Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1001 PM EDT Tue Sep 7 2021

.SYNOPSIS...
A cold front is expected to cross our area from the northwest late
Wednesday into early Thursday and bring more widespread showers and
thunderstorms to the region. Drying high pressure will spread back
over the region in the front's wake and linger through the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 950 pm EDT: Pesky late evening sbCAPE of 2000+ J/kg persists
in a narrow corridor northwest of I-85 in NE GA and the western
Upstate of SC. Forcing from continued weak vorticity lobes aloft and
near surface convergence are permitting isolated, but strong,
convection to continue late this evening. The surface-based
instability should slowly ebb by midnight, but with low-level
southwesterly upslope flow increasing through the overnight hours.
This will lead to an uptick to scattered shower coverage overnight,
with a few embedded thunderstorms. Strong storm potential should be
limited by the diminishing instability, and the heavy rain potential
should be limited by decent storm movement. The abundant clouds will
lead to mild mins some 3 degrees above climo in most areas. Mountain
valley fog will form quickly in any breaks in the clouds.

Once morning shower coverage and cloud cover thin out a bit,
guidance suggests robust instability will develop during the
afternoon, around the time that a frontal zone associated with
upstream height falls is expected to sweep across the forecast area.
Likely PoPs will be carried across portions of the mtns and across
the Piedmont, where less morning clouds/showers are anticipated.
Solid chance PoPs are advertised elsewhere. Deep-layer shear will be
meager in terms of the potential for organized storm structures.
However, 0-3 km shear in the 15-20 kts range should be sufficient to
support clustering along cold pools. Microbursts will be possible in
association with any clusters as well as with single cell pulse
storms. Temps are expected to be a little above climo through the
period.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 2:00 PM EDT Tuesday: The overall synoptic pattern for the
short term forecast has high pressure in the western United States
will gradually track east into the central United States while an
upper-level trough over the Great Lakes and Ohio Valley region
tracks east into the Northeast United States. At the sfc, a cold
front will continue tracking across the CWA Wednesday evening into
Wednesday night. This will act to keep shower and thunderstorm
chances around for the beginning of the short term period. Isolated
strong to severe storms will be possible through Wednesday evening,
with the main potential threat being damaging wind gusts. However,
PoPs are expected to gradually decrease Wednesday evening into
overnight Wednesday, so have PoPs capped at a slight chance to
chance. The cold front should be just southeast of the CWA by
Thursday morning. High pressure will fill in behind the departing
FROPA Thursday leading to drier conditions for the majority of the
CWA. Maintained a slight chance for showers and isolated
thunderstorms into Thursday afternoon across the far SE zones as the
front will be close enough to potentially keep isolated activity
around. Meanwhile, in the Gulf of Mexico a small area of low
pressure will approach the eastern Gulf Coast Wednesday evening.
This area of low pressure will track across the Florida Panhandle
overnight Wednesday before tracking across southern Georgia
Thursday. The low then tracks off the FL/GA coast into the western
Atlantic late Thursday. Global models are in better agreement
regarding the track of this system on Friday. All models now keep
the low offshore of the Carolinas and tracking northeast away from
the SE US coast overnight Friday into the day Friday. This low
staying offshore combined with high pressure continuing to build
across the eastern CONUS will lead to drier conditions Thursday
evening into Friday. High temps will be near or just above climo and
low temps will be several degrees above climo Wednesday night before
dropping a few degrees below climo Thursday night.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 2:15 PM EDT Tuesday: Throughout the extended forecast period,
high pressure will remain the dominate synoptic feature. This will
lead to dry conditions Friday night into early next week. Southerly
flow will be in place allowing temps to gradually increase this
weekend into early next week. High temps this weekend will be about
3 to 8 degrees above normal, becoming 5 to 10 degrees above normal
early next week. Tuesday southerly flow could act to pull in
moisture off the Gulf of Mexico potentially increasing shower and
thunderstorm chances. However, confidence on this is low as it is
towards the end of the forecast period.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and Elsewhere: Convective chances have dwindled at the TAF
sites this evening as continued low-level covergence is focusing
mainly on Piedmont sections south and west of the terminals.
Scattered convection is, however, expected to redevelop through the
overnight hours, especially in the southerly upslope prone areas.
Additional VCSH or PROB30 for SHRA or TSRA will be warranted again
overnight, mainly across the Upstate sites and near KAVL, and
especially perhaps at KAND. Signals remain a bit mixed regarding the
potential for early morning fog/low stratus, but any breaks in the
clouds will permit LIFR conditions to develop quickly in the
mountain valleys and around KAVL. Winds will be mainly light S to SW
for the bulk of the period throughout, but with an uptick closer to
10 kt with mixing on Wednesday, and with low end gusts during the
afternoon. Will feature PROB30 for convective chances mainly during
the afternoon hours with the approach of a front from the northwest.

Outlook: Convection will diminish Wed evening, with generally fair
weather and high pressure expected in the wake of the front Thu
through the weekend. Mtn valley fog and stratus will remain possible
each morning.

&&

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

&&

SYNOPSIS...DEO
NEAR TERM...HG
SHORT TERM...AP
LONG TERM...AP
AVIATION...HG

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
1038 PM EDT Tue Sep 7 2021

GAZ010-017-018-026-028-029-NCZ048-051>053-058-059-062>065-068>072-
082-507>510-SCZ001>014-019-090245-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Madison-Swain-Haywood-
Buncombe-Graham-Northern Jackson-Macon-Southern Jackson-Transylvania-
Henderson-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union NC-
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-
1038 PM EDT Tue Sep 7 2021

This Hazardous Weather Outlook is for northeast Georgia, the
Piedmont, southern foothills, and central and southern mountains of
western North Carolina, as well as Upstate South Carolina.

.DAY ONE...Tonight.

Isolated to scattered thunderstorms will redevelop from the southwest
through the overnight hours. The main impacts with any thunderstorms
that form will be briefly gusty winds, locally heavy rainfall, and
cloud-to-ground lightning strikes.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ033-035>037-049-050-056-057-501>506-090245-
Avery-Alexander-Iredell-Davie-Yancey-Mitchell-Catawba-Rowan-
Caldwell Mountains-Greater Caldwell-Burke Mountains-Greater Burke-
McDowell Mountains-Eastern McDowell-
1038 PM EDT Tue Sep 7 2021

This Hazardous Weather Outlook is for the northwest Piedmont,
northern foothills, and northern mountains of western North
Carolina.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
921 PM EDT Tue Sep 7 2021

GAZ026-080145-
Franklin GA-
921 PM EDT Tue Sep 7 2021

...A strong thunderstorm will impact portions of Franklin County
through 945 PM EDT...

At 920 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles east of Commerce, or 5 miles north of Ila, moving north at 15
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...
Carnesville, Canon, Victoria Bryant State Park and Franklin Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3425 8334 3426 8334 3433 8339 3439 8338
      3444 8339 3447 8338 3447 8329 3441 8310
      3435 8310 3424 8318 3425 8320 3424 8325
      3426 8330 3423 8335
TIME...MOT...LOC 0120Z 201DEG 14KT 3425 8332

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

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1146 PM EDT Tue Sep 7 2021

SCZ011-019-080415-
Abbeville SC-Greenwood SC-
1146 PM EDT Tue Sep 7 2021

...A THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT SOUTHEASTERN
ABBEVILLE AND SOUTHWESTERN GREENWOOD COUNTIES UNTIL 1215 AM EDT...

At 1145 PM EDT, Doppler radar was tracking a thunderstorm with
intense lightning near Abbeville, moving northeast at 15 mph.

Locations to be impacted include...
Greenwood, Abbeville, Due West, Hodges, Troy, Cokesbury, Calhoun
Falls, Promised Land and Bradley.

In addition to intense lightning, 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.

Frequent lightning is occurring with this storm. If outdoors, try to
get indoors or into a hard topped vehicle. Otherwise, stay away from
open areas and isolated high objects such as trees. When indoors,
stay away from windows and doors and avoid using wired electronic
devices. Do not take a shower or bath. Try to unplug unnecessary
appliances before the storm approaches.

&&

LAT...LON 3406 8233 3406 8246 3408 8248 3407 8250
      3407 8252 3411 8261 3436 8237 3422 8206
      3400 8222 3402 8225 3397 8231
TIME...MOT...LOC 0345Z 220DEG 15KT 3415 8236

CAC