Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
443 PM EDT SAT SEP 8 2012

.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE CAROLINAS AND NORTHEAST GEORGIA
THROUGH TONIGHT...PUSHING EAST OF THE AREA BY DAYBREAK SUNDAY. DRY
HIGH PRESSURE WILL BUILD IN FROM THE NORTH SUNDAY AND REMAIN IN
PLACE THROUGH THE END OF NEXT WEEK.

&&

.NEAR TERM /THROUGH SUNDAY/...
430 PM EDT UPDATE...THE LATEST STRONGER CONVECTION IS REMAINING
MARGINALLY SEVERE TO SEVERE WITH A COUPLE STORMS PRODUCING THICK
ELEVATED CORES AND 40+ KT OUTFLOWS...THUS AN ISOL SEVERE THREAT
CONTINUES. WITH RELATIVELY WEAK SBCAPE AND DECENT BULK
SHEAR...EXPECT THIS TREND TO CONTINUE OVER THE NEXT FEW HRS AS THE
PREFRONTAL LINE MOVES EAST AT ABOUT 25 MPH. PERHAPS 2-4 MORE SVRS
NEEDED OVER THE NEXT 3 HRS. POPS WERE ADJ SPATIALLY WITH THE HIGHER
AMOUNTS EAST PER RADAR COMP AND EXT IN TIME AND GRADUALLY DECREASING
FROM THE WEST ACROSS THE CWFA TIL 04Z PER THE LATEST WRF/HRRR
PROGS.

CONCERN FOR THE FIRST FEW HOURS OF THE PERIOD CONTINUES TO THE THE
FRONTAL PASSAGE AND ASSOCIATED PRECIP/CONVECTION. THE GREATEST
INSTABILITY AT ALL SITES WILL OCCUR BEFORE THE BETTER SHEAR SETS
IN...BUT THE BEST OVERLAP SHOULD BE IN THE LOWER PIEDMONT AREAS AS
ADVERTISED BY MODELS FOR THE PAST COUPLE OF DAYS. CLEARER SKIES THIS
AFTERNOON EAST AND SOUTH WILL ALLOW MORE DESTABILIZATION BEFORE THE
FRONT MOVES THROUGH. WE WILL PROBABLY SEE SOME DEVELOPMENT OVER THE
MOUNTAINS EARLY...WHICH SHOULD BE PRETTY TAME...FOLLOWED BY MORE
DEVELOPMENT OVER THE PIEDMONT.

AS FAR AS THE THREAT OF ORGANIZED OR SEVERE TSTMS...NOT ESPECIALLY
HIGH BUT THEY DEFINITELY CANNOT BE RULED OUT. 0-6KM BULK SHEAR IS
NOT PARTICULARLY STRONG /GENERALLY LESS THAN 30 KT/ BUT DEEP SHEAR
VECTORS WILL BE MOSTLY PARALLEL TO THE FRONT WHICH SUGGESTS
CONVECTION WILL FORM INTO A BROKEN LINE. FREEZING LEVELS OF 12-14
KFT ARE ON THE HIGH SIDE WHICH IS UNFAVORABLE FOR LARGE HAIL.
DAMAGING WINDS WILL BE A MORE SIGNIFICANT THREAT GIVEN DEEP MIXING
AND DRY MIDLEVEL AIR AHEAD OF THE FRONT.

MIDLEVEL RH IS UNDERSTANDABLY HIGH NEAR THE FRONT BUT DRIES OUT
QUICKLY AS BASE OF 500MB TROUGH ROLLS THROUGH OVERNIGHT. LOW LEVEL
RH STAYS FAIRLY HIGH. WE WILL PROBABLY SEE A FAIRLY SHARP LINE OF
CLEARING AS THE TROUGH PUSHES THROUGH BUT SOME PATCHY FOG MAY
DEVELOP LATE. ADDED A COMPONENT OF RAW MODEL TEMPS TO TONIGHT/S LOW
TEMP FORECAST SINCE THE FROPA IS NOT A CLIMATOLOGICALLY COMMON
OCCURRENCE...WHICH BROUGHT TEMPS DOWN A TAD ESPECIALLY OVER THE
MOUNTAINS.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF NOON SATURDAY...HIGH PRESSURE WILL BRING SUNNY AND MILD
WEATHER TO THE REGION MONDAY AND TUESDAY. DEWPOINTS WILL MIX INTO
THE U40S TO L50S DURING THE DAY WHICH WILL FEEL GREAT AFTER THE
RECENT SPELL OF VERY MUGGY CONDITIONS. TEMPERATURES WILL RUN 1 TO 2
CATEGORIES BELOW NORMAL. FOR AGENCIES INTERESTED IN CONTROLLED
BURNS...THE HUMIDITY VALUES ARE GENERALLY EXPECTED TO RUN BETWEEN 30
AND 40 PERCENT IN THE AFTERNOON HOURS. I DON/T SEE STRONG DOWNSLOPE
FLOW OR ANYTHING THAT SHOULD CAUSE THE DEWPOINTS TO VERIFY
APPRECIABLY LOWER...WHICH MEANS BURNING CONDITIONS WILL GENERALLY BE
GOOD WITH AFTERNOON MIXING HEIGHTS UP AROUND 6 TO 7 KFT. THE ONLY
CONCERN WILL BE VERY LIGHT WINDS EACH DAY AS THE BNDRY LAYER FLOW
WILL BE UNDER 5KTS.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 1200 PM SATURDAY...THE LATEST MEDIUM RANGE MODELS CONTINUE TO
INDICATE THAT BROAD UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN
ANCHORED OVER THE EASTERN CONUS THROUGH LATE IN THE WEEK. WITH
PERSISTENT N/NE FLOW AND STRONG CAPPING INVERSION ALOFT...WILL
FORECAST DRY THROUGH FRIDAY. TEMPERATURES WILL REMAIN 2-3
DEGREES BELOW NORMAL WITH AFTERNOON HIGHS IN THE LOW 80S OVER THE
PIEDMONT AND 70S FOOTHILLS/MOUNTAINS.

SATURDAY INTO SUNDAY MORNING...BOTH THE LATEST GFS AND THE ECMWF ARE
IN FAIRLY GOOD AGREEMENT ON A POSITIVELY TILTED UPPER TROUGH OVER
THE NORTHERN PLAINS FRIDAY PROGRESSING EASTWARD ACROSS THE OHIO
VALLEY ON LATE SATURDAY...BUT STILL KEEPS AN ASSOCIATED COLD FRONT
TO OUR WEST THRU THE PERIOD. WITH INCREASING MOISTURE AND DIURNAL
INSTABILITY AHEAD OF THE APPROACHING COLD FRONT...I MENTIONED SLIGHT
CHANCE FOR AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS OUR CWA ON
SATURDAY. TEMPERATURES WILL MODERATE TO NEAR NORMAL.

&&

.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
AT KCLT...THUNDER LOOKING HIGHLY LIKELY FOR A TIME THIS AFTERNOON
AND EARLY EVENING AHEAD OF AND ALONG COLD FRONT. REFLECTED THIS WITH
A TEMPO TSRA TO INDICATE LOWER CONFIDENCE IN START TIME...BUT BY 20Z
FEEL THERE WILL BE ONGOING CONVECTION ALL AROUND THE AIRPORT.
ACTIVITY SHOULD DIMINISH WITH THE SETTING SUN AND LOSS OF
INSTABILITY...BUT ISOLATED SHOWERS/STORMS MAY HOLD ON THROUGH THE
EVENING. GUIDANCE DID NOT PRODUCE ANY LOW CIGS OR VSBYS EARLY
SUNDAY BUT GIVEN THE DRY MID TO UPPER LEVELS BEHIND THE FRONT AND
MOIST LOW LEVELS...THREW IN AN MVFR CIG LATE. WINDS WILL GENERALLY
BE SOUTH TO SOUTHWESTERLY THIS AFTERNOON BUT SHOULD WHIP AROUND TO
THE NORTH BEHIND THE FRONT. THUNDERSTORM OUTFLOW NEAR THE AIRPORT
MAY CAUSE RAPID WIND SHIFTS.

ELSEWHERE...INCLUDED VARIATIONS ON THE THUNDER MENTION THIS
AFTERNOON TO REFLECT CURRENT PATTERN OF STORMS...AND TRIED TO
INDICATE APPROPRIATE END TIMES GIVEN MOVEMENT OF FRONT.
AFOREMENTIONED CLEARING BEHIND FRONT WITH LINGERING LOW LEVEL
MOISTURE POINTED TO A RISK OF FOG OR LOW STRATUS. GUIDANCE FAVORED
FOG. THIS IS INCLUDED AT KAVL...WITH A MVFR MENTION INCLUDED AT
KHKY. THE SAME IDEA OUTLINED ABOVE REGARDING WIND SHIFTS WITH
VICINITY THUNDERSTORMS APPLIES AT ALL SITES TODAY.

OUTLOOK...DRY AUTUMNAL HIGH PRES WILL DOMINATE THE WEATHER OVER THE
REGION SUNDAY THROUGH LATE NEXT WEEK.

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...JOH
NEAR TERM...JW/SBK
SHORT TERM...MCAVOY
LONG TERM...JOH
AVIATION...JW

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1255 PM EDT SAT SEP 8 2012

GAZ010-017-018-026-028-029-NCZ035>037-056-057-068>072-082-501>510-
SCZ001>014-019-091700-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-ALEXANDER-IREDELL-
DAVIE-CATAWBA-ROWAN-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-
1255 PM EDT SAT SEP 8 2012

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

NUMEROUS THUNDERSTORMS WILL DEVELOP ACROSS THE FOOTHILLS AND
PIEDMONT OF THE WESTERN CAROLINAS AND NORTHEAST GEORGIA THIS
AFTERNOON AND EVENING AS A COLD FRONT MOVES OUT OF THE MOUNTAINS.
WITH A VERY UNSTABLE AIRMASS IN PLACE AND INCREASING SHEAR...SOME
OF THE THUNDERSTORMS ARE LIKELY TO BECOME SEVERE...PRODUCING
DAMAGING STRAIGHT LINE WINDS AND A FEW INSTANCES OF LARGE HAIL.

THE STORMS WILL BECOME MORE ORGANIZED AS THEY MOVE TO THE EAST.
THEREFORE...THE GREATEST SEVERE THREAT WILL BE ACROSS THE PIEDMONT
OF THE CAROLINAS...ESPECIALLY ALONG THE I-77 URBAN CORRIDOR AND
THE UPSTATE EAST OF GREENVILLE. THERE IS EVEN A THREAT OF A
BRIEF...ISOLATED TORNADO OVER THE WESTERN NORTH CAROLINA PIEDMONT
THIS AFTERNOON AND EARLY EVENING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

DISPATCHERS PLEASE FORWARD THIS INFORMATION ON TO EMERGENCY
MANAGERS AND OTHER COUNTY OFFICIALS. SKYWARN SPOTTERS ARE
REQUESTED TO FORWARD ANY REPORTS OF LARGE HAIL...DAMAGING
WINDS...TORNADOES OR FLASH FLOODING TO OUR OFFICE.

NCZ033-048>053-058-059-062>065-091700-
AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-
NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-
1255 PM EDT SAT SEP 8 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

MCAVOY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
420 PM EDT SAT SEP 8 2012

SCZ006-010-082100-
ANDERSON-GREATER GREENVILLE-
420 PM EDT SAT SEP 8 2012

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN ANDERSON AND
SOUTHEASTERN GREENVILLE COUNTIES THROUGH 500 PM EDT...

AT 416 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 5 MILES EAST OF SANDY SPRINGS...OR 7 MILES NORTH
OF ANDERSON...MOVING EAST AT 25 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO DONALDSON
  CENTER...WILLIAMSTON...SIMPSONVILLE...PRINCETON...PIEDMONT...
  PELZER...FOUNTAIN INN...FORK SHOALS...BELTON AND ANDERSON.

SMALL HAIL...WIND GUSTS OF 40 TO 50 MPH AND TORRENTIAL RAIN ARE
EXPECTED WITH THIS STORM.

FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF OUTDOORS...TRY TO
GET INDOORS OR INTO A HARD TOPPED VEHICLE. OTHERWISE...STAY AWAY FROM
OPEN AREAS AND ISOLATED HIGH OBJECTS SUCH AS TREES. WHEN INDOORS...
STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING WIRED ELECTRONIC
DEVICES. TRY TO UNPLUG UNNECESSARY APPLIANCES BEFORE THE STORM
APPROACHES.

LAT...LON 3452 8273 3469 8276 3470 8273 3480 8217
      3474 8216 3459 8224 3454 8224 3449 8230

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
425 PM EDT SAT SEP 8 2012

SCZ002-003-005-006-082115-
GREATER GREENVILLE-GREATER PICKENS-GREENVILLE MOUNTAINS-PICKENS
MOUNTAINS-
425 PM EDT SAT SEP 8 2012

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL GREENVILLE AND EASTERN
PICKENS COUNTIES THROUGH 515 PM EDT...

AT 421 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR DACUSVILLE...OR 9 MILES NORTHWEST OF
DOWNTOWN GREENVILLE...MOVING EAST AT 25 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO PELHAM ROAD
  AT I-85...CHERRYDALE POINT...LAKE ROBINSON...HAYWOOD MALL...FURMAN
  UNIVERSITY...WELCOME...TRAVELERS REST...TAYLORS...PARIS MOUNTAIN
  STATE PARK...GREER...DOWNTOWN GREENVILLE...EASLEY...DACUSVILLE AND
  BEREA.

SMALL HAIL...WIND GUSTS OF 40 TO 50 MPH AND TORRENTIAL RAIN ARE
EXPECTED WITH THIS STORM.

FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF OUTDOORS...TRY TO
GET INDOORS OR INTO A HARD TOPPED VEHICLE. OTHERWISE...STAY AWAY FROM
OPEN AREAS AND ISOLATED HIGH OBJECTS SUCH AS TREES. WHEN INDOORS...
STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING WIRED ELECTRONIC
DEVICES. TRY TO UNPLUG UNNECESSARY APPLIANCES BEFORE THE STORM
APPROACHES.

LAT...LON 3498 8265 3508 8222 3485 8222 3480 8260

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
453 PM EDT SAT SEP 8 2012

NCZ057-071-072-082145-
CABARRUS-MECKLENBURG-ROWAN-
453 PM EDT SAT SEP 8 2012

...STRONG THUNDERSTORMS WILL AFFECT CABARRUS...MECKLENBURG AND
SOUTHEASTERN ROWAN COUNTIES THROUGH 545 PM EDT...

AT 450 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 4 MILES NORTHEAST OF
MOUNT PLEASANT TO 4 MILES WEST OF SOUTHPARK MALL...MOVING EAST AT 25
MPH.

THESE STORMS WILL IMPACT LOCATIONS NEAR...
  SOUTHPARK MALL...
  MINT HILL...
  MIDLAND...

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

HEAVY RAINS MAY FLOOD AREAS WITH POOR DRAINAGE...SUCH AS DITCHES AND
UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS. WATER
LEVELS OF SMALL STREAMS AND RIVERS MAY ALSO RISE RAPIDLY. SEEK HIGHER
GROUND IF THREATENED BY FLOOD WATERS.

LAT...LON 3550 8030 3524 8046 3520 8054 3521 8055
      3519 8058 3504 8088 3506 8090 3511 8093
      3528 8099 3556 8055 3555 8020 3550 8018

JOH

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