Severe Thunderstorm Warning 200, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
324 PM EDT SAT MAY 20 2006

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
CONVECTION HAS BLOSSOMED RAPIDLY OVER THE SOUTHWEST CWFA IN
MODERATELY UNSTABLE ENVIRONMENT OVER THE AREA. LOW LEVEL WIND HAS
YET TO MAKE THE TURN TO A WESTERLY DIRECTION...SO MIXING WAS
MINIMIZED IN THE SOUTH DESPITE NEARLY FULL SUN AND LAPSE RATES HAVE
BECOME QUITE STEEP. WIND SHEAR STILL SUFFICIENT FOR SUPERCELLS
THROUGH 21Z OR SO...THEN FORECAST DATA SUGGESTS WEAKENING SHEAR BUT
STILL A HAIL THREAT. UPSTREAM...A CONVECTIVE COMPLEX HAS DEVELOPED
OVER SOUTHERN TENNESSEE...AHEAD OF A VORT CENTER. THIS COMPLEX
SHOULD OVERSPREAD THE FAR WESTERN MOUNTAINS...NORTHEAST GEORGIA AND
THE WESTERN HALF OF THE UPSTATE THROUGH THROUGH EARLY EVENING...THEN
PERHAPS TREK A BIT TO THE EAST. NAM AND GFS BOTH BREAK UP THE PRECIP
FIELD IN FAVORED-DOWNSLOPE LOCATIONS...THEN ORGANIZE ANOTHER
CONVECTIVE CLUSTER OVER THE EASTERN ZONES AS THE COLD FRONT FROM UP
NORTH SAGS SOUTH. WE WILL FEATURE HIGH CHANCE TO LIKELY POPS IN THE
SOUTH...TRENDING TO ISOLATED NORTH OF INTERSTATE 40.

UPPER AIR ANALYSIS THIS MORNING SHOWED A TROF UPSTREAM THAT IS
EXPECTED TO MOVE IN OUR DIRECTION OVERNIGHT AND SUNDAY. AT THE SAME
TIME...MODELS SUGGEST A SECONDARY FRONT OR SURFACE BOUNDARY WILL
BACK DOOR FROM THE MID ATLANTIC STATES AS ANOTHER LOBE OF DPVA
AFFECTS THE REGION WITH SHORTWAVE. AGAIN...IT APPEARS THE SOUTHWEST
MOUNTAINS...NORTHEAST GEORGIA AND THE UPSTATE WILL HAVE GREATEST
COVERAGE OF PRECIPITATION. AT THE SAME TIME...FRONT CURRENTLY
ATTEMPTING TO DROP SOUTH ACROSS THE REGION WILL BE STATIONARY JUST
TO OUR SOUTH. ANY OSCILLATION OF THE FEATURE BACK NORTHWARD COULD
RESULT IN SLIGHTLY BETTER COVERAGE OVER THE SOUTHERN CWFA. WE WILL
PLAN CHANCE POPS FOR THE AFOREMENTIONED AREAS...AND LIMIT TO
ISOLATED OR LESS FOR THE MORE NORTHERN AREAS...WHERE RETURN FLOW
MAY NOT BE AS GREAT.

ANOTHER REINFORCING COLD FRONT WILL MOVE SOUTHWARD INTO NORTH
CAROLINA SUNDAY NIGHT...AS DIVERGENCE IN THE RIGHT ENTRANCE REGION
OF THE UPPER JETLET CROSSES THE SOUTHERN APPALACHIANS. TIMING OF
H5 SHORTWAVES VARIES WIDELY FROM MODEL TO MODEL FOR THE SUN NIGHT
THROUGH MON PERIOD...BUT CONSENSUS BRINGS THE BEST UPPER SUPPORT
TO THE SRN APPALACHIANS AROUND 12Z MONDAY. THE COLD FRONT WILL
CONTINUE TO PROVIDE A FOCUSING MECHANISM FOR SCATTERED CONVECTION
AS IT MOVES SOUTH ACROSS THE REGION ON MONDAY...THEN SLIP SOUTH OF
THE AREA ON TUESDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AN UPPER LEVEL LOW PRES SYSTEM IS EXPECTED TO DEVELOP IN THE MIDWEST
ON THURSDAY...AND SWING SLOWLY THROUGH THE CENTRAL APPALACHIANS
THROUGH NEXT WEEKEND. PRECIPITATION CHANCES WILL RAMP UP ACCORDINGLY
THU THROUGH SAT...AS A SURFACE FRONT REMAINS STALLED ACROSS THE
REGION.

&&

.AVIATION...
DELAY OF SURFACE FRONT PUSHING SOUTH ACROSS THE AREA HAS RESULTED
IN SOUTH TO SOUTHWEST SURFACE WINDS IN THE FOOTHILLS AND PIEDMONT.
WIND SHOULD VEER TO MORE OF A WESTERLY DIRECTION AS THE FRONT SAGS
SOUTH PAST KHKY LATE THIS AFTERNOON...BUT MAY MAINTAIN SOME
SEMBLENCE OF SOUTHWEST CHARACTERISTICS AS SHORTWAVE ENERGY
APPROACHES FROM THE WEST. TSRA ORGANIZING NOW OFF TO THE WEST. WE
INCLUDED A TEMPO GROUP AT KAND FOR MVFR VISIBILITY RESTRICTIONS IN
THE 20Z TO 23Z TIME FRAME...WITH VCSH INCLUDED FROM LATE AFTERNOON
TO 00Z AT ALL OTHER SITES EXCEPT FOR KHKY. AFTER THIS EVENING...A
GENERAL LIGHT WEST WIND SHOULD DOMINATE. THERE WILL LIKELY BE A
PERIOD OF VARIABLE WIND DIRECTION WITH LIGHT SPEEDS LATE TONIGHT
THROUGH THE EARLY OUTLOOK PERIOD. THE FINAL HOURS OF THE OUTLOOK
PERIOD AGAIN FEATURE WEST WINDS AROUND 6 TO 8 KTS...WITH VFR
CEILINGS.

&&

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

SHORT TERM...HG/SAB
LONG TERM...HG
AVIATION...SAB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
600 AM EDT SAT MAY 20 2006

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-211000-
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-
600 AM EDT SAT MAY 20 2006

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

.DAY ONE...TODAY AND TONIGHT

SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING OVER
MUCH OF THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...WITH THE
BEST CHANCE ALONG AND SOUTH OF A LINE FROM ASHEVILLE TO GREENVILLE
AND ROCK HILL.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORMS WILL AGAIN BE POSSIBLE OVER THE WESTERN CAROLINAS
AND NORTHEAST GEORGIA WEDNESDAY AND THURSDAY. A FEW OF THESE COULD
PRODUCE DAMAGING WINDS AND LARGE HAIL.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

MCAVOY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
726 PM EDT SAT MAY 20 2006

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

0535 PM     HAIL             ABBEVILLE               34.18N 82.38W
05/20/2006  E1.00 INCH       ABBEVILLE          SC   COUNTY OFFICIAL

&&

BSH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
748 PM EDT SAT MAY 20 2006

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

0715 PM     HAIL             TROUTMAN                35.70N 80.89W
05/20/2006  E0.25 INCH       IREDELL            NC   COUNTY OFFICIAL

&&

BSH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
802 PM EDT SAT MAY 20 2006

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

0515 PM     TSTM WND DMG     BELTON                  34.52N 82.50W
05/20/2006                   ANDERSON           SC   NWS EMPLOYEE

            NUMEROUS TREES SPLIT IN HALF WITH LARGE LIMBS DOWN IN
            BELTON.

&&

BSH

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
818 PM EDT SAT MAY 20 2006

NCZ062-210100-
MACON-
818 PM EDT SAT MAY 20 2006

...STRONG THUNDERSTORM TO AFFECT SOUTHERN MACON COUNTY THROUGH 900
PM EDT...

AT 818 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM IN THE VICINITY OF OTTO...MOVING SOUTHEAST AT 40
MPH. THIS THUNDERSTORM WILL AFFECT THE AREA FROM SCALY TO HIGHLANDS
THROUGH 9 PM. SMALL HAIL...WIND GUSTS TO 40 MPH...AND TORRENTIAL
DOWNPOURS WILL BE POSSIBLE WITH THIS THUNDERSTORM.

HG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
838 PM EDT SAT MAY 20 2006

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

0740 PM     HAIL             5 E CALHOUN FALLS       34.09N 82.51W
05/20/2006  E0.75 INCH       ABBEVILLE          SC   TRAINED SPOTTER

&&

HG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
849 PM EDT SAT MAY 20 2006

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

0700 PM     TSTM WND DMG     NEWTON                  35.67N 81.22W
05/20/2006                   CATAWBA            NC   TRAINED SPOTTER

            TREE DOWN ACROSS ST. JAMES CHURCH ROAD IN NEWTON.

&&

BSH