Severe Thunderstorm Warning 251, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
234 PM EDT SAT JUL 20 2013

.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEAST WILL WEAKEN OVER THE WEEKEND AS
A COLD FRONT MOVES SOUTHWARD FROM THE GREAT LAKES. THE FRONT WILL
STALL NORTH OF THE AREA ON SUNDAY AND THEN DISSIPATE OR RETURN
NORTHWARD INTO MONDAY. AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL
DEVELOP OVER THE EAST ON TUESDAY AND LINGER THROUGH LATE WEEK. A
SECOND WEAK COLD FRONT WILL ARRIVE FROM THE NORTHWEST ON THURSDAY
AND SETTLE JUST SOUTHEAST OF THE REGION THROUGH FRIDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
AT 230 PM EDT SATURDAY...AN UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY
OVER THE EASTERN USA TONIGHT AND SUNDAY. A SHORTWAVE WILL MOVE INTO
THE BASE OF THIS TROUGH OVER THE TN RIVER VALLEY LATE SUNDAY. DEEP
GULF MOISTURE WILL BE TRANSPORTED NORTH INTO OUR AREA BY A GENTLE SW
LOW LEVEL FLOW  ON THE WEST SIDE OF A BERMUDA HIGH...WHILE A COLD
FRONT DROPS SOUTH INTO VA. WITH LOW LEVEL FLOW NEARLY PARALLEL THE
TO THE BLUE RIDGE...UPSLOPE FLOW WILL BE LIMITED...THOUGH STILL
PRESENT. WITH THE LOWE LEVELS STABILIZING LATE THIS EVENING...
CONVECTIVE COVER SHOULD DIMINISH. MODEL SOUNDINGS SHOW CAPE
SURPASSING 1000 J/KG AGAIN ON SUNDAY...AND CONVECTIVE TRENDS ARE
EXPECTED TO MIMIC TODAY...WITH THE GREATEST COVERAGE IN THE
MOUNTAINS...WITH ACTIVITY SPREADING EAST INTO THE FOOTHILLS AND
PIEDMONT WITH TIME. SHEAR WILL REMAIN WEAK HOWEVER...LIMITING STORM
ORGANIZATION. MINIMUM TEMPERATURES WILL BE SEVERAL DEGREES ABOVE
NORMAL TONIGHT IN A MOIST AIR MASS. MAXIMUM TEMPERATURES SUNDAY WILL
BE SLIGHTLY BELOW NORMAL...WITH CLOUDS...MOISTURE A FALLING HEIGHTS
ALOFT LIMITING WARMING.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AT 230 PM SATURDAY... 500 MB HEIGHTS GRADUALLY LOWER OVER THE
SOUTHEAST MONDAY AND TUESDAY BUT SURFACE PATTERN CHANGES WILL BE
RATHER SUBTLE. DIURNAL CONVECTION WILL CONTINUE INTO THE FORECAST
PERIOD BEGINNING 00Z MONDAY THEN GRADUALLY DIMINISH DURING THE
NIGHT. MOIST AND MODERATELY UNSTABLE AIR MASS WILL CONTINUE OVER THE
REGION AND GFS DEPICTS SHORT WAVE TROUGH APPROACHING CWA BY 12Z
MONDAY... SO AT LEAST SLIGHT CHANCE POPS WILL CONTINUE WELL INTO THE
NIGHT. DURING DAYTIME MONDAY... CWA REMAINS IN AIRMASS CONDUCIVE TO
CONVECTIVE STORM DEVELOPMENT SO POPS WILL INCREASE WITH DAYTIME
HEATING INTO CHANCE CATEGORY WITH LIKELY POPS OVER HIGHER TERRAIN.
GFS HAS ANOTHER SHORT WAVE TROUGH DROPPING INTO LONG WAVE TROUGH
POSITION EARLY TUESDAY... SO CHANCE POPS WILL CONTINUE THROUGH THE
NIGHT AND INTO TUESDAY WHEN DIURNAL HEATING CYCLE ONCE AGAIN LEADS
TO HIGHER PROBABILITIES DURING AFTERNOON. NO SIGNIFICANT TEMPERATURE
CHANGES WILL OCCUR DURING MONDAY TUESDAY. HIGHS OUTSIDE THE
MOUNTAINS WILL BE IN THE UPPER 80S AND LOWER 90S WHILE MOUNTAIN
VALLEY TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 80S. VERY WARM
LOW TEMPERATURES IN THE 60S AND LOWER 70S ARE EXPECTED TO CONTINUE.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM SATURDAY... FLOW PATTERN ACROSS U.S. DURING THE PERIOD
WILL CONSIST OF RIDGE IN THE WEST AND TROUGH OVER THE EASTERN
STATES. BOUNDARY LAYER WILL REMAIN WARM AND MOIST SO COOL
TEMPERATURES ALOFT ON WEDNESDAY WILL SUPPORT LAPSE RATES
SUFFICIENTLY STEEP TO PROMOTE CONVECTION WITH APPROACH AND PASSAGE
EARLY THURSDAY OF COLD FRONT. THEREAFTER DETAILS BECOME DIFFICULT TO
RESOLVE AS FRONT DRIFTS SLOWLY SOUTHEAST AND APPEARS IN CURRENT
GUIDANCE TO BECOME NEARLY STATIONARY JUST AFTER CROSSING CWA.
THUS... AIR MASS CHANGE WILL NOT BE SUFFICIENTLY SIGNIFICANT TO
ELIMINATE POPS BUT NUMBERS WILL BE IN THE LOWER END OF THE CHANCE
SPECTRUM AND WILL DISPLAY A DIURNAL TREND. NO SIGNIFICANT CHANGES IN
TEMPERATURE EXPECTED.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AT KCLT...A BLEND OF MAV AND MET GUIDANCE SUPPORTS MVFR FOG AT
DAYBREAK SUNDAY. GUIDANCE WAS ALL OVER THE PLACE ON CIGS...SO A
NEARLY PERSISTENCE FORECAST WAS USED...TAKING THE CIG DOWN TO THE
LOW END OF MVFR BY DAYBREAK. THUNDERSTORM COVERAGE IS EXPECTED TO BE
SUFFICIENT TO WARRANT A MENTION IN THE TAF THIS AFTERNOON...WITH
POSSIBLE MVFR VSBY AND CIG RESTRICTIONS. WINDS WILL REMAIN LIGHT
FROM THE SW.

ELSEWHERE...MODEL GUIDANCE IS SUPPORTIVE OF DAYBREAK MVFR FOG SUNDAY
MORNING AT ALL FOOTHILLS SITES EXCEPT KGMU...AND SUPPORTS IFR FOG AT
KAVL. GUIDANCE VARIED WILDLY ON CIGS...SO A NEAR PERSISTENCE
FORECAST WAS USED...TAKING FOOTHILL SITES DOWN TO LOW END MVFR..AND
KAVL BACK DOWN TO LIFR. CONVECTIVE CHANCES SUPPORT CARRYING THUNDER
IN THE TAFS THIS AFTERNOON. LIGHT WINDS WILL PERSIST FROM THE
SW...EXCEPT AT KAVL WHERE THEY WILL VEER TO NW LATE TONIGHT.

OUTLOOK...A COLD FRONT WILL SAG SEWD INTO THE AREA THIS WEEKEND.
EXPECT ABOVE NORMAL TSRA COVERAGE SUNDAY AND INTO EARLY NEXT
WEEK...WITH BEST CHANCES STILL DURING AFTERNOONS AND EVENINGS.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH  97%     HIGH 100%     HIGH  80%     MED   78%
KGSP       HIGH  97%     HIGH  98%     MED   74%     MED   72%
KAVL       HIGH 100%     HIGH  98%     MED   67%     MED   65%
KHKY       HIGH  97%     HIGH  98%     LOW   54%     MED   68%
KGMU       HIGH  96%     HIGH  98%     MED   74%     MED   70%
KAND       HIGH 100%     HIGH 100%     MED   70%     MED   76%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

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

&&

SYNOPSIS...PAT
NEAR TERM...JAT
SHORT TERM...LGL
LONG TERM...LGL
AVIATION...JAT

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
459 AM EDT SAT JUL 20 2013

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-210900-
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-
459 AM EDT SAT JUL 20 2013

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

.DAY ONE...TODAY AND TONIGHT.

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE REGION
THIS AFTERNOON AND EVENING. A FEW OF THESE STORMS MAY BECOME
SEVERE...PRODUCING HAIL AS LARGE AS QUARTERS...AND BRIEF BUT
DAMAGING WIND GUSTS. IN ADDITION...ANY THUNDERSTORMS THAT FORM
TODAY WILL MOVE SLOWLY. THE RESULTING HEAVY RAINFALL COULD PRODUCE
ISOLATED FLASH FLOODING...ESPECIALLY IN ANY LOCATIONS REPEATEDLY
AFFECTED BY THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

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.

HG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1154 AM EDT SAT JUL 20 2013

NCZ033-050-501>506-201630-
AVERY-BURKE MOUNTAINS-CALDWELL MOUNTAINS-EASTERN MCDOWELL-GREATER
BURKE-GREATER CALDWELL-MCDOWELL MOUNTAINS-MITCHELL-
1154 AM EDT SAT JUL 20 2013

...THUNDERSTORMS THAT HAVE DEVELOPED ALONG THE BLUE RIDGE ESCARPMENT
WILL AFFECT CALDWELL...EASTERN AVERY...NORTHERN BURKE...NORTHERN
MCDOWELL AND SOUTHEASTERN MITCHELL COUNTIES THROUGH 1230 PM EDT...

PEA SIZE HAIL...AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS
STORM.  LOCALLY HEAVY RAIN CAN CAUSE WATER LEVELS TO RISE IN
CREEKS... STREAMS... AND POOR DRAINAGE AREAS.

BE ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS DURING THE
AFTERNOON.

LAT...LON 3616 8182 3612 8181 3613 8166 3607 8141
      3602 8133 3575 8140 3563 8228 3617 8184

LGL

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1231 PM EDT SAT JUL 20 2013

NCZ048-052-053-059-063>065-SCZ003-201730-
BUNCOMBE-GREENVILLE MOUNTAINS-HAYWOOD-HENDERSON-MADISON-NORTHERN
JACKSON-SOUTHERN JACKSON-TRANSYLVANIA-
1231 PM EDT SAT JUL 20 2013

...SCATTERED THUNDERSTORMS WILL AFFECT EASTERN JACKSON...
HAYWOOD...HENDERSON...MADISON...NORTHWESTERN GREENVILLE...
TRANSYLVANIA... AND WESTERN BUNCOMBE COUNTIES THROUGH 130 PM EDT...

AT 1230 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED
NUMEROUS SHOWERS AND THUNDERSTORMS... SOME PRODUCING HEAVY RAIN...
OVER THE HIGHER TERRAIN WEST OF THE ASHEVILLE AND HENDERSONVILLE
AREA. THE STORMS WERE MOVING SLOWLY TO THE EAST.

THE STORMS WILL AFFECT LOCATIONS NEAR...
  ASHEVILLE...
  WAYNESVILLE...
  CANTON...
  BREVARD...
  HENDERSONVILLE...

PEA SIZE HAIL...WIND GUSTS UP TO 40 MPH... AND LIGHTNING ARE
EXPECTED WITH THE STORMS. LOCALLY HEAVY RAIN CAN CAUSE RAPID RISES
OF WATER LEVELS IN CREEKS... STREAMS... AND POOR DRAINAGE AREAS.

BE ALERT FOR RAPIDLY CHANGING WEATHER THIS AFTERNOON.

LAT...LON 3594 8257 3526 8234 3519 8236 3519 8234
      3500 8311 3575 8309

LGL

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1238 PM EDT SAT JUL 20 2013

NCZ033-049-050-501>506-201730-
AVERY-BURKE MOUNTAINS-CALDWELL MOUNTAINS-EASTERN MCDOWELL-GREATER
BURKE-GREATER CALDWELL-MCDOWELL MOUNTAINS-MITCHELL-YANCEY-
1238 PM EDT SAT JUL 20 2013

...THUNDERSTORMS WILL AFFECT AVERY...BURKE...CALDWELL...MCDOWELL...
MITCHELL AND YANCEY COUNTIES THROUGH 130 PM EDT...

AT 1235 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED
NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS EXTENDING FROM YANCEY
AND MITCHELL COUNTIES EAST ACROSS THE BLUE RIDGE ESCARPMENT INTO THE
FOOTHILLS.  THE SHOWERS AND THUNDERSTORMS WERE MOVING SLOWLY TO THE
EAST.

PEA SIZE HAIL... WIND GUSTS UP TO 40 MPH... AND LIGHTNING ARE
EXPECTED WITH THE STORMS. VERY HEAVY RAIN WILL CAUSE STREAMS AND
POOR DRAINAGE AREAS TO HAVE HIGH WATER LEVELS.

BE ALERT FOR RAPIDLY CHANGING THUNDERSTORM WEATHER DURING THE
REMAINDER OF THE AFTERNOON.

LAT...LON 3611 8212 3615 8203 3612 8181 3611 8153
      3607 8141 3583 8134 3557 8158 3557 8168
      3561 8175 3557 8184 3557 8218 3569 8229
      3571 8228 3575 8234 3580 8234 3582 8240
      3593 8250 3616 8222 3615 8215

LGL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
125 PM EDT SAT JUL 20 2013

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0114 PM     TSTM WND DMG     1 SE LENOIR             35.90N 81.52W
07/20/2013                   CALDWELL           NC   911 CALL CENTER

            1 TREE DOWN IN LENOIR

&&

PTANNER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
148 PM EDT SAT JUL 20 2013

NCZ036-037-201830-
DAVIE-IREDELL-
148 PM EDT SAT JUL 20 2013

...A STRONG THUNDERSTORM WILL AFFECT DAVIE AND NORTHEASTERN IREDELL
COUNTIES THROUGH 230 PM EDT...

AT 144 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR SHEFFIELD...OR 9 MILES NORTHWEST OF
MOCKSVILLE...MOVING EAST AT 10 MPH.

THIS STORM WILL IMPACT LOCATIONS NEAR...
  FARMINGTON...
  MOCKSVILLE...

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

LAT...LON 3583 8043 3582 8047 3580 8046 3579 8047
      3593 8080 3606 8074 3606 8053 3604 8044
      3601 8041 3599 8041 3596 8037

07