Severe Thunderstorm Warning 168, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
804 PM EDT FRI MAY 13 2011

.SYNOPSIS...
LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL APPROACH THE AREA
FROM THE WEST TONIGHT...AND WILL MOVE EAST THROUGH THE AREA ON
SATURDAY. THIS LOW WILL LINGER ALONG THE CAROLINA COAST THROUGH THE
FIRST PART OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
A QUICK UPDATE FOR SVR WATCH 299 UNTIL 11 PM. AT 515 PM...MULTIPLE
COOL POOLS ARE EXPANDING ACROSS THE MTNS AND ADJACENT FOOTHILLS.
ADDITIONAL CONVECTION WILL DEVELOP ALONG THE OUTFLOW
BOUNDARIES...ESPECIALLY ACROSS THE NC FOOTHILLS AND PIEDMONT. I WILL
INCREASE POPS SIGNIFICANTLY THROUGH 3Z ACROSS THE MTNS EAST TO THE
I-77 CORRIDOR.

PREVIOUS DISCUSSION...

VIGOROUS IMPULSE RIDING UP THE BACKSIDE OF DAMPENING UPPER RIDGE
WILL CONTINUE TO AID IN LOCALLY SEVERE TSTM ORGANIZATION ACRS THE
MTNS INTO THIS EVENING. ACRS THE NC FTHLS/PIEDMONT...WHERE SFC DWPTS
SHOULD NOT CRASH...AS THEY HAVE DONE SO ACRS THE UPSTATE AND NE
GA...TSTM ACTIVITY SHOULD ALSO EXPAND IN CVRG WITHIN DEVELOPING
MODERATE INSTABILITY. PROBABLY WILL SEE A DIURNAL WEAKENING TREND
LATER THIS EVENING...BUT GIVEN FAVORABLE FLOW REGIME...SLIGHT UPPER
DIFFLUENCE...AND THE POTENTIAL FOR ADDITIONAL ENERGY TO ROTATE INTO
THE WESTERN CAROLINAS...SHOWER AND EMBEDDED TSTM ACTIVITY STANDS
THE CHANCE OF REDEVELOPMENT OVERNIGHT. ANOTHER MILD NIGHT IS
EXPECTED WITH SATURDAY MORNING MIN TEMPS ABOUT 5-7 DEG F ABV CLIMO.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
AS OF 225 PM FRI...A COLD FRONT WILL CROSS THE REGION SATURDAY
AFTERNOON. MODEL SOUNDINGS OFF THE GFS AND NAM SHOW AMPLE
INSTABILITY FOR SHRA AND TSTMS ALONG AND AHEAD OF THE FRONT.
HOWEVER...THERE WILL BE A COUPLE LIMITING FACTORS. A WELL DEFINED
SHORT WAVE WELL AHEAD OF THE UPPER LOW OVER MO WILL CROSS THE REGION
OVERNIGHT AND PUSH EAST OF THE FA SAT MORNING. THIS WILL KEEP THE FA
UNDER NVA UNTIL THE AFTN HOURS. EVEN AS PVA STARTS TO IMPROVE AGAIN
IN THE AFTN...A WEAKNESS IN THE MID-TROPOSPHERIC WIND FIELD WILL
PERSIST ACROSS THE FA. WINDS UP AROUND H5 WILL ONLY BE AROUND 25 TO
30 KTS. LAPSE RATES ARE NOT VERY STEEP. AS THE UPSTREAM AIRMASS HAS
BEEN OVERTURNED BY CONVECTION THE PAST FEW DAYS...THIS MAKES SENSE.
THEREFORE...WHILE I THINK THERE WILL BE GOOD COVERAGE...I DON/T
THINK THERE WILL BE MORE THAN AN ISOLATED SEVERE THREAT. I DID CUT
POPS A HAIR...BUT I/VE KEPT THEM IN THE LIKELY RANGE.

WIND SHEAR WILL INCREASE OVER THE REGION ON SUNDAY AS THE UPPER LOW
CONSOLIDATES OVER THE MID-WEST. HOWEVER...THE LLVL AIRMASS WILL BE
MUCH DRIER AND MODEL SOUNDINGS ARE GENERALLY CAPPED. SYNOPTIC SCALE
FORCING WILL INCREASE LATE IN THE DAY...AND SCT SHRA WILL BE
POSSIBLE...ESPECIALLY ACROSS THE NC MTNS WHERE NW FLOW WILL AID
ASCENT...AND OVER THE NC FOOTHILLS AND NRN PIEDMONT WILL LLVL
CONVERGENCE WILL INCREASE AHEAD OF THE LOW.

BY LATE SUNDAY NIGHT INTO MONDAY CONSIDERABLE SENSIBLE WX
DIFFERENCES DEVELOP BETWEEN THE MODELS. THE GFS QUICKLY MOVES A
STRONG UPPER WAVE ACROSS THE REGION BY MON AFTN. THE COMBINATION OF
INSTABILITY AND FORCING BRINGS QUITE A BIT OF PCPN THE
FA...ESPECIALLY THE NC ZONES...LATE MONDAY. THE EC IS MUCH SLOWER
AND DEEPER WITH THE WAVE...DROPPING IT TOWARD THE GULF. THEREFORE
IT/S DRIER ON MONDAY...BUT WETTER ABOUT 36 HOURS LATER. I COULD GO
ON AS NEARLY EVERY MODEL IS DIFFERENT. IN SHORT...FORECAST
CONFIDENCE IS QUITE LOW STARTING MONDAY AND INTO THE MIDDLE OF THE
WEEK WITH THIS PACKAGE. NOT SURPRISINGLY...THIS RESULTS IN A LOT OF
30 TO 50 PERCNET TYPE POPS FOR THIS PERIOD.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 1200 PM FRIDAY...NOT MUCH CHANGE TO THE PATTERN FROM WHAT WAS
OBSERVED BY THE MID SHIFT. A COMPLEX UPPER LOW...WITH SEVERAL
EMBEDDED SHORT WAVES...WILL BE ROUGHLY CENTERED OVER THE SRN
APPALACHIANS THROUGH WED BEFORE LIFTING TO THE NORTH IN RESPONSE TO
HEIGHT FALLS OVER THE SRN/CNTL PLAINS.

THE GFS IS FARTHER NORTH THAN THE EC AND CANADIAN WITH THE LOW
THROUGH MOST OF THE EXTENDED. THE 00 UTC RUNS OF THE LATER TWO
MODELS WERE ACTUALLY IN PRETTY GOOD AGREEMENT AS THEY TAKE ONE SHORT
WAVE WELL SOUTH OF THE AREA MON NIGHT...THEN BRING IT UP THE COAST
ON THE E SIDE OF THE UPPER LOW TUE INTO WED MORNING. THIS RESULTS IN
SFC CYCLOGENESIS OVER THE ERN CAROLINAS. IF THIS HAPPENS...PARTS OF
THE FA WOULD SEE A GOOD RAIN EVENT LATE TUE INTO EARLY WED. I HAVE
FAIRLY HIGH POPS FOR THIS PERIOD...BUT OWING TO THE RUN TO RUN
DIFFERENCES IN THE FINER SHORT WAVE FEATURES OVER THE REGION...WE/LL
NEED TO WAIT A FEW RUNS BEFORE GOING ANY HIGHER.

CONDITIONS DO LOOK TO IMPROVE LATER WED INTO FRIDAY...THOUGH SOME OF
THE FASTER MODEL SOLUTIONS BRING PCPN BACK INTO THE FA BY THE END OF
DAY 7.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...SC UPSTATE OUTFLOW BOUNDARY SHOULD REACH THE TERMINAL
BETWEEN 1Z TO 2Z. THE BOUNDARY SHOULD RESULT IN A WIND SHIFT TO WSW
AND A INCREASE IN CB POTENTIAL. THE TSRA RISK WILL DECREASE
SIGNIFICANTLY BY 6Z. LATE TONIGHT...HZ AND BR IS FORECAST TO DEVELOP
ACROSS THE TERMINAL. AT THIS TIME...IT APPEARS THAT VIS WILL REMAIN
MVFR BETWEEN 9Z AND 12Z. MVFR LEVEL CLOUDS MAY DEVELOP AROUND
SUNRISE...I WILL KEEP COVERAGE LIMITED TO SCT WITH THE 0Z ISSUANCE.
MORE SHRA AND TSRA EXPECTED LATE SATURDAY AFTERNOON...I WILL START
SHRA AND CB IN THE SKY GROUP AT 20Z.

ELSEWHERE...CONVECTION SHOULD BE OVER FOR KAVL...KAND...KGMU...AND
KGSP. TSRA MAY LINGER AROUND KHKY THROUGH THE REMAINDER OF THE
EVENING. WITH RAINFALL OCCURRING IN AND AROUND MOST TERMINAL
SITES...I WILL FORECAST DECREASING VIS THROUGH 12Z. MOST AREAS WILL
SEE VIS FALL TO MVFR BY LATE TONIGHT. KAVL SHOULD HAVE THE GREATEST
POTENTIAL FOR IFR OR LESS VIS IN BR/FG. CONDITIONS WILL BEGIN TO
IMPROVE SHORTLY AFTER SUNRISE...RETURNING TO VFR BY MID MORNING.
SHRA AND TSRA SHOULD REDEVELOP DURING THE EARLY TO MID AFTERNOON.

OUTLOOK...SCATTERED CEILINGS 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...TJB
NEAR TERM...NED/CSH
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...NED

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
714 PM EDT FRI MAY 13 2011

GAZ018-026-028-029-NCZ036-037-056-057-065-068>072-082-507>510-
SCZ001>014-019-142315-
STEPHENS-FRANKLIN-HART-ELBERT-IREDELL-DAVIE-CATAWBA-ROWAN-HENDERSON-
CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION NC-
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-
714 PM EDT FRI MAY 13 2011

...SEVERE THUNDERSTORM WATCH 299 IN EFFECT UNTIL 11 PM EDT THIS
EVENING...

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

.DAY ONE...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.

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

NUMEROUS THUNDERSTORMS WILL AFFECT THE REGION SATURDAY AFTERNOON
AND EVENING. SOME OF THE THUNDERSTORMS MAY BECOME SEVERE...
PRODUCING LARGE HAIL AND DAMAGING WINDS.

.SPOTTER INFORMATION STATEMENT...

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

GAZ010-017-NCZ033-035-048>053-058-059-062>064-501>506-142315-
RABUN-HABERSHAM-AVERY-ALEXANDER-MADISON-YANCEY-MITCHELL-SWAIN-
HAYWOOD-BUNCOMBE-GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-
TRANSYLVANIA-CALDWELL MOUNTAINS-GREATER CALDWELL-BURKE MOUNTAINS-
GREATER BURKE-MCDOWELL MOUNTAINS-EASTERN MCDOWELL-
714 PM EDT FRI MAY 13 2011

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

.DAY ONE...TONIGHT.

SCATTERED TO NUMEROUS THUNDERSTORMS WILL AFFECT THE REGION THIS
EVENING. A FEW OF THESE THUNDERSTORMS MAY BECOME
SEVERE...PRODUCING LARGE HAIL AND DAMAGING WINDS.

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

NUMEROUS THUNDERSTORMS WILL AFFECT THE REGION SATURDAY AFTERNOON
AND EVENING. SOME OF THE THUNDERSTORMS MAY BECOME SEVERE...
PRODUCING LARGE HAIL AND DAMAGING WINDS.

.SPOTTER INFORMATION STATEMENT...

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
659 PM EDT FRI MAY 13 2011

NCZ053-503>508-140000-
BUNCOMBE-BURKE MOUNTAINS-EASTERN MCDOWELL-GREATER BURKE-GREATER
RUTHERFORD-MCDOWELL MOUNTAINS-RUTHERFORD MOUNTAINS-
659 PM EDT FRI MAY 13 2011

...STRONG THUNDERSTORMS WILL AFFECT MCDOWELL...NORTHWESTERN
RUTHERFORD...SOUTHEASTERN BUNCOMBE AND WESTERN BURKE COUNTIES THROUGH
800 PM EDT...

AT 655 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 5 MILES NORTHEAST OF BAT CAVE...OR 18 MILES
SOUTHWEST OF MARION...MOVING EAST AT 20 MPH.

PEOPLE IN MCDOWELL...NORTHWESTERN RUTHERFORD...SOUTHEASTERN BUNCOMBE
AND WESTERN BURKE COUNTIES...INCLUDING THE FOLLOWING LOCATIONS...

LAKE LURE...THERMAL CITY AND GLENWOOD...

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

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

LAT...LON 3564 8190 3542 8187 3540 8227 3544 8228
      3546 8227 3549 8231 3566 8231 3588 8196
      3589 8173

MOORE

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
719 PM EDT FRI MAY 13 2011

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

0633 PM     TSTM WND DMG     4 NNE PICKENS           34.93N 82.69W
05/13/2011                   PICKENS            SC   AMATEUR RADIO

            TREES DOWN ON A HOUSE AND GARAGE NEAR THE INTERSECTION OF
            PLEASANT VIEW RD AND SHALIMAR RD.

&&

MCAVOY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
722 PM EDT FRI MAY 13 2011

SCZ007-132345-
SPARTANBURG-
722 PM EDT FRI MAY 13 2011

...STRONG THUNDERSTORMS WILL AFFECT NORTHERN SPARTANBURG COUNTY
THROUGH 745 PM EDT...

AT 720 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM GOWENSVILLE TO 3
MILES EAST OF GSP AIRPORT...MOVING EAST AT 20 MPH.

THESE STORMS WILL BE NEAR...
  DUNCAN...
  LYMAN...
  INMAN...
  LAKE BOWEN...
  BOILING SPRINGS SC...

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

LAT...LON 3488 8223 3512 8222 3519 8194 3519 8188
      3485 8183

RB

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
732 PM EDT FRI MAY 13 2011

NCZ035-036-056-140015-
ALEXANDER-CATAWBA-IREDELL-
732 PM EDT FRI MAY 13 2011

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN CATAWBA...SOUTHERN
ALEXANDER AND WESTERN IREDELL COUNTIES THROUGH 815 PM EDT...

AT 728 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR HICKORY...MOVING NORTHEAST AT 20 MPH.

PEOPLE IN NORTHERN CATAWBA...SOUTHERN ALEXANDER AND WESTERN IREDELL
COUNTIES...INCLUDING THE FOLLOWING LOCATIONS...

HICKORY...LAKE HICKORY...ST. STEPHENS...BETHLEHEM...CONOVER...
CLAREMONT...LOOKOUT SHOALS LAKE AND STONY POINT...

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

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

LAT...LON 3573 8098 3565 8131 3567 8138 3572 8140
      3579 8135 3580 8133 3583 8134 3596 8109

MOORE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
736 PM EDT FRI MAY 13 2011

SCZ007-008-013-140000-
CHEROKEE-SPARTANBURG-UNION-
736 PM EDT FRI MAY 13 2011

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN UNION...SOUTHERN
CHEROKEE AND SOUTHERN SPARTANBURG COUNTIES THROUGH 800 PM EDT...

AT 732 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR WOODRUFF...OR 15 MILES SOUTHWEST OF
SPARTANBURG...MOVING EAST AT 30 MPH.

THIS STORM WILL BE NEAR...
  ROEBUCK...
  PACOLET...

WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM.

LAT...LON 3471 8207 3474 8208 3475 8211 3479 8216
      3481 8217 3500 8167 3473 8159 3466 8200

RB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
743 PM EDT FRI MAY 13 2011

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

0630 PM     TSTM WND DMG     3 SE PUMPKINTOWN        34.97N 82.62W
05/13/2011                   PICKENS            SC   AMATEUR RADIO

            SEVERAL TREES UPROOTED AND SOME SNAPPED OFF NEAR 4700
            DACUSVILLE RD. WINDS LASTED ABOUT 10 MINUTES.

&&

MCAVOY