Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
259 PM EDT Thu Aug 19 2021

.SYNOPSIS...
A weak upper trough and abundant moisture will continue across the
region into Friday leading to scattered afternoon and evening
showers and thunderstorms. Saturday an upper-level low will meander
around the Ohio Valley and Mid-Atlantic region before lifting
northeast into New England late this weekend into early next week as
a ridge of high pressure to the south nudges eastward. This should
lead to drier conditions for the weekend with only isolated showers
and thunderstorms during the afternoon and evening hours expected.
Highs will remain above climo this week into next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 2:45pm EDT Thursday:  Round of typical diurnal thunderstorms
is underway this afternoon, expected to die out after dark.  Storms
are being enhanced by the passage of a weak upper wave. This shows
nicely as updraft strength in hi-res models. This wave will have
most of its energy east of the region by tomorrow, and while some
thunder will still be possible, the coverage and intensity will be
much reduced from today.  For today, forcing from the wave might
give some severe storms today, despite only 500-1000 j/kg of MLCAPE.
Bulk shear and hodographs are unimpressive, with pulse severe wind
gusts the main threat.  Storm motion is also eastward at 10 to
20kts, which should reduce the risk from hydro issues.  Should mid
and upper clouds clear behind weak surface boundary ahead of upper
wave later tonight, fog could become an issue overnight as surface
layer remains very moist from recent rains, but this is not clear.
Fading tropical air mass will have highs and lows near to a couple
degrees above normal tomorrow.  Winds are fairly light around weak
frontal boundary, and will be lighter on Friday as surface high
behind boundary moves in.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 215 PM EDT Thursday...A ridge of high pressure will continue
to dominate across the southern United States through the short term.
Meanwhile an upper-level closed low will meander around the Ohio
Valley and Mid-Atlantic region Friday night into Saturday. This low
will be forced to lift northeast into New England as the ridge of
high pressure in the southern CONUS nudges eastward Saturday night
into early Monday. As a result of this ridge pushing east into the
western Carolinas and northeast Georgia, flow will be mainly
northerly and northwesterly. This will lead to limited moisture
across the CWA this weekend. Capped PoPs to a slight chance to
chance for the entire period as only isolated showers and
thunderstorms look possible. Highs this weekend should be a couple
degrees above climo.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 215 PM EDT Thursday...The closed low keeps lifting northeast
out of New England into Nova Scotia during the first half of the
extended term forecast period. This will allow the ridge to remain
over the southeastern CONUS through the middle of next week. Towards
the end of the forecast period, this ridge should start to
retrograde back west of the CWA. Meanwhile, a surface trough looks
to linger along the Southeast coast throughout the extended. Monday
and Tuesday are looking like the drier days as the eastern periphery
of the ridge will remain over the area. Capped PoPs to a slight
chance to chance for this reason. Wednesday into Thursday moisture
associated with this trough could push further inland as the high
retreats west. This would increase the moisture influx. Both the GFS
and ECMWF have PWAT values increasing Wednesday into Thursday. As a
result, have PoPs at chance for the end of the forecast period.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
At KCLT and elsewhere:  Thunderstorms now spreading across the area
from west to east.  Expect a typical diurnal pattern with storms
dying out just after sunset.  Upper trough crossing the area will
assist storm development today with some severe.  Weak surface
boundary has generally SW winds of 5 to 10 kts.  As this boundary
moves eastward, surface high comes in, and winds become light and
VRB overnight, becoming more NW to northerly on Friday.  Opted to
keep in some mention of fog at all locations as some possible
clearing overnight above a still moist surface layer and light
winds, will create good conditions for fog formation at some level.
For KCLT, have kept in a PROB30 for thunder tomorrow afternoon,
though storms will be much more widely scattered than today.

Outlook: A typical, diurnal summertime convective pattern is
expected to prevail into early next week, with coverage scattered at
best. Mtn valley low stratus and fog will be possible each morning.

Confidence Table...

            12-18Z        18-24Z        00-06Z        06-12Z
KCLT       High 100%     High 100%     High 100%     High  89%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High  92%     High 100%     High  84%
KHKY       High 100%     High 100%     High  95%     Med   76%
KGMU       High 100%     High 100%     High 100%     High  95%
KAND       High 100%     High 100%     High 100%     High  95%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables are available at
the following link:

www.weather.gov/gsp/aviation

&&

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

&&

SYNOPSIS...AP
NEAR TERM...WJM
SHORT TERM...AP
LONG TERM...AP
AVIATION...WJM

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
513 AM EDT Thu Aug 19 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-200915-
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-
513 AM EDT Thu Aug 19 2021

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

.DAY ONE...Today and tonight.

Thunderstorms are expected to develop today as an upper level
disturbance moves through. After a few early morning storms, new
thunderstorms are expected to develop in the late morning and early
afternoon mainly over the mountains. The storms may become numerous
and organized as they move east across the Upstate, foothills, and
western Piedmont this afternoon and into the early part of the
evening. Some of the storms will become strong to severe, with
frequent cloud-to-ground lightning, damaging wind gusts, and large
hail. Heavy downpours are also possible. The storms will end in the
early to mid evening hours around the Charlotte metro area.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

PM

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
241 PM EDT Thu Aug 19 2021

NCZ052-059-063-064-191915-
Transylvania NC-Haywood NC-Southern Jackson NC-Northern Jackson NC-
241 PM EDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of central
Transylvania, central Jackson and southeastern Haywood Counties
through 315 PM EDT...

At 241 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles southeast of Sylva, or 4 miles southeast of Cullowhee, moving
east at 25 mph.

HAZARD...Winds in excess of 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Cullowhee, Rosman, Webster, B.R. Parkway-Black Balsam To Mount
Pisgah, Graveyard Fields, Lake Glenville, B.R. Parkway-Balsam Gap To
Black Balsam Area, Black Balsam Area, Lake Toxaway and Tuckasegee.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3536 8324 3541 8277 3513 8276 3516 8322
      3522 8322 3524 8323
TIME...MOT...LOC 1841Z 268DEG 22KT 3527 8311

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
251 PM EDT Thu Aug 19 2021

NCZ053-191915-
Buncombe NC-
251 PM EDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of southeastern
Buncombe County through 315 PM EDT...

At 251 PM EDT, Doppler radar was tracking a strong thunderstorm 4
miles southwest of Downtown Asheville, or near Enka, moving east at
25 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Downtown Asheville, East Asheville, Arden, West Asheville, North
Asheville, Black Mountain, Woodfin, Swannanoa, Fairview In Buncombe
County and Biltmore Forest.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3568 8229 3567 8228 3565 8229 3561 8228
      3559 8229 3558 8228 3547 8227 3550 8233
      3548 8237 3546 8237 3547 8242 3545 8247
      3547 8270 3565 8271 3570 8228
TIME...MOT...LOC 1851Z 268DEG 22KT 3556 8262

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
318 PM EDT Thu Aug 19 2021

NCZ064-065-191945-
Transylvania NC-Henderson NC-
318 PM EDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of southeastern
Transylvania and southwestern Henderson Counties through 345 PM
EDT...

At 318 PM EDT, Doppler radar was tracking a strong thunderstorm near
Brevard, moving east at 25 mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Hendersonville, Brevard, Flat Rock, Etowah, Laurel Park, Rosman,
Looking Glass, Dupont State Forest, Valley Hill and Tuxedo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3536 8241 3521 8240 3517 8244 3516 8246
      3518 8246 3516 8253 3516 8255 3515 8257
      3514 8261 3513 8263 3513 8264 3512 8266
      3513 8268 3511 8270 3510 8269 3511 8283
      3530 8284
TIME...MOT...LOC 1918Z 266DEG 22KT 3522 8275

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
337 PM EDT Thu Aug 19 2021

GAZ026-028-192000-
Hart GA-Franklin GA-
337 PM EDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of Franklin and western
Hart Counties through 400 PM EDT...

At 337 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles west of Carnesville, moving east at 25 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Carnesville, Royston, Lavonia, Canon, Franklin Springs, Bowersville,
Victoria Bryant State Park, Gumlog and Vanna.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3427 8312 3424 8317 3425 8320 3424 8325
      3425 8329 3426 8329 3425 8334 3426 8334
      3433 8339 3443 8338 3446 8340 3448 8323
      3447 8299 3423 8302 3423 8308
TIME...MOT...LOC 1937Z 274DEG 23KT 3436 8336

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
359 PM EDT Thu Aug 19 2021

GAZ026-028-029-192030-
Elbert GA-Hart GA-Franklin GA-
359 PM EDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of central Franklin,
northwestern Elbert and southwestern Hart Counties through 430 PM
EDT...

At 359 PM EDT, Doppler radar was tracking a strong thunderstorm near
Carnesville, moving east at 20 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Hartwell, Carnesville, Royston, Bowman, Canon, Franklin Springs,
Bowersville, Victoria Bryant State Park, Lavonia and Vanna.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3418 8310 3420 8309 3423 8308 3427 8312
      3424 8317 3425 8320 3424 8325 3425 8329
      3426 8329 3425 8333 3425 8334 3446 8327
      3440 8289 3414 8297
TIME...MOT...LOC 1959Z 282DEG 19KT 3433 8323

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
414 PM EDT Thu Aug 19 2021

NCZ065-504>510-SCZ003-007-192045-
McDowell Mountains NC-Greater Rutherford NC-Greater Burke NC-
Henderson NC-Polk Mountains NC-Eastern McDowell NC-
Rutherford Mountains NC-Eastern Polk NC-Greenville Mountains SC-
Spartanburg SC-
414 PM EDT Thu Aug 19 2021

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL IMPACT MCDOWELL...
CENTRAL RUTHERFORD...EASTERN HENDERSON...POLK...SOUTHWESTERN BURKE...
NORTHEASTERN GREENVILLE AND NORTHWESTERN SPARTANBURG COUNTIES UNTIL
445 PM EDT...

At 414 PM EDT, Doppler radar indicated thunderstorms with torrential
rainfall along a line extending from 3 miles northeast of Marion to
10 miles northwest of Rutherfordton to 15 miles north of Greenville
Downtown, and moving east at 20 mph.

Locations to be impacted include...
Morganton, Marion, Rutherfordton, Columbus, Spindale, Flat Rock,
Landrum, Tryon, Glen Alpine and Lake Lure.

Very heavy rainfall rates up to 2 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.

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 3585 8164 3582 8162 3553 8175 3502 8221
      3506 8222 3503 8233 3506 8259 3549 8231
      3546 8225 3552 8223 3553 8217 3557 8226
      3573 8214 3579 8196 3577 8193 3588 8172
TIME...MOT...LOC 2014Z 255DEG 19KT 3572 8199 3546 8210 3507 8246

RWH