Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
230 PM EDT Mon Jul 17 2017

.SYNOPSIS...
A weak frontal boundary across the area today will dissipate over
the next few days. A strong upper ridge will then gradually build
into the region during the mid-to-late week, bringing hot
temperatures and reducing the coverage of diurnal showers and
thunderstorms.

&&

.NEAR TERM /THROUGH TUESDAY/...
Isolated -shra and tstms are developing across the mtns...generally
along the BR area. This activity has been pulsing up and down with
updraft strength remaining relatively low and within the SPS range.
Instability is pretty strong...arnd 2500 J/kg...yet no real triggers
are available so the main mechanism for development will be thermal
forcing. Expect better coverage as the afternoon progresses with
some activity developing over the non/mtns associated with existing
outflow bndrys. A few of these storms could reach severe levels with
damaging winds being the main threat.

A well agreed upon h5 s/w will cross the FA this evening and will
interact with elev instability keeping -shra/tstms active through
the overnight to some degree. Expect lingering debris clouds and
moisture leading to stcu development to persist arnd daybreak. The
best chance for denser fg development will be across the mtn
valleys....yet all areas could see patchy ground fg lifting by 14z
or so. Afternoon and evening convection will once again be probable
Tue as the upper trof continues to influence the pattern. Mid-level
LRs will be conducive for stg/svr storms as LFCs are easily reached
once again and sbCAPE reaches moderate levels. Max and min temps
thru the period will remain near normal levels.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 200 PM EDT Monday:  The short term fcst period kicks off
on Tuesday evening as a weak upper trof/disturbance slides east
across the Carolinas, while high pressure dominates at the surface.
Meanwhile to the west, a large H5 anticyclone will build, before
sliding east through the entire period.  With that, heights will
gradually rise through Wednesday and into Thursday atop northeast GA
and the western Carolinas leading to warming temperatures through
the profile.  Said warming will work to gradually tamp down
convective chances on Wednesday, and even further on Thursday.
With below climo pops fcst given decreased chances for diurnal
convection, the primary headline for the short term will be the
building heat.  Temperatures will warm each day with mid 90s
prevailing by Thursday across the piedmont, while upper 80s are
expected in the mtn valleys.  As such, given dewpoints in the upper
60s to lower 70s, am expecting heat indices to approach/exceed
100 degrees by Thursday.

&&

.LONG TERM /FRIDAY THROUGH SUNDAY/...
As of 240 PM EDT Monday: Mid level ridging will be in place across
the area for Friday through the weekend into Monday leading to the
hottest period of the summer so far. Expect highs climbing into the
middle to upper 90s outside the mountains each day. Afternoon heat
indices will reach 100-105 in the Piedmont so will have to consider
heat advisories. Overnight lows will be warm also with mid to upper
70s common across the lower terrain.

Due to mid level warming, afternoon and evening thunderstorm
activity will be limited to the more favorable areas. The exception
will be Monday as the ridge begins to break down.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: A good Cu field is encompassing the area this
afternoon with some deeper destabilization indicated across the higher
terrain. Expect most of the thunder to remain across the mtns until
later this afternoon when cells begin firing across existing outflow
bndrys. Hard to pinpoint favored locales and hi-res models are back
and forth with timings and locales. Anyway...have maintained a TEMPO
TSRA at KCLT this afternoon with the other sites getting a VCTS. An
ulvl s/w will cross from the northwest overnight and help maintain
-shra and possibly a few tstms. With debris cloudiness and llvl
moisture lingering thru daybreak...periods of STCU may develop and
expand. For now...will keep the IFR CIGS limited to the mtn sites.
Some lowering of VSBY is also expected arnd daybreak with IFR VSBY
possible at KAVL and likely MVFR VSBY all other sites before
lifting/dissipating aft 14z or so.

Outlook: Scattered to afternoon and evening thunderstorms are
expected into Wednesday across the area, with better coverage over
the mountains. Morning fog development can be expected in the
mountain valleys and in areas that receive rainfall the previous
afternoon/evening. Drier air will likely limit convective coverage
for Thursday, with typical mid-summer conditions returning by Friday.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High  99%     Med   68%     Med   79%
KGSP       High 100%     High 100%     High  83%     High  91%
KAVL       High 100%     High  97%     High  91%     High  92%
KHKY       High 100%     High 100%     Med   78%     High  92%
KGMU       High 100%     High 100%     High  91%     High  90%
KAND       High 100%     High 100%     High  83%     High  87%

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:

www.weather.gov/gsp/aviation

&&

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

&&

SYNOPSIS...SW
NEAR TERM...SBK
SHORT TERM...CDG
LONG TERM...SW
AVIATION...SBK

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
613 AM EDT Mon Jul 17 2017

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-181015-
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-
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-Chester-Greenwood-
613 AM EDT Mon Jul 17 2017

This Hazardous Weather Outlook is for northeast Georgia, piedmont
North Carolina, western North Carolina and upstate South Carolina.

.DAY ONE...Today and Tonight.

Isolated to scattered thunderstorms are expected to develop again
across the area this afternoon and evening. The main threats will be
from cloud to ground lightning and locally heavy rainfall. However,
a few storms could become severe, with damaging winds being the
primary threat.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

..Tuesday...No hazardous weather is expected at this time.
..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.

.SPOTTER INFORMATION STATEMENT...

None.

JPT

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
322 PM EDT MON JUL 17 2017

SCZ001-002-171945-
Pickens Mountains SC-Oconee Mountains SC-
322 PM EDT MON JUL 17 2017

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN PICKENS AND
NORTHEASTERN OCONEE COUNTIES UNTIL 345 PM EDT...

At 322 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles northwest of Pickens, or over Jocassee Gorges, moving southeast
at 10 mph.

Locations to be impacted include...
Devils Fork State Park, Lake Keowee, Keowee Toxaway State Park,
Jocassee Gorges, Lake Jocassee, Sunset, Nine Times and Rocky Bottom.

Wind gusts up to 50 mph and pea size hail will be possible in these
areas.

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.

Lake Jocassee is in the path of this storm. Cloud to ground
lightning and gusty winds will create dangerous boating conditions.
Move to shore immediately.

&&

LAT...LON 3506 8287 3507 8283 3497 8262 3489 8274
      3482 8288 3496 8301
TIME...MOT...LOC 1922Z 315DEG 8KT 3496 8284

ARK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
349 PM EDT MON JUL 17 2017

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

0340 PM     HEAVY RAIN       4 WSW HENDERSONVILLE    35.31N 82.53W
07/17/2017  M1.70 INCH       HENDERSON          NC   COCORAHS

            1.70 INCHES OF RAIN IN PAST 40 MINUTES.

&&

OUTLAW

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
351 PM EDT MON JUL 17 2017

NCZ049-050-053-172015-
Buncombe NC-Yancey NC-Mitchell NC-
351 PM EDT MON JUL 17 2017

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL MITCHELL...
NORTHEASTERN BUNCOMBE AND SOUTHEASTERN YANCEY COUNTIES UNTIL 415 PM
EDT...

At 351 PM EDT, Doppler radar was tracking a strong thunderstorm near
Burnsville, moving south at 5 mph.

Locations to be impacted include...
Burnsville, Mount Mitchell State Park, B.R. Parkway-Craggy To Little
Switzerland, Celo, Busick and Micaville.

Wind gusts up to 40 mph and pea size hail will be possible in these
areas.

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.

Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.

&&

LAT...LON 3594 8211 3583 8211 3582 8212 3582 8213
      3581 8215 3580 8215 3580 8216 3579 8217
      3578 8216 3574 8219 3570 8226 3576 8243
      3597 8233
TIME...MOT...LOC 1951Z 010DEG 6KT 3589 8224

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
405 PM EDT MON JUL 17 2017

NCZ071-072-172030-
Cabarrus NC-Mecklenburg NC-
405 PM EDT MON JUL 17 2017

...A STRONG THUNDERSTORM WILL IMPACT WEST CENTRAL CABARRUS AND
NORTHEASTERN MECKLENBURG COUNTIES UNTIL 430 PM EDT...

At 404 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles southeast of Huntersville, or near UNC Charlotte, moving west
at 5 mph.

Locations to be impacted include...
Huntersville, Northeast Charlotte, Northwest Charlotte, West Concord,
Cornelius, Davidson, Harrisburg, Reedy Creek Park, Charlotte Motor
Speedway and UNC Charlotte.

Wind gusts up to 45 mph and pea size hail will be possible in these
areas.

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 3540 8061 3523 8067 3525 8094 3551 8086
TIME...MOT...LOC 2004Z 104DEG 6KT 3535 8073

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
408 PM EDT MON JUL 17 2017

GAZ010-017-SCZ001-172045-
Rabun GA-Habersham GA-Oconee Mountains SC-
408 PM EDT MON JUL 17 2017

...A STRONG THUNDERSTORM WILL IMPACT NORTHERN HABERSHAM...
SOUTHWESTERN RABUN AND WEST CENTRAL OCONEE COUNTIES UNTIL 445 PM
EDT...

At 408 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles south of Clayton, or near Lakemont, moving west at 15 mph.

Locations to be impacted include...
Tiger, Tallulah Falls, Lake Rabun, Lake Burton, Moccasin Creek State
Park, Lakemont, Tallulah Gorge State Park, Batesville, Turnerville
and Hollywood.

Wind gusts up to 40 mph and pea size hail will be possible in these
areas.

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.

Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.

&&

LAT...LON 3482 8365 3484 8366 3487 8365 3486 8332
      3468 8329 3467 8332 3469 8334 3467 8337
      3466 8337 3460 8363 3468 8364 3474 8362
      3477 8363 3479 8366 3481 8367
TIME...MOT...LOC 2008Z 081DEG 15KT 3477 8340

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
421 PM EDT MON JUL 17 2017

NCZ068-508-172045-
Greater Rutherford NC-Cleveland NC-
421 PM EDT MON JUL 17 2017

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN RUTHERFORD AND WEST
CENTRAL CLEVELAND COUNTIES UNTIL 445 PM EDT...

At 421 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles northeast of Forest City, or 5 miles northeast of Bostic,
moving west at 10 mph.

Locations to be impacted include...
Forest City, Rutherfordton, Spindale, Ellenboro, Bostic, Polkville
and Sunshine.

Wind gusts up to 45 mph and pea size hail will be possible in these
areas.

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 3547 8164 3531 8170 3532 8198 3554 8191
      3554 8184 3556 8184
TIME...MOT...LOC 2021Z 105DEG 7KT 3542 8176

ARK