Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1034 AM EDT SUN JUL 24 2011

.SYNOPSIS...
AN UPPER LEVEL RIDGE WILL CONTINUE TO DOMINATE THE WEATHER TODAY. AN
UPPER LEVEL TROUGH WILL DEVELOP ALONG THE EAST COAST EARLY THIS
WEEK...BUT A RIDGE OF HIGH PRESSURE WILL RETURN LATE IN THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
1430Z ISSUANCE... SURFACE PRESSURE ANALYSIS ACROSS AREA THIS MORNING
FEATURED A LEE TROUGH EXTENDING FROM THE MID-ATLANTIC STATES
SOUTHWEST THROUGH THE CAROLINAS INTO NORTHEAST GEORGIA. ANALYSIS
ALOFT FEATURED VERY WEAK HEIGHT GRADIENTS. 850-300 MB RUC MEAN WIND
WAS NORTHWEST AT 10 KT OR LESS AND THIS WILL CHANGE LITTLE INTO
AFTERNOON. SO ANY CONVECTIVE STORMS THAT DEVELOP SHOULD MOVE... BUT
VERY SLOWLY.  MOST UNSTABLE RUC LI FOR THE EARLY AFTERNOON IS
FORECAST TO BE PRIMARILY EAST OF THE CWA.  DURING MID TO LATE
AFTERNOON AXIS OF -5 TO -7 LI APPEARS ALONG THE BLUE RIDGE
ESCARPMENT. APPROXIMATELY THE SAME AREA COVERED BY CAPE AROUND 2K
J/KG. EXPECT CONVECTIVE TEMPERATURES IN MID 80S TO INITIATE MOUNTAIN
CONVECTION THAT WILL DISPLAY VERY SLOW MOVEMENT TOWARD SOUTHEAST.
ANY CONVECTIVE STORMS EAST OF MOUNTAINS WILL REQUIRE TEMPERATURES IN
THE LOWER TO MID 90S. SPC SREF THUNDERSTORM GUIDANCE INDICATES MOST
RAPID INCREASE IN THUNDERSTORM CHANCE OCCURS AFTER 18Z. LATE MORNING
SATELLITE IMAGERY SHOWED CU ALREADY DEVELOPING OVER RIDGES... SO
EXPECT ISOLATED TO WIDELY SCATTERED SHOWERS TO DEVELOP BY 16Z.

PREVIOUS DISCUSSION...
THIS AFTERNOON...WE WILL SEE THE CENTER OF THE UPPER RIDGE CONTINUE
ITS SUBTLE TRANSITION BACK TO THE WEST OVER THE CENTRAL CONUS. THIS
WILL LEAVE THE FA WITH SLIGHTLY LOWER HEIGHTS ON THE EASTERN FRINGE
OF THE RIDGE. AS SUCH...H85 TEMPS ARE PROGGED TO BE A BIT COOLER
THAN PREVIOUS DAYS. WILL GO WITH HIGHS IN THE MID TO UPPER 90S
OUTSIDE THE MOUNTAINS AND UPPER 80S IN THE MOUNTAIN VALLEYS. MY
FORECAST TEMPS AND DEWPOINTS DO COMBINE TO GENERATE HEAT INDEX
VALUES IN THE 100 TO 103 RANGE FOR A FEW HOURS FROM AROUND GREENWOOD
TO CHARLOTTE THIS AFTERNOON. CONTEMPLATED A HEAT ADVISORY FOR TODAY
BUT HAVE DECIDED AGAINST IT SINCE HEAT INDEX VALUES THE PAST FEW
DAYS SEEM TO HAVE BARELY MET CRITERIA. FOR CONVECTION TODAY...EXPECT
MORE GARDEN VARIETY STORMS. SEVERE THREAT IS VERY MINIMAL AND THE
MAIN ISSUES FROM STORMS THAT DO DEVELOP WILL BE FROM CLOUD TO GROUND
LIGHTNING AND LOCALLY HEAVY RAINFALL. COVERAGE SHOULD BE A BIT
BETTER THAN PREVIOUS DAYS WITH THE UPPER RIDGE SHIFTING TO THE
WEST...BUT STILL ISOLATED TO SCATTERED AT BEST. STORMS WILL
DISSIPATE IN THE EVENING BUT A FEW SHOWERS WILL LIKELY BE AROUND
THROUGH THE EARLY MORNING HOURS.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AT 2 AM EDT SUNDAY...AN UPPER LEVEL TROUGH WILL AMPLIFY ALONG THE
EAST COAST ON MONDAY AND TUESDAY....CAUSING HEIGHTS TO FALL ALOFT
OVER THE SOUTHERN APPALACHIANS...WHILE AND UPPER RIDGE REMAINS
UPSTREAM OVER THE SOUTHERN PLAINS. A COLD FRONT WILL DROP SOUTH INTO
NC ON MONDAY...REACHING GA AND SC ON MONDAY NIGHT...AND MOVING SOUTH
OF OUR AREA BY TUESDAY NIGHT. THIS BOUNDARY WILL SERVE AS A FOCUSING
MECHANISM FOR CONVECTIVE DEVELOPMENT AS IT SLOWLY CROSSES OUR
AREA...AND LIKELY POPS WILL BE CARRIED DURING DAYLIGHT HOURS
MONDAY...WITH HIGH END CHANCE POPS IN THE EVENING. MOISTURE AND POPS
WILL LINGER ON TUESDAY...MAINLY N THE SOUTHERN PORTION OF OUR
AREA...BUT WILL DECREASE TUESDAY NIGHT AS THE FRONT MOVES FARTHER
SOUTH. TEMPERATURES WILL COOL WITH LOWER HEIGHTS ALOFT...BUT WILL
STILL BE ABOVE NORMAL.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AT 2 AM EDT SUNDAY...AN UPPER TROUGH WILL WEAKEN ALONG THE EAST
COAST WEDNESDAY AND PROGRESS OUT OT SEA...WHILE UPPER RIDGING IN THE
LOWER MS RIVER VALLEY SPREADS EAST. THE RIDGE CENTER MIGRATES TO GA
AND THE CAROLINAS LATE IN THE WEEK...WHERE IT STRENGTHENS. A WARM
AND HUMID AIR MASS WILL BE IN PLACE OVER OUR AREA...AND TEMPERATURES
WILL INCREASE AS HEIGHTS RISE ALOFT. ISOLATED TO SCATTERED PULSE
TYPE THUNDERSTORMS ARE EXPECTED EACH DAY...MAINLY IN THE AFTERNOON
AND EVENING...HOWEVER INSTABILITY MAY BE LIMITED BY WARMING MID
LEVEL TEMPERATURES UNDER THE RIDGE CENTER.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
KCLT... SMALL AREA OF CLOUD NEAR 10K FT JUST NORTH OF AIRFIELD
DOES NOT SHOW RECENT GROWTH TENDENCY AND DOES NOT SEEM TO BE
MOVING SOUTH. OTHWERWISE... MOSTLY CI WITH CU NEAR 5K FT FORMING
AROUND 16Z. CB MENTION WILL BE RETAINED FOR LATE AFTERNOON.
SURFACE WIND DURING AFTERNOON WILL BE SOUTHWEST LESS THAN 10 KT.

ELSEWHERE... MAINLY HIGH CLOUDS WILL CONTINUE BUT CU ARE
DEVELOPING OVER MOUNTAINS AND WILL FORM EAST OF MOUNTAINS DURING
AFTERNOON. CONVECTIVE COVERAGE IS EXPECTED TO BE MARGINALLY BETTER
THAN YESTERDAY BUT STILL SCATTERED AT BEST. WILL KEEP A CB
MENTIONED AT ALL SITES WITH CU IN THE 5 TO 6 KFT RANGE.

OUTLOOK...THE RIDGE WILL BREAK DOWN A BIT ON MONDAY WITH DEEPER
MOISTURE EARLY NEXT WEEK. THE BEST CONVECTIVE COVERAGE IS EXPECTED
MONDAY AFTERNOON AND EVENING AS A FRONTAL BOUNDARY MOVES INTO THE
REGION. MORE VERY HOT CONDITIONS AGAIN FROM MID TO LATE WEEK AS THE
RIDGE BUILDS BACK IN ACROSS THE EAST.

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...JAT
NEAR TERM...LGL/BSH
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...LGL/BSH

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
552 AM EDT SUN JUL 24 2011

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-251000-
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-
552 AM EDT SUN JUL 24 2011

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

.DAY ONE...TODAY AND TONIGHT.

THUNDERSTORMS ARE IN THE FORECAST TODAY AND TONIGHT. THE MAIN
HAZARDS FROM THESE THUNDERSTORMS WILL BE CLOUD TO GROUND LIGHTNING
AND LOCALLY HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1256 PM EDT SUN JUL 24 2011

NCZ501-241730-
CALDWELL MOUNTAINS-
1256 PM EDT SUN JUL 24 2011

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN CALDWELL COUNTY
THROUGH 130 PM EDT...

AT 1251 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 5 MILES SOUTHEAST OF BLOWING ROCK...MOVING EAST
AT 5 MPH. ANOTHER STRONG STORM WAS LOCATED NEAR THE AVERY COUNTY
LINE. THIS STORM WAS ALSO MOVING SLOWLY TO THE EAST.

WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THESE STORMS.

HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS. WATER
LEVELS OF SMALL STREAMS AND RIVERS MAY ALSO RISE...THEREFORE SEEK
HIGHER GROUND IF THREATENED BY FLOOD WATERS.

FREQUENT LIGHTNING IS OCCURRING WITH THESE STORMS. IF
OUTDOORS...STAY AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE
INDOORS IF POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS
AND AVOID USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG
UNNECESSARY ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.

LAT...LON 3608 8144 3607 8144 3603 8157 3604 8175
      3605 8175 3607 8173 3607 8175 3609 8176
      3611 8180 3613 8159

MCAVOY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
121 PM EDT SUN JUL 24 2011

NCZ064-065-241745-
HENDERSON-TRANSYLVANIA-
121 PM EDT SUN JUL 24 2011

...A STRONG THUNDERSTORM WILL AFFECT EASTERN TRANSYLVANIA AND
SOUTHERN HENDERSON COUNTIES THROUGH 145 PM EDT...

AT 116 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR CEDAR MOUNTAIN...OR 7 MILES SOUTHEAST OF
BREVARD...MOVING EAST AT 10 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO LITTLE
  RIVER AND CEDAR MOUNTAIN.

FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.

LAT...LON 3519 8243 3516 8252 3516 8255 3514 8258
      3513 8262 3512 8263 3513 8265 3512 8267
      3513 8268 3510 8269 3510 8271 3522 8277
      3530 8251

MCAVOY