Severe Thunderstorm Warning 110, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
247 PM EDT THU MAY 14 2009

.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST ACROSS THE ATLANTIC OCEAN FRIDAY AND
SATURDAY...ALLOWING MOISTURE TO RETURN FROM THE GULF OF MEXICO AHEAD
OF AN APPROACHING COLD FRONT. THE FRONT IS EXPECTED TO MOVE IN FROM
THE WEST SUNDAY AND MAY LINGER ACROSS THE CAROLINAS INTO MONDAY.

&&

.NEAR TERM /THROUGH FRIDAY/...
DEEP MOISTURE BAND ASSOCIATED WITH WEAKENING FRONTAL ZONE WILL MOVE
INTO THE NC MTNS BY EARLY EVENING. THIS COMBINED WITH A MODERATE
DEGREE OF INSTABILITY SHOULD RESULT IN SCATTERED CONVECTIVE
DEVELOPMENT ACROSS THE HIGHER TERRAIN THIS EVENING. WITH THE BAND OF
MOISTURE REMAINING OVER WESTERN SECTIONS OF THE CWFA...AT LEAST
SLIGHT CHANCE POPS WILL BE CARRIED THROUGH THE OVERNIGHT ACROSS THE
MTNS.

THE FRONT WILL DISSIPATE OVER THE SOUTHEAST ON FRIDAY...ALTHOUGH
MOISTURE WILL REMAIN ENSCONCED ACROSS THE AREA. IN FACT...A
DEEPENING SOUTHEAST FLOW WILL ACTUALLY ALLOW FOR AN INCREASE IN
ATLANTIC MOISTURE ACROSS THE CAROLINAS. IN ADDITION...MODEL
SOLUTIONS AGREE THAT MODERATE DESTABILIZATION WILL OCCUR FRIDAY
AFTERNOON. THIS IS EXPECTED TO RESULT IN AT LEAST SCATTERED DIURNAL
CONVECTION ACROSS THE AREA...WITH THE HIGHEST POPS EXISTING ACROSS
THE MTNS...PARTICULARLY THE SOUTHERN ESCARPMENT.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM THURSDAY...WARM...MOIST AND UNSTABLE AIR MASS REMAINS
IN PLACE FRI NITE AND SATURDAY. HIGHEST POP CHANCES WILL BE MAINLY
DIURNAL. HOWEVER...WITH THE VERY MOIST AND WEAKLY UNSTABLE AIR MASS
AND SELY FLOW...CONVECTION WILL LINGER/FIRE DURING THE NON-DIURNAL
TIMES AS WELL. DISREGARDED THE VERY LOW CAPE ON THE OPS NAM GIVEN
THE MODERATE INSTABILITY SEEN ON THE OPS GFS AND THE SREF. SHEAR
WILL BE VERY WEAK THOUGH...SO HEAVY RAINFALL A POSSIBILITY WITH SLOW
MOVING STORMS. FOLLOWED A GUIDANCE BLEND FOR TEMPS.

COLD FRONT MOVES INTO THE AREA SAT NITE AND THRU THE AREA SUNDAY.
POP INCREASES INTO AT LEAST THE LIKELY RANGE WITH THE ADDED FORCING
AND UPPER DIVERGENCE FROM A JET MAX. SHEAR IS A LITTLE BETTER
SUNDAY...BUT INSTABILITY DROPS OFF BY AFTERNOON AS THE FRONT MOVES
THRU. LOWS REMAIN MILD SAT NITE WITH HIGHS TAKING A SIGNIFICANT
TUMBLE...AROUND 10 DEGREES...SUNDAY WITH PRECIP AND FROPA.

GFS HAS COME INTO BETTER AGREEMENT WITH THE ECMWF TAKING ON A MORE
PROGRESSIVE PATTERN MONDAY WITH THE FRONT AND ANY DEVELOPING UPPER
CLOSED LOW. THIS MEANS DECREASING POP SUNDAY NIGHT...AND ONLY A
SLIGHT CHC ALONG THE SRN TIER OF THE CWFA FOR MONDAY. LOWS SUN NITE
AROUND 10 DEGREES COOLER THAN SAT NITE WITH HIGHS MONDAY FROM 5 TO
10 DEGREES COOLER THAN SUN.

&&

.LONG TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM THURSDAY...VERY LITTLE CONFIDENCE REMAINS IN THE EXT
PERIOD. THE 12Z GFS HAS COME INTO LINE A BIT WITH THE 00Z
ECMWF...HOWEVER THE LARGE SCALE PATTERN AND SENSIBLE WX EXPECTED
WITH EACH SCENARIO ARE AT MAJOR ODDS WITH EACH OTHER. AN ATTEMPT WAS
MADE TO FIND A CONSENSUS MODEL...HOWEVER THE GGEM AND NOGAPS BOTH
HAVE UNIQUE SOLNS OF THEIR OWN. THE FORMER INDICATING A TROPICAL
SYSTEM MOVING UP THE EAST COAST...AND THE LATTER PROGRESSING A
FRONTAL BAND OUT TO SEA WITH NO CLOSED OFF UPPER LOW. THIS LEAVES
LITTLE GUIDANCE TO RELY ON...SO THE LARGE SCALE UPPER PATTERN WILL
ENTAIL A COMPROMISE BTW THE 00Z EC AND THE 12Z GFS. THUS...A CLOSED
UPPER LOW OF MODERATE STRENGTH WILL BE EXPECTED TO DEVELOP OFF THE
ATL COAST LATE IN THE DAY TUE...AND SLOWLY RETROGRADE WEST SOUTH OF
RISING HEIGHTS AND A DEVELOPING HIGH ACROSS THE OH VALLEY AND GL
REGION.

AT THE LOW LEVELS...DRY AIR WILL BE SLOW TO OVERCOME TUE AS DEEP
SUBSIDENCE SHOULD BE THE STRONGEST IN A FAIRLY TIGHT Z/GRAD ALOFT
AND A WEDGE HIGH BUILDING IN AT THE SFC PRODUCING RATHER STAUNCH AND
GUSTY NE WINDS. WONT EXPECT MUCH CLOUD COVER IN THIS SITUATION...SO
EVEN THO SFC THETA/E WILL BE LOWERING DURING THE...MAX TEMPS SHOULD
STILL BE ABLE TO REACH NEAR NORMAL LEVELS. THE FORECAST GETS MUCH
TRICKIER AND LESS CONFIDENT WED THROUGH THU....YET THE MAIN IDEA
WILL BE TO ADVECT HIGHER AMOUNTS OF ATL MOISTURE TO THE AREA AS THE
SFC WAVE EITHER PERSISTS ALONG THE COASTAL BOUNDARY OR MOVES WEST
ACROSS S/RN GA. THEREFORE...POPS WILL BE INCREASED TO LOW END
CHANCES THROUGH THU...PRIMARILY ACROSS THE UPSLOPE REGIONS. MAX
TEMPS WILL REMAIN ADVERTISED NEAR NORMAL OR EVEN A FEW DEGREES BELOW
AS WIDESPREAD CLOUDINESS IS EXPECTED TO DEVELOP IN E/LY OR NE/LY
FLOW.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
LOW STRATUS HAS SCATTERED OUT/LIFTED TO AN EXPANSIVE CUMULUS FIELD
ACROSS MUCH OF THE AREA THIS AFTERNOON. ALTHOUGH ISOLATED/SCATTERED
CONVECTION WILL BE POSSIBLE JUST ABOUT ANYWHERE THIS AFTERNOON...THE
MOST LIKELY TERMINAL TO BE AFFECTED WILL BE KAVL...AS A FRONTAL
BOUNDARY MOVES INTO THE MTNS LATE THIS AFTERNOON THEREFORE...A CB
CLOUD GROUP WILL BE MAINTAINED THERE THROUGH ABOUT MIDNIGHT.

ALTHOUGH THE PROBABILITY OF LATE NIGHT/EARLY MORNING STRATUS IS NOT
AS HIGH AS THIS MORNING...MAINLY DUE TO WEAKER LIFT...A RECURRENCE
CANNOT BE RULED OUT BY ANY MEANS. THEREFORE...WE HAVE INCLUDED
SCATTERED IFR/MVFR CLOUDS AT MOST TERMINALS TO ALLUDE TO THIS
POSSIBILITY. IT APPEARS THAT FOG MAY BE A BIT MORE OF AN ISSUE
FRIDAY MORNING THAT IT HAS BEEN OF LATE. WE HAVE INCLUDED 5-6SM AT
ALL TERMINALS (A LITTLE WORSE AT KAVL) FOR THE LATE NIGHT/EARLY
MORNING HOURS. IF STRATUS DOES NOT DEVELOP PRIOR TO ANY FOG
DEVELOPMENT...WOULD EXPECT IFR VISBY TO BE A REAL POSSIBILITY AT
KAVL.

OUTLOOK...PRECIP CHANCES INCREASE THROUGH SATURDAY...ESPECIALLY OVER
THE MTNS. MORNING FOG AND STRATUS ARE POSSIBLE...ESPECIALLY WHERE
RAIN FALLS. A COLD FRONT WILL CROSS THE AREA ON SUNDAY...POSSIBLY
BRINGING WIDESPREAD FLIGHT RESTRICTIONS TO THE AREA. VFR IS EXPECTED
MONDAY...THOUGH MOISTURE MAY NOT BE TOO FAR OFF TO OUR SOUTHEAST
ALONG THE STALLING FRONT.

&&

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

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
342 PM EDT THU MAY 14 2009

GAZ010-017-018-026-NCZ033-035>037-048>053-056>059-062>065-068>070-
501>510-SCZ001>008-010-151945-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-AVERY-ALEXANDER-IREDELL-DAVIE-
MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-CATAWBA-ROWAN-GRAHAM-
NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-
CLEVELAND-LINCOLN-GASTON-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-ANDERSON-
342 PM EDT THU MAY 14 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 THUNDERSTORMS ARE IN THE FORECAST FOR THIS EVENING. THE
MAIN THREAT FROM THESE STORMS WILL BE LIGHTNING.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

GAZ028-029-NCZ071-072-082-SCZ009-011>014-019-151945-
HART-ELBERT-MECKLENBURG-CABARRUS-UNION NC-YORK-ABBEVILLE-LAURENS-
UNION SC-CHESTER-GREENWOOD-
342 PM EDT THU MAY 14 2009

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

ISOLATED THUNDERSTORMS ARE IN THE FORECAST FOR THIS EVENING. THE
MAIN THREAT FROM THESE STORMS WILL BE LIGHTNING.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
556 PM EDT THU MAY 14 2009

NCZ052-142230-
HAYWOOD-
556 PM EDT THU MAY 14 2009

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

AT 555 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 6 MILES SOUTHWEST OF WATERVILLE...OR 18 MILES
NORTHWEST OF WAYNESVILLE...MOVING EAST AT 15 MPH.

THIS STORM WILL BE NEAR...
  WATERVILLE THROUGH 620 PM...

SMALL HAIL...AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM. HEAVY RAINFALL UP TO ONE INCH WILL BE POSSIBLE IN THE
HEAVIEST DOWNPOURS AS WELL.

HG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
612 PM EDT THU MAY 14 2009

NCZ052-142245-
HAYWOOD-
612 PM EDT THU MAY 14 2009

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

AT 612 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 6 MILES SOUTHEAST OF WATERVILLE...OR 15 MILES
NORTH OF WAYNESVILLE...MOVING EAST AT 20 MPH.

SMALL HAIL...AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM. TORRENTIAL RAINFALL WILL ALSO AFFECT THE INTERSTATE 40
CORRIDOR FROM COVE CREEK TO WATERVILLE.

HG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
618 PM EDT THU MAY 14 2009

NCZ049-050-142245-
MITCHELL-YANCEY-
618 PM EDT THU MAY 14 2009

...STRONG THUNDERSTORMS WILL AFFECT NORTHERN YANCEY AND MITCHELL
COUNTIES THROUGH 645 PM EDT...

AT 616 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SERIES OF STRONG THUNDERSTORMS STRETCHING FROM 5 MILES SOUTHWEST OF
BANNER HILL TO JUST NORTH OF ROCKY FORK...MOVING EAST AT 15 MPH.

THESE THUNDERSTORMS WILL MOVE ACROSS NORTHERN PARTS OF YANCEY AND
MITCHELL COUNTIES THROUGH 645 PM EDT. SMALL HAIL...WIND GUSTS OF 30
TO 40 MPH...AND TORRENTIAL RAINFALL ARE EXPECTED WITH THESE
STORMS.

HG