Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1031 PM EDT WED AUG 1 2012

.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION
TONIGHT...THEN WEAK HIGH PRESSURE WILL BUILD OVER THE AREA THURSDAY
THROUGH SATURDAY. THE HIGH PRESSURE WILL START TO BREAK DOWN FROM
THE NORTHWEST ON SUNDAY...WITH A SURFACE COLD FRONT APPROACHING THE
REGION MONDAY...AND LINGERING IN THE VICINITY THROUGH WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
0230 UTC UPDATE...POPS HAVE BEEN REDUCED FURTHER BASED ON RADAR
TRENDS...EXCEPT IN THE SW NC MOUNTAINS WHERE THEY WERE INCREASED AS
ISOLATED CELL APPROACH FROM TN. SKY COVER WAS ADJUSTED PER INFRARED
IMAGERY.

AT 930 PM EDT WEDNESDAY...A MEAN UPPER TROUGH REMAIN ALONG THE EAST
COAST TONIGHT...WITH ONE SHORTWAVE ROUNDING ITS BASE OFF THE NC
COAST...AND ANOTHER DIVING INTO THE TN RIVER VALLEY. CONVECTION
ASSOCIATED WITH THE SHORTWAVE IN KY HAS BEEN FOCUSED MORE TO THE
WEST OVER CENTRAL TN...W GA AND N AL...AND POPS WILL BE LOWERED OVER
OUR AREA TONIGHT...BUT NOT COMPLETELY ELIMINATED. FOG WAS FAIRLY
WIDESPREAD THIS MORNING...AND MODEL GUIDANCE SUGGESTS ANOTHER ROUND
OF FOG THURSDAY MORNING IN AN AIR MASS WHERE THE BOUNDARY LAYER
REMAINS MOIST. MINIMUM TEMPERATURES WILL BE NEAR NORMAL.

H5 HEIGHTS RISE A LITTLE TOMORROW AS THE SRN PLAINS RIDGE WILL
BRIEFLY PUSH TO THE EAST. HOWEVER...A WEAK SFC FRONT WILL SET UP
OVER THE FOOTHILLS. THE NAM GENERATES GOOD CONVERGENCE OVER THE
FOOTHILLS AND PIEDMONT IN THE AFTN. THE MASS AND MOISTURE
CONVERGENCE RESULTS IS CONSIDERABLE CONVECTIVE COVERAGE ON THAT
MODEL EAST OF THE MTNS LATE IN THE DAY. EVEN THE SREF IS SHOWING
SOME FAIRLY HIGH 3-HLY POPS. THEREFORE I/VE RAISED POPS INTO THE LOW
CHANCE RANGE OVER PARTS OF THE I-85 URBAN CORRIDOR FOR TMRW. IT WILL
ALSO BE A HOT DAY WITH MANY FOOTHILL AND PIEDMONT LOCATIONS WARMING
INTO THE MID 90S.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
AS OF 230 PM EDT WED...THE OVERALL PATTERN THROUGH THE SHORT RANGE
CONTINUES TO SHOW A WEAKNESS ALONG THE EAST COAST BETWEEN TWO RIDGES
TO OUR EAST AND WEST. EXPECT ISOLATED CONVECTION TO DIMINISH
THURSDAY EVENING WITH THE LOSS OF HEATING. FRIDAY LOOKS MORE
FAVORABLE FOR A LARGER NUMBER OF STORMS. THE MODELS SHOW SOME SORT
OF SHORT WAVE MOVING ACROSS THE TN VALLEY AND CUMBERLAND PLATEAU IN
THE AFTERNOON...WHICH SHOULD HELP TO ORGANIZE STORMS OVER THE MTNS.
ONCE FORMED...THE STORMS SHOULD SPREAD OUT ACROSS THE FOOTHILLS AND
PIEDMONT LATE IN THE DAY IN THE USUAL MANNER. TEMPS WERE NUDGED
TOWARD A GUIDANCE BLEND...WHICH WAS A FEW DEGREES COOLER THAN THE
PREVIOUS FCST. THE WAVE DAMPENS OUT ON SATURDAY BUT MOISTURE IS
DEEPER WITH A MORE SW FLOW AT LOW LEVELS. WE SHOULD SEE AN INCREASE
IN UPPER DIVERGENCE LATE IN THE DAY. THIS SHOULD LEAD TO COVERAGE A
BIT BETTER YET THAN FRIDAY...SO POP WAS RAISED WELL INTO THE CHANCE
RANGE. TEMPS WERE KEPT NEAR THE OLD FCST.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM EDT WED...THE LATEST MEDIUM RANGE MODELS CONTINUE TO
INDICATE THAT A DEEP MOIST SW FLOW REMAINS IN PLACE OVER THE REGION
THROUGH THE WEEKEND AS WEAK RIDGE OF HIGH PRESSURE PERSISTS OVER THE
SOUTHEASTERN STATES. THE HEIGHTS WILL GRADUALLY FALL SUN INTO MON AS
A STRONG NORTHERN STREAM UPPER LOW PRESSURE MOVES THROUGH THE GREAT
LAKES REGION. A COLD FRONT WILL APPROACH FROM THE NW ON LATE SUNDAY
AND LIKELY STALL IN OR JUST NORTH OF THE AREA THROUGH WEDNESDAY.
HAVE MENTIONED HEALTHY DIURNAL SCATTERED POPS EACH AFTN/EVENING AS
MODEL SOUNDINGS SHOW HIGH PW VALUES (OVER 2 INCHES) AND MODERATE
INSTABILITY ACROSS OUR CWA. TEMPERATURES WILL REMAIN NEAR...OR A
COUPLE DEGREES BELOW SEASONAL AVERAGES THROUGH THE PERIOD.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AT KCLT...LESS CONFIDENCE EXISTS FOR EVENING CONVECTION BASED ON
RADAR TREND...AND THE TAF WILL REFLECT THIS. MODEL GUIDANCE
GENERALLY FAVORS MVFR VSBY IN FOG AT DAYBREAK...BUT NOT A CIG
RESTRICTION. MORE CONVECTION IS EXPECTED ON THURSDAY AS THE REMAINS
OF A FRONT ARRIVE FROM THE NORTH...BUT AT THIS TIME CONFIDENCE IS
NOT HIGH ENOUGH TO SUPPORT. WINDS WILL BACK FROM WSW TO MORE OF A
SOUTHERLY COMPONENT.

ELSEWHERE...CONVECTIVE CHANCES WILL BE GREATEST IN THE MOUNTAINS
THIS EVENING...BUT BASED ON TRENDS...NOT HIGH ENOUGH TO MENTION.
GUIDANCE IS SUPPORTIVE OF MVFR FOG AT DAYBREAK...EXCEPT LIFR TO
VLIFR IN MOUNTAIN VALLEYS. CIG RESTRICTIONS WERE NOT FAVORED BY
GUIDANCE...BUT WILL BE CARRIED AT KAVL PER TRENDS LAST NIGHT.
ANOTHER ROUND OF CONVECTION IS EXPECTED THURSDAY AFTERNOON WITH THE
REMAINS OF A COLD FRONT DROPPING SOUTH...BUT CONFIDENCE IS NOT HIGH
ENOUGH TO SUPPORT A PROB30 FOR THUNDER. WINDS WILL BACK FROM A
WESTERLY COMPONENT TO A SOUTHERLY ONE.

OUTLOOK...SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL
SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG.

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...JOH
NEAR TERM...JAT/MCAVOY
SHORT TERM...PM
LONG TERM...JOH
AVIATION...JAT

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
248 PM EDT WED AUG 1 2012

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-021900-
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-
248 PM EDT WED AUG 1 2012

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 EXPECTED TO DEVELOP OVER THE MOUNTAINS
LATE THIS AFTERNOON AND THEN PUSH EASTWARD INTO THE FOOTHILLS AND
PIEDMONT. A FEW OF THESE STORMS MAY BECOME SEVERE AND PRODUCE
DAMAGING WINDS AND LARGE HAIL.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTERS ARE REQUESTED TO FORWARD ANY REPORTS OF LARGE
HAIL...DAMAGING WINDS OR FLASH FLOODING TO OUR OFFICE.

MCAVOY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1034 PM EDT WED AUG 1 2012

NCZ051-058-020315-
GRAHAM-SWAIN-
1034 PM EDT WED AUG 1 2012

...A STRONG THUNDERSTORM WILL AFFECT WESTERN GRAHAM AND WESTERN SWAIN
COUNTIES THROUGH 1115 PM EDT...

AT 1030 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 4 MILES SOUTHEAST OF CITICO BEACH...OR 19 MILES
SOUTH OF MARYVILLE...MOVING SOUTHEAST AT 10 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO SANTEETLAH
  LAKE...TAPOCO...SANTEETLAH AND FONTANA VILLAGE.

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

LAT...LON 3537 8401 3541 8403 3545 8399 3548 8392
      3553 8388 3548 8376 3527 8391 3535 8404

07

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
115 AM EDT THU AUG 2 2012

NCZ035-036-502-020600-
ALEXANDER-GREATER CALDWELL-IREDELL-
115 AM EDT THU AUG 2 2012

...STRONG THUNDERSTORMS WILL AFFECT ALEXANDER...EASTERN CALDWELL AND
NORTHWESTERN IREDELL COUNTIES THROUGH 200 AM EDT...

AT 114 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 3 MILES NORTH OF
WINDY GAP TO 6 MILES NORTHWEST OF LOVE VALLEY TO 4 MILES EAST OF
ELKVILLE...MOVING SOUTH AT 10 MPH.

THESE STORMS WILL IMPACT LOCATIONS NEAR...
  KINGS CREEK...
  TAYLORSVILLE...

WIND GUSTS UP TO 40 MPH ARE POSSIBLE AHEAD OF THIS CLUSTER OF
THUNDERSTORMS. IF THE STRONGER THUNDERSTORMS THEMSELVES MOVE INTO
THE NORTHERN PARTS OF THESE COUNTIES...DIME SIZE HAIL COULD OCCUR AS
WELL. EXPECT TORRENTIAL RAINFALL WITH THE ARRIVAL OF THE
THUNDERSTORMS.

LAT...LON 3600 8132 3604 8121 3603 8107 3606 8099
      3606 8085 3594 8081 3580 8108 3581 8114
      3583 8115 3582 8119 3586 8145 3605 8145
      3607 8140

HG