Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
136 PM EDT Sun Aug 9 2020

.SYNOPSIS...
We can expect the isolated to scattered showers and thunderstorms
early in the week to become more numerous in the afternoon and
evening from mid to late week.  High high temperatures of a couple
degrees above normal early in the week will be near normal late in
the week under the considerable cloud cover.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 130 PM: Main update for the 18Z TAF issuance along with
minor adjustments made to temps/sky/PoPs to coincide with latest
trends as the rest of the near term forecast remains on track.
A few showers and thunderstorms are beginning to pop up per
latest radar imagery attm with otherwise quiet conditions across
the area. Current temperatures are in the mid to upper 80s.

Previous discussion: The synoptic pattern will be characterized by
general bagginess in the upper height field, with a weak short wave
trough forecast to approach the area from the TN Valley by the end
of the day. Forecast instability parameters look very similar to
yesterday...basically typical mid-summer 2000-ish J/kg sbCAPE across
much of the forecast area. Isolated to widely scattered convection
is expected to develop during mid/late across the Blue Ridge, and
perhaps along subtle surface trough draped across the Piedmont, with
overall coverage likely being a bit higher than on Saturday. As
usual, can't rule out a couple of brief pulse storms producing
microbursts, but it would appear that heavy rainfall will be the
main concern, as conditions are conducive to backbuilding
multicells. Max temps will be a couple of degrees above climo in
most locations.

The approach of aforementioned short wave may be enough to keep
scattered convection going well into the evening, if not the
overnight as seasonably warm/muggy conditions persist.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 305 AM EDT Sunday: the short-term fcst picks up at 12z on
Monday with weak, NWLY flow aloft and broad upper ridging in place
across the region. Little change is expected wrt the upper-level
pattern thru the period, as broad upper ridging persists across most
of the CONUS and weak, embedded upper shortwave energy gradually
ripples eastward over the region. At the sfc, on Monday some degree
of moistening is likely as return flow from the gulf gradually
increases thru the day and profiles become more conducive for
convection. On Tuesday, a weak cold front approaches the fcst
area from the NW but stalls out as it lays north of the CWFA late
Tuesday. Although the front is weak and fairly diffuse, it should
provide at least some degree of low-lvl forcing Tues into early
Wed, especially over the higher terrain. Overall, no significant
changes were made to the sensible fcst. PoPs increase to near climo
for Monday aftn/evening and above climo on Tuesday into early Wed.
Temps should be just above normal on Monday and Tuesday, with Heat
Indices remaining below 100 degrees for all but our southern-most
zones.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 245 AM EDT Sunday: the extended forecast picks up at 12z on
Wednesday with continued weak flow aloft and extensive upper ridging
spread across most of the CONUS. As the period begins the long-range
guidance depicts a fairly robust and embedded upper shortwave moving
over the Mississippi River Valley. This feature is currently much
more well-defined based on the GFS depiction as compared to the ECMWF
or CMC. Regardless, over the next couple of days the shortwave is
expected to track NE and over the Ohio River Valley. Towards the end
of the period the models try and close off whatever is left of the
upper shortwave, however it's not clear at this point if it will
actually become a closed low. Otherwise, the upper-lvl pattern is
not expected to change much thru the period, with the polar jet
remaining well to the north and over Canada while upper ridging
persists across most of the CONUS. The sfc pattern will remain
fairly messy thru the period with the Bermuda High keeping generally
moist, SLY flow over the region. A weak lee trof tries to develop
on Wednesday as deeper moisture begins to pool over the region.
This pattern will likely continue for the rest of the period as
improving SLY flow brings a resurgence of gulf moisture for Thursday
and beyond. Overall, there were no significant changes made to the
fcst with diurnally-driven, above-climo PoPs each day and temps a
degree or 2 above normal on Wednesday and near normal for the rest
of the period.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
At KCLT and Elsewhere: Expect VFR to prevail through tonight with
the exception of intermittent, short-lived flight restrictions in
any shower or thunderstorm that moves over a TAF site, as noted by
TEMPO groups for afternoon/evening convection. Per latest guidance,
isolated showers may linger into the overnight hours, but confidence
on the the potential for -SHRA moving directly over a TAF site is
low attm. Low stratus/fog will be possible before daybreak on
Monday, mainly across the mountain valleys. Otherwise expect VFR
through the end of the valid TAF period.

Outlook: Diurnal convection will increase in coverage each day from
Monday through Wednesday, with above average coverage expected thru
the end of the work week. Morning fog/stratus restrictions will also
be possible each morning, especially over the usual mountain
valleys. Otherwise expect VFR.

Confidence Table...

            17-23Z        23-05Z        05-11Z        11-12Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High  83%
KAVL       High 100%     High 100%     High  83%     Low   43%
KHKY       High 100%     High 100%     High 100%     High  83%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High 100%

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...JPT
NEAR TERM...JDL/12
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...12

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
557 AM EDT Sun Aug 9 2020

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-101000-
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-
557 AM EDT Sun Aug 9 2020

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 showers and thunderstorms are expected to
develop across the region again this afternoon and evening. Any of
the thunderstorms may produce cloud to ground lightning, heavy
downpours, and gusty winds. Isolated flash flooding may be possible
if storms train over specific locations.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

JPT

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
118 PM EDT Sun Aug 9 2020

GAZ010-017-SCZ001-091800-
Rabun GA-Habersham GA-Oconee Mountains SC-
118 PM EDT Sun Aug 9 2020

...A CLUSTER OF THUNDERSTORMS WILL IMPACT NORTHERN HABERSHAM...SOUTH
CENTRAL RABUN AND WEST CENTRAL OCONEE COUNTIES UNTIL 200 PM EDT...

At 117 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 7 miles southeast of
Clayton to 9 miles north of Clarkesville, and moving southeast at 10
mph.

Locations to be impacted include...
Tallulah Falls, Lake Rabun, Lakemont, Tallulah Gorge State Park,
Batesville, Seed Lake, Turnerville and Long Creek.

Wind gusts up to 40 mph and pea size hail 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 3468 8364 3471 8364 3473 8362 3474 8363
      3475 8362 3482 8329 3472 8324 3463 8364
      3466 8366
TIME...MOT...LOC 1717Z 320DEG 8KT 3480 8332 3474 8356

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
150 PM EDT Sun Aug 9 2020

SCZ001-091815-
Oconee Mountains SC-
150 PM EDT Sun Aug 9 2020

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN OCONEE COUNTY UNTIL
215 PM EDT...

At 150 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Walhalla, or near Oconee State Park, moving southeast
at 10 mph.

Locations to be impacted include...
Walhalla, Salem, Oconee State Park and Mountain Rest.

Wind gusts up to 40 mph, pea size hail and 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 3492 8315 3494 8313 3493 8311 3495 8312
      3498 8308 3489 8291 3488 8291 3476 8308
      3490 8318
TIME...MOT...LOC 1750Z 320DEG 9KT 3491 8308

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
206 PM EDT Sun Aug 9 2020

SCZ002-003-091830-
Pickens Mountains SC-Greenville Mountains SC-
206 PM EDT Sun Aug 9 2020

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN GREENVILLE AND
NORTH CENTRAL PICKENS COUNTIES UNTIL 230 PM EDT...

At 206 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles north of Pickens, or near Table Rock State Park, moving
southeast at 15 mph.

Locations to be impacted include...
Caesars Head State Park, Table Rock State Park, Pumpkintown,
Sassafras Mountain and Rocky Bottom.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour 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 3494 8267 3506 8281 3508 8278 3507 8278
      3507 8275 3508 8275 3508 8274 3509 8273
      3510 8270 3510 8269 3511 8270 3512 8268
      3509 8257
TIME...MOT...LOC 1806Z 311DEG 12KT 3505 8270

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
221 PM EDT Sun Aug 9 2020

GAZ017-018-026-SCZ001-004-091845-
Franklin GA-Stephens GA-Habersham GA-Greater Oconee SC-
Oconee Mountains SC-
221 PM EDT Sun Aug 9 2020

...STRONG THUNDERSTORMS WILL IMPACT NORTHWESTERN FRANKLIN...
STEPHENS...SOUTHEASTERN HABERSHAM AND SOUTHERN OCONEE COUNTIES UNTIL
245 PM EDT...

At 221 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 9 miles northeast of Toccoa to 6 miles south of
Clarkesville, and moving east at 15 mph.

Locations to be impacted include...
Toccoa, Seneca, Cornelia, Baldwin, Westminster, Mount Airy, Martin,
Avalon, Alto and Gumlog.

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.

&&

LAT...LON 3476 8324 3471 8286 3470 8286 3470 8285
      3433 8334 3436 8339 3443 8338 3446 8340
      3448 8347 3449 8354 3446 8359 3448 8363
TIME...MOT...LOC 1821Z 288DEG 13KT 3470 8324 3451 8350

ARK