Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
452 PM EDT Thu Aug 6 2020

.SYNOPSIS...
Passing upper-level disturbances will produce greater than
typical coverage of showers and thunderstorms through Friday. A
return to more typical isolated to scattered summertime thunderstorm
activity is expected over the weekend as weak drying arrives from
the west. Moisture will gradually return late in the weekend through
the middle of next week to support a more active pattern once again.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 450 PM Thursday: Convection remaining relatively sparse this
afternoon, better coverage over the northern mountains and Blue
Ridge. The CAMs are still suggesting that the bulk of the convective
activity will happen during the evening hours over the wrn Piedmont
and Upstate, while convection may carry on into the late evening
across the entire region. That seems reasonable as it is what often
happens on days with a late start. Still think we also remain on
track for scattered severe storms with a wind damage threat, given
sfc-based CAPE already around 2500 J/kg, dCAPE above 800 J/kg, and
some mid-level dry air seen on satellite imagery. Temps were in good
shape.

Persistence will be the rule for the weather and the forecast of
the same for the next 24 hours as the upper trof axis remains in
place to our west. Just like last night, we may keep showery precip
around parts of the forecast area for the better part of the tonight
period before it finally wanes in the pre-dawn hours. On Friday,
more of the same. Hard to say if there will be the same amount of
morning cloudiness that will delay the onset again, but the fcst
looks the same in terms of coverage that will go beyond climo in
the afternoon. The environment should be conducive to a few pulse
severe storms again as well, with sfc-based CAPE in the 2000 -
3000 J/kg range and sfc-delta Theta-e above 30 deg. Temps will be
near normal as well.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 1230 pm EDT Thursday: Deeper moisture and higher PWAT values
will be displaced off to our east this weekend as weak upper trough
axis translates east and fills.  Essentially, for the upcoming
weekend, wx conds are expected to be pretty typical of early August,
featuring a developing weaker flow regime, and seasonable humidity
levels.  Dirunally fired deeper convective chances will be close to
climo values with piedmont maximum apparent temperatures approaching
95 each day.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 100 pm EDT Thursday: Still expectimg a weak westerly flow
regime with embedded weak s/wv's rippling thru to exist atop the SE
CONUS to start off the work week.  PWAT progs starting on Monday
depict a moisting trend after a weekend featuring below climo values.
Despite limited Gulf moisture fetch, expecting a daily uptick in
diurnal PoPs for showers and thunderstorms each day.

PoPs may increase further above climo Wednesday and Thursday as
moisture begins to pool over the region as a frontal boundary lays
out across the Mid-Atlantic to the north. Anticipate plenty of lower
90s Piedmont to upper 80s mountain valley max temperatures each
afternoon, with mins a degree or so above climo through the period.

&&

.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
At KCLT and Elsewhere: Thunderstorms have moved away from the TAF
sites, but a cell will move near KAND in the next hour or two. Will
keep TEMPO/VCTS in place as convection should continue to develop
through the evening. Otherwise...VFR with a light wind that has a
southerly component. The CAMs are somewhat at odds as to the timing
of thunderstorms across the region, but agree that all sites will be
affected by one at SOME point through the evening hours. Rather than
mess with PROB30s that have to be resolved later, the fcst goes
straight to a TEMPO at all sites for some 4-hr window in the evening
hours. Any convection after that will be handled with amendments, as
it is possible the storms will persist into the early morning hours.
After some convective debris thins out, guidance remains on the
track of developing MVFR/IFR stratus and fog before daybreak across
much of the region. Several sites get at least an MVFR restriction
in ceiling and/or vis, but confidence not really high enough to go
IFR everywhere yet. Might be another late initiation again on
Friday, so only KCLT gets a thunderstorm mention after 18Z.
Southerly flow will also persist.

Outlook: Coverage of thunderstorms will be more isolated to
scattered during the afternoon and evening over the weekend. Morning
fog/stratus restrictions will also be possible, especially over
the usual mountain valleys. Diurnal storms will become more likely
again from Monday onward.

Confidence Table...

            21-03z        03-09Z        09-15Z        15-18Z
KCLT       High 100%     High  98%     Med   76%     High  90%
KGSP       High 100%     High 100%     Low   56%     High  98%
KAVL       High 100%     High  93%     Med   70%     High  96%
KHKY       High 100%     High  90%     Med   67%     High  92%
KGMU       High 100%     High 100%     Low   59%     High  98%
KAND       High 100%     High 100%     Med   68%     High  90%

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...CSH
NEAR TERM...PM/RWH
SHORT TERM...CSH
LONG TERM...CSH
AVIATION...PM/RWH

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
408 AM EDT Thu Aug 6 2020

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-070815-
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-
408 AM EDT Thu Aug 6 2020

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

.DAY ONE...Today and tonight.

Numerous thunderstorms are expected to develop across the region this
afternoon and evening, with the most widespread coverage likely
occurring across western North Carolina. Any of these thunderstorms
will be capable of producing dangerous lightning, gusty winds, and
torrential downpours. Some of these storms may become severe, with
damaging wind gusts being the primary threat. Any locations
repeatedly affected by thunderstorms over a short period of time will
be prone to localized flash flooding from the heavy rainfall.

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

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
416 PM EDT Thu Aug 6 2020

NCZ033-062045-
Avery NC-
416 PM EDT Thu Aug 6 2020

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
NORTHWESTERN AVERY COUNTY UNTIL 445 PM EDT...

At 415 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning near Beech Mountain, or near Beech Mountain In
Avery County, moving northeast at 15 mph.

Locations to be impacted include...
Banner Elk, Elk Park, Beech Mountain In Avery County, Sugar Mountain
and Seven Devils.

In addition to intense lightning, wind gusts up to 40 mph and pea
size hail 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 3627 8189 3625 8190 3624 8190 3623 8191
      3621 8190 3619 8188 3619 8186 3616 8183
      3614 8182 3609 8191 3616 8201 3629 8192
TIME...MOT...LOC 2015Z 232DEG 12KT 3617 8191

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
420 PM EDT Thu Aug 6 2020

SCZ019-062045-
Greenwood SC-
420 PM EDT Thu Aug 6 2020

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT CENTRAL
GREENWOOD COUNTY UNTIL 445 PM EDT...

At 420 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 6 miles south of Greenwood, moving northeast at 15
mph.

Locations to be impacted include...
Greenwood, Ninety Six, Ninety Six Historic Site, Promised Land,
Bradley and Epworth.

In addition to intense lightning, 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.

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 3409 8229 3411 8226 3414 8225 3427 8214
      3413 8197 3403 8224
TIME...MOT...LOC 2020Z 232DEG 12KT 3411 8219

KRENTZ

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