Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1249 AM EDT Sun Aug 1 2021

.SYNOPSIS...
A front will remain nearly stationary from the Gulf coast states to
the North Carolina coast through next Friday. Waves of low pressure
will ride along the front giving our area scattered to at times
numerous showers and a few thunderstorms.  The front is expected to
dissipate at the end of the week.

&&

.NEAR TERM /THROUGH TODAY/...
As of 1245 AM: Convection along the stalled boundary to our
south has ended by this point in time. However, our attention
has turned toward loosely organized convection working southeast
through TN. SPC mesoanalysis showed a tight gradient of
instability from near St. Louis to NW GA. The activity is still
progged to glide along the edge of this feature along and ahead
of a sagging cold front. Still looking like any potential for
stronger storms should remain to the south of the area given the
unfavorable diurnal time frame and relative lack of
instability/dynamics. Increasingly moist upslope flow ahead of
this feature will probably support isolated showers near the TN
border beginning after midnight with a bit better coverage
pressing further into the mountains between roughly 4 and 6 am.
With limited haze, localized fog already present in the
mountains in particular and unexpected lack of clouds overhead,
have added more widespread fog across the mountains tonight.
Increasing clouds late tonight should largely limit any dense
fog concerns, however.

The front will continue to settle south by afternoon; it appears
timed to coincide with peak heating for portions of the CWA.
Furthermore the downslope component will be less of a factor as it
sags past the more rugged terrain. This will warrant above-climo
PoPs for the bulk of the day, mainly likely over the mountains
and the high chance range across most of the Piedmont. Despite
the drying effect of the downslope, PWATs are progged to rebound
to near the 90th percentile of climo. Unidirectional flow results
in short MBE vectors. The expected deep layer shear of 20-30 kt
suggests clusters of storms producing heavy rainfall will be the
most significant threat.

Mins tonight and maxes tomorrow will be a little above normal.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
As of 220 PM EDT Saturday: A longwave trough will dig across the
Great Lakes to the Lower MS Valley Sunday night thru Tuesday,
with the strongest height falls/Q-vector convergence over the FA
Monday night into Tuesday. This forcing should trigger plenty of
convective activity along a stalled frontal boundary draped along
the Deep South to the Carolina Coast. There will be a fairly tight
gradient of moisture/PWATs across the FA, as a modifying continental
air mass settles across the OH Valley to the Mid-Atlantic. This
makes for below average confidence forecast for PoPs and QPF in the
short term. Based on the position of the front, I would think the
bulk of heavier rain should stay to our south and east. But enough
moisture should make it into our area to keep us fairly cloudy and
still have above climo PoPs starting Monday night. Monday looks
like a transition day, with some chc for aftn convection across
the southern third of the FA. Temps will be near normal Monday,
but then as much as 10 deg below normal Tuesday under mostly cloudy
skies and a wedge-like pattern.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 200 PM EDT Saturday: Models are in good agreement on another
shortwave trough riding into and sharpening the large upper trough
over the Southeast Wednesday, inducing another sfc wave along a
persistent stationary front along the Gulf Coast or the Coastal
Plain. A sfc ridge will push in from the north and could shunt
the deeper moisture to the south and east of the area. As such,
PoPs trend down Wednesday thru Friday. The upper longwave trough
does gradually weaken/flatten out, but not completely thru next
Saturday. The flattening flow may allow the stationary coastal
front to lift back north into the area an increase our rain
chances. Despite the slightly drier trend in the models, PoPs remain
above climo in the fcst for now thru the entire medium range. Max
temps will be 5-10 deg below normal, trending toward normal by
next Saturday. Min temps will be near to slightly below normal.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: A weak cold front will support scattered
SHRA with isolated TSRA in the mountains near the TN border mainly
after midnight with little if any impact to TAF sites before
sunrise. Lee convergence may reinforce the frontal zone as it
passes through the area after 16Z with best chances for TSRA from
KAVL east to KCLT or just to the south, which carry the longest
period of prob30 as a result. NW/W wind should prevail with low
end gusts possible after 16Z.

Outlook: SHRA/TSRA continue at times at least into the middle of
next week. Morning fog or low stratus will be possible, especially
for areas with appreciable rain.

Confidence Table...

            04-10Z        10-16Z        16-22Z        22-00Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
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...DEO
NEAR TERM...MPR/Munroe
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...Munroe

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
1130 PM EDT Sat Jul 31 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-020330-
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-
1130 PM EDT Sat Jul 31 2021

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

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
250 AM EDT Sun Aug 1 2021

NCZ051-058-059-062-010715-
Graham NC-Swain NC-Northern Jackson NC-Macon NC-
250 AM EDT Sun Aug 1 2021

...A CLUSTER OF THUNDERSTORMS WILL IMPACT NORTHWESTERN MACON...
NORTHWESTERN JACKSON...SWAIN AND GRAHAM COUNTIES UNTIL 315 AM EDT...

At 250 AM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 9 miles south of
Gatlinburg to 15 miles northwest of Robbinsville to 11 miles east of
Madisonville to 6 miles north of Ducktown, and moving east at 35 mph.

Locations to be impacted include...
Bryson City, Robbinsville, Sylva, Cherokee, Balsam, Dillsboro, Town
Of Santeetlah, Smoky Mountains-Newfound Gap, Smoky Mountains-Fontana
Area and Lake Santeetlah.

Wind gusts up to 45 mph 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 3537 8401 3541 8402 3552 8388 3556 8377
      3556 8350 3563 8339 3558 8317 3551 8318
      3541 8304 3534 8340 3527 8353 3512 8363
      3516 8366 3515 8374 3523 8369 3526 8371
      3525 8385 3522 8396 3523 8400 3531 8404
TIME...MOT...LOC 0650Z 286DEG 29KT 3559 8350 3549 8400 3549 8417 3513
8435

RWH