High Wind Watch 4, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
316 PM EDT SAT APR 14 2007

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
SURFACE LOW SUPPORTED BY STRONG UPPER DPVA WIL MOVE ACROSS THE
REGION OVERNIGHT. DESPITE THE CLOSENESS OF THE EVENT...STILL SOME
RATHER LARGE DISCONTINUITIES IN THE DETAILS BETWEEN THE 12Z GFS/NAM.
NAM IS FARTHER NORTH WITH SURFACE LOW AND SUBSEQUENTLY DEVELOPS MUCH
MORE INSTABILITY OVER THE REGION THROUGH THE OVERNIGHT AND A SLOWER
PROGRESSION OF COLD FRONT. GFS A LITTLE FARTHER SOUTH WITH LOW TRACK
AND FASTER...SO CONSEQUENTLY THE DEWPOINTS/INSTABILITY NOT AS HIGH.
WILL SETTLE ON A BLEND OF THESE SOLUTIONS WHICH PUTS NE
GEORGIA...UPSTATE SC AND THE NC PIEDMONT UNDER THE GUN FOR SEVERE
STORMS. WIND PROFILES INDICATE PLENTY OF SHEAR...SO A FEW TORNADOES
POSSIBLY ASSOCIATED WITH A QUASI-LINEAR CONVECTIVE SYSTEM CANT BE
RULED OUT. HEAVY RAIN ALSO IS A GOOD BET FOR ABOUT A 6 HOUR WINDOW.
WIDESPREAD 1-2 INCHES IS LIKELY OVERNIGHT WITH SOME 2+ INCHES
POSSIBLE. PER HPC GUIDANCE THIS AXIS OF HEAVIEST RAINFALL WOULD NOSE
UP INTO NC PIEDMONT AND FOOTHILLS. PER COLLABORATION WITH NEIGHBORS
WILL PUT UP A FLOOD WATCH FOR THE NC PIEDMONT AND FOOTHILLS. EXPECT
THAT METRO CHARLOTTE WILL CERTAINLY HAVE SOME FLOOD ISSUES. STRONG
LOW LEVEL JET WILL PUNCH INTO THE AREA IN ADVANCE OF THE SURFACE
LOW...SO HAVE INCREASED WINDS AND PLACED GUSTS TO 30-40 MPH IN THE
GRIDS FOR A FEW HOURS.

LOW AND ASSOCIATED WIDESPREAD RAIN/THUNDERSTORMS WILL EXIT TO THE
EAST EARLY SUNDAY. PROBABLY WILL BE A LULL IN SHOWERS FOR A FEW
HOURS SUNDAY MORNING. AS STRONG UPPER TROUGH AND COLD POOL TRANSITS
THE AREA MIDDAY TO MID AFTERNOON. EXPECT SHOWERS TO DEVELOP
AGAIN...MOST NUMEROUS FOR THE MOUNTAINS AND EASTERN PART OF THE
UPSTATE AND NC PIEDMONT. THUNDERSTORMS ALSO A GOOD BET OUTSIDE OF
THE MOUNTAINS ALONG WITH SMALL HAIL. SNOW LEVELS WILL CRASH IN THE
MOUNTAINS SUNDAY AFTERNOON WITH PASSAGE OF UPPER TROUGH...SO WILL
FORECAST SNOW SHOWERS ABOVE 2500FT BY LATE AFTERNOON ALONG WITH
FALLING TEMPERATURES. STRONG WINDS WIL ALSO BEGIN TO MIX DOWN BY
LATE IN THE DAY WITH >50MPH IN THE MOUNTAINS AND 30-40MPH OUTSIDE OF
MOUNTAINS.

A NORTHWEST FLOW SNOW AND WIND EVENT IS IN STORE FOR THE MOUNTAINS
SUNDAY NIGHT AND MONDAY BEHIND THE DEPARTING SURFACE WAVE AND ITS
ASSOCIATED SHORTWAVE ROUNDING THE UPPER LOW. MODEL THICKNESS AND
SOUNDINGS SUPPORT ALL SNOW SUNDAY NIGHT AND MONDAY MORNING...EXCEPT
AT THE VERY LOWEST VALLEY ELEVATIONS...WITH MOISTURE ALL THE WAY
DOWN THE TENNESSEE BORDER. AT THIS POINT THE BEST ACCUMULATIONS WILL
BE IN THE NORTHERN MOUNTAINS...WHERE AMOUNTS SUPPORT WARNING
CRITERIA. SNOW AMOUNTS COULD APPROACH WARNING CRITERIA IN THE SMOKY
MOUNTAINS...BUT CONFIDENCE IS NOT AS HIGH THAT FAR SOUTH. THE WIND
WILL ALSO BE AN ISSUE...WITH THE MODELS CARRYING 60 KNOTS OF WIND AT
850 MB OVER A BROAD AREA SUNDAY NIGHT AND MONDAY. MOIST SOIL
RESULTING FROM THE RAINFALL TONIGHT WILL ALLOW TREES TO BE EASILY
TOPPLED...MEANING DAMAGE POTENTIAL MAY REPLACE WIND SPEED CRITERIA.
CONFIDENCE IS HIGH ENOUGH ON WIND AND SNOW IN THE NORTHERN MOUNTAINS
THAT A WINTER STORM WARNING WILL BE ISSUED FOR SUNDAY AFTERNOON
THROUGH MONDAY FROM AVERY TO MADISON COUNTIES IN THE NC MOUNTAINS. A
HIGH WIND WATCH WILL BE ISSUED FOR THE REST OF THE MOUNTAINS...AS
WELL AS THE ADJACENT NC FOOTHILLS...EVEN THROUGH WINDS MAY BE BELOW
WARNING CRITERIA IN SOME PORTIONS OF THE WATCH.

MOISTURE DECREASES RAPIDLY SUNDAY AFTERNOON...WHILE THICKNESS AND
TEMPERATURES RISE...ENDING THE SNOW EVENT. THE HIGH WINDS MAY WELL
CONTINUE INTO MONDAY NIGHT...AND MAYBE EVEN TUESDAY MORNING...BUT
CONFIDENCE IS LOWER AT THAT TIME FRAME. TEMPERATURES WILL BE COOL
ENOUGH FOR A FREEZE WATCH IN THE NC MOUNTAINS MONDAY MORNING...AND
ANOTHER NIGHT OF FREEZING TEMPERATURES IS SCHEDULED FOR TUESDAY
MORNING...HOWEVER LOCAL POLICY IS NOT TO ISSUE FREEZE PRODUCTS WHEN
WINTER WEATHER IS FORECAST. AFTERNOON MAXIMUM TEMPERATURES WILL
RECOVER WITH DOWNSLOPE FLOW AND RISING HEIGHTS ALOFT.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AN UPPER LEVEL OMEGA BLOCK DOMINATES THE PATTERN OVER NORTH AMERICA
FOR MOST OF THE EXTENDED FORECAST...WITH THE SOUTHERN APPALACHIANS
ON THE BACK SIDE OF THE DOWNSTREAM UPPER LOW...IN A MEAN NORTHWEST
FLOW ALOFT. A WEAK CLIPPER LIKE SYSTEM CROSSES THE AREA FROM THE
WEST ON WEDNESDAY...SUPPORTING LITTLE MORE THAN SLIGHT CHANCE
POPS...WHILE A BETTER DEFINED LOW ORGANIZES IN THE NORTHWEST GULF.
THE GULF LOW CROSSES NORTH FL THURSDAY...FAR ENOUGH SOUTH THAT POPS
WILL BE LIMITED...BUT WITH AN EASTERLY UPSLOPE COMPONENT NORTH OF
THE LOW...CHANCE POPS WILL BE CARRIED ALONG THE BLUE RIDGE
ESCARPMENT. A DRY SURFACE RIDGE WILL MOVE SLOWLY EAST OVER THE AREA
ON FRIDAY AND SATURDAY. TEMPERATURES WILL GRADUALLY MODERATE FROM
BELOW NORMAL TOWARD NORMAL AS THE OMEGA BLOCK WEAKENS AND HEIGHTS
RISE.

&&

.AVIATION /19Z-18Z/...
TAFS WILL BECOME QUITE COMPLICATED OVERNIGHT AS LOW PRESSURE TRACKS
ACROSS THE REGION. CURRENTLY VFR WITH ONLY MID LEVEL CLOUDS.
HOWEVER...EXPECT RAIN AND SCATTERED THUNDERSTORMS TO SPREAD RAPIDLY
WEST TO EAST ACROSS THE AREA FROM 22Z-02Z. WITH THE ONSET OF THE
RAIN...EXPECT CEILINGS TO RAPIDLY LOWER INTO THE MVFR RANGE. A 4-6
HOUR PERIOD OF HEAVY RAIN EXPECTED FROM ABOUT 03-09Z WITH EMBEDDED
THUNDERSTROMS WHICH SHOULD LOWER CEILINGS INTO IFR CATEGORY.
WIDESPREAD PRECIPITATION SHOULD MOVE EAST OF THE AREA IN 08Z-12Z
TIMEFRAME WITH CELINGS BUMPING UP INTO MVFR RANGE WITH VFR CELINGS
LIKELY BY 14Z-16Z SUNDAY. SHOWERS EXPECTED TO REDEVELOP MIDDAY
SUNDAY AS UPPER TROUGH SWINGS THROUGH. COULD EVEN HAVE SOME
THUNDERSTORMS OUTSIDE OF THE MOUNTAINS.

VISIBILITIES WILL LOWER TO IFR RANGE IN THE HEAVIER RAIN OVERNIGHT
AND THEN BOUNCE BACK TO VFR 09Z-12Z TIMEFRAME.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
     AFTERNOON FOR NCZ033-048>050.

SC...NONE.
&&

SHORT TERM...JAT/LG
LONG TERM...JAT
AVIATION...LG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
543 AM EDT SAT APR 14 2007

NCZ033-048>050-150945-
AVERY-MADISON-YANCEY-MITCHELL-
543 AM EDT SAT APR 14 2007

...WINTER STORM WATCH IN EFFECT FROM SUNDAY AFTERNOON THROUGH MONDAY
AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT

A POWERFUL STORM SYSTEM AND ASSOCIATED COLD FRONT WILL APPROACH
THE NORTHERN MOUNTAINS THIS AFTERNOON...BRINGING WIDESPREAD RAIN
AND SCATTERED THUNDERSTORMS TO THE REGION THIS AFTERNOON AND
TONIGHT. THE MAIN THREAT ACROSS THE MOUNTAINS WILL BE FROM HEAVY
RAINFALL...AS MOST LOCATIONS CAN EXPECT 1.5 TO 2 INCHES OF RAIN
BY SUNRISE SUNDAY. LOCALLY HIGHER TOTALS WILL BE POSSIBLE.

AN ISOLATED SEVERE THUNDERSTORM CANNOT BE RULED OUT...BUT THE
GREATEST SEVERE WEATHER THREAT WILL EXIST SOUTH AND EAST OF THE
MOUNTAINS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   WINTER STORM WATCH

IN ADDITION TO THE POTENTIAL FOR HEAVY SNOW...VERY STRONG NORTHWEST
WINDS WILL DEVELOP BEHIND THE COLD FRONT FOR SUNDAY...AND CONTINUE
THROUGH AT LEAST MONDAY. SUSTAINED WINDS OF 25 TO 35 MPH...WITH
GUSTS IN EXCESS OF 50 MPH WILL BE POSSIBLE ACROSS THE AREA...
ESPECIALLY SUNDAY AFTERNOON AND EVENING. IT IS POSSIBLE THAT THE
WINDS COULD REACH DAMAGING LEVELS ACROSS PORTIONS OF THE MOUNTAINS
DURING THIS TIME. HOWEVER...UNCERTAINTY REMAINS REGARDING THE
TIMING...LOCATION...AND STRENGTH OF THE STRONGEST WINDS. IT IS
LIKELY THAT A WIND ADVISORY...OR PERHAPS A HIGH WIND WARNING WILL
BE ISSUED LATER TODAY.

WIDESPREAD FREEZING TEMPERATURES ARE EXPECTED ACROSS THE MOUNTAINS
BY SUNRISE MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

NCZ051>053-058-059-062>065-501-503-505-507-509-150945-
SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-NORTHERN JACKSON-MACON-
SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-CALDWELL MOUNTAINS-
BURKE MOUNTAINS-MCDOWELL MOUNTAINS-RUTHERFORD MOUNTAINS-
POLK MOUNTAINS-
543 AM EDT SAT APR 14 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT

A POWERFUL STORM SYSTEM AND ASSOCIATED COLD FRONT WILL APPROACH
THE SOUTHERN AND CENTRAL MOUNTAINS THIS AFTERNOON...BRINGING
WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS TO THE REGION THIS
AFTERNOON AND TONIGHT. THE MAIN THREAT ACROSS THE MOUNTAINS WILL
BE FROM HEAVY RAINFALL...AS MOST LOCATIONS CAN EXPECT 1.5 TO 2
INCHES OF RAIN BY SUNRISE SUNDAY. LOCALLY HIGHER TOTALS WILL BE
POSSIBLE...ESPECIALLY IN LOCATIONS ALONG AND NEAR THE SOUTHERN
ESCARPMENT OF THE BLUE RIDGE.

AN ISOLATED SEVERE THUNDERSTORM CANNOT BE RULED OUT...BUT THE
GREATEST SEVERE WEATHER THREAT WILL EXIST SOUTH AND EAST OF THE
MOUNTAINS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

AS SNOW LEVELS FALL BEHIND THE COLD FRONT SUNDAY AFTERNOON AND
EVENING...LINGERING MOISTURE IS EXPECTED TO RESULT IN SCATTERED TO
NUMEROUS SNOW SHOWERS ACROSS THE MOUNTAINS. SOME LIGHT
ACCUMULATIONS WILL BE POSSIBLE...PARTICULARLY IN THE HIGHER
ELEVATIONS ALONG THE TENNESSEE BORDER. HEAVIER SNOWFALL WILL BE
POSSIBLE IN AREAS FROM MADISON COUNTY NORTH.

IN ADDITION TO THE POTENTIAL FOR SNOW...VERY STRONG NORTHWEST WINDS
WILL DEVELOP BEHIND THE COLD FRONT FOR SUNDAY...AND CONTINUE
THROUGH AT LEAST MONDAY. SUSTAINED WINDS OF 20 TO 30 MPH...WITH
GUSTS IN EXCESS OF 50 MPH WILL BE POSSIBLE ACROSS THE AREA...
ESPECIALLY SUNDAY AFTERNOON AND EVENING. IT IS POSSIBLE THAT THE
WINDS COULD REACH DAMAGING LEVELS ACROSS PORTIONS OF THE MOUNTAINS
DURING THIS TIME. HOWEVER...UNCERTAINTY REMAINS REGARDING THE
TIMING...LOCATION...AND STRENGTH OF THE STRONGEST WINDS. IT IS
LIKELY THAT A WIND ADVISORY...OR PERHAPS A HIGH WIND WARNING WILL
BE ISSUED LATER TODAY.

WIDESPREAD FREEZING TEMPERATURES ARE EXPECTED ACROSS THE MOUNTAINS
BY SUNRISE MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

GAZ010-017-018-026-028-029-NCZ035>037-056-057-068>072-082-502-504-
506-508-510-SCZ001>014-019-150945-
RABUN-HABERSHAM-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-OCONEE MOUNTAINS-PICKENS MOUNTAINS-
GREENVILLE MOUNTAINS-GREATER OCONEE-GREATER PICKENS-
GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-ANDERSON-ABBEVILLE-
LAURENS-UNION SC-CHESTER-GREENWOOD-
543 AM EDT SAT APR 14 2007

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

.DAY ONE...TODAY AND TONIGHT

A POWERFUL STORM SYSTEM AND ASSOCIATED COLD FRONT WILL APPROACH
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA THIS AFTERNOON...
BRINGING WIDESPREAD RAIN AND SCATTERED TO NUMEROUS THUNDERSTORMS
TO THE FOOTHILLS AND PIEDMONT BY THIS EVENING. AS SOUTHERLY WINDS
BRING AN INCREASINGLY MOIST AND UNSTABLE AIRMASS INTO THE REGION
AHEAD OF THE COLD FRONT...SOME OF THE THUNDERSTORMS COULD REACH
SEVERE LEVELS THIS EVENING. THE STRENGTH OF THE WIND FIELDS
THROUGH THE DEPTH OF THE ATMOSPHERE WILL BE MORE THAN ADEQUATE FOR
SEVERE WEATHER AND EVEN TORNADOES. HOWEVER...THERE IS UNCERTAINTY
REGARDING THE DEGREE OF INSTABILITY THIS EVENING. IF THE ATMOSPHERE
REMAINS WEAKLY UNSTABLE...THE MAIN SEVERE WEATHER THREAT WILL BE
FROM DAMAGING STRAIGHT LINE WINDS AND ISOLATED...BRIEF TORNADOES.
HOWEVER...IT IS POSSIBLE THAT MODERATE INSTABILITY COULD BE
REALIZED. IF THIS IS THE CASE...THE TORNADO THREAT WILL BE
GREATER...AND THERE WILL BE THE POTENTIAL FOR ONE OR TWO STRONG
TORNADOES. ALTHOUGH SEVERE WEATHER WILL BE POSSIBLE JUST ABOUT
ANYWHERE ACROSS THE AREA FROM LATE THIS AFTERNOON THROUGH THIS
EVENING...SEVERE WEATHER WILL BE MOST LIKELY IN AREAS EAST OF I-26
AND SOUTH OF I-85...FROM ABOUT MID EVENING TO JUST AFTER MIDNIGHT.

IN ADDITION TO THE SEVERE WEATHER THREAT...HEAVY RAINFALL CAN ALSO
BE EXPECTED. MOST LOCATIONS CAN EXPECT 1 TO 2 INCHES OF RAIN BY
SUNRISE SUNDAY. LOCALLY HIGHER TOTALS WILL BE POSSIBLE...ESPECIALLY
IN LOCATIONS NEAR THE SOUTHERN ESCARPMENT OF THE BLUE RIDGE. SOME
LOCALIZED FLASH FLOODING WILL BE POSSIBLE...ESPECIALLY IN ANY
URBAN AREAS THAT ARE AFFECTED BY REPEATING THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

STRONG AND GUSTY WEST AND NORTHWEST WINDS WILL DEVELOP BEHIND THE
COLD FRONT FOR SUNDAY...AND CONTINUE THROUGH MONDAY. SUSTAINED
WINDS OF 20 TO 30 MPH...WITH GUSTS IN EXCESS OF 50 MPH WILL BE
POSSIBLE ACROSS THE AREA...ESPECIALLY SUNDAY AFTERNOON AND
EVENING. IT IS POSSIBLE THAT THE WINDS COULD REACH DAMAGING LEVELS
ACROSS PORTIONS OF THE FOOTHILLS AND PIEDMONT DURING THIS TIME.
HOWEVER...UNCERTAINTY REMAINS REGARDING THE TIMING...LOCATION...
AND STRENGTH OF THE STRONGEST WINDS. IT IS LIKELY THAT A WIND
ADVISORY...OR PERHAPS A HIGH WIND WARNING WILL BE ISSUED LATER
TODAY.

SOME AREAS COULD SEE A BRIEF PERIOD OF FREEZING TEMPERATURES
MONDAY MORNING...BUT A WIDESPREAD FREEZE IS NOT ANTICIPATED AT
THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING.

LANE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
217 PM EDT SAT APR 14 2007

GAZ010-017-018-026-028-029-NCZ070>072-082-SCZ001>014-019-142030-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-GASTON-MECKLENBURG-
CABARRUS-UNION NC-OCONEE MOUNTAINS-PICKENS MOUNTAINS-
GREENVILLE MOUNTAINS-GREATER OCONEE-GREATER PICKENS-
GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-ANDERSON-ABBEVILLE-
LAURENS-UNION SC-CHESTER-GREENWOOD-
INCLUDING THE CITIES OF...CLAYTON...CLARKESVILLE...TOCCOA...
HARTWELL...ELBERTON...GASTONIA...CHARLOTTE...CONCORD...MONROE...
GREENVILLE...SPARTANBURG...GAFFNEY...ROCK HILL...ANDERSON...
ABBEVILLE...LAURENS...UNION...CHESTER...GREENWOOD
217 PM EDT SAT APR 14 2007

...SEVERE WEATHER POSSIBLE TONIGHT...
THERE IS A THREAT OF SEVERE THUDNERSTORMS TONIGHT FROM NORTHEAST
GEORGIA...THROUGH THE UPSTATE OF SOUTH CAROLINA INTO THE NORTH
CAROLINA. THIS WOULD ROUGHLY BE ALONG AND SOUTH OF INTERSTATE 85.

DAMAGING THUNDERSTORM WINDS ALONG WITH ISOLATED BRIEF TORNADOES
ARE POSSIBLE. IF YOU HAVE A NOAA WEATHER RADIO...MAKE SURE YOU
HAVE IT SET OVERNIGHT INTO STANDBY MODE FOR POSSIBLE WARNINGS.

LISTEN TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA FOR UPDATES AND
POSSIBLE WARNINGS

LG