Severe Thunderstorm Warning 368, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
222 PM EDT THU AUG 27 2009

.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AS A UPPER LEVEL LOW
APPROACHES THE COAST OFF OF THE CAROLINAS. THE REMAINS OF THIS LOW
WILL CROSS THE AREA FRIDAY. MEANWHILE A COLD FRONT WILL MOVE IN FROM
THE WEST ON SATURDAY...CROSSING THE AREA ON SUNDAY. HIGH PRESSURE
WILL BUILD OVER THE AREA EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
DEEP SLY FLOW REMAINS OVER THE AREA TONIGHT AS AN UPPER LOW ALONG
THE GULF COAST MOVES EASTWARD. THIS KEEPS DEEP PLUME OF TROPICAL
MOISTURE OVER THE AREA. UPPER JET MAX AND SHORT WAVES MOVING AROUND
THE LOW MOVE INTO THE AREA AS WELL. THIS WILL LEAD TO INCREASING
FORCING AND UPPER DIVERGENCE OVERNIGHT. EVEN THOUGH INSTABILITY WILL
BE WEAK...THE FORCING AND MOISTURE WILL LEAD TO INCREASING
CONVECTIVE COVERAGE FROM WEST TO EAST. WITH VERY HIGH PRECIP WATER
VALUES...SLY FLOW AND DECENT FORCING...PERIODS OF HEAVY RAIN COULD
DEVELOP ACROSS THE WRN CWFA...ESP AFTER MIDNIGHT. WITH FLASH FLOOD
GUIDANCE RUNNING QUITE HIGH AND THE POSSIBILITY OF GULF COAST
CONVECTION ROBBING BEST LOW LEVEL MOISTURE TRANSPORT...DO NOT EXPECT
ANY WIDESPREAD FLOODING. HOWEVER...IF CELLS TRAIN OR BECOME ANCHORED
TO TERRAIN...ISOLATED FLOODING IS CERTAINLY POSSIBLE. LOWS SHOULD BE
WARM AND MUGGY WITH INCREASING CLOUDS AND PRECIP.

THIS GENERAL SCENARIO CONTINUES FRIDAY AS THE UPPER LOW SLOWLY OPENS
AND TURNS NORTHEAST. THE VERY MOIST ATMOSPHERE REMAINS OVER THE AREA
WITH GOOD UPPER DIVERGENCE AND FORCING CONTINUING. EXPECT AT LEAST
LIKELY COVERAGE OF CONVECTION SPREADING ACROSS THE AREA THRU THE
DAY. THE HEAVY RAIN THREAT CONTINUES WITH ALL THESE MAJOR FEATURES
REMAINING IN PLACE. THE POTENTIAL LIMITING FACTOR OF GULF COAST
CONVECTION ALSO CONTINUES...SO WILL HAVE TO SEE HOW MUCH RAIN FALLS
OVERNIGHT TO DETERMINE IF WIDESPREAD FLOODING BECOMES MORE PROBABLE.
THE ISOLATED THREAT WILL CONTINUE THOUGH. HIGHS WILL BE WELL BELOW
NORMAL WITH THE CLOUDS AND PRECIP.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AS OF 205 PM THU...AS THE AREA OF UPPER FORCING/DEEP LAYER MOISTURE
LIFTS TO THE NORTHEAST...LIKELY POPS WILL BE MAINTAINED ACROSS THE
NORTHWEST NC PIEDMONT/NRN FOOTHILLS FRI EVENING...BEFORE DIMINISHING
TO SLIGHT/LOW CHANCES AFTER MIDNIGHT. ALTHOUGH THE DEEPER TROPICAL
MOISTURE WILL BE NORTHEAST OF THE CWFA ON SATURDAY...A FRONTAL
BOUNDARY APPROACHES FROM THE WEST DURING THE AFTERNOON...DRAWING
ADDITIONAL MOISTURE FROM THE GULF. HOWEVER...DO NOT SEE MUCH SUPPORT
FOR ANYTHING OTHER THAN LOW/MID CHANCE POPS SATURDAY AFTERNOON. WITH
THE FRONT SLOWLY PUSHING ACROSS THE AREA SATURDAY NIGHT INTO
SUNDAY...CHANCE POPS WILL LINGER THROUGH THE END OF THE SHORT TERM.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM THU...THE GLOBAL MODELS ARE IN FAIRLY SOLID AGREEMENT
IN DEPICTING A MAINLY DRY AND UNSEASONABLY MILD MEDIUM RANGE...AS
THE LONG WAVE PATTERN WILL FAVOR AN EASTERN TROUGH THROUGH THE
PERIOD. OTHER THAN SOME SLIGHT CHANCE POPS EARLY IN THE PERIOD...
MAINLY NEAR THE DEEPER MOISTURE ACROSS THE SOUTHERN AND SOUTHEAST
TIER OF THE CWFA...THE FORECAST WILL BE DRY. OTHERWISE...TEMPS ARE
EXPECTED TO BE DOWNRIGHT PLEASANT ACROSS MUCH OF THE AREA DURING THE
FIRST HALF OF THE WEEK...WITH MAXES EXPECTED TO AVERAGE A SOLID
CATEGORY BELOW CLIMATOLOGY.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
KCLT AND ELSEWHERE...SCT CONVECTION WILL CONTINUE THRU THE AFTERNOON
IN THE DEEP MOISTURE...WEAK INSTABILITY AND SLY FLOW. BEST CHC FOR
ANY TERMINAL AFFECTS WILL BE THE SC SITES AND KAVL.

CONVECTION WILL WEAKEN BUT CONTINUE INTO THE EVENING AS DEEP
MOISTURE AND SLY FLOW CONTINUE AHEAD OF AN APPROACHING UPPER LEVEL
LOW. EXPECT A BRIEF INCREASE IN CIGS BEFORE WRN SITES BECOME MVFR
TOWARD MORNING. PRECIP COVERAGE...AND MVFR VSBY...WILL INCREASE FROM
WEST TO EAST AS THE BETTER FORCING MOVES IN. LOOKS LIKE KCLT HAS THE
LEAST CHC FOR ANY RESTRICTIONS DUE TO EXPECTED TIMING OF PRECIP
ONSET. EXPECT GOOD COVERAGE OF PRECIP TO CONTINUE FRIDAY MORNING
WITH SOME IMPROVEMENT TO LOW VFR. THAT SAID...CANNOT RULE OUT IFR
ESPECIALLY AROUND DAYBREAK AT THE WRN SITES.

WINDS WILL BE LIGHT SOUTH THE SE THIS AFTERNOON AND EARLY EVENING.
LIGHT AND VARIABLE WINDS WILL CONTINUE THRU THE REST OF THE PERIOD.
HOWEVER...NE WINDS COULD BECOME THE PREDOMINANT DIRECTION DURING THE
MORNING.

OUTLOOK...SHOWERS AND THUNDERSTORMS WILL CONTINUE FRIDAY
AFTERNOON...ALONG WITH POSSIBLE CIG AND VSBY RESTRICTIONS.
CONDITIONS WILL REMAIN UNSETTLED SATURDAY AND SUNDAY AS A COLD FRONT
FRONT CROSSES THE REGION. BETTER WEATHER IS EXPECTED MONDAY AND
TUESDAY.

&&

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

&&

SYNOPSIS...PAT
NEAR TERM...RWH
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...RWH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
313 PM EDT THU AUG 27 2009

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-281915-
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-
313 PM EDT THU AUG 27 2009

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP ACROSS THE AREA THIS EVENING THROUGH THE OVERNIGHT HOURS.
ALTHOUGH THE MAIN HAZARDS FROM THESE THUNDERSTORMS WILL BE CLOUD
TO GROUND LIGHTNING AND HEAVY RAINFALL...LOCALLY EXCESSIVE
RAINFALL AND ISOLATED FLASH FLOODING WILL BE POSSIBLE. URBAN
AREAS AND MOUNTAINOUS TERRAIN WILL BE ESPECIALLY SUSCEPTIBLE TO
FLOODING THROUGH TONIGHT.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTERS ARE REQUESTED TO FORWARD ANY REPORTS OF FLASH
FLOODING TO OUR OFFICE.

LANE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
250 PM EDT THU AUG 27 2009

NCZ033-501-503-271945-
AVERY-BURKE MOUNTAINS-CALDWELL MOUNTAINS-
250 PM EDT THU AUG 27 2009

...THUNDERSTORMS PRODUCING HEAVY RAINFALL WILL AFFECT NORTHWESTERN
BURKE...NORTHWESTERN CALDWELL AND SOUTHEASTERN AVERY COUNTIES
THROUGH 345 PM EDT...

AT 248 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
NEARLY STATIONARY THUNDERSTORM NEAR JONAS RIDGE...OR 7 MILES SOUTH
OF NEWLAND. THIS THUNDERSTORM WAS PRODUCING RAINFALL AT THE RATE OF
1 TO 2 INCHES PER HOUR...AND WILL LIKELY CONTINUE TO PRODUCE HEAVY
RAINFALL THROUGH 4 PM.

MOST AFFECTED IN THIS AREA WILL BE THE LINVILLE RIVER...WILSON
CREEK...AND HARPER CREEK. STREAM LEVELS MAY APPROACH OR EXCEED
BANKFULL IN THESE AREAS...AND DEEP STANDING WATER WILL LIKELY
DEVELOP IN NEARBY LOW LYING AREAS.

HG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
331 PM EDT THU AUG 27 2009

GAZ010-017-018-NCZ062>065-SCZ001>005-272100-
RABUN-HABERSHAM-STEPHENS-MACON-SOUTHERN JACKSON-TRANSYLVANIA-
HENDERSON-OCONEE MOUNTAINS-PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-
GREATER OCONEE-GREATER PICKENS-
INCLUDING THE CITIES OF...CLAYTON...CLARKESVILLE...TOCCOA...
FRANKLIN...BREVARD...HENDERSONVILLE
331 PM EDT THU AUG 27 2009

...HEAVY RAINFALL TO AFFECT THE EXTREME SOUTHERN APPALACHIANS
THROUGH 5 PM THIS EVENING...

A LINE OF HEAVY SHOWERS AND STRONG THUNDERSTORMS WILL MOVE SLOWLY
NORTHWEST ACROSS THE WESTERN UPSTATE OF SOUTH CAROLINA...AND REACH
THE NORTHEAST GEORGIA AND SOUTHERN NORTH CAROLINA MOUNTAINS
THROUGH 5 PM THIS EVENING. THESE THUNDERSTORMS WILL PRODUCE
RAINFALL AT RATES UP TO TWO INCHES PER HOUR...AND COULD PRODUCE
ISOLATED FLOODING AND DEEP PONDING OF WATER ON ROADWAYS. THE
HEAVIEST RAINFALL WILL AFFECT THE AREA FROM ROCKY BOTTOM TO
WALHALLA THROUGH 415 PM...AND THEN LIKELY STRETCH FROM ROSMAN TO
CASHIERS TO CLAYTON GEORGIA BY 5 PM. FLOOD ADVISORIES OR FLASH
FLOOD WARNINGS COULD BE NEEDED IN THIS AREA IF ANY OF THE HEAVY
SHOWERS PERSIST AGAINST THE EASTERN SLOPES OF THE HIGH TERRAIN.

GERAPETRITIS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
355 PM EDT THU AUG 27 2009

SCZ013-272045-
UNION-
355 PM EDT THU AUG 27 2009

...A STRONG THUNDERSTORM WILL AFFECT UNION COUNTY IN SOUTH CAROLINA
THROUGH 445 PM EDT...

AT 355 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR UNION...MOVING NORTHWEST AT 10 MPH.

THIS STORM WILL BE NEAR...
  UNION...
  BUFFALO...
  JONESVILLE...

PEA SIZE HAIL...AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM.

HG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
428 PM EDT THU AUG 27 2009

SCZ007-012-013-272130-
LAURENS-SPARTANBURG-UNION-
428 PM EDT THU AUG 27 2009

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN LAURENS...
SOUTHEASTERN SPARTANBURG AND WESTERN UNION COUNTIES THROUGH 530 PM
EDT...

AT 428 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR CROSS KEYS...OR 10 MILES SOUTHWEST OF
UNION...MOVING NORTHWEST AT 10 MPH.

THIS STORM WILL BE NEAR...
  ENOREE...

SMALL HAIL...AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS
STORM...AND PERHAPS WELL AHEAD OF THE MAIN THUNDERSTORM DOWNPOURS.

HG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
444 PM EDT THU AUG 27 2009

NCZ053-272130-
BUNCOMBE-
444 PM EDT THU AUG 27 2009

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL BUNCOMBE COUNTY THROUGH
530 PM EDT...

AT 445 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR ASHEVILLE...MOVING NORTH AT 5 MPH.

THIS STORM WILL BE NEAR...
  ASHEVILLE...
  DOWNTOWN ASHEVILLE...
  UNC ASHEVILLE...
  WOODFIN...

SMALL HAIL...AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM.

HG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
512 PM EDT THU AUG 27 2009

GAZ010-272200-
RABUN-
512 PM EDT THU AUG 27 2009

...VERY HEAVY RAINFALL WILL AFFECT WESTERN RABUN COUNTY THROUGH 600
PM EDT...

AT 509 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SERIES OF THUNDERSTORMS MOVING SLOWLY NORTHWEST ACROSS THE WESTERN
HALF OF RABUN COUNTY. THESE THUNDERSTORMS WERE PRODUCING RAINFALL AT
RATES UP TO 2 INCHES PER HOUR...AND THESE HEAVY RAINFALL RATES WILL
LIKELY CONTINUE THROUGH 600 PM EDT.

RAPID STREAM RISES ARE EXPECTED ALONG DICKS CREEK...SOUTH FORK
MOCCASIN CREEK... AND NEARBY TRIBUTARIES TO THE TALLULAH RIVER. DEEP
PONDING OF WATER WILL ALSO DEVELOP IN LOW SPOTS IN AREA ROADWAYS.
USE CAUTION IF TRAVELING IN THESE AREAS AND BE ON THE LOOKOUT FOR
HIGH WATER CONDITIONS.

HG