Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
936 PM EDT Wed Aug 12 2020

.SYNOPSIS...
Daily showers and thunderstorms will become more numerous as the
week progresses.  High temperatures will be slightly below normal
for the end of the week due to more moisture and considerable cloud
cover.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 930 pm EDT Wednesday: Upped shower and thunderstorms coverage
near the Upper Savannah Valley to match the latest trends as
thunderstorms continue to fire along a lingering boundary,
fueled by CAPE values in excess of 2000 J/kg. Flooding and
frequent lightning are the main concerns with this slow moving
activity with rainfall totals locally near two inches. Cloud
cover is still fairly extensive across the area, which could
limit fog formation later tonight focused across mountain
valleys and areas that saw decent rain totals today.

Otherwise coverage will diminish late this evening, will keep
isolated to scattered showers going through much of the overnight as
low-level convergence and weak upper divergence continues. Mountain
valley fog is likely toward daybreak, and low stratus may invade the
Piedmont from the east. Mins will again be a few degrees above climo
overnight with the moisture and clouds.

The closed upper low over southern Illinois this afternoon will open
up and drift east toward the Appalachians through Thursday. With all
of the favorable features still in place from Wed., e.g. low-level
convergence, weak upper divergence, very moist profiles, light east
to southeast upslope flow, anticipate yet another uptick in PoPs
through the diurnal heating hours. Lapse rates may be a touch
better, but clouds could inhibit surface heating a bit, so
instability profiles will be similar overall with a continued threat
of localized flooding from slowly moving cells. Maxes will be very
near climo.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 200 pm Wednesday: A slow moving mid level trof will move
across the Ohio Valley through this period. This will lead to above
normal Pops each period. While there will be the typical enhancement
with daytime heating, rain chances will continue through the night.
Due to precipitable water values around 2 inches and the slow moving
nature of the storms, some heavy rainfall and flooding will be
possible. Extensive cloud cover can be expected, which will keep
highs on Friday and Saturday a few degrees below climo.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 200 pm Wednesday: The mid level trof will move slowly east of
the area on Sunday allowing pops to drop back to near climo early in
the week. Another trof looks to move through the mid level flow by
the middle of next week leading to an increase in pops. With
increased sunshine, highs will climb back to near climo by the
middle of next week.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
At KCLT and Elsewhere: Below normal confidence in 00Z TAFs
especially through 13Z due to uncertainty in low cigs/vsbys
potential. Remnant debris clouds from earlier convection may clear
out to support a IFR or lower cigs/vsbys for mountain valleys (incl
KAVL) and some foothill locations (incl KHKY) between 08Z and 12Z.
Light easterly upslope flow should support MVFR to locally IFR or
lower cig development after 08Z east of the mountains, most notably
for the NC terminals. Low cigs may be slow to lift from 12Z through
16Z or so. The upslope flow may -shra near the foothills. Above
normal diurnal convection expected again Thursday with an earlier
start (around 15Z) possible along and west of I-26 including KGSP
and KAVL.

Outlook: Above normal coverage of diurnal convection is expected
thru the upcoming weekend and into early next week. Morning fog/low
stratus restrictions will be possible each morning, especially over
the usual mountain valleys.

Confidence Table...

            01-07Z        07-13Z        13-19Z        19-00Z
KCLT       High 100%     High  81%     High  83%     High 100%
KGSP       High 100%     High  91%     High  95%     High 100%
KAVL       High  95%     Med   62%     High  89%     High  98%
KHKY       High 100%     Low   59%     Med   74%     High 100%
KGMU       High 100%     High  95%     High  99%     High 100%
KAND       High 100%     High  96%     High  96%     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...SW
NEAR TERM...HG/65
SHORT TERM...SW
LONG TERM...SW
AVIATION...65

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
229 PM EDT Wed Aug 12 2020

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-131830-
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-
229 PM EDT Wed Aug 12 2020

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

.DAY ONE...This afternoon and tonight.

Scattered to numerous thunderstorms have developed across the region
this afternoon, and these storms will persist into the evening hours
before slowly diminishing overnight. The primary threats from these
storms will be from frequent cloud to ground lightning, locally heavy
rainfall, and gusty winds. Slowly-moving, and occasionally
stationary, thunderstorms and heavy rain showers will pose a threat
of locally excessive rainfall and flash flooding, especially in
locations that have received heavy rainfall over the past few days.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1018 PM EDT Wed Aug 12 2020

GAZ028-029-SCZ006-010-130300-
Elbert GA-Hart GA-Anderson SC-Greater Greenville SC-
1018 PM EDT Wed Aug 12 2020

...A CLUSTER OF THUNDERSTORMS WILL IMPACT NORTHWESTERN ELBERT...
HART...SOUTHEASTERN GREENVILLE AND ANDERSON COUNTIES UNTIL 1100 PM
EDT...

At 1017 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 11 miles south of
Greenville Downtown to 11 miles northeast of Danielsville, and moving
southeast at 10 mph.

Locations to be impacted include...
Anderson, Hartwell, Elberton, Homeland Park, Piedmont, Belton,
Williamston, Northlake, Reed Creek and Iva.

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 3408 8300 3410 8304 3411 8303 3412 8305
      3415 8306 3417 8310 3422 8308 3426 8311
      3432 8310 3474 8244 3459 8224 3457 8224
      3404 8298
TIME...MOT...LOC 0217Z 322DEG 7KT 3469 8243 3425 8309

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1033 PM EDT Wed Aug 12 2020

GAZ029-SCZ006-010>012-019-130315-
Elbert GA-Laurens SC-Anderson SC-Abbeville SC-Greenwood SC-
Greater Greenville SC-
1033 PM EDT Wed Aug 12 2020

...A CLUSTER OF THUNDERSTORMS WILL IMPACT EASTERN ELBERT...WEST
CENTRAL LAURENS...SOUTHEASTERN GREENVILLE...SOUTHEASTERN ANDERSON...
ABBEVILLE AND NORTHWESTERN GREENWOOD COUNTIES UNTIL 1115 PM EDT...

At 1032 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 12 miles west of Laurens
to 5 miles southwest of Elberton, and moving southeast at 15 mph.

Locations to be impacted include...
Elberton, Honea Path, Ware Shoals, Calhoun Falls, Due West, Lake
Secession, Donalds, Lowndesville, Russell State Park and Shoals
Junction.

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 3399 8283 3398 8284 3398 8286 3401 8291
      3401 8294 3403 8294 3404 8295 3403 8296
      3404 8298 3460 8223 3446 8204 3398 8270
      3398 8273 3397 8278
TIME...MOT...LOC 0232Z 305DEG 12KT 3456 8223 3405 8294

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1112 PM EDT Wed Aug 12 2020

SCZ010-011-130345-
Anderson SC-Abbeville SC-
1112 PM EDT Wed Aug 12 2020

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT SOUTHEASTERN
ANDERSON AND NORTHEASTERN ABBEVILLE COUNTIES UNTIL 1145 PM EDT...

At 1112 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 12 miles north of Abbeville, or near Due West,
moving southeast at 10 mph.

Locations to be impacted include...
Belton, Honea Path, Due West, Donalds, Antreville and Broadway Lake.

Wind gusts up to 40 mph will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3440 8266 3454 8252 3447 8231 3445 8228
      3444 8228 3443 8226 3442 8226 3423 8247
TIME...MOT...LOC 0312Z 316DEG 7KT 3436 8243

12

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1114 PM EDT Wed Aug 12 2020

GAZ029-SCZ010-011-130345-
Elbert GA-Anderson SC-Abbeville SC-
1114 PM EDT Wed Aug 12 2020

...A CLUSTER OF THUNDERSTORMS WILL IMPACT EASTERN ELBERT AND SOUTHERN
ABBEVILLE COUNTIES UNTIL 1145 PM EDT...

At 1114 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 9 miles northwest of
Abbeville to 11 miles east of Elberton, and moving southeast at 10
mph.

Locations to be impacted include...
Abbeville, Elberton, Calhoun Falls, Lake Secession, Lowndesville,
Bobby Brown State Park, Lake Strom Thurmond, Russell State Park,
Nancy Hart State Park and Middleton.

Wind gusts up to 40 mph will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3398 8261 3397 8264 3399 8265 3397 8278
      3399 8283 3398 8286 3401 8291 3401 8294
      3403 8294 3404 8298 3432 8261 3413 8226
      3406 8233 3406 8244 3408 8248 3407 8253
      3401 8260 3396 8257
TIME...MOT...LOC 0314Z 301DEG 8KT 3424 8252 3405 8268

12

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1148 PM EDT Wed Aug 12 2020

GAZ029-SCZ011-019-130415-
Elbert GA-Abbeville SC-Greenwood SC-
1148 PM EDT Wed Aug 12 2020

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL IMPACT SOUTHEASTERN
ELBERT...ABBEVILLE AND WEST CENTRAL GREENWOOD COUNTIES UNTIL 1215 AM
EDT...

At 1148 PM EDT, Doppler radar indicated thunderstorms with torrential
rainfall along a line extending from 5 miles northeast of Abbeville
to 15 miles southeast of Elberton. These storms were nearly
stationary.

Locations to be impacted include...
Abbeville, Greenwood, Calhoun Falls, Due West, Bobby Brown State
Park, Lake Strom Thurmond, Lake Russell, Promised Land, Broad River
Campground and Richard B Russell Dam.

Wind gusts up to 40 mph and very heavy rainfall rates up to 2 inches
per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3398 8261 3397 8264 3399 8265 3398 8267
      3410 8272 3436 8238 3417 8214 3401 8232
      3406 8233 3406 8244 3408 8248 3407 8250
      3407 8253 3401 8260 3399 8258 3396 8257
TIME...MOT...LOC 0348Z 316DEG 4KT 3425 8233 3402 8262

12

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1230 AM EDT Thu Aug 13 2020

NCZ037-130500-
Davie NC-
1230 AM EDT Thu Aug 13 2020

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT DAVIE COUNTY
UNTIL 100 AM EDT...

At 1229 AM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 5 miles northeast of Mocksville, or 4 miles
southwest of Bermuda Run, moving north at 10 mph.

Locations to be impacted include...
Mocksville, Bermuda Run, Fork Church, Advance and Farmington.

Wind gusts up to 40 mph will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3589 8040 3588 8042 3587 8039 3585 8039
      3585 8042 3583 8043 3583 8046 3584 8048
      3583 8049 3581 8047 3580 8047 3592 8066
      3605 8061 3604 8049 3606 8046 3601 8042
      3599 8042 3596 8038 3589 8037
TIME...MOT...LOC 0429Z 193DEG 9KT 3594 8047

12