Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
258 PM EDT Mon Jul 26 2021

.SYNOPSIS...
A weak cold front will move south across our area tonight and
Tuesday.  This will result in scattered to numerous showers and
thunderstorms with a few locations getting excessive rainfall in a
short time.  Expect drier and hotter conditions Wednesday through
Friday with high temperatures feeling like 100 degrees in the
piedmont.  A weak cold front will drop south this weekend cooling
temperatures to near normal.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 240 PM EDT Monday: Ridging remains entrenched over the western
U.S. with modest troughing over the Eastern Seaboard.  The wind
maximum is well to our north, with the Carolinas situated beneath
a comparatively relaxed wind pattern.  Meanwhile, a persistent
Bermuda high sits over the western Atlantic, and continues to
dominate surface flow, pumping moisture into areas east of the
Appalachians.  A weak shortwave crosses the region this afternoon,
inducing minor height falls and providing weak QG forcing.  At the
surface, the attendant cold front is already crossing the CWA,
generating convective activity as it encounters moderately-unstable,
moisture-rich air across the foothills.  Afternoon PWATs exceed 2"
across much of the Piedmont/Upstate in the wake of several days'
worth of southerly flow and moisture advection off the Atlantic
coast, so convection should have no trouble continuing well into
this evening.  CAMs favor increased SBCAPE toward the south, over
the southern Appalachians, SC Upstate and perhaps the southern
Piedmont of NC.

Slightly higher-than-anticipated effective shear across the
Carolinas means that a few stray severe cells cannot be ruled out
this afternoon, but as convection continues, the primary threat
will be heavy rainfall.  MBE velocities won't exceed 5kts, and
warm cloud depth will crest 12 kft for several hours.  Already, a
few backbuilding cells have been detected on radar, so this may be
the trend for the next few hours.  The HREF's probability-matched
mean depicts upwards of an inch of QPF in some spots across the
Upstate, and accordingly the WPC has placed the entire CWA under
a marginal risk for excessive rainfall.

Heights may tick up a tad on Tuesday, but with the weakening
boundary stalling along or south of the I-85 corridor, we'll retain
the risk of widespread showers, especially across the southern
tier of our counties.  CAMs suggest there will be a lull in precip
overnight tonight as upper forcing diminishes, before a rebound in
instability in the early afternoon tomorrow allows convection to
begin firing off again.  With SBCAPE values potentially exceeding
2500 J/kg, warm cloud depths at least 10-11 kft, and afternoon
LFCs even a bit lower than today's, convection will once again
be widespread, and these cells be will rain-producers similar
to today's.  The entire CWA remains in the WPC's marginal risk
for excessive rainfall tomorrow.  While confidence remains low
on the exact coverage and behavior of tomorrow's convection, the
CAMs agree that the most intense activity should have moved to our
south and east by late Tuesday evening, though scattered showers
will likely linger across the Upstate and perhaps the Southern
Piedmont through the end of the near term.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 245pm EDT Monday:  After rain trails off Tuesday night,
temperatures rebound on Wednesday following the clouds and rain that
kept temperatures in check on Tuesday.  Mid-90s are expected over
most of the foothills and Piedmont areas, and 80s to near 90 in the
mountains.  Weak FROPA on Tuesday only drops surface dewpoints a few
degrees over the mountains, and with continued high humidity, heat
index values will be on the sultry side a few degrees above observed
temperatures.  MLCAPE and convective forcing both are much reduced
Wed. and Thurs, and PWATs drastically decline to around 1.5" on
Wednesday, with low chances of rain or thunder.

General northwest flow aloft continues through Thursday and beyond
with weak surface high pressure giving light and somewhat variable
winds.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 2:45pm EDT Monday:  General northwest flow continues through
the extended with generally weak and variable surface winds and
occasional shortwave passages that enhance the chances for afternoon
thunder.  Persistent ridge keeps the central CONUS in its grip, with
a deep upper trough over the eastern half of the CONUS. There is
some chance for thunder, mostly in the afternoons, each day, with
the best chance for enchancement Saturday or Sunday as eastern CONUS
trough deepens considerably as it is reinforced by a large shortwave.

Temperatures across the area remain seasonally warm to hot, a few
degrees above normal, with slight cooling towards the end of the
week as eastern CONUS trough deepens.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: All TAF sites are VFR at this time.
Scattered clouds are increasing in coverage across the region
as a cold front approaches from the northwest.  This front has
already begun to spin up a line of showers and thunderstorms
over the northern foothills, and should continue to produce such
activity throughout the afternoon and evening.  All TAF sites
carry at least chance TSRA and vicinity thunder from 19Z until 00Z.
The most intense convection should diminish past this point in time,
though scattered showers should persist for several more hours into
the night.  There is increased confidence in the development of
IFR restrictions at KHKY, and LIFR restrictions at KAVL owing to
the development of fog/low stratus in the hours before sunrise.
All other sites remain VFR/MVFR into the morning.  We should
see scattered showers and storms tomorrow afternoon again, but
confidence is low enough on the timing and coverage to simply
carry VCSH and a few PROB30s.

Outlook: With the frontal boundary gradually becoming more diffuse
past Tuesday evening, drier air filters into the area and results in
a lull in activity Wednesday and Thursday.  Diurnally-drive pulse
thunderstorms should pick up again on Friday, along with a chance
for fog and low stratus Friday and Saturday morning.

Confidence Table...

            19-01Z        01-07Z        07-13Z        13-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High  94%     High  92%
KAVL       High 100%     High 100%     Med   66%     Med   77%
KHKY       High 100%     High  95%     High  82%     Med   77%
KGMU       High 100%     High  95%     High  98%     High  91%
KAND       High 100%     High 100%     High 100%     High  93%

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
SHORT TERM...WJM
LONG TERM...WJM
AVIATION...MPR

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
405 AM EDT Mon Jul 26 2021

NCZ036-037-057-270815-
Iredell-Davie-Rowan-
405 AM EDT Mon Jul 26 2021

This Hazardous Weather Outlook is for piedmont North Carolina.

.DAY ONE...Today and tonight.

A backdoor cold front will allow for shower and thunderstorm
development this afternoon into this evening. The main hazards are
cloud- to-ground lighting, isolated strong to severe storms bringing
the potential for damaging wind gusts, and heavy downpours. Any
areas that repeatedly see heavy downpours could experience excessive
rainfall leading to the potential for isolated flooding or flash
flooding.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ010-017-018-026-028-029-NCZ033-035-048>053-056-058-059-062>065-
068>072-082-501>510-SCZ001>014-019-270815-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Alexander-
Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Catawba-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-
405 AM EDT Mon Jul 26 2021

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

.DAY ONE...Today and tonight.

A backdoor cold front will allow for shower and thunderstorm
development this afternoon into this evening. The main hazards are
cloud- to-ground lighting and heavy downpours. Any areas that
repeatedly see heavy downpours could experience excessive rainfall
leading to the potential for isolated flooding or flash flooding.
Isolated strong to severe thunderstorms cannot be ruled out. The main
potential impact from any strong to severe storm would be isolated
damaging wind gusts.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
308 PM EDT Mon Jul 26 2021

NCZ036-037-056-057-262000-
Rowan NC-Davie NC-Iredell NC-Catawba NC-
308 PM EDT Mon Jul 26 2021

...STRONG THUNDERSTORMS WILL IMPACT EAST CENTRAL CATAWBA...DAVIE...
SOUTHEASTERN IREDELL AND NORTHWESTERN ROWAN COUNTIES UNTIL 400 PM
EDT...

At 307 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 7 miles south of Yadkinville to 5 miles southwest
of Statesville, and moving east at 5 mph.

Locations to be impacted include...
Statesville, Mocksville, Troutman, Bermuda Run, Harmony, Lake Norman
State Park, Cleveland, Catawba, Mooresville and Lake Norman.

Wind gusts up to 40 mph and pea size hail 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.

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 3561 8080 3569 8109 3605 8075 3605 8050
      3604 8049 3605 8047 3606 8047 3606 8046
      3603 8044 3600 8041
TIME...MOT...LOC 1907Z 288DEG 6KT 3603 8068 3573 8096

ARK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
348 PM EDT MON JUL 26 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0330 PM     TSTM WND DMG     3 WSW BELWOOD           35.46N 81.58W
07/26/2021                   CLEVELAND          NC   AMATEUR RADIO

            AMATEUR RADIO REPORTED TREES DOWN NEAR 900 BLOCK OF
            CASAR-LAWNDALE RD

&&

WIMBERLEY

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
358 PM EDT Mon Jul 26 2021

NCZ065-509-510-262030-
Henderson NC-Polk Mountains NC-Eastern Polk NC-
358 PM EDT Mon Jul 26 2021

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL HENDERSON AND
WESTERN POLK COUNTIES UNTIL 430 PM EDT...

At 358 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles east of Hendersonville, or 5 miles north of Saluda, moving east
at 10 mph.

Locations to be impacted include...
Tryon, Saluda, Dana, East Flat Rock and Lake Adger.

Wind gusts up to 40 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.

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 3526 8241 3537 8239 3537 8221 3521 8224
TIME...MOT...LOC 1958Z 283DEG 7KT 3532 8233

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
409 PM EDT Mon Jul 26 2021

NCZ071-072-262045-
Cabarrus NC-Mecklenburg NC-
409 PM EDT Mon Jul 26 2021

...A STRONG THUNDERSTORM WILL IMPACT WESTERN CABARRUS AND CENTRAL
MECKLENBURG COUNTIES UNTIL 445 PM EDT...

At 409 PM EDT, Doppler radar was tracking a strong thunderstorm 5
miles northeast of Uptown Charlotte, or near Hidden Valley, moving
east at 15 mph.

Locations to be impacted include...
Uptown Charlotte, Huntersville, Kannapolis, Northeast Charlotte, East
Charlotte, Northwest Charlotte, West Concord, Harrisburg, Freedom
Park and University City.

Wind gusts up to 40 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.

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 3517 8087 3534 8094 3547 8065 3521 8055
TIME...MOT...LOC 2009Z 250DEG 12KT 3529 8079

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
415 PM EDT Mon Jul 26 2021

GAZ010-SCZ001-262045-
Rabun GA-Oconee Mountains SC-
415 PM EDT Mon Jul 26 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN RABUN AND CENTRAL
OCONEE COUNTIES UNTIL 445 PM EDT...

At 415 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles northwest of Walhalla, or 5 miles west of Oconee State Park,
moving southeast at 10 mph.

Locations to be impacted include...
Walhalla, Oconee State Park, Pine Mountain, Mountain Rest and Long
Creek.

Wind gusts up to 40 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.

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 3481 8333 3497 8327 3494 8298 3471 8309
TIME...MOT...LOC 2015Z 295DEG 10KT 3486 8321

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
417 PM EDT Mon Jul 26 2021

SCZ003-006-007-262045-
Greenville Mountains SC-Spartanburg SC-Greater Greenville SC-
417 PM EDT Mon Jul 26 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN GREENVILLE AND
NORTHWESTERN SPARTANBURG COUNTIES UNTIL 445 PM EDT...

At 417 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles south of Columbus, or 4 miles southwest of Campobello, moving
east at 10 mph.

Locations to be impacted include...
Lyman, Landrum, Wellford, Inman, Campobello, Lake Bowen, Lake
Robinson and Gowensville.

Wind gusts up to 40 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.

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 3500 8232 3518 8229 3519 8202 3519 8201
      3493 8207
TIME...MOT...LOC 2017Z 282DEG 7KT 3508 8220

ARK