Severe Thunderstorm Warning 151, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
310 PM EDT THU MAY 18 2006

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
CONVECTION HAS BEEN ISOLATED...AND CONFINED TO THE NORTH CAROLINA
SOUTHERN PIEDMONT THE PAST FEW HOURS BUT AN ORGANIZED LINE OF
SHOWERS AND THUNDERSTORMS ORGANIZING NOW ACROSS THE NORTHERN TIER
AREAS OF THE NORTHERN MOUNTAINS AND THE FOOTHILLS OF NORTH
CAROLINA. LINE SHOULD FILL IN EVEN MORE AS COLD POOL ASSOCIATED
WITH A MAJOR VORTICITY LOBE...EJECTING FROM AN UPPER LOW DIPPING
SOUTH TOWARD THE AREA...BEGINS TO IMPACT THE CWFA. MOST OF THE
GUIDANCE IS IN AGREEMENT THAT THE MOUNTAINS AND NORTH CAROLINA
FOOTHILLS/PIEDMONT WILL SEE THE GREATEST COVERAGE. WE BROUGHT 50
POPS TO THE MOUNTAINS AND THE INTERSTATE 40 CORRIDOR...WITH 40S
FOR THE SOUTHERN PIEDMONT/FOOTHILLS OF NORTH CAROLINA AND THE
EASTERN PIEDMONT OF SOUTH CAROLINA. UPSTATE SOUTH CAROLINA AND THE
NORTHEAST GEORGIA FOOTHILLS/PIEDMONT SHOULD SEE THE LEAST
COVERAGE...BUT WE INCLUDED A CHANCE OF SHOWERS AND THUNDERSTORMS
THERE NONETHELESS.

A SPECIAL 18Z BALLOON WAS RELEASED FROM THE UPPER AIR SITE AT
BLACKSBURG THIS AFTERNOON. IT SHOWED THE FREEZING LEVEL HAD DROPPED
ABOUT 1K FEET SINCE 12Z. WET BULB ZEROES REMAIN LOW. IT WILL NOT
TAKE TALL STORMS TO PRODUCE HAIL OR DAMAGING WIND.

SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY WORKING ACROSS CENTRAL
TENNESSEE. TIGHTENING GRADIENT...THEN COLD ADVECTION WITH ADVENT OF
COLD POOL ALOFT AND IN THE POST-FRONTAL ENVIRONMENT MAY KEEP GUSTY
WINDS UP THROUGH THE EVENING. WE DECIDED TO EXTEND THE WIND ADVISORY
FOR AREA LAKES THROUGH 8 PM FOR FOOTHILLS AND PIEDMONT OF THE
CAROLINAS AND NORTHEAST GEORGIA...AND WILL KEEP ONE UP FOR ALL OF
THE NORTH CAROLINA MOUNTAINS THROUGH 6 AM FRIDAY.

FRONT SHOULD CLEAR THE REGION OVERNIGHT...AS UPPER LOW AND
ASSOCIATED TROF REACH NADIR THEN BEGIN A RETREAT. THIS SHOULD RESULT
IN LIGHT WINDS DEVELOPING OUTSIDE HIGHER TERRAIN AREAS AFTER
MIDNIGHT. WINDS MAY STAY UP THROUGH THE OVERNIGHT IN THE NORTHERN
MOUNTAINS AND WE WILL HAVE TO LOOK CLOSELY AT EXTENDING THE LAKE
WIND ADVISORY FOR THE NORTHERN MOUNTAINS INTO THE OVERNIGHT HOURS.

FRIDAY...ANOTHER STRONG VORT IS EXPECTED TO DIP DOWN TOWARD THE
REGION AS STRONG WARM ADVECTION ORGANIZES INTO THE TENNESSEE VALLEY.
A DEFINITE WIND SHEAR MAXIMUM IS SHOWN BY THE MODELS COMING CLOSE TO
THE WESTERN CWFA LATE FRIDAY INTO FRIDAY EVENING. LOWER
LEVELS...HOWEVER...SHOULD NOT HAVE MUCH TIME TO RECOVER
MOISTURE-WISE AND WE WILL STILL HAVE LOTS OF WESTERLY FLOW TO DEAL
WITH. FOR NOW...WE LIMITED POPS TO THE FAR WESTERN MOUNTAINS OF
NORTH CAROLINA INTO THE GEORGIA MOUNTAINS...WITH ISOLATED
SHOWERS/THUNDERSTORMS INDICATED FOR THE REST OF THE NORTH CAROLINA
AND SOUTH CAROLINA MOUNTAINS...AND THE WESTERN HALF OF UPSTATE SOUTH
CAROLINA AND THE GEORGIA FOOTHILLS/PIEDMONT. CURRENT DAY 2 SLIGHT
RISK AREA JUST OFF TO THE WEST.

HEIGHTS RISE THIS WEEKEND AS THE UPPER LOW THAT HAS INFLUENCED OUR
WEATHER RECENTLY CONTINUES ITS TREK NORTHEAST. NORTHWESTERLY FLOW
DEVELOPS OVER THE AREA AS UPPER TROF SLIDES EAST AND STRONG RIDGE
SLIDES WEST. SOME WEAK SHORT WAVES CROSS THE AREA SATURDAY AND
SUNDAY. SFC FRONT MOVES BACK NORTH INTO THE AREA FRIDAY NIGHT AS A
SFC LOW MOVES ALONG IT. THIS COULD CREATE AN MCS THAT MOVES INTO THE
AREA. NAM STILL FARTHER SOUTH THAN THE GFS WITH THE AXIS OF MOISTURE
AND PRECIP. HAVE CHC WEST AND SLIGHT CHC EAST. DRY FORECAST FOR
SATURDAY RIGHT NOW AS DRY AIR MASS MOVES IN BEHIND THIS SYSTEM.
THERE MAY BE SOME LINGERING SHOWERS OVER THE SOUTH HOWEVER. FRONT
MOVES BACK INTO THE AREA SATURDAY NIGHT AND SUNDAY. MODELS OF COURSE
DIFFER ON THE AMOUNT OF MOISTURE AND ISENTROPIC LIFT. THEREFORE HAVE
LIMITED POP TO SLIGHT CHC FOR THE MOUNTAINS AND NORTHERN TIER. THE
EXCEPTION IS CHC FOR THE NORTHERN MOUNTAINS SUNDAY. WARMING TREND
THRU THE WEEKEND. BELOW NORMAL LOWS FRIDAY NIGHT...THEN ABOVE NORMAL
TEMPS THE REST OF THE PERIOD.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE FORECAST REMAINS LOW CONFIDENCE FOR ANOTHER DAY AS
MODELS CONTINUE TO DIFFER FROM RUN TO RUN WITH DETAILS. GIVEN ALL
THIS UNCERTAINTY...HAVE CLOSELY FOLLOWED THE NATIONAL GUIDANCE FROM
HPC. PERIOD STARTS OUT WITH STRONG UPPER RIDGE OVER THE PLAINS
STATES. SOUTHEAST REMAINS IN NORTHWESTERLY FLOW ALOFT AS BROAD FLAT
TROF HOLDS TO OUR NORTH. A SERIES OF SHORT WAVES IN THE NORTHWEST
FLOW MOVE ACROSS THE AREA. A SURFACE FRONT STARTS OUR OVER THE CWFA
AND WOBBLES BACK AND FORTH ACROSS THE AREA UNTIL LATE WEDNESDAY WHEN
IT FINALLY MOVES NORTH. A COLD FRONT THEN APPROACHES THE AREA FROM
THE WEST THURSDAY. THAT IS THE CONSENSUS FORECAST. MODELS DIFFER IN
THE TIMING OF THE SHORT WAVES AND THE POSITION AND MOVEMENT OF THE
FRONT...THEREFORE THE LOW CONFIDENCE. HAVE SLIGHT CHC TO CHC POP
MOUNTAINS AND NORTHERN TIER WITH LITTLE POP TO THE SOUTH THRU THE
EARLY PERIODS. CHC MOUNTAINS/SLIGHT CHC ELSEWHERE WED...AND CHC POP
MOST LOCATIONS THU. ABOVE NORMAL TEMPS FCST EACH DAY.

&&

.AVIATION...
STRONG AND GUSTY WEST TO NORTHWEST WINDS WILL DOMINATE THE FIRST FEW
HOURS OF THE NEW TAF PACKAGE. NUMEROUS GUSTS TO NEAR 30 KTS ARE
EXPECTED IN THE FIRST FEW HOURS...AS MIXING MAXIMIZES WITH DAYTIME
HEATING AND CWFA BEGINS TO FEEL THE EFFECTS OF AN IMMINENT FRONTAL
PASSAGE AND FORCING FROM A MAJOR SHORTWAVE. WE EXPECT THESE WINDS TO
REMAIN STRONG UNTIL AFTER 00Z. THERE WILL ALSO BE SOME SCATTERED
SHOWERS...AND EVEN THUNDERSTORMS...BUT CONFIDENCE IS LOW AT THIS
TIME FOR INCLUSION IN ANY KIND OF CHANGE GROUP. APPROACH OF THE
UPPER LOW AND ITS SHORTWAVE SHOULD ALLOW CONVECTION TO BLOSSOM IN
THE 21Z TO 00Z/19 TIME FRAME. WE INCLUDED VCSH AT ALL SITES FOR THE
FIRST PART OF THE TAF...AND WILL PLAN TO AMEND AS TRENDS MAKE
THEMSELVES KNOWN.

BY MIDNIGHT...WINDS SHOULD HAVE CALMED DOWN ENOUGH TO GO NEARLY
LIGHT AND VARIABLE AND WE EXPECT THAT MOST ANY LOWER CLOUDINESS WILL
HAVE EITHER MOVED ON OR ERODED. THE OUTLOOK PERIODS FEATURE GUSTY
WEST WINDS ONCE AGAIN...AS YET ANOTHER DAY OF STRONG WIND FIELDS AND
ANOTHER APPROACHING VORTICITY MAXIMUM IMPACT THE REGION. WE HELD OFF
ON INCLUSION OF ANY PRECIPITATION UNTIL AFTER 18Z FRIDAY.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...LAKE WIND ADVISORY FOR GAZ010-017-018-026-028-029 UNTIL 8 PM
     THURSDAY.
NC...LAKE WIND ADVISORY FOR NCZ033-034-048>055-058-059-062>066-501-
     503-505-507-509 UNTIL 6 AM FRIDAY.
  ...LAKE WIND ADVISORY FOR NCZ035>037-056-057-067>072-082-502-504-
     506-508-510 UNTIL 8 PM THURSDAY.
SC...LAKE WIND ADVISORY FOR SCZ001>014-019 UNTIL 8 PM THURSDAY.
&&

SHORT TERM...RWH/SAB
LONG TERM...RWH
AVIATION...SAB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
619 AM EDT THU MAY 18 2006

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-191030-
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-
619 AM EDT THU MAY 18 2006

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

.DAY ONE...TODAY AND TONIGHT

WINDY WEST WINDS OF 15 TO 25 MPH SUSTAINED WITH GUSTS UP TO 40 MPH
CAN BE EXPECTED MAINLY DURING THE AFTERNOON THEN DIMINISHING
TONIGHT. OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED AT THIS
TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

BREEZY NORTHWEST WIND OF 10 TO 20 MPH CAN BE EXPECTED ON FRIDAY
WITH SOME GUSTS OVER 30 MPH. THERE IS ALSO SOME POTENTIAL FOR
STRONG STORMS OVER NORTHEAST GEORGIA AND THE WESTERN UPSTATE
FRIDAY AFTERNOON.  OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED AT
THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

DEO

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1120 AM EDT THU MAY 18 2006

NCZ035>037-056-057-068>072-082-502-504-506-508-510-SCZ008-009-013-
014-181730-
ALEXANDER-IREDELL-DAVIE-CATAWBA-ROWAN-CLEVELAND-LINCOLN-GASTON-
MECKLENBURG-CABARRUS-UNION NC-GREATER CALDWELL-GREATER BURKE-
EASTERN MCDOWELL-GREATER RUTHERFORD-EASTERN POLK-CHEROKEE-YORK-
UNION SC-CHESTER-
INCLUDING THE CITIES OF...STATESVILLE...MOCKSVILLE...HICKORY...
SALISBURY...SHELBY...LINCOLNTON...GASTONIA...CHARLOTTE...
CONCORD...MONROE...LENOIR...MORGANTON...MARION...RUTHERFORD...
COLUMBUS...GAFFNEY...ROCK HILL...UNION...CHESTER
1120 AM EDT THU MAY 18 2006

...SEVERE WEATHER OUTLOOK...

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
THE MOUNTAINS THIS AFTERNOON. AS THESE STORMS SHIFT INTO THE
NORTH CAROLINA FOOTHILLS AND PIEDMONT...SOME OF THEM COULD BECOME
SEVERE...ESPECIALLY ALONG AND NORTH OF INTERSTATE 40...AND EAST
TOWARD CHARLOTTE TO JUST NORTH AND WEST OF MONROE. THE STORM
PREDICTION CENTER IN OKLAHOMA HAS HIGHLIGHTED THIS AREA AS BEING
IN A SLIGHT RISK FOR SEVERE WEATHER THIS AFTERNOON.

THE PRIMARY SEVERE WEATHER THREAT TODAY IS LARGE HAIL...AND
DAMAGING WINDS. EVEN THUNDERSTORMS THAT DO NOT BECOME SEVERE COULD
PRODUCE LARGE QUANTITIES OF SMALL HAIL.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL RADIO AND TELEVISION OR
CABLE TELEVISION FOR THE LATEST WEATHER INFORMATION.

44

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1122 AM EDT THU MAY 18 2006

NCZ035>037-056-057-068>072-082-502-504-506-508-510-SCZ008-009-013-
014-182300-
ALEXANDER-IREDELL-DAVIE-CATAWBA-ROWAN-CLEVELAND-LINCOLN-GASTON-
MECKLENBURG-CABARRUS-UNION NC-GREATER CALDWELL-GREATER BURKE-
EASTERN MCDOWELL-GREATER RUTHERFORD-EASTERN POLK-CHEROKEE-YORK-
UNION SC-CHESTER-
INCLUDING THE CITIES OF...STATESVILLE...MOCKSVILLE...HICKORY...
SALISBURY...SHELBY...LINCOLNTON...GASTONIA...CHARLOTTE...
CONCORD...MONROE...LENOIR...MORGANTON...MARION...RUTHERFORD...
COLUMBUS...GAFFNEY...ROCK HILL...UNION...CHESTER
1122 AM EDT THU MAY 18 2006

...SEVERE WEATHER OUTLOOK...

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
THE MOUNTAINS THIS AFTERNOON. AS THESE STORMS SHIFT INTO THE
NORTH CAROLINA FOOTHILLS AND PIEDMONT...SOME OF THEM COULD BECOME
SEVERE...ESPECIALLY ALONG AND NORTH OF INTERSTATE 40...AND EAST
TOWARD CHARLOTTE TO JUST NORTH AND WEST OF MONROE. THE STORM
PREDICTION CENTER IN OKLAHOMA HAS HIGHLIGHTED THIS AREA AS BEING
IN A SLIGHT RISK FOR SEVERE WEATHER THIS AFTERNOON.

THE PRIMARY SEVERE WEATHER THREAT TODAY IS LARGE HAIL...AND
DAMAGING WINDS. EVEN THUNDERSTORMS THAT DO NOT BECOME SEVERE COULD
PRODUCE LARGE QUANTITIES OF SMALL HAIL.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL RADIO AND TELEVISION OR
CABLE TELEVISION FOR THE LATEST WEATHER INFORMATION.

44

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
326 PM EDT THU MAY 18 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0323 PM     HAIL             SALISBURY               35.67N 80.48W
05/18/2006  E0.75 INCH       ROWAN              NC   TRAINED SPOTTER

            SPOTTER REPORTED PENNY SIZED HAIL IN DOWNTOWN SALISBURY.

&&

GMS