Damaging Wind in South Carolina, August 21, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
749 PM EDT SUN AUG 21 2011

.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION TONIGHT...AND SETTLE JUST
SOUTHEAST OF THE AREA ON MONDAY. DRIER AIR WILL ARRIVE AS HIGH
PRESSURE BUILDS TO THE NORTHWEST ON TUESDAY. ATLANTIC MOISTURE WILL
THEN STEADILY RETURN TO THE REGION DURING THE LATER PART OF THE
WEEK. THE PROGRESS OF TROPICAL SYSTEM IRENE WILL NEED TO BE CLOSELY
MONITORED FOR NEXT WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY/...
THE CONVECTION TOOK ITS OWN SWEET TIME TO INITIATE...BUT FINALLY
DID. THIS WAS EXPECTED WITH A SHORT WAVE MOVING OVER A MOIST
UNSTABLE AIRMASS. STILL...EXPECT CONVECTION TO REMAIN ISOLATED TO
SCT AS IT MOVES OVER THE PIEDMONT THIS EVENING AND END BEFORE
MIDNIGHT. MODELS TIME A WEAK COLD FRONT TO MOVE NW TO SE ACROSS THE
CWA LATE TONIGHT AND EARLY MONDAY MORNING. EXPECT CLEARING BEHIND
THE FRONT...EXCEPT OVER THE MTNS WHERE LOW LEVEL MOISTURE AND NWLY
FLOW CONTINUE. GUIDANCE HAS SLOWED THE DRIER AIR MOVING IN BEHIND
THE FRONT AND THE STRENGTH OF THE WNW FLOW. THIS WILL LIKELY LEAD TO
MORE FOG FORMATION OVERNIGHT THAN PREVIOUSLY EXPECTED. LOW
TEMPERATURES SHOULD RANGE AROUND NORMAL. EXPECT ISOLATED SHRA/TSRA
TO REMAIN ACROSS THE WESTERN SLOPES THROUGH DAYBREAK.

MONDAY...THE COLD FRONT WILL COMPLETLEY MOVE SOUTH OF THE
CWA...RESULTING IN A STEADY FALL IN DEWPOINTS. HOWEVER...DAYTIME
HEATING AND CONVERGENCE ALONG THE FRONT MAY SUPPORT A FEW SHRA/TSRA
ACROSS THE UPPER SAVANNAH RIVER VALLEY AND SOUTHERN UPSTATE...I WILL
FORECAST 20 POPS. OTHERWISE...TEMPS WILL WARM QUICKLY WITH MOSTLY TO
PARTLY SUNNY CONDITIONS. HIGHS MAY VERIFY 2 TO 4 DEGREES ABOVE
TODAY/S VALUES.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 130 PM SUNDAY...THE SHORT TERM FCST PICKS UP AT 00Z ON TUESDAY
WITH THE AXIS OF THE UPPER TROF LOCATED TO OUR NORTHEAST AND A STEEP
UPPER RIDGE COVERING THE WESTERN TWO THIRDS OF THE CONUS. HEIGHTS
ARE EXPECTED TO RISE THRU THE PERIOD AS THE UPPER TROF LIFTS TO THE
NE AND THE UPPER RIDGE MAINTAINS ITS STRENGTH TO OUR WEST. ON
WED..MODELS GENERATE A FAIRLY POTENT LOOKING H5 SHORTWAVE OVER THE
GREAT LAKES AND PROPAGATE IT TOWARDS THE FCST AREA WED
AFTERNOON/EVENING. ITS LOOKING LIKE THE SW MIGHT PASS TO FAR TO THE
NORTH TO PROVIDE MUCH IN THE WAY OF DYNAMIC LIFTING OVER THE CWFA
BUT OF COURSE IT COULD TRACK FARTHER TO THE SOUTH.

ON TUESDAY...A SFC HIGH WILL RIDGE DOWN FROM THE NW BRINGING COOLER
AND DRIER NORTHERLY LOW LVL FLOW WITH MOSTLY CLEAR SKIES AND TEMPS
RIGHT AROUND CLIMO. ON WEDNESDAY...THE SFC HIGH GETS PUSHED OFF THE
EASTERN SEABOARD AND OUR BOUNDARY LAYER FLOW VEERS AROUND TO THE NE
AND THEN EAST. THIS SHOULD PROVIDE SOME INCREASED LOW TO MID LVL
MOISTURE...HOWEVER AT THIS POINT MOST OF THE MODEL GUIDANCE IS
SUGGESTING THAT ANY MOISTURE SURGE WILL BE MODEST THRU 00Z THURS.
THERE WILL LIKELY BE A BROAD AREA OF UPPER LVL DIVERGENCE OVER THE
FCST AREA WED AFTERNOON/EVENING...HOWEVER MOST OF THE LIFT COULD BE
GENERATED TO OUR NORTH. I DO RAMP POPS UP FROM THE LATE MORNING
HOURS THRU THE EVENING WITH AT LEAST A SLIGHT CHANCE OVER MOST OF
THE CWFA AT SOME POINT...YET I DOUBT WE WILL SEE ANY WIDESPREAD
CONVECTION. TEMPS ARE EXPECTED TO BE A DEGREE OR TWO COOLER THAN THE
PREVIOUS DAY...WITH THE LOWER ELEVATIONS REACHING THE UPPER 80S AND
THE LOWER 80S IN THE MT VALLEYS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 215 PM SUNDAY...THE MEDIUM RANGE PART OF THE FORECAST WILL
CONTINUE TO FOCUS UPON THE FATE OF IRENE NEXT WEEKEND. BEFORE THE
STORM MAKES ITS APPROACH FROM THE SOUTH...WE WILL HAVE TO DEAL WITH
SOME MINOR CONCERNS LATE IN THE WEEK...MADE MORE COMPLICATED BY THE
PRESENCE OF IRENE. THE TREND IN THE GUIDANCE IS TO SHEAR APART A
SHORT WAVE DROPPING DOWN FROM THE NORTHWEST ON WEDNESDAY NIGHT AS A
COL REGION DEVELOPS OVER THE CAROLINAS WITH IRENE MOVING NORTH OF
CUBA. THIS WILL LIKELY HALT THE PROGRESS OF A SURFACE FRONT AND
CAUSE IT TO STALL ON THE W SIDE OF THE MTNS ON THURSDAY. IF THAT
HAPPENS...WE WILL LOSE SOME OF THE IMPETUS FOR SHOWER AND
THUNDERSTORM ACTIVITY FOR THURSDAY AND FRIDAY. IN FACT...THE MODELS
RETAIN SOME WEAK HIGH PRESSURE ACROSS THE WESTERN CAROLINAS IN
BETWEEN THE FRONT W OF THE MTNS AND IRENE TO THE S. THIS WOULD ALSO
BE MORE UNFAVORABLE FOR CONVECTION. BOTTOM LINE IS THINGS ARE
LOOKING SOMEWHAT DRIER FOR THURSDAY AND FRIDAY AND PRECIP CHANCES
WILL BE DIMINISHED...WHILE TEMPS ARE NUDGED UP A BIT.

FOR SATURDAY AND SUNDAY...THE LATEST GUIDANCE CONTINUES TO MOVE A
LOW OF TROPICAL ORIGIN SOMEWHERE ACROSS THE CAROLINAS...BUT THERE IS
A GREAT DEAL OF UNCERTAINTY REGARDING THE TRACK. SOMETHING FARTHER
WEST LIKE THE 00Z ECMWF WOULD RESULT IN A SIGNIFICANT AMOUNT OF RAIN
AND A HIGH POTENTIAL FOR FLOODING...WHILE A TRACK SIMILAR TO THE 12Z
GFS MIGHT ONLY AFFECT THE WRN PIEDMONT. THE FORECAST WILL CONTAIN A
40-50 PERCENT CHANCE OF RAIN WHICH IS MORE OF A MEASURE OF THE
UNCERTAINTY IN THE LOW TRACK. OBVIOUSLY IF THE LOW TAKES A WESTERN
TRACK WE ARE LOOKING AT CERTAIN HEAVY RAIN...BUT EVEN THE EASTERN
TRACK WOULD REQUIRE A CATEGORICAL POP AROUND CHARLOTTE. THE BEST
ADVICE FOR NOW IS FOR ALL INTERESTS ACROSS THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA TO MONITOR THE FORECAST FOR NEXT WEEKEND.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...IT TOOK A WHILE BUT THE SHORT WAVE MOVING
ACROSS THE AREA FINALLY PRODUCED ENUF LIFT TO TAP THE MOIST UNSTABLE
AIR MASS AND PRODUCE ISOLATED TO SCT CONVECTION. IN GENERAL...EXPECT
VFR CONDITIONS UNLESS A CELL MOVES OVER THE AIRFIELD. ALTHOUGH I
HAVE PUT IN TS AT SITES WHERE CELLS ARE CURRENTLY IN PLAY. ACTIVITY
SHOULD MOVE EAST OF THE AREA BY EARLY EVENING. A WEAK COLD FRONT IS
EXPECTED TO SWEEP NW TO SE ACROSS THE REGION TONIGHT AND EARLY
MONDAY MORNING. AFTER FROPA...WINDS WILL FAVOR A DIRECTION BETWEEN
340 TO 010 DEGREES AROUND 8 KTS. GUIDANCE HAS SLOWED THE DROP IN
DEWPOINTS ACROSS THE AREA. GIVEN THIS...GUIDANCE NOW ALL AGREES ON
MVFR MOST SITES OUTSIDE OF THE MTNS...AND IFR MTN VALLEYS. HAVE GONE
WITH THIS SCENARIO. EXPECT NLY WINDS AND SCT CU DURING THE AFTERNOON
WITH ISOLATED CONVECTION POSSIBLE OVER THE UPPER SAV RVR VALLEY.

OUTLOOK...DRIER CONDITIONS ARE EXPECTED TO CONTINUE ON TUESDAY. MORE
UNSETTLED WEATHER IS EXPECTED TO RETURN BY MID WEEK AS ANOTHER COLD
FRONT STALLS OVER THE AREA. MORNING FOG WILL BE POSSIBLE...ESP IN
MTN VALLEYS AND WHERE RAIN FALLS THE DAY BEFORE.

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...JPT
NEAR TERM...NED/RWH
SHORT TERM...JPT
LONG TERM...PM
AVIATION...NED/RWH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
401 PM EDT SUN AUG 21 2011

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-222015-
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-
401 PM EDT SUN AUG 21 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG AND EAST OF THE BLUE
RIDGE THIS AFTERNOON...AND THEN MOVE EASTWARD THROUGH THE
PIEDMONT THROUGH THE EVENING HOURS. SOME OF THESE THUNDERSTORMS
MAY BECOME SEVERE...PRODUCING DAMAGING WIND GUSTS AND HAIL AS
LARGE AS QUARTERS. THE THUNDERSTORMS WILL ALSO PRODUCE FREQUENT
LIGHTNING AND TORRENTIAL RAINFALL. ANY LOCATIONS AFFECTED BY
MULTIPLE THUNDERSTORMS COULD SEE LOCALIZED FLOODING.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

A LOW PRESSURE SYSTEM OF TROPICAL ORIGIN...CURRENTLY KNOWN AS
IRENE...MAY AFFECT PARTS OF THE WESTERN CAROLINAS AND NORTHEAST
GEORGIA NEXT WEEKEND. FUTURE DEVELOPMENTS WITH REGARD TO THE TRACK
OF THE SYSTEM WILL DETERMINE HOW MUCH...IF ANY...HEAVY RAIN AND
FLOODING WILL IMPACT THE REGION.

.SPOTTER INFORMATION STATEMENT...

NONE.

MOORE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
741 PM EDT SUN AUG 21 2011

SCZ006-007-220030-
GREATER GREENVILLE-SPARTANBURG-
741 PM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL SPARTANBURG AND EASTERN
GREENVILLE COUNTIES THROUGH 830 PM EDT...

AT 734 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR GREER...OR 10 MILES NORTHEAST OF DOWNTOWN
GREENVILLE...MOVING EAST AT 20 MPH.

THIS STORM WILL BE NEAR...
  GSP AIRPORT...
  DUNCAN...
  REIDVILLE...
  ROEBUCK...

VERY HEAVY RAINFALL...SMALL HAIL...AND WIND GUSTS OF 40 TO 50 MPH
ARE EXPECTED WITH THIS STORM.

FREQUENT 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.

LAT...LON 3487 8237 3504 8232 3504 8228 3503 8180
      3470 8191

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
747 PM EDT SUN AUG 21 2011

NCZ036-056-069-071-220030-
CATAWBA-IREDELL-LINCOLN-MECKLENBURG-
747 PM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN LINCOLN...NORTHERN
MECKLENBURG...SOUTHEASTERN CATAWBA AND SOUTHERN IREDELL COUNTIES
THROUGH 830 PM EDT...

AT 743 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR MAIDEN...OR 6 MILES SOUTHEAST OF NEWTON...
MOVING EAST AT 15 MPH.

THIS STORM WILL BE NEAR...
  DENVER...
  TERRELL...
  LAKE NORMAN...
  CORNELIUS...

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

FREQUENT 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.

LAT...LON 3539 8082 3552 8129 3570 8123 3566 8077
      3565 8076

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
803 PM EDT SUN AUG 21 2011

NCZ082-220030-
UNION-
803 PM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT EASTERN UNION COUNTY THROUGH 830
PM EDT...

AT 759 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR WINGATE...OR 7 MILES EAST OF MONROE...MOVING
EAST AT 20 MPH.

THIS STORM WILL BE NEAR...
  MARSHVILLE...
  STURDIVANTS...

VERY HEAVY RAINFALL...SMALL HAIL...AND WIND GUSTS OF 40 TO 50 MPH
ARE EXPECTED WITH THIS STORM.

FREQUENT 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.

LAT...LON 3496 8029 3495 8030 3483 8031 3483 8053
      3508 8048 3511 8029 3503 8029

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
813 PM EDT SUN AUG 21 2011

NCZ068>070-220100-
CLEVELAND-GASTON-LINCOLN-
813 PM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL CLEVELAND...SOUTHERN
LINCOLN AND WESTERN GASTON COUNTIES THROUGH 900 PM EDT...

AT 808 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR KINGSTOWN...OR 5 MILES NORTHWEST OF
SHELBY...MOVING EAST AT 20 MPH.

THIS STORM WILL BE NEAR...
  SHELBY...
  CHERRYVILLE...
  KINGS MOUNTAIN...
  BESSEMER CITY...

VERY HEAVY RAINFALL...SMALL HAIL...AND WIND GUSTS OF 40 TO 50 MPH
ARE EXPECTED WITH THIS STORM.

LAT...LON 3544 8115 3519 8118 3526 8170 3544 8168

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
820 PM EDT SUN AUG 21 2011

SCZ009-014-220045-
CHESTER-YORK-
820 PM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN CHESTER AND
SOUTHEASTERN YORK COUNTIES THROUGH 845 PM EDT...

AT 816 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 4 MILES SOUTHWEST OF EDGEMOOR...OR 10 MILES
NORTHEAST OF CHESTER...MOVING EAST AT 20 MPH.

THIS STORM WILL BE NEAR...
  RICHBURG...
  CATAWBA...
  FORT LAWN...

VERY HEAVY RAINFALL...SMALL HAIL...AND WIND GUSTS OF 40 TO 50 MPH
ARE EXPECTED WITH THIS STORM.

FREQUENT 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.

LAT...LON 3467 8088 3463 8089 3471 8118 3488 8113
      3486 8086 3484 8086 3482 8089 3477 8086
      3474 8087 3469 8085

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
832 PM EDT SUN AUG 21 2011

NCZ070>072-220115-
CABARRUS-GASTON-MECKLENBURG-
832 PM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL MECKLENBURG...
NORTHEASTERN GASTON AND WESTERN CABARRUS COUNTIES THROUGH 915 PM
EDT...

AT 829 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR MOUNTAIN ISLAND LAKE...OR 10 MILES NORTHWEST
OF CENTER CITY CHARLOTTE...MOVING EAST AT 20 MPH.

THIS STORM WILL BE NEAR...
  PAW CREEK...
  HUNTERSVILLE...
  I-77 AT I-85...
  UNC CHARLOTTE...
  HARRISBURG...

VERY HEAVY RAINFALL...SMALL HAIL...AND WIND GUSTS OF 40 TO 50 MPH
ARE EXPECTED WITH THIS STORM.

LAT...LON 3520 8054 3521 8055 3513 8065 3524 8108
      3540 8105 3540 8096 3543 8095 3546 8050

07