Hail and Damaging Wind in North Carolina, August 19, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
246 PM EDT FRI AUG 19 2011

.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN IN PLACE THROUGH SATURDAY. A COLD
FRONT WILL APPROACH FROM THE NORTHWEST LATE SUNDAY AND STALL ACROSS
THE REGION INTO MONDAY...THEN MOVE SLOWLY SOUTH DURING THE MIDDLE OF
THE WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
MODIFIED OBSERVED SOUNDINGS FROM KGSO/KFFC AND MODEL GUIDANCE
INDICATES THAT CAPE THIS AFTERNOON WILL RANGE FROM 1500 TO 2500
J/KG. WATER VAPOR IMAGES INDICATE SEVERAL SMALL SCALE DISTURBANCES
NW OF THE CWA...EXPECTED TO PUSH ACROSS ACROSS THE REGION LATER THIS
AFTERNOON AND EVENING. IN ADDITION...A BROKEN LINE OF TSRA HAVE
DEVELOPED ALONG AN OLD OUTFLOW BOUNDARY OVER EAST TN. THESE STORMS
SHOULD ARRIVE OVER THE SOUTHERN APPALACHIANS LATER THIS
AFTERNOON...POSSIBLY CONTINUING EAST ACROSS THE FOOTHILLS THIS
EVENING.  MID LEVEL FLOW AT 20 TO 25 KTS...FZL BETWEEN 13 TO 13.5
KFT...AND MODERATE CAPE MAY SUPPORT A FEW SEVERE STORMS. THE CURRENT
HWO HIGHLIGHTS THE THREATS WELL. I WILL FORECAST POPS BETWEEN 30 TO
40...FAVORING THE MTNS THIS AFTERNOON AND THEN THE PIEDMONT THIS
EVENING. CONVECTION IS EXPECTED TO PUSH EAST OF THE CWA LATE THIS
EVENING...DECREASING POPS BELOW SCHC. DEBRIS CLOUDS MAY LINGER
THROUGH LATE TONIGHT...THEN SKY COVER WILL DECREASE STEADILY DURING
THE PRE DAWN HOURS. LIGHT WINDS AND CLEARING SKY MAY SUPPORT THE
FORMATION FOR PATCHY FOG LATE TONIGHT. NORMAL MINS EXPECTED
TONIGHT...L60S ACROSS THE MTNS VALLEYS TO AROUND 70 EAST.

SATURDAY...S/W RIDGING WILL BUILD ACROSS THE SOUTHERN APPALACHIAN
REGION THROUGH THE DAY. FORECAST SOUNDINGS INDICATES A SIGNIFICANT
INVERSION AROUND H6...RESULTING IN A LLVL CIN AROUND 25 J/KG EAST OF
THE MTNS THROUGH THE AFTERNOON. ACROSS THE MTNS...CAPES WILL REMAIN
LIMITED TO A 1000 J/KG OR LESS. I WILL FORECAST CHC POPS ACROSS THE
MTN BY MID AFTERNOON...POPS EAST OF THE MTNS WILL REMAIN LIMITED TO
A SCHC. HIGH TEMPS SHOULD VERIFY 1 TO 2 DEGREES OVER TODAY/S VALUES.
SVR POTENTIAL TOMORROW LOOKS MINIMAL.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 205 PM FRIDAY...EXPECTING DIURNALLY DRIVEN DEEP CONVECTION TO
DIMINISH IF NOT DISSIPATE SATURDAY EVENING LEADING TO A FAIR AND
SEASONABLY MILD NIGHT. WEAK TO MODERATELY FORCED...BUT BROADLY
CONVERGENT FRONTAL ZONE EXPECTED TO CROSS THE CWFA SUNDAY INTO
SUNDAY NIGHT. WITHIN A MODERATE AMT OF DEEP SHEAR...ESPECIALLY
FOR LATE SUMMER...SCATTERED TO NUMEROUS TSTMS WILL HAVE THE
POTENTIAL TO PRODUCE LOCALLY DAMAGING WIND GUSTS.

MODEL CROSSSECTIONS DEPICT ENCROACHMENT OF DRY SLOT AS EARLY AS THE
PRE-DAWN HOURS ON MONDAY...AND SFC FRONT SE OF THE CWFA EVEN BEFORE
NOON. WITH THE NAM PROGGING STEADILY FALLING BLYR DWPTS THROUGHOUT
THE DAY...LINGERING SLIGHT CHANCE POPS WILL ATTRIBUTED TO TIMING
UNCERTAINTIES AND LATER FCSTS MAY BE ABLE TO FURTHER LOWER POPS
IF THESE TRENDS CONTINUE. DESPITE THE ONSET OF LLVL POST FRONTAL
AIRMASS...ENUF OF A DOWNSLOPE COMPONENT TO FLOW EXISTS TO KEEP
MAX TEMPS ABOVE CLIMO.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 1130 AM FRIDAY...EXTRAPOLATION OF THE NEWLY POSTED 19/12 UTC
OP NAM SUPPORTS A DRY FCST MONDAY NIGHT FEATURING WEAK SFC RIDGING
BUILDING INTO THE CWFA. I WOULD EXPECT THE ONSET OF LIKELY
NEGLIGIBLE LLVL MOISTURE RETURN TUESDAY WITHIN A NON-DESCRIPT WNW
FLOW ALOFT. IT IS NOT CONCLUSIVE AT THIS JUNCTION WHETHER INHERITED
TOKEN SLIGHT CHANCE POP CAN BE REMOVED SO WILL LET THE VIRTUALLY
DRY AND SEASONABLY WARM FCST STAND AS IS.

THE LATEST AVAILABLE OP AND ENSEMBLE MEDIUM RANGE MODELS ARE TRENDING
MORE BULLISH WITH SHOWER/TSTM CHANCES ON WEDNESDAY WITHIN THE
BROADENING WAA REGIME DOWNSTREAM OF CENTRAL CONUS FRONTAL ZONE
AND UPPER LEVEL ENERGY. THIS TREND CONTINUES INTO THURSDAY AND
PROBABLY INTO FRIDAY. WE ALSO WILL HAVE TO START TO BE WARY OF
POSSIBLE HEAVIER CONVECTIVE PCPN AS THE OP GFS HINTS AT A TROPICAL
CONNECTION DEVELOPING...AND PWATS IN EXCESS OF 2 INCHES SPREADING
INTO THE SE CONUS DURING THE LATTER HALF OF THE PERIOD.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...SHRA/TSRA COVERAGE WILL EXPAND ACROSS THE
MTNS THROUGH 19Z. STEERING FLOW IS GREATER THIS AFTERNOON THAN THE
PAST SEVERAL DAYS. I EXPECT THAT CONVECTION WILL GRADUALLY INCREASE
EAST OF THE MTNS AS STORMS TRAVEL EAST AND ATMOSPHERE DESTABILIZES. I
WILL CARRY CB AT ALL TAF SITES. KAVL AND KHKY STAND THE GREATEST CHC
FOR MEASURABLE RA...I WILL TIME IFR FOG OVERNIGHT. CONDITIONS
SHOULD IMPROVE QUICKLY AFTER SUNRISE.

OUTLOOK...THROUGH EARLY NEXT WEEK...A MORE UNSETTLED WEATHER PATTERN
SHOULD RESULT IN CONTINUED DEVELOPMENT OF ISOLATED TO WIDELY
SCATTERED DIURNAL CONVECTION EACH AFTN. MORNING FOG WILL ALSO BE
POSSIBLE...ESP IN MTN VALLEYS AND WHERE RAIN FALLS THE DAY BEFORE.

AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...

WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM

&&

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

&&

SYNOPSIS...TJB
NEAR TERM...NED
SHORT TERM...CSH
LONG TERM...CSH
AVIATION...NED

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
252 PM EDT FRI AUG 19 2011

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-201900-
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-
252 PM EDT FRI AUG 19 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP INTO
THIS EVENING ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA.
A FEW OF THE THUNDERSTORMS COULD BECOME SEVERE...PRODUCING HAIL AS
LARGE AS QUARTERS AND DAMAGING WIND GUSTS. HEAVY RAINFALL AND
CLOUD TO GROUND LIGHTNING CAN BE EXPECTED WITH ANY THUNDERSTORMS
THAT DEVELOP.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ASKED TO RELAY ANY REPORTS OF SEVERE WEATHER TO THE
NATIONAL WEATHER SERVICE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
359 PM EDT FRI AUG 19 2011

NCZ056-069-502-504-192045-
CATAWBA-GREATER BURKE-GREATER CALDWELL-LINCOLN-
359 PM EDT FRI AUG 19 2011

...A STRONG THUNDERSTORM WILL AFFECT CATAWBA...EASTERN BURKE...
EASTERN LINCOLN AND SOUTHEASTERN CALDWELL COUNTIES THROUGH 445 PM
EDT...

AT 355 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR HICKORY...MOVING SOUTHEAST AT 20 MPH.

THIS STORM WILL BE NEAR...
  CONOVER...
  NEWTON...
  CLAREMONT...
  MAIDEN...

SMALL HAIL...AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS
STORM.

LAT...LON 3585 8134 3580 8133 3581 8125 3567 8096
      3564 8095 3562 8093 3561 8094 3559 8093
      3543 8107 3571 8148 3586 8136

RWH