Severe Thunderstorm Warning 365, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
152 PM EDT THU JUL 31 2008

.SYNOPSIS...
A SURFACE BOUNDARY WILL CROSS THE AREA THIS AFTERNOON...BEFORE WASHING
OUT TO THE SOUTH ON FRIDAY. A COLD FRONT WILL MOVE IN FROM THE NORTH
SATURDAY AND STALL OVER THE AREA FOR THE FIRST PART OF THE
WEEK...BEFORE MOVING BACK TO THE NORTH TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
LATEST SOUNDINGS SHOW HIGH FREEZING LEVELS AND PW/S OVER 2 INCHES AT
FFC AND OHX. SO THE UPSTREAM AIRMASS IS VERY MOIST AND WARM.
THEREFORE...DON/T EXPECT A LOT OF ICE ABOVE THE FREEZING LEVEL IN
TSTMS THIS AFTERNOON. I DO...HOWEVER...EXPECT GOOD CONVECTIVE
COVERAGE AS MORNING UPPER AIR SHOWED THE LLVL THERMAL AXIS RIGHT
OVER THE FA WITH THE MOIST AXIS DROPPING INTO THE REGION FROM THE
NORTH. SUB-CLOUD TEMP/DWPT DEPRESSIONS WILL LIKELY RISE TO AROUND 20
TO 25 DEG THIS AFTERNOON...AND COULD BE A LITTLE HIGHER WITH A
LITTLE DOWNSLOPE AND CLEARING. WITH STORMS ALREADY OVER ERN TN...WE
SHOULD HAVE PLENTY OF LIFT THIS AFTERNOON IN THE FORM OF OUTFLOW
BOUNDARIES AND DIFFERENTIAL HEATING BETWEEN THE WEST AND EAST SLOPES
OF THE APPALACHIANS. WITH BULK SHEAR UP AROUND 15 TO 20 KTS...STORMS
MOVEMENT SHOULD BE OVER 10 MPH...WHICH WILL LIMIT MICROBURST
POTENTIAL A LITTLE. ALL THIS SAID...THERE WILL BE AMPLE TRIGGERING
MECHANISMS FOR STORMS...AND A GOOD CHANCE OF SOME UPSCALE
ORGANIZATION EAST OF THE MOUNTAINS. WILL BUMP POPS UP TO LIKELY
ACROSS ALL NC ZONES...AND INTO THE CAT RANCE OVER THE NRN MTNS. I
DON/T THINK THE VERY MOIST AND WARM AIRMASS WILL SUPPORT A LOT OF
SEVERE STORMS...BUT AREAS IN THE LEE...WHERE DOWNSLOPE WILL STEEPEN
LLVL LAPSE RATES...WILL STAND THE BEST CHANCE OF SEEING SEVERE
STORMS...MAINLY IN THE FORM OF DAMAGING WINDS.

SEVERE STORMS MAY NEED 50-55 DBZ VALUES BETWEEN 32-34 KFT...OR 65
DBZ VALUES AROUND 20 KFT. MULTICELL STORMS MAY SHOW A MARC SIGNATURE
BETWEEN 13-15 KFT BEFORE PRODUCING SEVERE WINDS.

TSRA SHOULD PUSH EAST OF THE CWA BY MIDNIGHT. DEBRIS CLOUDS SHOULD
GRADUALLY THIN...ALLOWING TEMPERATURES TO REACH THE MID TO LOW 60S
IN THE MTN VALLEYS WITH WEAK CAA. TEMPERATURES EAST OF THE MTNS
SHOULD FALL AROUND 70. PRE DAWN PATCHY FOG COULD DEVELOP IN THE MTN
VALLEYS...LIMITING VIS BETWEEN 3-5 MILES.

&&

.SHORT TERM /FRIDAY THROUGH MONDAY NIGHT/...
AT 120 PM EDT THURSDAY...A S/W APPROACHES THE AREA FROM THE NW...AS
IT ROUNDS THE WRN SIDE OF AN EASTERN CONUS TROF. A WEAK FRONT/SFC
TROF ASSOC WITH THIS ENERGY IS EXPECTED TO REMAIN N OF THE AREA THRU
SATURDAY AFTN. MEANWHILE...BOTH THE GFS AND ECMWF HAVE A STALLED
BNDRY ALONG THE GULF COAST...KEEPING THE DEEP GULF AND ATLANTIC
MOISTURE S OF THE AREA. SO MEAGER MODEL QPF IS GENERATED WITH THE
PASSING S/W ACROSS THE SRN APPLNS. HENCE...I HAVE JUST A LOW-END CHC
POP FOR MOST OF THE MTNS AND NC FOOTHILLS/NW PIEDMONT...AND SCHC S.
AN AXIS OF 20-22C H8 TEMPS ACROSS THE SE STATES THRU THE CAROLINAS
SHUD ALLOW MAX TEMPS TO REACH THE MID/UPR 90S ACROSS MOST OF THE
PIEDMONT SATURDAY.

AXIS OF UPR TROF WILL SHIFT E OF THE APPLNS SATURDAY NIGHT...KEEPING
THE AREA UNDER NW FLOW FROM SUNDAY THRU MONDAY NIGHT. A MID LVL
RIDGE BUILDS OVR THE LWR MS VALLEY AND EWD...WITH RELATIVELY DRY HI
PRES AT THE SFC ALLOWING FOR A DRY FCST WITH SLIGHTLY ABV AVG MAX
TEMPS AND PLEASANT OVRNGT MINS (FOR EARLY AUG). A BLEND OF 00Z/31
MEX MOS AND HPC GUIDANCE WAS USED FOR SUNDAY AND MONDAY.

&&

.LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 130 PM THURSDAY...THE GFS AND THE ECMWF APPEARED TO BE IN
GOOD STANDING WITH EACH OTHER OUT UNTIL DAYS 6 AND 7...SO DECIDED
TO GO WITH THE HPC DECISION OF USING GFS FOR THE EXTENDED RANGE
FORECAST. A STRONG UPPER LEVEL RIDGE CONTINUES TO DOMINATE THE
REGION FROM 12Z WEDNEDSDAY THROUGH THE DAY THURSDAY UNTIL THE
RIDGE WEAKENS AND IS PUSHED OUT BY AN UPPER LEVEL TROF. THE WEAK
FRONT AHEAD OF THE TROF IS EXPECTED TO BRING SOME ISOLATED SHOWERS
AND THUNDERSTORMS TO THE NORTH CAROLINA MOUNTAINS STARTING
THURSDAY AFTERNOON AND CONTINUING THROUGH THE WEEKEND AS THE FRONT
APPROACHES THE AREA FROM THE NORTH. TEMPERATURES WILL RUN ANYWHERE
FROM 5 TO 8 DEGREES ABOVE NORMAL FOR THE CWFA UNTIL THE FRONT
PASSES THROUGH THE AREA...THEN TEMPERATURES WILL REMAIN AT OR
SLIGHTLY ABOVE NORMAL.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THUNDERSTORMS ARE BEGINNING TO ORGANIZE OVER THE NE FOOTHILLS. ATTM
THE ONLY SITE I/M HIGHLY CONFIDENT WILL GET TSTMS IS KHKY WHERE I
HAVE A TEMP GROUP THE NEXT FEW HOURS. IN FACT...LOOKING AT THE 35 KT
INBOUNDS JUST TO THEIR WEST ON THE TDWR...I/LL GO VRB 35KT. HAVE
VCTS AT ALL OTHER SITES...AND I/M FAIRLY CERTAIN THAT TSTMS WILL
AFFECT THE AIRFIELD AT KCLT LATER IN THE AFTERNOON. I/LL TEMPO THAT
WHEN I FEEL THEY ARE WITHIN 90 MIN TO 2 HOURS OF THE SITE. WINDS
THIS AFTERNOON WILL GENERALLY BE OUT OF THE WSW...EXPECT AT KAVL AND
KHKY WHERE A LEE TROUGH AS HAS ALREADY PASSED. CONVECTION SHOULD
LARGELY BE OVER BY 00 UTC...BUT I HAVE HELD ON TO VCTS LONGER AS A
PASSING UPPER LOW WILL KEEP SOME ACTIVITY GOING AFTER DARK. WINDS ON
FRIDAY ARE INTERESTING AS THE GFS HAS SW WINDS IN THE AFTERNOON
WHILE THE NAM HAS N. THEY USUALLY ARE NOT THIS FAR OFF...BUT I  AM
CONFIDENT THAT THE NAM IS A BETTER BET AS THE SREF WINDS ALSO HAVE A
NNW COMPONENT.

OUTLOOK...A COLD FRONT WILL APPROACH FROM THE NW SAT BRINGING A
CHANCE OF TSTMS. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT SUN
WITH FAIR CONDITIONS EARLY IN THE WEEK.

&&

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

&&

SYNOPSIS...SBK
NEAR TERM...MCAVOY
SHORT TERM...ARK
LONG TERM...SIEGEL
AVIATION...MCAVOY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
601 AM EDT THU JUL 31 2008

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-011015-
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-
601 AM EDT THU JUL 31 2008

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

.DAY ONE...TODAY AND TONIGHT.

A COLD FRONT WILL MOVE INTO THE AREA TODAY AND PRODUCE SCATTERED
TO NUMEROUS RAIN SHOWERS AND THUNDERSTORMS. THE ENVIRONMENT AHEAD
OF THIS FRONT WILL BE HIGHLY UNSTABLE AND SEVERAL THUNDERSTORMS
ARE EXPECTED TO REACH SEVERE LEVELS. STRONG DAMAGING WINDS...LARGE
HAIL AND HEAVY DOWNPOURS WILL ACCOMPANY THESE STRONGER
THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A HEAT ADVISORY MAY BE NEEDED IN PORTIONS OF THE FOOTHILLS AND
PIEDMONT MONDAY THROUGH WEDNESDAY FOR HOT TEMPERATURES COMBINED
WITH HUMIDITY.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

KRENTZ

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
110 PM EDT THU JUL 31 2008

NCZ053-065-311815-
BUNCOMBE-HENDERSON-
110 PM EDT THU JUL 31 2008

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN HENDERSON AND
SOUTHEASTERN BUNCOMBE COUNTIES THROUGH 215 PM EDT...

AT 106 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR FAIRVIEW...OR 9 MILES EAST OF ASHEVILLE...
MOVING EAST AT 25 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO FAIRVIEW...
  SWANNANOA...BLACK MOUNTAIN AND BAT CAVE.

WIND GUSTS OF 40 TO 50 MPH ARE EXPECTED WITH THIS STORM.

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
118 PM EDT THU JUL 31 2008

NCZ501>506-311815-
BURKE MOUNTAINS-CALDWELL MOUNTAINS-EASTERN MCDOWELL-GREATER
BURKE-GREATER CALDWELL-MCDOWELL MOUNTAINS-
118 PM EDT THU JUL 31 2008

...STRONG THUNDERSTORMS WILL AFFECT BURKE...CALDWELL AND NORTHERN
MCDOWELL COUNTIES THROUGH 215 PM EDT...

AT 112 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 4 MILES NORTHWEST OF
COLLETTSVILLE TO OLD FORT...MOVING EAST AT 24 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO RUTHERFORD
  COLLEGE...LAKE RHODHISS...LAKE JAMES...NEBO...PATTERSON...KINGS
  CREEK...VALDESE...TABLE ROCK...SAWMILLS...RHODHISS...PLEASANT
  GROVE...MORGANTON...MARION...LENOIR...ICARD...HUDSON...GRANITE
  FALLS...GLEN ALPINE...GAMEWELL...DREXEL...CONNELLY SPRINGS...
  COLLETTSVILLE AND CAJAHS MOUNTAIN.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THESE STORMS.

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.

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
144 PM EDT THU JUL 31 2008

NCZ056-069-504-311845-
CATAWBA-GREATER BURKE-LINCOLN-
144 PM EDT THU JUL 31 2008

...A STRONG THUNDERSTORM WILL AFFECT CATAWBA...EASTERN BURKE AND
NORTHEASTERN LINCOLN COUNTIES THROUGH 245 PM EDT...

AT 139 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 5 MILES SOUTH OF LONGVIEW...OR 7 MILES SOUTHWEST
OF HICKORY...MOVING EAST AT 20 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO TERRELL...
  NEWTON...MAIDEN...LONGVIEW...HILDEBRAN...HICKORY...DENVER...
  COOKSVILLE...CONOVER...CLAREMONT AND CATAWBA.

WIND GUSTS OF 40 TO 50 MPH ARE EXPECTED WITH THIS STORM.

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
147 PM EDT THU JUL 31 2008

NCZ036-037-057-311845-
DAVIE-IREDELL-ROWAN-
147 PM EDT THU JUL 31 2008

...A STRONG THUNDERSTORM WILL AFFECT DAVIE...NORTHERN IREDELL AND
NORTHWESTERN ROWAN COUNTIES THROUGH 245 PM EDT...

AT 144 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 9 MILES WEST OF HARMONY...OR 12 MILES NORTH OF
STATESVILLE...MOVING EAST AT 18 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO BERMUDA
  RUN...WOODLEAF...UNION GROVE...TURNERSBURG...SHEFFIELD...
  MOCKSVILLE...LOVE VALLEY...HARMONY...FORK CHURCH...FARMINGTON...
  COOLEEMEE AND ADVANCE.

WIND GUSTS OF 40 TO 50 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.

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
158 PM EDT THU JUL 31 2008

NCZ065-506>510-311900-
EASTERN MCDOWELL-EASTERN POLK-GREATER RUTHERFORD-HENDERSON-POLK
MOUNTAINS-RUTHERFORD MOUNTAINS-
158 PM EDT THU JUL 31 2008

...STRONG THUNDERSTORMS WILL AFFECT EASTERN HENDERSON...POLK...
RUTHERFORD AND SOUTHEASTERN MCDOWELL COUNTIES THROUGH 300 PM EDT...

AT 157 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM THERMAL CITY TO 7
MILES EAST OF FLAT ROCK...MOVING EAST AT 28 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO BOSTIC...
  THERMAL CITY...SUNSHINE...SPINDALE...SALUDA...RUTHERFORDTON...MILL
  SPRING...LAKE LURE...LAKE ADGER...HARRIS...FOREST CITY...FLAT
  ROCK...FERO...ELLENBORO...EAST FLAT ROCK...DANA...COLUMBUS...
  CLIFFSIDE AND ALEXANDER MILLS.

WIND GUSTS OF 40 TO 50 MPH ARE EXPECTED WITH THESE STORMS.

07