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.

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

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

0830 PM     FLASH FLOOD      1 SSE CULLOWHEE         35.29N 83.17W
07/25/2021                   JACKSON            NC   911 CALL CENTER

            WEST ROGERS ROAD WAS WASHED OUT AND COMTINUES TO BE
            CLOSED TODAY AS REPAIR WORK IS BEING DONE WITH EXPECTED
            REOPENING LATE TODAY. NEARBY LEDBETTER ROAD WAS CLOSED
            TEMPORARILY SUNDAY EVENING DUE TO A TREE THAT FELL ACROSS
            THE ROADWAY WHERE THE ROOTS MAY HAVE BEEN WASHED OUT
            CAUSING THE TREE TO FALL.

&&

OUTLAW

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

NCZ033-050-501>507-261745-
McDowell Mountains NC-Caldwell Mountains NC-Burke Mountains NC-
Greater Burke NC-Greater Caldwell NC-Eastern McDowell NC-
Rutherford Mountains NC-Avery NC-Mitchell NC-
122 PM EDT Mon Jul 26 2021

...A CLUSTER OF THUNDERSTORMS WILL IMPACT MCDOWELL...SOUTHEASTERN
MITCHELL...CALDWELL...SOUTHEASTERN AVERY AND WESTERN BURKE COUNTIES
UNTIL 145 PM EDT...

At 121 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 10 miles south of Deep
Gap to 16 miles southwest of Marion, and moving southeast at 15 mph.

Locations to be impacted include...
Lenoir, Marion, Morganton, Gamewell, Glen Alpine, Old Fort, Cedar
Rock, Linville Falls, B.R. Parkway-Craggy To Little Switzerland and
Lake James State Park.

Wind gusts up to 35 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.

&&

LAT...LON 3612 8155 3607 8141 3604 8139 3602 8134
      3600 8133 3555 8200 3554 8208 3547 8213
      3553 8218 3553 8217 3560 8228 3562 8227
      3568 8229 3574 8219 3579 8216 3611 8179
TIME...MOT...LOC 1721Z 325DEG 12KT 3608 8147 3555 8225

ARK

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

NCZ035-501>506-261830-
McDowell Mountains NC-Caldwell Mountains NC-Burke Mountains NC-
Greater Burke NC-Greater Caldwell NC-Alexander NC-
Eastern McDowell NC-
145 PM EDT Mon Jul 26 2021

...STRONG THUNDERSTORMS WILL IMPACT NORTHEASTERN MCDOWELL...NORTHERN
ALEXANDER...CALDWELL AND BURKE COUNTIES UNTIL 230 PM EDT...

At 145 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 9 miles northeast of Lenoir to 8 miles west of
Morganton, and moving southeast at 15 mph.

Locations to be impacted include...
Lenoir, Morganton, Marion, Sawmills, Granite Falls, Valdese,
Gamewell, Hudson, Cajah's Mountain and Drexel.

Wind gusts up to 45 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 3607 8141 3604 8140 3602 8135 3600 8133
      3603 8127 3604 8120 3603 8117 3604 8113
      3603 8107 3605 8103 3602 8102 3558 8181
      3558 8182 3556 8184 3579 8211 3610 8152
TIME...MOT...LOC 1745Z 303DEG 11KT 3598 8139 3574 8185

ARK

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

NCZ035-036-056-502-261845-
Iredell NC-Greater Caldwell NC-Alexander NC-Catawba NC-
222 PM EDT Mon Jul 26 2021

...STRONG THUNDERSTORMS WILL IMPACT NORTH CENTRAL CATAWBA...
ALEXANDER...NORTHERN IREDELL AND SOUTHEASTERN CALDWELL COUNTIES UNTIL
245 PM EDT...

At 221 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 9 miles south of Jonesville to 11 miles east of
Taylorsville to 6 miles north of Hickory, and moving southeast at 10
mph.

Locations to be impacted include...
Taylorsville, Hickory, Sawmills, Granite Falls, Bethlehem, Hudson,
Stony Point, Harmony, Love Valley and Lake Hickory.

Wind gusts up to 45 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 3605 8069 3598 8070 3590 8079 3575 8137
      3577 8137 3576 8140 3585 8153 3605 8101
TIME...MOT...LOC 1821Z 295DEG 9KT 3610 8083 3597 8098 3584 8133

ARK

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

NCZ068-504-506-508-261900-
Greater Rutherford NC-Cleveland NC-Greater Burke NC-
Eastern McDowell NC-
236 PM EDT Mon Jul 26 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN MCDOWELL...
NORTHEASTERN RUTHERFORD...NORTHWESTERN CLEVELAND AND SOUTHERN BURKE
COUNTIES UNTIL 300 PM EDT...

At 236 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles south of Morganton, or 5 miles west of South Mountains State
Park, moving southeast at 10 mph.

Locations to be impacted include...
Morganton, South Mountains State Park, Casar, Pleasant Grove and
Dysartsville.

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 3565 8146 3561 8151 3558 8152 3543 8175
      3562 8196 3574 8173
TIME...MOT...LOC 1836Z 303DEG 10KT 3561 8176

ARK

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

NCZ056-068-069-504-508-261930-
Greater Rutherford NC-Cleveland NC-Lincoln NC-Greater Burke NC-
Catawba NC-
301 PM EDT Mon Jul 26 2021

...STRONG THUNDERSTORMS WILL IMPACT SOUTHWESTERN CATAWBA...
NORTHEASTERN RUTHERFORD...NORTHWESTERN LINCOLN...NORTHWESTERN
CLEVELAND AND SOUTHEASTERN BURKE COUNTIES UNTIL 330 PM EDT...

At 301 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 10 miles southwest of Hickory to 8 miles
northeast of Rutherfordton, and moving southeast at 15 mph.

Locations to be impacted include...
Casar, South Mountains State Park, Icard, Mountain View, Pleasant
Grove, Thermal City, Cooksville, Sunshine, Propst and Union Mills.

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.

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 8125 3538 8186 3549 8205 3553 8196
      3554 8185 3558 8182 3573 8147
TIME...MOT...LOC 1901Z 307DEG 13KT 3565 8147 3547 8189

ARK