Severe Thunderstorm Warning 99, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
912 AM EDT SAT MAY 9 2009

.SYNOPSIS...
A COLD FRONT WILL REACH THE MOUNTAINS LATE TODAY...AND WILL CROSS
OUR AREA TONIGHT...STALLING JUST TO THE SOUTH ON SUNDAY. THIS FRONT
WILL FINALLY MOVE OFF TO THE SOUTH LATE MONDAY. HIGH PRESSURE WILL
THEN BUILD OVER THE REGION FOR THE MIDDLE OF NEXT WEEK...BEFORE THE
NEXT FRONT APPROACHES FROM THE NORTHWEST.

&&

.NEAR TERM /THROUGH TONIGHT/...
UNLIKE YESTERDAY CONVECTION HAS DIED DOWN NW OF CWA THIS MORNING.
MODELS IN FAIR AGREEMENT BRINGING H5 SHORTWAVE AND ASSOC SFC
BOUNDARY IN FROM THE NW THIS AFTN WITH M60 DEW POINTS IN
PLACE...CAPE REACHING OVER 1000 J/KG AND SOME SHEAR. EXPECT IT TO
ALL COME TOGETHER THIS AFTN...ESP AFTER 18Z...AND HPC HAS EXPANDED
SLIGHT RISK OF SVR STORMS AREA TO COVER ENTIRE CWA. GRIDS HAVE THIS
COVERED SO JUST MADE MINOR ADJUSTMENTS TO REFLECT LATEST GUIDANCE
AND TRENDS FOR THIS UPDATE.

PREVIOUS DISCUSSION...LOOKS LIKE ANOTHER DAY WITH A THREAT OF SEVERE
THUNDERSTORMS ACROSS THE WESTERN CAROLINAS. MOST LOCATIONS HAVE HAD
MEASURABLE RAIN EVERY DAY FOR THE LAST WEEK AND TODAY SHOULD BE NO
EXCEPTION. WHAT A DIFFERENCE A YEAR MAKES. WE REMAIN UNDERNEATH THE
NEARLY ZONAL FLOW FOR THE NEAR TERM...WHICH FEATURES SHORT WAVES
(CONVECTIVELY INDUCED OR OTHERWISE) RACING EASTWARD. MODELS ARE IN
DECENT AGREEMENT THAT THE NEXT IN THE SERIES SHOULD ARRIVE THIS
AFTERNOON OR EARLY THIS EVENING. CONVECTION STRUNG OUT EAST TO WEST
AHEAD OF A SURFACE FRONT SHOULD PROVIDE A FOCUS FOR MORE CONVECTIVE
DEVELOPMENT INTO THE AREA AHEAD OF THE WAVE MAINLY THIS AFTERNOON.
TO THE SOUTH OF THE BOUNDARY THE AIR MASS CONTAINS PLENTY OF LOW
LEVEL MOISTURE TO ALLOW BUOYANCY TO CLIMB INTO THE 1K-2K RANGE BY
MIDDAY. SHEAR SHOULD BE SUFFICIENT TO ALLOW STORMS TO ORGANIZE AND
PRODUCE WIND DAMAGE/LARGE HAIL IN SOME PLACES. THERE SHOULD ALSO BE
ENOUGH SHEAR/HELICITY TO ALLOW SOME UPDRAFTS TO HAVE SUSTAINED
ROTATION. AREA IS IN DAY1 SLIGHT RISK AND I WOULD ANTICIPATE A WATCH
AT SOME POINT LATER IN THE DAY. THIS WILL BE FEATURED IN THE HWO.
AFTER A RELATIVELY QUIET MORNING...HAVE RAMPED UP THE POP IN THE
AFTERNOON TO LIKELY ACROSS THE MTNS/FOOTHILLS WITH THE EXPECTATION
OF AN MCS MOVING IN FROM THE WEST. KEPT PIEDMONT IN THE CHANCE RANGE
FOR NOW JUST TO SEE HOW THINGS WILL DEVELOP...BUT EXPECT THIS PRECIP
CHANCE WILL HAVE TO BE RAISED AT LEAST TO LIKELY RANGE IF CONVECTION
DEVELOPS TO THE EXTENT THAT I SUSPECT IT EVENTUALLY WILL. THE HIGH
TEMP WAS DROPPED A DEGREE OR TWO THINKING THAT SHOWERS AND
THUNDERSTORMS WILL KEEP TEMPS DOWN...ESPECIALLY WEST. THE CONVECTION
MAY PERSIST WELL INTO THE OVERNIGHT...ESPECIALLY ACROSS THE SOUTH AS
THE SURFACE BOUNDARY DROPS IN FROM THE NORTH.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
ZONAL UPPER LEVEL FLOW REMAINS OVER THE SOUTHEAST ON SUNDAY...BUT
AMPLIFICATION OF A TROUGH BEINGS SUNDAY NIGHT OVER THE TN VALLEY. BY
MONDAY NIGHT A LOW AMPLITUDE TROUGH IS ESTABLISHED ALONG THE EAST
COAST. A COLD FRONT WILL BE TO OUR SOUTH ON SUNDAY AND MONDAY...BUT
ENOUGH MOISTURE WILL BE NORTH OF THE BOUNDARY FOR SCATTERED SHOWERS
AS SHORTWAVE ENERGY MOVES THROUGH THE BASE OF THE UPPER TROUGH. THE
BEST CHANCE OF SHOWERS WILL BE PRIMARILY OVER NE GA AND UPSTATE SC
WHERE BOTH THE NAM AND GFS HAVE THE BEST MOISTURE. POPS WILL BE
HIGHEST SUNDAY NIGHT AND MONDAY AS A BETTER DEFINED SHORTWAVE MOVES
ACROSS THE AREA. MAXIMUM TEMPERATURES WILL FALL FROM NEAR NORMAL ON
SUNDAY TO ABOUT 5 DEGREES BELOW NORMAL ON MONDAY IN COOL NORTHEAST
FLOW BEHIND THE FRONT...WHILE MINIMUM FALL MORE SLOWLY FROM JUST
ABOVE NORMAL TO JUST BELOW NORMAL UNDER CLOUD COVER.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AT 12Z TUESDAY BOTH THE GFS AND ECMWF HAVE AN EAST COAST UPPER
LEVEL TROUGH. BY 12Z WEDNESDAY AGREEMENT BETWEEN THESE MODELS IS
GONE...AS THE GFS BECOMES UNCHARACTERISTICALLY SLOWER MOVING THE
TROUGH OFFSHORE. BY THURSDAY BOTH MODELS HAVE AN EAST COAST
RIDGE...BUT BY FRIDAY THE GFS HAS ZONAL FLOW OVER THE SOUTHEAST...
WHILE THE ECMWF HAS A RIDGE JUST OFFSHORE AND A TROUGH IN THE TN
VALLEY. THE HPC SOLUTION FROM YESTERDAY LEANED TOWARD THE ECMWF
EARLY IN THE PACKAGE...THEN TRENDED TOWARD THE EUROPEAN ENSEMBLE
MEAN.

THE LATEST GFS SURFACE SOLUTION RESEMBLES THE HPC SOLUTION ON
TUE...WITH A DRY SURFACE RIDGE OVER MI...AND A COLD FRONT ALONG THE
GULF COAST. ON WED THE A COLD FRONT IS IN THE PLAINS...WITH THE DRY
EAST COAST RIDGE REAMING EAST OF THE MOUNTAINS. THE GFS IS SLOWER TO
MOVE A WARM FRONT NORTH AHEAD OF THE COLD FRONT...BUT THIS SHOULD
HAVE LITTLE IMPACT ON OUR AREA...AND THE FORECAST WILL REMAIN DRY
BOTH TUESDAY AND WEDNESDAY.

THE HPC COLD FRONT IS NOTABLY SLOWER ON THU...WHEN IT IS STILL IN
THE OH VALLEY...WHILE THE GFS FRONT IS ALMOST TO THE SOUTHERN
APPALACHIANS. THIS WILL RESULT IN A LATER ONSET OF PRECIPITATION
THAN THE GFS WOULD SUGGEST. BY FRIDAY THE GFS COLD FRONT IS AT THE
COAST...WHILE THE HPC POSITION IS OVER OUR AREA JUST EAST OF THE
MOUNTAINS...AND POPS WILL REMAIN IN THE FORECAST INTO FRIDAY.

TEMPERATURES WILL BE COOLER IN NORTHEAST FLOW ASSOCIATED WITH THE
DRY RIDGE...THEN WILL WARM IN ADVANCE OF THE NEXT COLD FRONT LATE IN
THE WEEK. FRONTAL PASSAGE WILL BE TOO LATE TO REALIZE MUCH COOLING
BY THE END OF THE PACKAGE.

&&

.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
AIR MASS ACROSS THE REGION REMAINS RICH WITH LOW LEVEL MOISTURE.
MVFR VISIBILITY IN FOG STILL POSSIBLE AT TAF SITES THROUGH 13Z...SO
THIS IS INCLUDED AT KHKY/KCLT. OTHERWISE...IT LOOKS LIKE ANOTHER
ROUGH DAY WITH MORE CONVECTION TO DEAL WITH. LEADING MCS REMNANTS
ARE EXPECTED TO DIE AS THEY HIT THE NC MTNS BY THE MID TO LATE
MORNING. SOME OF THIS ACTIVITY COULD REACH KAVL SO A VICINITY SHOWER
IS CARRIED IN THE TAF FOR THE TIME BEING. DEBRIS CLOUDINESS WILL
OVERSPREAD THE REGION BRINGING HIGH CEILINGS FOR THE LATTER PART OF
THE MORNING AND INTO THE EARLY AFTERNOON BEFORE THEY THIN OUT.
CONVECTIVE CLOUDS SHOULD DEVELOP BY LATE MORNING WITH CLOUD BASES
LIFTING ABOVE 3K FEET BY MIDDAY. A BRIEF MVFR CEILING COULD HAPPEN
ANYWHERE ACROSS THE REGION AS CU FIELD DEVELOPS...BUT THIS WILL NOT
BE INCLUDED IN TAFS BECAUSE IT WILL BE BRIEF. INDICATIONS ARE THAT
AN AREA OF SHOWERS AND THUNDERSTORMS WILL DEVELOP TO THE WEST DURING
THE DAY AND MOVE ACROSS THE REGION IN THE MID AFTERNOON TO EARLY
EVENING. THIS WOULD MEAN A FEW HOURS OF MVFR/IFR CEILING/VIS
RESTRICTIONS AT ALL SITES IF IT IN FACT DEVELOPS. FOR NOW...WILL
JUST GO WITH A VCTS/CB GROUP IN ALL THE TAFS. THE STORMS SHOULD MOVE
EAST BY MID EVENING LEAVING BEHIND CONVECTIVE DEBRIS CLOUDS.

AT KCLT...MVFR VISIBILITY WILL BE POSSIBLE FOR AN HOUR OR TWO AFTER
SUNRISE OWING TO THE ABUNDANT SURFACE MOISTURE. THE FOG SHOULD BURN
OFF BY 13Z TO 14Z. IF THE FOG DEVELOPS...THEN A BRIEF MVFR
CONVECTIVE CLOUD CEILING IS MORE LIKELY IN THE 13Z-15Z TIME
FRAME...BEFORE LOW CLOUDS LIFT AND SCATTER. WIND SHOULD COME UP FROM
THE SOUTH OR SOUTHWEST THIS MORNING. BE ON THE LOOKOUT FOR SEVERE
THUNDERSTORMS FROM 18Z ONWARD.

OUTLOOK...A COLD FRONT SHOULD DRIFT IN FROM THE N LATE SATURDAY
NIGHT/EARLY SUNDAY WHICH COULD RESULT IN MVFR CONDITIONS.
THUNDERSTORMS WILL BE LESS LIKELY SUNDAY AND MONDAY WITH THE FRONT
TO THE SOUTH. GENERALLY VFR CONDITIONS EXPECTED FROM SUNDAY MORNING
ONWARD.

&&

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

&&

SYNOPSIS...JAT
NEAR TERM...PM/RB
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...PM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
119 PM EDT SAT MAY 9 2009

GAZ010-017-018-026-028-029-NCZ033-048>053-058-059-062-063-SCZ001>014-
019-101730-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-AVERY-MADISON-YANCEY-
MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-NORTHERN JACKSON-MACON-
SOUTHERN JACKSON-OCONEE MOUNTAINS-PICKENS MOUNTAINS-
GREENVILLE MOUNTAINS-GREATER OCONEE-GREATER PICKENS-
GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-ANDERSON-ABBEVILLE-
LAURENS-UNION SC-CHESTER-GREENWOOD-
119 PM EDT SAT MAY 9 2009

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

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

THUNDERSTORMS ARE IN THE FORECAST SUNDAY FOR NORTHEAST GEORGIA
AND UPSTATE SOUTH CAROLINA...AS WELL AS THE NORTH CAROLINA
MOUNTAINS. ISOLATED SEVERE STORMS...WITH LARGE HAIL AND DAMAGING
WIND ARE POSSIBLE...MAINLY OVER NORTHEAST GEORGIA AND UPSTATE
SOUTH CAROLINA.

.SPOTTER INFORMATION STATEMENT...

NONE.

NCZ035>037-056-057-064-065-068>072-082-501>510-101730-
ALEXANDER-IREDELL-DAVIE-CATAWBA-ROWAN-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-
119 PM EDT SAT MAY 9 2009

...SEVERE THUNDERSTORM WATCH 281 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PIEDMONT NORTH CAROLINA AND
WESTERN NORTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

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

   SEVERE THUNDERSTORM WATCH.

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

THUNDERSTORMS ARE IN THE FORECAST SUNDAY FOR NORTHEAST GEORGIA
AND UPSTATE SOUTH CAROLINA...AS WELL AS THE NORTH CAROLINA
MOUNTAINS. ISOLATED SEVERE STORMS...WITH LARGE HAIL AND DAMAGING
WIND ARE POSSIBLE...MAINLY OVER NORTHEAST GEORGIA AND UPSTATE
SOUTH CAROLINA.

.SPOTTER INFORMATION STATEMENT...

NONE.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
938 AM EDT SAT MAY 09 2009

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

0618 PM     HAIL             2 W FONTANA VILLAGE     35.44N 83.85W
05/08/2009  E1.00 INCH       GRAHAM             NC   PUBLIC

            PUBLIC REPORT OF NICKEL TO QUARTER SIZED HAIL BETWEEN
            FONTANA VILLAGE AND TAPOCO ALONG MEADOW BRANCH ROAD.

&&

OUTLAW

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
110 PM EDT SAT MAY 9 2009

NCZ052-091745-
HAYWOOD-
110 PM EDT SAT MAY 9 2009

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN HAYWOOD COUNTY THROUGH
145 PM EDT...

AT 108 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 9 MILES SOUTH OF WATERVILLE...OR 14 MILES
NORTHWEST OF WAYNESVILLE...MOVING EAST AT 30 MPH.

WIND GUSTS OF 40 TO 50 MPH ARE EXPECTED WITH THIS STORM.

PEOPLE IN NORTHERN HAYWOOD COUNTY...INCLUDING THE COVE CREEK...FINES
CREEK...AND CRABTREE COMMUNITIES...

SHOULD MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE
WARNINGS AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE
WEATHER THREATEN.

LANE