Damaging Wind in South Carolina, August 20, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
236 PM EDT SUN AUG 20 2006

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
TONIGHT AND MONDAY...
ISOLATED MICROBURST THREAT INTO THE EARLY EVENING HOURS SHAPING UP
TO BE WITHIN THE RECOVERING AIRMASS ACRS SW NC AND WITHIN THE
GREATER INSTABILITY IN NE GA AND THE WRN UPSTATE. CU FIELD ENHANCING
ALONG THE SE FRINGES OF THE CWFA WILL HAVE TO WATCHED AS WELL. ON
THE LARGER SCALE...THE COMBINATION OF A SOUTHEAST DROPPING S/WV AND
SHARPENING LEE/PIEDMONT TROUGH WITHIN HIGH PWAT AIR SHOULD PRODUCE
SOLID SCATTERED TO NUMEROUS SHOWERS AND TSTMS REGION WIDE THROUGH
MID-EVENING. BLYR STABILIZATION EXPECTED TO RESULT IN DIMINISHING
CONVECTIVE CVRG AS THE EVENING WEARS ON...AND WILL HANG ONTO JUST
SOME LOW CHANCE POPS WITHIN LINGERING DEEPER RH BAND IN THE PIEDMONT
OVERNIGHT. QUASI-STATIONARY E-W ORIENTED FRONTAL BNDRY WILL BE THE
FEATURE OF INTEREST ON MONDAY AS IT LINGERS IN OUR VCNTY. THE
COMBINATION OF DEVELOPING LLVL WAA FLOW WORKING ON DEEPER FRONTAL
BAND MOISTURE EXPECTED TO RESULT IN SCATTERED TO NUMEROUS SHOWERS
AND TSTMS ONCE AGAIN.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...
THE GFS MOS CARRIES LIKELY POPS FOR THE ENTIRE FORECAST AREA
MONDAY NIGHT. MODEST LOW LEVEL ISENTROPIC UPGLIDE - WITH A
SOUTHWESTERLY COMPONENT - DEVELOPS ACROSS THE PIEDMONT AND
FOOTHILLS DURING THE NIGHT. THERE IS ALSO GOOD CONVERGENCE ALONG
THE FRONT AND THE GFS KEEPS CAPE VALUES FAIRLY HIGH THROUGH THE
NIGHT. HOWEVER...DEEP LAYER FORCING IS NOTICEABLY ABSENT...AND I
THINK THAT CONVECTION WILL STILL FAVOR THE DAYLIGHT HOURS. AS A
RESULT...WL CARRY A BLANKET 50 POP ACROSS THE FORECAST AREA MONDAY
NIGHT. THERE WAS VERY GOOD AGREEMENT AMONG NEIGHBORING OFFICES ON
THIS SOLUTION.

WITH THE SURFACE FRONT IN THE REGION...LOW LEVEL CONVERGENCE
CONTINUES TUE. THE WRF DEVELOPS A LOW LEVEL CIRCULATION ALONG THE
FRONT - EVIDENT AND H7 AND H8 - WHICH IT VERY SLOWLY TRACKS EAST
ACROSS THE FORECAST AREA BETWEEN 12 UTC TUE AND 00 UTC THU. I
DON/T REALLY LIKE THIS FEATURE...OR THE WAY THE MASS FIELDS ADJUST
TO IT. THE GFS HAS A LESS AMPLIFIED LOW LEVEL PATTERN...WHICH I
MUCH PREFER. AGAIN...OTHER OFFICES WERE ALSO ON BOARD WITH THIS
SOLUTION. I/D LIKE TO SEE A LITTLE MORE SHORT WAVE ENERGY...BUT
THE LIKELY POPS WE HAVE STILL LOOK GOOD.

PRESSURES RISE ACROSS THE MID ATLANTIC STATES ON WED AS SURFACE HIGH
PRESSURE BUILDS INTO NEW ENGLAND. THIS WILL HELP TO DRIVE THE FRONT
SOUTH OF THE FORECAST AREA BY WED AFTERNOON...AND THE BEST
INSTABILITY AND LLVL CONVERGENCE SHOULD SET UP ACROSS THE MIDLANDS
AND CENTRAL GA IN THE AFTERNOON. WILL TAPER POPS FROM NOTHING ACROSS
THE MOUNTAINS TO HIGH CHANCE ACROSS THE EXTREME SOUTHEAST. THERE
WILL BE SOME UPSLOPE FLOW WED AND WED NIGHT...AND THIS COULD RESULT
IN A FEW MORE SHOWERS THAN ADVERTISED...BUT CONSIDERING HOW DRY THE
MID LEVELS AREA OVER NC...I DON/T THINK MUCH WILL HAPPEN DURING THIS
TIME.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THU AND FRI THE GFS BRINGS THE FRONT BACK NORTH AS A WARM FRONT WITH
HIGH LAYER RH VALUES AND A GOOD CHANCE OF RAIN. THIS SOLUTION ALSO
HAS A FAIR AMOUNT OF SUPPORT FROM THE ECMWF...AND I FEEL GOOD ABOUT
HPC/S CHANCE POPS BOTH DAYS. IF THE SYNOPTIC SCALE FORCING WERE
STRONGER...LIKELY POPS MIGHT EVEN BE WARRANTED. HPC POPS LOOK A
LITTLE TOO HIGH FOR THE WEEKEND AS WE WILL BE ON THE BACK SIDE OF A
BROAD LONG WAVE TROF. GFS LAYER RH VALUES DRY OUT QUITE A BIT AND I
DON/T SEE MUCH REASON TO CARRY A CHANCE OF RAIN. WHILE I DID LOWER
POPS BELOW CHANCE IN THE NC FOOTHILLS AND PIEDMONT...DIDN/T WANT TO
STRAY TOO FAR FROM HPC...SO I KEPT CHANCE POPS IN ELSEWHERE FOR THE
WEEKEND.

&&

.AVIATION...
TIMING OF PCPN CHANCES THIS AFTERNOON WERE ROUGHED OUT USING
SOUTHEASTWARD MOVEMENT OF S/WV ENERGY...DIURNAL DESTABILIZATION AND
STRENGTHENING LLVL CONVERGENCE ALONG LEE/PIEDMONT TROUGH. GREATEST
CHANCES... ALBEIT WITH JUST A VCTS FOR FOR NOW...REMAIN AT KCLT WITH
LATE AFTERNOON THROUGH LATE EVENING TSTM CHANCES. CHANCES ARE A
LITTLE LESS AND OF SHORTER DURATION ELSEWHERE...WHETHER IT BE FROM
RETARDED HEATING THANKS TO DEBRIS CLDS/LEFTOVER MORNING
CONVECTION...OR FURTHER AWAY FROM BETTER LIFT OR RH.

ALL TERMINALS WILL EVENTUALLY DRIFT INTO A PCPN FREE PERIOD...AS
EARLY AS 01 UTC AT KAVL/KHKY TO 03 UTC AT KCLT. MODEL TIMEHEIGHT
CROSSSECTIONS AND MOS GUIDANCE GENERALLY FAVOR SCT OR BKN VFR LVL
STRATOCU OVERNIGHT WITHIN LINGERING WEAK WAA PATTERN. WILL PLAN ON
KEEPING MVFR BR FCST AS IS WHERE CURRENTLY ADVERTISED...WITH AN IFR
VSBY/CIG LIMITED TO KAVL DEVELOPING DURING THE PRE-DAWN HOURS.
WITHIN THE WEAK EASTERLY FLOW MONDAY MORNING...WILL HAVE TO WATCH
FOR DEVELOPMENT OF MVFR CIGS...BUT WILL KEEP CLOUD FCST SCATTERED
FOR NOW. WILL NOT INTRODUCE ANY LATE PERIOD SHOWER CHANCES JUST YET
AS UNCERTAIN HOW STRONG OR FAST WAA FLOW WILL REDEVELOP THOUGH
MIDDAY MONDAY.

&&

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

SHORT TERM...BPM/CSH
LONG TERM...BPM
AVIATION...CSH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
600 AM EDT SUN AUG 20 2006

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-211000-
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-
600 AM EDT SUN AUG 20 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

THUNDERSTORMS ARE EXPECTED TODAY AND TONIGHT...WITH NUMEROUS
COVERAGE OVER THE MOUNTAINS...NORTHERN FOOTHILLS AND NORTHWEST
PIEDMONT NORTH CAROLINA. SCATTERED COVERAGE IS EXPECTED ELSEWHERE.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED MONDAY THROUGH
WEDNESDAY...THEN AGAIN ON SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
341 PM EDT SUN AUG 20 2006

GAZ010-202045-
RABUN-
341 PM EDT SUN AUG 20 2006

...A STRONG THUNDERSTORM WAS AFFECTING RABUN COUNTY...

AT 340 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER MOCCASIN CREEK STATE PARK...OR 9 MILES WEST
OF CLAYTON...MOVING EAST AT 10 MPH.

THIS STORM WILL BE NEAR...
  CLAYTON BY 415 PM EDT.
  LAKEMONT BY 420 PM EDT.

SMALL HAIL...AND WINDS 40 TO 50 MPH ARE EXPECTED WITH THIS STORM.
TAKE SHELTER AS THIS STORM APPROACHES. IF THE STORM GAINS ANY MORE
STRENGTH...A WARNING MAY BE ISSUED.

MOORE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
431 PM EDT SUN AUG 20 2006

SCZ014-202130-
CHESTER-
431 PM EDT SUN AUG 20 2006

...A STRONG THUNDERSTORM WAS AFFECTING CHESTER COUNTY...

AT 430 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR CHESTER...MOVING SOUTHEAST AT 10 MPH.

THIS STORM WILL BE NEAR...
  5 MILES SOUTHWEST OF RICHBURG BY 520 PM EDT.

SMALL HAIL...AND WINDS 40 TO 50 MPH ARE EXPECTED WITH THIS STORM. IF
YOU LIVE IN THE MIDDLE OF CHESTER COUNTY...BE ON THE LOOKOUT FOR
THIS STORM AND TAKE SHELTER AS THE STORM APPROACHES.

MOORE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
506 PM EDT SUN AUG 20 2006

SCZ002-003-005-006-202230-
GREATER GREENVILLE-GREATER PICKENS-GREENVILLE MOUNTAINS-PICKENS
MOUNTAINS-
506 PM EDT SUN AUG 20 2006

...SEVERAL STRONG THUNDERSTORMS DEVELOPING OVER NORTHERN GREENVILLE
AND NORTHERN PICKENS COUNTIES...

AT 504 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 6 MILES SOUTHWEST OF CAESARS HEAD...OR 11 MILES
NORTH OF PICKENS...MOVING SOUTHEAST AT 15 MPH.

SMALL HAIL...AND WINDS 40 TO 50 MPH ARE EXPECTED WITH THE STORMS.

PEOPLE IN NORTHERN GREENVILLE AND NORTHERN PICKENS
COUNTIES...INCLUDING THE CITIES OF MARIETTA...TRAVELERS
REST...GREENVILLE AND TAYLORS...SHOULD MONITOR THE WEATHER SITUATION
CLOSELY. LISTEN FOR POSSIBLE WARNINGS AND BE PREPARED TO TAKE
APPROPRIATE ACTION SHOULD SEVERE WEATHER THREATEN.

MOORE