Severe Thunderstorm Warning 225, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
206 PM EDT TUE AUG 11 2015

.SYNOPSIS...
A COLD FRONT WILL BE CROSSING THE CAROLINA COAST EARLY WEDNESDAY
WHILE DRY HIGH PRESSURE BUILDS OVER OUR REGION.  EXPECT HIGH
PRESSURE TO BE IN CONTROL OF OUR WEATHER INTO EARLY NEXT WEEK. A FEW
MOUNTAIN SHOWERS AND STORMS MAY RETURN BY THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AN AMPLIFYING UPPER TROUGH AND AN APPROACHING COLD FRONT...COMBINED
WITH NOTABLE INSTABILITY...WILL SUPPORT CONVECTIVE DEVELOPMENT THIS
AFTERNOON. THE MODELS SHOW MORE SHEAR WITH THIS ACTIVITY THAN THEY
DID YESTERDAY...AND ORGANIZED STORMS CANNOT BE COMPLETELY RULED OUT.
THE BEST INSTABILITY WILL BE EAST OF THE BLUE RIDGE. WITH MOIST
VERTICAL PROFILES...HEAVY RAINFALL WILL BE POSSIBLE...THOUGH
STEERING FLOW SHOULD KEEP CELLS MOVING. LOW LEVEL FLOW IS PARALLEL
TO THE BLUE RIDGE...LIMITING UPSLOPE FLOW.

ACTIVITY SHOULD END THIS EVENING AS THE FRONT DEPARTS THE AREA.
COOLER...DRIER AIR WILL BE SLOW TO INFILTRATE OUR AREA...AND MINIMUM
TEMPERATURES WILL RUN NEAR NORMAL OVERNIGHT. NORTH WINDS SHOULD STAY
UP ENOUGH TO PREVENT DAYBREAK FOG FROM FORMING OVER MOST OF THE
AREA. WEDNESDAY FEATURES DRIER CONDITIONS...WITH HIGH TEMPERATURES
SLIGHTLY BELOW NORMAL.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 155 PM TUE...A PATTERN CHANGE IS IN STORE ACROSS THE REGION
THRU THE SHORT RANGE. A DEEP UPPER TROF OVER THE ERN SEABOARD BEGINS
TO MOVE EAST ON THU. HOWEVER...A WEAK SHORT WAVE AND RELATIVELY
STRONG UPPER JET MAX DIVE INTO THE TROF LATE THU INTO FRI. THIS
HELPS PINCH OFF THE SRN END OF THE TROF AND KEEP IT ACROSS THE SE.
THE NAM REACTION TO THIS DEVELOPMENT IS MUCH STRONGER THAN THE OTHER
GUIDANCE DEVELOPING A CLOSED LOW ALONG THE SE COAST...WHILE THE REST
OF THE GUIDANCE KEEPS IT AS AN OPEN WAVE. A WEAK LOW PRESSURE CENTER
FORMS ON THE STALLED SFC FRONT NEAR THE COAST. THIS COMBINED WITH
THE WEAK SFC HIGH MOVING INTO THE MID ATLANTIC STATES HELPS TURN THE
LOW LEVEL FLOW TO AN ELY OR SELY DIRECTION...ALLOWING A MOIST
UPSLOPE FLOW TO DEVELOP. THE RESULT IS LOW LEVEL MOISTURE RETURNING
ACROSS THE AREA ALONG WITH INSTABILITY ACROSS THE MTNS. THE NAM IS
MOST AGGRESSIVE WITH THIS PATTERN...AS IT WAS ON MONDAY. HOWEVER...
THE GFS IS NOW COMING AROUND TO THIS SCENARIO. THEREFORE...WILL NOT
GO AS STRONG AS THE NAM...BUT WILL TREND IN THAT DIRECTION. HAVE
GONE WITH ISOLATED DIURNAL CONVECTION ALONG AND NEAR THE BLUE RIDGE
ON THU...AND INCREASED THE AREA OF 20 POP TO INCLUDE THE FOOTHILLS
ON FRI...WITH AN AREA OF CHC POP ACROSS THE MTNS. HAVE INCREASED
CLOUD COVER IN RESPONSE AS WELL...BUT REMAINED BELOW MOSTLY CLOUDY
FOR NOW. HIGHS WILL BE A FEW DEGREES BELOW NORMAL...WITH LOWS NEAR
NORMAL.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 150 PM TUE...THE 500MB PATTERN CONTINUES TO EVOLVE WITH THE
EAST COAST MAIN TROUGH LIFTING OUT TO THE NE WHILE THE SOUTHERN END
ELONGATES TOWARD THE GULF COAST.  CURRENT MODEL RUNS ARE LESS
CERTAIN THAT THERE WILL BE A CUT OFF UPPER LOW OVER THE NRN GULF.
THE 500MB RIDGE WILL CONTINUE OVER AZ AND SRN CALIFORNIA WHILE THE
MAIN FLOW BECOMES GENERALLY WEST TO EAST OVER THE NRN TIER OF THE
LOWER 48 AT 12Z MONDAY.  MODELS DIVERGE ON DAY 7 AS THE ECMWF
DEVELOPS A TROUGH OVER THE MID SECTION TUES NIGHT WHILE GFS
CONTINUES GENERAL WEST TO EAST FLOW OVER NRN TIER.

AT THE SURFACE...HIGH PRESSURE OVER THE APPALACHIANS WILL SHRINK IN
EXTENT OF INFLUENCE OVER THE WEEKEND AND INTO EARLY NEXT WEEK. A
STATIONARY FRONT FROM THE NRN GULF ACROSS NRN FL TO OFF THE CAROLINA
COAST WILL GRADUALLY DISSIPATE. THE NEXT COLD FRONT WILL CROSS THE
GREAT LAKES ON MONDAY AND REACHES THE OHIO RIVER EARLY TUESDAY.
LIGHT LOW LEVEL UPSLOPE FROM THE EAST AND SE COMBINED WITH
DIFFERENTIAL HEATING OF THE RIDGE TOPS AND VALLEYS IN THE MTNS WILL
CONTRIBUTE TO SOME DEVELOPING LATE DAY MTN CONVECTION EACH DAY.
TEMPS SLIGHTLY BELOW NORMAL SATURDAY THEN GETTING BACK TO AROUND
NORMAL INTO EARLY NEXT WEEK.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...MODEL DATA SUPPORTS ROBUST CONVECTION THIS AFTERNOON...
WHICH COULD PRODUCE RESTRICTIONS AND GUSTY SURFACE WINDS AT THE
FIELD. WINDS WILL SHIFT FROM SW TO NW BEHIND THE FRONT THIS
EVENING...AND N AFTER MIDNIGHT. GUIDANCE DOES NOT SUPPORT DAYBREAK
FOG AS WINDS AND GUSTS STAY UP OVERNIGHT. WEDNESDAY FEATURES N WINDS
AND DRY WEATHER.

ELSEWHERE...ROBUST CONVECTION AHEAD OF A COLD FRONT WILL AFFECT THE
MOUNTAINS FIRST...THEN THE FOOTHILLS...WITH ASSOCIATED RESTRICTIONS
AND WIND GUSTS. WINDS WILL VEER FROM SW TO NW AND THEN N BEHIND THE
FRONT THIS EVENING. ALTHOUGH SOME GUIDANCE SUPPORTS DAYBREAK FOG IN
THE MOUNTAINS...GUSTY N WINDS SHOULD PREVENT FOG FROM FORMING
ANYWHERE. DRIER WEATHER AND N WINDS PREVAIL ON WEDNESDAY.

OUTLOOK...INTRUDING HIGH PRESSURE WILL YIELD GENERALLY DRIER/VFR
CONDITIONS THRU WEEKS END...WITH THE POSSIBLE EXCEPTION OF EARLY
MORNING FOG/STRATUS AND AFTERNOON THUNDERSTORMS IN THE MOUNTAINS.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       LOW   55%     LOW   55%     LOW   59%     MED   69%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH  94%     HIGH  94%

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...DEO
NEAR TERM...JAT
SHORT TERM...RWH
LONG TERM...DEO
AVIATION...JAT

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
404 AM EDT TUE AUG 11 2015

GAZ018-026-028-029-NCZ036-037-056-057-068>072-082-SCZ004>014-019-
120815-
STEPHENS-FRANKLIN-HART-ELBERT-IREDELL-DAVIE-CATAWBA-ROWAN-CLEVELAND-
LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION-GREATER OCONEE-
GREATER PICKENS-GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-
ANDERSON-ABBEVILLE-LAURENS-CHESTER-GREENWOOD-
404 AM EDT TUE AUG 11 2015

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

.DAY ONE...TODAY AND TONIGHT.

SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AHEAD OF AN
INTRUDING COLD FRONT. MODEST DESTABILIZATION AND SHEAR WILL
PRESENT MARGINAL CONDITIONS FOR SEVERE THUNDERSTORMS. SOME OF
THESE STRONGER STORMS COULD PRODUCE DAMAGING WIND GUSTS...LARGE
HAIL...HEAVY RAINFALL...AND FREQUENT CLOUD TO GROUND LIGHTNING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

..WEDNESDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..THURSDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..FRIDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SATURDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SUNDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..MONDAY...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.

GAZ010-017-NCZ033-035-048>053-058-059-062>065-501>510-SCZ001>003-
120815-
RABUN-HABERSHAM-AVERY-ALEXANDER-MADISON-YANCEY-MITCHELL-SWAIN-
HAYWOOD-BUNCOMBE-GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-
TRANSYLVANIA-HENDERSON-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-
404 AM EDT TUE AUG 11 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
GEORGIA...THE MOUNTAINS AND FOOTHILLS OF WESTERN NORTH
CAROLINA...AND THE MOUNTAINS OF UPSTATE SOUTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

A COLD FRONT WILL SLIDE EAST TODAY WITH ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS DEVELOPING OUT AHEAD. SOME OF THESE
STORMS COULD PRODUCE GUSTY WINDS...HEAVY RAINFALL...AND FREQUENT
CLOUD TO GROUND LIGHTNING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

..WEDNESDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..THURSDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..FRIDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SATURDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SUNDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..MONDAY...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.

CDG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
251 PM EDT TUE AUG 11 2015

NCZ036-056-057-069-071-072-111930-
CABARRUS NC-ROWAN NC-IREDELL NC-CATAWBA NC-MECKLENBURG NC-LINCOLN NC-
251 PM EDT TUE AUG 11 2015

...STRONG THUNDERSTORM WILL IMPACT PORTIONS OF NORTHWESTERN
MECKLENBURG...SOUTHWESTERN ROWAN...SOUTHEASTERN CATAWBA...
NORTHWESTERN CABARRUS...SOUTHEASTERN IREDELL AND EASTERN LINCOLN
COUNTIES UNTIL 330 PM EDT...

AT 250 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 10
MILES NORTHWEST OF HUNTERSVILLE...OR NEAR LAKE NORMAN...MOVING EAST
AT 20 MPH.

PEA SIZE HAIL AND WIND GUSTS UP TO 45 MPH WILL BE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
HUNTERSVILLE...KANNAPOLIS...CORNELIUS...MOORESVILLE...DAVIDSON...
LANDIS...ENOCHVILLE...WESTPORT...LAKE NORMAN AND CODDLE CREEK
RESERVOIR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

&&

LAT...LON 3549 8113 3565 8097 3555 8053 3531 8076
TIME...MOT...LOC 1850Z 291DEG 17KT 3555 8093

MOORE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
257 PM EDT TUE AUG 11 2015

NCZ069-070-111945-
GASTON NC-LINCOLN NC-
257 PM EDT TUE AUG 11 2015

...STRONG THUNDERSTORM WILL IMPACT PORTIONS OF NORTHEASTERN GASTON
AND LINCOLN COUNTIES UNTIL 345 PM EDT...

AT 257 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
LINCOLNTON...OR OVER BOGER CITY...MOVING EAST AT 20 MPH.

PEA SIZE HAIL AND WIND GUSTS UP TO 45 MPH WILL BE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
LINCOLNTON...MT HOLLY...STANLEY...WESTPORT...HIGH SHOALS...IRON
STATION...DENVER...BOGER CITY...LAKE NORMAN AND LOWESVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

GUSTY WINDS CAN BLOW DOWN TREES THAT ARE DEAD...OR THAT HAVE WEAKENED
ROOT SYSTEMS. OUTDOOR FURNITURE AND SIMILAR ITEMS CAN BE TOSSED
AROUND IF NOT ANCHORED. SEEK SHELTER INDOORS.

&&

LAT...LON 3553 8095 3552 8096 3551 8096 3549 8095
      3526 8101 3548 8135 3556 8124 3554 8095
      3553 8094
TIME...MOT...LOC 1857Z 291DEG 16KT 3549 8120

MOORE