLOW...AND UPPER RIDGE HOLDING ON ACROSS THE DEEP SOUTH. LOW LVL
THICKNESSES AND SKY COVER SUGGEST A MAINLY PERSISTENCE FCST. LOW LVL
MOISTURE SHOULD BE AMPLE ENOUGH TO PRODUCE CAPES TO 2000+ J/KG OVER
THE MTNS. SINCE THERE WILL BE LITTLE SHEAR OR UPPER LEVEL SUPPORT
FOR ORGANIZED CONVECTION...ONLY ISO/SCT COVERAGE CONFINED TO MAINLY
THE MTN ZONES IS EXPECTED. THERE MAY BE SOME ISOLATED PULSE SEVERE
CONVECTION AS HAS BEEN THE CASE THE LAST COUPLE OF DAYS...AND THAT
IS ALREADY IN THE HWO. MAX TEMPS SHOULD BE IN THE MIDDLE TO UPPER
90S PIEDMONT (80S TO LOWER 90S MTN VALLEYS).

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
ANY REMAINING CONVECTION FRIDAY NIGHT SHOULD END WITH LOSS OF
HEATING...SO ONLY CARRYING ISOLATED POP FOR THE MTNS UNTIL MIDNIGHT.
SHOULD BE ANOTHER WARM NIGHT WITH LOWS IN THE LOWER 70S OUTSIDE OF
THE MTNS AND 60S MTNS.

RIDGE WEAKENS A LITTLE SATURDAY AS SHORT WAVES MOVING THROUGH THE
WESTERLIES MOVE A TROF EASTWARD TO OUR NORTH. WILL NOT BE MUCH IN
THE WAY OF SYNOPTIC SCALE FORCING...BUT LOW LEVEL MOISTURE AND
CONVERGENCE SHOULD INITIATE SCT CONVECTION OVER THE MTNS. THE NAM
MOVES THIS CONVECTION INTO THE FOOTHILLS AND I-85 CORRIDOR BEFORE
ENDING WITH LOSS OF HEATING. THE GFS KEEPS THE CONVECTION CONFINED
TO THE MTNS. WILL BRING SCT CONVECTION OFF THE MTNS FOR THE LATE
AFTERNOON AND EVENING...BUT NOT AS FAR EAST AS THE NAM. THICKNESSES
AND H85 TEMPS REMAIN QUITE HIGH SATURDAY EVEN WITH WEAKER RIDGING
OVER US. THEREFORE...HAVE GONE CLOSER TO THE WARMER MAV GIVING US
MID TO UPPER 90S OUTSIDE OF THE MTNS AND AROUND 90 MTN VALLEYS.
THESE TEMPERATURES COMBINED WITH DEW POINT VALUES IN THE REASONABLE
RANGE FROM UPPER 60 MOST OF THE AREA TO AROUND 70 UPPER SAVANNAH
RIVER VALLEY...PRODUCES HEAT INDEX VALUES OVER 100 BUT LESS THAN 105
FOR MUCH OF THE CWFA FOR A LONG STRETCH IN THE AFTERNOON. THIS WILL
NEED TO BE WATCHED CLOSELY. LOWS SATURDAY NIGHT REMAINING ABOVE
NORMAL IN THE LOWER 70S OUTSIDE OF THE MTNS AND 60S MTNS.

UPPER RIDGE RETROGRADES TO THE WEST SUNDAY AS HEIGHTS CONTINUE TO
LOWER SLIGHTLY WITH THE TROF MOVING THROUGH THE EAST. A SURFACE
FRONT MOVES INTO THE AREA SUNDAY INCREASING THE LOW LEVEL
CONVERGENCE. LOW LEVEL MOISTURE REMAINS HIGH LEADING TO MODERATE
INSTABILITY OVER THE AREA. SUNDAY LOOKS TO BE THE BEST DAY IN THE
SHORT RANGE FOR CONVECTION...BUT AS DRY AS IT HAS BEEN THIS YEAR
WILL HAVE TO WAIT AND SEE WHAT DEVELOPS. THAT SAID...DID GO WITH 40
POP FOR THE MTNS AND 30 ELSEWHERE FOR THE AFTERNOON. HARD TO CALL IT
A COOLING TREND...BUT HIGHS WILL BE IN THE LOW TO MID 90S OUTSIDE OF
THE MTNS AND UPPER 80S TO AROUND 90 MTN VALLEYS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MODELS IN PRETTY GOOD AGREEMENT FOR THE MEDIUM RANGE. CENTER OF
UPPER RIDGE REMAINS TO OUR WEST. WHILE IT IS HARD TO CALL IT
TROFFING OVER THE EAST...A WEAKNESS IN THE RIDGING DEVELOPS OVER THE
SOUTHEAST. WEAK SHORT WAVES DROP INTO THIS WEAKNESS UNTIL THURSDAY
WHEN THE RIDGE AXIS MOVES WESTWARD ALLOWING A STRONGER SHORT WAVES
TO CARVE OUT AN ACTUAL TROF OVER THE EAST. A FRONTAL SYSTEM STALLS
OVER THE AREA MONDAY AND DISSIPATES TUESDAY. THIS KEEPS A MOIST AND
UNSTABLE AIR MASS OVER THE AREA. WILL GO AHEAD AND INCLUDE SCT
AFTERNOON CONVECTION FOR THESE DAYS EVEN THOUGH WE ARE IN A DROUGHT
AS ALL GUIDANCE INCLUDING ENSEMBLES SHOW PRECIP. MOISTURE DECREASES
WEDNESDAY AND THE AREA WILL BE BETWEEN SYNOPTIC SYSTEMS.
HOWEVER...DECENT INSTABILITY IS FORECAST...SO WILL GO WITH SCT
CONVECTION MTNS WHERE MOISTURE IS BEST AND ISOLATED ELSEWHERE.
FRONTAL SYSTEM MOVES INTO THE AREA THURSDAY...SO SCATTERED
CONVECTION RETURNS. WE SHOULD SEE A SIGNIFICANT DECREASE IN TEMPS
THROUGH THE PERIOD...BUT WILL STILL BE ABOVE NORMAL MOST LOCATIONS.
THE EXCEPTION IS NC FOOTHILLS AND PIEDMONT WHERE THEY WILL BE NEAR
TO A LITTLE ABOVE NORMAL.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
FOR THE FIRST FEW HOURS OF THE 18Z ISSUANCE...THERE WILL BE
SCATTERED SHRA/TSRA ACROSS THE AREA. SINCE THE COVERAGE LOOKS TO BE
30-40%...DID NOT HAVE DIRECT MENTION OF TS AT THE SITE...EXCEPT KAVL
WHERE THUNDERSTORMS WERE WITHIN 20SM OF THE SITE. OTHERWISE...VFR
THROUGH EARLY TONIGHT. THERE WILL LIKELY BE SOME MVFR FOG AT LEAST
AT KAVL (WITH POSSIBLY LOWER VSBYS). GUIDANCE HAS ALL SITES DROPPING
VSBY TO MVFR AROUND 9Z. GIVEN THE LIGHT WINDS AND INCREASING LOW
LEVEL MOISTURE...THINK THAT ALL SITES MAY SEE SOME REDUCTION IN VSBY
FOR A FEW HOURS AROUND DAWN. THEN BR/HZ MIX OUT BY 13Z AND SCT VFR
CU SHOULD DEVELOP.

ISOLATED TO WIDELY SCATTERED AFTERNOON CONVECTION AND LIGHT MORNING
FOG WILL BE POSSIBLE THIS WEEKEND...ESPECIALLY IN THE MTNS. COVERAGE
OF CONVECTION MAY INCREASE FROM WHAT IS EXPECTED FRIDAY THROUGH THIS
WEEKEND...AS A FRONT APPROACHES FROM THE NORTHWEST SUNDAY. THIS
FRONT STALLS OVER THE AREA MONDAY AND TUESDAY.

&&

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

&&

SYNOPSIS...TJB
NEAR TERM...ARK
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...ARK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
548 AM EDT THU AUG 23 2007

GAZ010-017-NCZ033-048>053-058-059-062>065-501-503-505-507-509-
SCZ001>003-241000-
RABUN-HABERSHAM-AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-
GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-
HENDERSON-CALDWELL MOUNTAINS-BURKE MOUNTAINS-MCDOWELL MOUNTAINS-
RUTHERFORD MOUNTAINS-POLK MOUNTAINS-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-
548 AM EDT THU AUG 23 2007

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS OF THE CAROLINAS
AND NORTHEAST GEORGIA THIS AFTERNOON. THE ATMOSPHERE WILL BECOME
VERY UNSTABLE LATER TODAY...AND SEVERAL OF THE STORMS COULD BECOME
SEVERE...PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH AND LARGE
HAIL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A FEW SEVERE STORMS WILL BE POSSIBLE AGAIN FRIDAY AFTERNOON OVER
THE MOUNTAINS. THE MAIN SEVERE THREAT IS EXPECTED TO BE DAMAGING
WINDS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND AGAIN FRIDAY
AFTERNOON.

GAZ018-026-028-029-NCZ035>037-056-057-068>072-082-502-504-506-508-
510-SCZ004>014-019-241000-
STEPHENS-FRANKLIN-HART-ELBERT-ALEXANDER-IREDELL-DAVIE-CATAWBA-ROWAN-
CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION NC-
GREATER CALDWELL-GREATER BURKE-EASTERN MCDOWELL-GREATER RUTHERFORD-
EASTERN POLK-GREATER OCONEE-GREATER PICKENS-GREATER GREENVILLE-
SPARTANBURG-CHEROKEE-YORK-ANDERSON-ABBEVILLE-LAURENS-UNION SC-
CHESTER-GREENWOOD-
548 AM EDT THU AUG 23 2007

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL DEVELOP OVER THE FOOTHILLS AND PIEDMONT
OF THE WESTERN CAROLINAS AND NORTHEAST GEORGIA THIS AFTERNOON. THE
ATMOSPHERE WILL BECOME VERY UNSTABLE LATER TODAY...AND SEVERAL OF
THE STORMS COULD BECOME SEVERE...PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH AND LARGE HAIL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATER TODAY.

MCAVOY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
922 AM EDT THU AUG 23 2007

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

1017 PM     TSTM WND DMG     CHESTER                 34.71N 81.21W
08/22/2007                   CHESTER            SC   COUNTY OFFICIAL

            ROOF BLOWN OFF TURKEY HOUSE AND TRAILER OVERTURNED.

&&

07

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1105 AM EDT THU AUG 23 2007

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

0425 PM     TSTM WND DMG     5 S CASAR               35.44N 81.62W
08/22/2007                   CLEVELAND          NC   COUNTY OFFICIAL

            SEVERAL TREES AND LARGE LIMBS DOWN, ONE TREE ON BRIDGE.

&&

BENTHALL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1147 AM EDT THU AUG 23 2007

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

0405 PM     TSTM WND DMG     WILLIAMSTON             34.62N 82.48W
08/22/2007                   ANDERSON           SC   LAW ENFORCEMENT

            ONE TREE DOWN AND ONE LIMB ON POWER LINE.

&&

07

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1206 PM EDT THU AUG 23 2007

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

0410 PM     TSTM WND DMG     4 SW VALE               35.50N 81.45W
08/22/2007                   LINCOLN            NC   TRAINED SPOTTER

            ESTIMATED GUSTS 50 TO 60 MPH. NUMEROUS LARGE LIMBS DOWN,
            ABOVE GROUND POOL BLOWN OVER, ALL ITEMS IN CARPORT BLOWN
            ACROSS STREET.

&&

BENTHALL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1246 PM EDT THU AUG 23 2007

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

0500 PM     NON-TSTM WND DMG FINGERVILLE             35.13N 82.01W
08/22/2007                   SPARTANBURG        SC   COUNTY OFFICIAL

            FEW LARGE LIMBS DOWN AND STORAGE BUILDING BLOWN OVER IN
            ONE ISOLATED SPOT.

&&

BENTHALL

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
112 PM EDT THU AUG 23 2007

NCZ033-231800-
AVERY-
112 PM EDT THU AUG 23 2007

...A STRONG THUNDERSTORM WILL AFFECT AVERY COUNTY THROUGH 200 PM
EDT...

AT 109 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 4 MILES SOUTHEAST OF NEWLAND...MOVING SOUTHWEST
AT 5 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO SUGAR
  MOUNTAIN...NEWLAND...MINNEAPOLIS...INGALLS...GRANDFATHER MOUNTAIN
  AND CROSSNORE.

PEA SIZE HAIL...AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM.

INTENSE LIGHTNING IS OCCURRING WITH THIS STORM. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.

ARK