Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
805 PM EDT Fri Aug 6 2021

.SYNOPSIS...
A moist stationary front will linger across the Southeast through
Saturday. Drier high pressure builds into the area Sunday, then
settles near Bermuda by Monday, which will return typical summertime
weather across the region into the middle of next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 715 PM: A line of light showers continues to make its way
northward over the Piedmont this evening with a larger area of
sct showers and thunderstorms making its way northward across
CAE's forecast area. Most of the latest CAM guidance has this
activity to our south fizzling out by the time it reaches our
CWA, but I wouldn't rule out a few isolated lightning strikes
reaching our southernmost Piedmont zones later tonight.

Otherwise, showers will return to the eastern part of the fcst
area as a sfc low slowly develops over the southeast in response
to the approach of the mid/upper trof from the west. After
midnight, upper divergence and mid-level dpva will support an
increase in precip coverage, but mainly over the I-77 corridor and
east where a surge of higher PW air will be confined. The main
concern will be heavy rain early Saturday morning across metro
Charlotte. The latest guidance has backed off on the QPF, though,
so a Flood Watch is not currently supported by the fcst. The
track of the low should be just to the east of the fcst area on
Saturday morning, which should focus a better threat also to our
east. The main upper trof will move in from the west during the
day, perhaps bringing a second round of convective precip across
the fcst area from midday onward. Nothing out of the ordinary the
way it looks right now, but some of the CAMs suggest some sort
of organization as convection moves off the mtns, driven east
by 20kts of effective bulk shear. Precip chances may drop in the
morning and then go back up in the afternoon as a result. Temps
are tricky because of uncertain timing, but should probably top
out slightly below normal again.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 105 PM EDT Friday...An upper s/w will continue to cross the FA
Sat night and instigate periods of light showers and possibly a
couple general tstms thru daybreak. The chances for convec remain
quite low for Sun afternoon as a small scale ridge crosses and warms
the mid levels with increasing subsidence. Showers and thunderstorms
that do develop will be mainly confined to the mtns in ridgetop
convg as the overall column flow weakens sigfnt/ly. A dry period is
in store Sun night with a better, altho still low, chance of thunder
Mon afternoon. Soundings show the mlvl cap weakening and roughly
1500 J/kg of sbCAPE developing by early afternoon. This activity
will remain rather isolated to perhaps scattered across the higher
terrain. Not a good setup for severe storms as deep-layered flow
remains weak and large scale forcing will be negligible. Max temps
will return to normal levels, while mins continue near seasonal
values.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 155 PM EDT Friday...Confidence in the ext range continues
above average as the large-scale pattern remains well agreed upon by
the op models with little divergence seen in the ensembles. The
upper flow becomes dominated by the subTrop high and surface ridging
becomes stationed off the coast in a typical Bermuda High config.
This will bring in a GOM moisture flux within the llvls and make for
warm temps at or a bit abv normal with muggy conds each day. The
flow remains weak thru the column and soundings are unremarkable
indicating a pulse to multi-cell convec mode each afternoon favoring
the higher terrain. There could be isol storms reaching stg/svr
levels briefly each afternoon, but mainly expect diurnal general
thunderstorms. PWATs will increase to arnd 1.8 inches by Wed, so
slow moving or anchored storms could present isol hydro issues as
well.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Expect conditions to remain VFR thru the
rest of the evening at all terminals. A surge of low-lvl moisture
after midnight will bring MVFR to IFR ceiling restrictions over
the Piedmont. The bulk of the precipitation, and the visibility
restrictions, will be around KCLT late tonight as a sfc low moves
northward over the Carolinas. Other TAF sites outside the mtns may
only briefly go MVFR as scattered showers move past in the early
morning hours. Winds will be light/variable at most sites. The
precip should move away from KCLT in the late morning, however
it's looking more likely that MVFR cigs will linger well into
the afternoon at KCLT with winds favoring a NELY direction again.
Another round of shower/thunderstorm activity is expected to
organize over the mtns during the afternoon, ahead of the main
upper trof. This was handled with PROB30s for TSRA beginning
around 20z (give or take a few hours) at all taf sites.

Outlook: Shower activity should remain mostly over the mtns on
Sunday, but will be more diurnal in nature over the entire fcst
area for the first part of next week. Fog and low stratus will
be possible each morning, particularly over the mtn valleys and
areas primed by rainfall from the previous evening.

Confidence Table...

            00-06Z        06-12Z        12-18Z        18-00Z
KCLT       High  98%     High  93%     High  86%     High  87%
KGSP       High  99%     High  89%     High  98%     High 100%
KAVL       High  95%     High  85%     High  90%     High 100%
KHKY       High 100%     High  97%     High  95%     High 100%
KGMU       High 100%     High  91%     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...SBK
NEAR TERM...JPT/PM
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...JPT

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
426 PM EDT Fri Aug 6 2021

NCZ035>037-056-057-068>072-082-SCZ007>009-011>014-019-072030-
Alexander-Iredell-Davie-Catawba-Rowan-Cleveland-Lincoln-Gaston-
Mecklenburg-Cabarrus-Union NC-Spartanburg-Cherokee-York-Abbeville-
Laurens-Union SC-Chester-Greenwood-
426 PM EDT Fri Aug 6 2021

This Hazardous Weather Outlook is for piedmont North Carolina and
upstate South Carolina.

.DAY ONE...Tonight.

Scattered showers and thunderstorms are expected to develop across
the Piedmont and eastern Upstate this evening through the overnight
tonight. The main threats will be cloud-to-ground lightning and locally
heavy rainfall. Isolated minor flooding cannot be ruled out.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ010-017-018-026-028-029-NCZ033-048>053-058-059-062>065-501>510-
SCZ001>006-010-072030-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Madison-Yancey-
Mitchell-Swain-Haywood-Buncombe-Graham-Northern Jackson-Macon-
Southern Jackson-Transylvania-Henderson-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-Anderson-
426 PM EDT Fri Aug 6 2021

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

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

JPT

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
835 PM EDT Fri Aug 6 2021

NCZ051-070115-
Swain NC-
835 PM EDT Fri Aug 6 2021

...HEAVY RAIN SHOWERS WILL IMPACT CENTRAL SWAIN COUNTY UNTIL 915 PM
EDT...

At 828 PM EDT, Doppler radar was tracking a series of heavy rain
showers redeveloping near Bryson City, or near Smoky Mountains-Deep
Creek. These showers were nearly stationary, or redeveloping in
place.

Locations to be impacted include...Bryson City, Deep Creek,
Clingmans Dome, Newfound Gap, Oconaluftee, Fontana Area, Whittier,
and other sections in and near the Great Smoky Mountains National
Park. Rapid stream rises are expected along Bridge Creek, Lands
Creek, and tributaries to the Tuckasegeee River.

Very heavy rainfall rates up to one inch per hour will be possible
in these areas. Deep ponding of water will develop in low-lying and
poor drainage 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 3556 8361 3557 8357 3556 8350 3558 8348
      3560 8336 3542 8336 3538 8357
TIME...MOT...LOC 0028Z 171DEG 3KT 3547 8348

HG