Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
733 AM EDT MON OCT 15 2012

.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING. HIGH PRESSURE
WILL BUILD IN BEHIND THE FRONT TONIGHT THROUGH TUESDAY AND LINGER
INTO WEDNESDAY. ANOTHER COLD FRONT WILL APPROACH THE REGION LATE IN
THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 650 AM...LINE OF SH/TSRA AHEAD OF THE FRONT MOVING THRU THE
AREA ATTM. THERE COULD BE REDEVELOPMENT OVER THE ERN CWFA AS THE
ACTUAL FRONT MOVES IN DURING THE EARLY AFTERNOON. EXPECT WINDS TO
BECOME GUSTY WITH THE FRONT WITH CLEARING BEHIND THE FRONT. ADDED
PATCHY DENSE VALLEY FOG OVERNIGHT AS WELL.

SCT SHRA DEVELOPING ALONG THE BLUE RIDGE IN THE INCREASING LOW LEVEL
MOISTURE AND UPSLOPE FLOW AHEAD OF THE COLD FRONT OVER MIDDLE TN. A
BKN LINE OF CONVECTION CONTINUES TO SLOWLY MOVE TOWARD THE MTNS
AHEAD OF THE FRONT. EXPECT THE UPSLOPE SHRA TO INCREASE EVEN AS THE
CONVECTION MOVES INTO THE MTNS EARLY THIS MORNING. THE MESOSCALE
GUIDANCE HAS THIS TREND...BUT SOME MDLS INCREASE THE PRE-FRONTAL
PRECIP MUCH MORE RAPIDLY THAN OTHERS...OR THE SYNOPTIC SCALE MDLS.
HAVE FOLLOWED THE TRENDS OF THE MESOSCALE GUIDANCE...BUT LEFT OUT
THE RAPID INCREASE IN PRE-FRONTAL PRECIP. STILL...THIS MEANS A RAPID
INCREASE IN PRE-DAWN PRECIP OVER THE WESTERN CWFA. THIS PRECIP
SWINGS ACROSS THE CWFA AFTER DAYBREAK WITH PRECIP ENDING FROM SW TO
NE BY EARLY AFTERNOON. STILL...EXPECT SOME LINGERING CONVECTION OVER
THE I-77 CORRIDOR THRU THE AFTERNOON AS THE FRONT COULD SLOW IF A
WAVE FORMS ALONG THE FRONT. SVR STORM CHANCES APPEAR TO BE LIMITED
DUE TO THE TIME OF DAY OF FROPA. HOWEVER...THERE WILL BE GOOD
FORCING WITH THE FRONT...ALONG WITH ELEVATED INSTABILITY AND DECENT
SHEAR. DAMAGING WIND GUSTS WOULD BE THE MAIN SVR THREAT WITH THE
BEST CHC OVER THE NC PIEDMONT AND ERN UPSTATE DURING THE LATE
MORNING AND EARLY AFTERNOON. LARGE HAIL LOOKS TO BE LESS LIKELY AS
WET BULB ZERO LEVELS DO NOT FALL SIGNIFICANTLY UNTIL AFTER FROPA.
STILL...WILL HAVE TO KEEP AN EYE ON ALL STORMS THIS MORNING AS SVR
CANNOT BE RULED OUT ANYWHERE UNTIL FROPA.

GUSTY WINDS WILL ACCOMPANY THE FRONT AS IT MOVES ACROSS THE AREA.
HOWEVER...BEST GUSTS WILL BE OVER THE MTNS AND WRN UPSTATE AFTER
FROPA AND GENERALLY LESS THAN 35 MPH. ANY FALLING THICKNESSES ARE
WELL BEHIND THE FRONT...SO DO NOT EXPECT A QUICK DROP IN TEMPS POST
FROPA. SKIES SHUD QUICKLY CLEAR BEHIND THE FRONT AS WELL...XCPT FOR
SOME LINGERING CLOUDS OVER THE MTNS.

DRY HIGH PRESSURE BEGINS TO BUILD IN BEHIND TONIGHT...BUT THERE WILL
BE SOME LINGERING CLOUDS OVER THE MTNS IN LINGERING LOW LEVEL
MOISTURE AND NWLY FLOW. EVEN THO THE AIR MASS MOVING INTO THE AREA
IS COOLER...850-700 THICKNESSES ACTUALLY RISE OVERNIGHT AS WINDS
REMAIN NWLY IN THE LINGERING PRESSURE GRADIENT. THIS SHUD KEEP LOWS
FROM DROPPING AS MUCH AS THE OPERATIONAL MOS GUIDANCE SUGGESTS. HAVE
GONE WITH THE BIAS CORRECTED GUIDANCE WHICH IS GENERALLY WARMER ALL
AREAS BUT AVERY CO. EVEN THERE...TEMPS AND WINDS SHOULD KEEP ANY
FROST TO A MINIMUM. EXPECT A MUCH FLATTER LAPSE RATE...OR EVEN
INVERSE LAPSE RATE...THAN NORMAL. EXPECT THE THERMAL BELT WILL BE
QUITE EVIDENT IN THE OBS AND IR SAT PIX OVERNIGHT. EXPECT LOWS TO
END UP NEAR NORMAL MTNS AND SLIGHTLY BELOW ELSEWHERE.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 215 AM MONDAY...DRY HIGH PRESSURE SETTLES OVER THE REGION
UNDER QUASI-ZONAL SPLIT FLOW ALOFT TUESDAY...THEN SHIFTS EAST ON
WEDNESDAY. A COMPACT SRN STREAM SHORTWAVE WILL CROSS THE REGION
TUESDAY NIGHT...BUT BE ACCOMPANIED BY ONLY SOME UPPER LEVEL
MOISTURE. SO OTHER THAN SOME CIRRUS...NOT EXPECTING AN IMPACT ON
SENSIBLE WEATHER. TEMPS WILL BE ONE OR TWO CATEGORIES BELOW NORMAL
TUESDAY AND TUESDAY NIGHT. UNDER RETURN FLOW AND RISING HEIGHTS
ALOFT...WEDNESDAY LOOKS QUITE PLEASANT WITH TEMPS NEAR NORMAL.

MODELS ARE PERHAPS A HAIR SLOWER WITH APPROACH OF ANOTHER COLD FRONT
WEDNESDAY NIGHT. SO I HAVE BACKED OFF INTRODUCING POPS IN THE WEST
LATE...BUT STILL EXPECT ABOVE NORMAL OVERNIGHT TEMPS WITH INCREASING
CLOUD COVER.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 230 AM MONDAY...ONLY SOME MINOR TWEAKS WERE MADE TO THE FIRST
COUPLE PERIODS OF THE MEDIUM RANGE TO BLEND IN LATEST GUIDANCE. THE
MAIN FEATURE IN THE MEDIUM RANGE IS A COLD FRONT ASSOCIATED WITH A
DEEPENING CLOSED LOW IN THE UPPER MIDWEST AND MID MS VLY. MODELS ARE
TRENDING A LITTLE SLOWER WITH THE ARRIVAL OF THE FRONT. THE 00Z GFS
HAS COME IN MUCH DRIER WITH THE FRONTAL BAND...AND HAS IT THRU THE
AREA BY 06Z FRIDAY. I HAVE OPTED TO LEAVE THE POPS ALONE FOR LATE
THURSDAY INTO FRIDAY...GIVEN THE INCONSISTENCIES OF THE GUIDANCE.

PREVIOUS DISCUSSION...
AS OF 2 PM EDT SUNDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
THURSDAY WITH AN EMBEDDED SOUTHERN STREAM SHORTWAVE JUST TO OUR
SOUTH AND A DEEP UPPER TROF DIGGING DOWN OVER THE SOUTHERN PLAINS.
THE UPPER TROF WILL SPIN UP INTO A CLOSED H5 LOW ON THURSDAY AND
GRADUALLY MAKE ITS WAY EAST TOWARDS THE FCST AREA. BEYOND THIS
POINT...THE LONG RANGE MODEL SOLUTIONS DIVERGE QUITE A BIT WITH THE
LATEST GFS MOVING THE LOW/TROF OVER THE CWFA LATE FRIDAY/EARLY SAT
AND THEN LIFTING THE TROF TO THE NE BY LATE SAT. THE ECMWF...ON THE
OTHER HAND...MAINTAINS A CLOSED H5 LOW THRU THE WEEKEND AND INTO
EARLY NEXT WEEK.

AT THE SFC...A COLD FRONT WILL APPROACH THE CAROLINAS THURS MORNING
WITH THE GFS ABOUT 12 HOURS FASTER WITH THE FROPA COMPARED TO THE
ECMWF. THE GFS DRIES THINGS OUT BY EARLY FRI AND SLIDES HIGH
PRESSURE OVER THE AREA LATER IN THE DAY WHILE THE ECMWF KEEPS A
FAIRLY BROAD AREA OF DEEP MOISTURE OVER THE AREA THRU SAT AFTERNOON
BEFORE DRIER AIR WORKS ITS WAY IN. THE CANADIAN SOLUTION IS NOW MORE
SIMILAR TO THE 12Z GFS WRT TO THE EARLIER DRYING. HAVE TWEAKED THE
SENSIBLE FCST TO REFLECT THIS TREND. I NOW HAVE POPS INCREASING TO A
SOLID CHANCE BY THURS AFTERNOON OVER MOST OF THE CWFA AND REMAINING
AT SLIGHT TO SOLID CHANCE THRU EARLY SAT AND BEFORE TAPERING OFF.
TEMPS SHOULD REMAIN A FEW DEGREES BELOW CLIMO FOR MOST OF THE PERIOD
WITH A SLIGHT WARMING ON DAY 7.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AT KCLT...LINE OF SH/TSRA WILL MOVE ACROSS THE AIRFIELD BETWEEN NOW
AND 14Z. THERE SHUD BE SOME GUSTY VARIABLE WIND WITH THE STORMS.
RESTRICTIONS WILL BE AT LEAST MVFR AND POSSIBLY IFR. THE FRONT MAY
SLOW DOWN WITH TSRA REDEVELOPING DURING THE EARLY AFTERNOON BUT
VFR PREDOMINANT. VFR WILL CONTINUE OVERNIGHT. SSW WIND BECOMES SW
AND GUSTY BY EARLY AFTERNOON...THEN WNW WITH GUSTS ENDING BY LATE
AFTERNOON AND NW BY SUNSET. WIND BECOMES LIGHT NLY OVERNIGHT.

ELSEWHERE...SIMILAR TRENDS TO KCLT...EXCEPT IFR MORE LIKELY.
ALSO...WHEN THE SH/TSRA MOVE THRU DO NOT EXPECT ANY REDEVELOPMENT
BEHIND THE FRONT. VFR SHUD DEVELOP AFTER FROPA AS DRIER AIR MOVES
THRU. SWLY WINDS BECOME WLY AND GUSTY THEN NWLY BY LATE AFTERNOON
THEN NLY OVERNIGHT. VFR EXPECTED OVERNIGHT...XCPT IN THE MTN VALLEYS
WHERE IFR IN VALLEY FOG DEVELOPS BY MORNING.

OUTLOOK...DRY HIGH PRESSURE WILL RETURN FOR TUESDAY AND WEDNESDAY. A
STORM SYSTEM IS EXPECTED TO APPROACH THE AREA LATE IN THE WEEK...
WITH BRIEF RESTRICTIONS POSSIBLE.

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...ARK
NEAR TERM...RWH
SHORT TERM...ARK
LONG TERM...ARK/JPT
AVIATION...RWH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
447 AM EDT MON OCT 15 2012

GAZ018-026-028-029-NCZ035>037-056-057-068>072-082-502-504-506-508-
510-SCZ004>014-019-160900-
STEPHENS-FRANKLIN-HART-ELBERT-ALEXANDER-IREDELL-DAVIE-CATAWBA-ROWAN-
CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION NC-
GREATER CALDWELL-GREATER BURKE-EASTERN MCDOWELL-GREATER RUTHERFORD-
EASTERN POLK-GREATER OCONEE-GREATER PICKENS-GREATER GREENVILLE-
SPARTANBURG-CHEROKEE-YORK-ANDERSON-ABBEVILLE-LAURENS-UNION SC-
CHESTER-GREENWOOD-
447 AM EDT MON OCT 15 2012

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 QUICKLY MOVE ACROSS THE FOOTHILLS AND PIEDMONT
OF THE CAROLINAS AND NORTHEAST GEORGIA TODAY. A LINE OF SHOWERS
AND THUNDERSTORMS WILL MOVE ACROSS THE AREA AHEAD OF THIS FRONT.
AS THE LINE MOVES EAST...IT COULD INTENSIFY AND PRODUCE AREAS OF
DAMAGING WINDS AND POSSIBLY LARGE HAIL. THE BEST CHANCE FOR
SEVERE WEATHER WILL BE ACROSS NORTH CAROLINA PIEDMONT AND THE
EASTERN UPSTATE OF SOUTH CAROLINA...ESPECIALLY NEAR AND TO THE
EAST OF INTERSTATE 77.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.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-NCZ033-048>053-058-059-062>065-501-503-505-507-509-
SCZ001>003-160900-
RABUN-HABERSHAM-AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-
GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-
HENDERSON-CALDWELL MOUNTAINS-BURKE MOUNTAINS-MCDOWELL MOUNTAINS-
RUTHERFORD MOUNTAINS-POLK MOUNTAINS-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-
447 AM EDT MON OCT 15 2012

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

.DAY ONE...TODAY AND TONIGHT.

AN AREA OF SHOWERS AND A FEW THUNDERSTORMS WILL MOVE ACROSS THE
MOUNTAINS EARLY THIS MORNING. LOCALIZED DAMAGING WINDS ARE POSSIBLE
WITH A FEW OF THE STORMS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.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
742 AM EDT MON OCT 15 2012

NCZ068-508-SCZ007-008-151230-
CHEROKEE-CLEVELAND-GREATER RUTHERFORD-SPARTANBURG-
742 AM EDT MON OCT 15 2012

...STRONG THUNDERSTORMS WILL AFFECT CLEVELAND...NORTHERN CHEROKEE...
NORTHERN SPARTANBURG AND SOUTHEASTERN RUTHERFORD COUNTIES THROUGH 830
AM EDT...

AT 742 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM SPINDALE TO 5 MILES
NORTHEAST OF FINGERVILLE TO 4 MILES WEST OF INMAN...MOVING EAST AT 40
MPH.

THESE STORMS WILL IMPACT LOCATIONS NEAR...
  BOSTIC...
  ELLENBORO...
  CLIFFSIDE...
  POLKVILLE...
  COWPENS...
  LAWNDALE...

WIND GUSTS UP TO 40 MPH AND TORRENTIAL RAIN ARE EXPECTED WITH THESE
STORMS. A FEW LOCATIONS COULD SEE PEA SIZE HAIL.

LAT...LON 3541 8145 3536 8141 3533 8136 3528 8135
      3501 8158 3498 8222 3503 8222 3519 8201
      3519 8197 3525 8196 3527 8198 3540 8193
      3553 8152

HG