Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
607 PM EDT Mon Jul 12 2021

.SYNOPSIS...
A Bermuda high will maintain seasonably hot and humid conditions,
with afternoon to evening showers and thunderstorms, through the
remainder of the week.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 600 PM EDT Monday: Convection is peaking across the forecast
area as daytime heating has produced late day sbCAPE values of 2000
to 3000 J/kg in many areas. The most unstable area is the I-77
corridor in the Piedmont, and the convection allowing models are not
handling this very well. Will boost PoPs to likely to high chance in
this area, mainly around CLT and northward, for the next couple of
hours. Coverage is also filling in around the southern mountains
where light southerly upslope forcing is the strongest. The models
have been handling that well, and solid likely PoPs for showers and
thunderstorms will be featured, with continued chance PoPs through
the overnight hours. The third area of focus is better coverage
approaching the southern Piedmont on increasing Atlantic moisture
near the CSRA. Will adjust southern tier PoPs up through the evening
hours to account for that. Mins will be near climo overnight.

Otherwise, there won't be much change with regards to the large-
scale pattern through the near-term. The Southeast will remain
situated between the persistent subtropical upper ridge to our east
and an embedded upper trof/closed upper low centered over the MS
River Valley to our west. Towards the end of the period tomorrow,
the upper trof/low will begin to lift northward and deamplify. At
the sfc, warm and moist SLY flow will persist over the region thru
the near-term with PWs in excess of 1.75 inches. Mid/upper level
forcing will remain weak, however the low-level SLY to SWLY flow
should provide some support for convective development again
tomorrow, especially across the the higher terrain. Severe potential
once again appears minimal, with slightly better potential over the
higher terrain. Overall, heavy rainfall/flash flooding appears to be
the bigger threat. Temps will remain at or slightly above normal for
mid-July.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 205 pm Monday: The westerlies will be rather active across the
northern half of the country during the short term, with periodic
height falls allowing the weakening/suppression of the subtropical
anticyclone off the Mid-Atlantic coast. The latter feature will
evolve into an elongated ridge that cover much of the Southeast
through the period and into at least the early part of the medium
range, while the center of the weakening anticyclone may move into
the Carolina coast by the end of the period. That being the case,
probabilities for diurnal convection are expected to revert to
around normal (primarily 40-50% mountains to 30% Piedmont) by
Thursday afternoon/evening. Weak flow aloft will yield the usual
mid-summer convective threats: possibly a pulse severe storm or two
along with perhaps a highly localized excessive rainfall threat due
to slow-moving and/or anchoring cells. Temps are forecast to average
right around normal through the period.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 215 pm Monday: Global models are converging toward a consensus
solution in allowing the subtropical ridge to become suppressed
south of the Conus by early next week, in response to periodic
height expected to impact the northern half of the country
throughout this week. In fact, there is a strong consensus in
anomalously low upper heights covering much of the eastern third of
the country by Day 7. It therefore appears increasingly likely that
a frontal zone will sag toward into the forecast area during the
Sunday/Monday time frame and enhance convective chances. Above climo
PoPs (with a strong, but not exclusively diurnal bent)...generally
50-70%...are advertised both days. While temps will be around normal
through much of the period, slightly below climo conditions are
advertised for next Monday in anticipation of lower heights along
with the likelihood of enhanced cloud cover and convective coverage.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
At KCLT and Elsewhere: Training thunderstorms near the KCLT airport
will require categorial TSRA mention and gusty winds for the next
hour or two. Otherwise, more typical summertime VCTS mentions will
be carried at the other TAF sites through evening before chances
diminish overnight. Winds will remain SLY to SWLY thru the period,
with some low-end gusts included again on Tuesday afternoon. Another
round of fog/low stratus is likely Tuesday morning, but outside of
the usual mtn valleys its development will largely depend on which
sites receive appreciable precipitation today.

Outlook: An unsettled pattern, with morning fog/stratus restrictions
followed by afternoon/evening storms, is expected to persist thru the
week.

Confidence Table...

            22-04Z        04-10Z        10-16Z        16-18Z
KCLT       High 100%     High 100%     High  95%     High 100%
KGSP       High 100%     High  97%     High  92%     High  97%
KAVL       High 100%     High 100%     Low   55%     High 100%
KHKY       High 100%     High  97%     High  95%     High 100%
KGMU       High 100%     High  97%     High  80%     High  97%
KAND       High 100%     High  97%     High  95%     High  97%

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...JDL
NEAR TERM...HG/JPT
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...HG/JPT

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
554 AM EDT Mon Jul 12 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-131000-
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-
554 AM EDT Mon Jul 12 2021

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

.DAY ONE...Today and tonight.

Thunderstorms are expected to develop again this afternoon and
evening across the area. Storms should be most numerous across the
mountains and the western part of the Upstate, and scattered over the
remainder of Upstate South Carolina, the western Piedmont, and northeast
Georgia. Frequent cloud-to-ground lightning and heavy downpours are
the main threats from the storms, which could result in localized
flooding where storms persist. One or two of the storms could
become strong enough to produce damaging wind gusts and large hail.
The thunderstorms should diminish by late evening.

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

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

PM

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
407 PM EDT Mon Jul 12 2021

SCZ013-014-122030-
Union SC-Chester SC-
407 PM EDT Mon Jul 12 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN CHESTER AND
SOUTHEASTERN UNION COUNTIES UNTIL 430 PM EDT...

At 407 PM EDT, Doppler radar was tracking a strong thunderstorm 16
miles northwest of VC Summer Nuclear Station, or 6 miles south of
Carlisle, moving northeast at 20 mph.

Locations to be impacted include...
Carlisle, Tuckertown and Leeds.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

LAT...LON 3450 8159 3474 8144 3458 8118 3456 8121
      3457 8142 3453 8143 3450 8142 3449 8143
      3450 8144 3449 8144 3449 8149 3445 8153
TIME...MOT...LOC 2007Z 215DEG 12KT 3450 8146

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
436 PM EDT Mon Jul 12 2021

SCZ009-014-122100-
York SC-Chester SC-
436 PM EDT Mon Jul 12 2021

...A STRONG THUNDERSTORM WILL IMPACT WESTERN CHESTER AND SOUTH
CENTRAL YORK COUNTIES UNTIL 500 PM EDT...

At 436 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles west of Chester, or 5 miles west of Chester State Park, moving
northeast at 20 mph.

Locations to be impacted include...
Chester, Lowrys, Chester State Park and Leeds.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

LAT...LON 3466 8145 3468 8145 3489 8133 3473 8107
      3456 8128 3457 8130
TIME...MOT...LOC 2036Z 215DEG 9KT 3468 8133

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
503 PM EDT Mon Jul 12 2021

SCZ009-014-122130-
York SC-Chester SC-
503 PM EDT Mon Jul 12 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL CHESTER AND
EASTERN YORK COUNTIES UNTIL 530 PM EDT...

At 503 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles southwest of Rock Hill, or 4 miles east of Mcconnells, moving
northeast at 20 mph.

Locations to be impacted include...
Rock Hill, Fort Mill, Tega Cay, Newport, Lesslie, Mcconnells, Lake
Wylie and Edgemoor.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

LAT...LON 3474 8111 3485 8128 3514 8107 3512 8103
      3510 8103 3509 8106 3506 8106 3504 8104
      3508 8098 3503 8090 3501 8091 3499 8089
      3497 8088 3496 8087 3493 8087
TIME...MOT...LOC 2103Z 219DEG 19KT 3486 8114

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
534 PM EDT Mon Jul 12 2021

NCZ071-SCZ009-122200-
Mecklenburg NC-York SC-
534 PM EDT Mon Jul 12 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHERN MECKLENBURG AND
NORTHEASTERN YORK COUNTIES UNTIL 600 PM EDT...

At 533 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles northwest of Indian Land, or near Carowinds, moving northeast
at 20 mph.

Locations to be impacted include...
Uptown Charlotte, Central Charlotte, South Charlotte, Southwest
Charlotte, East Charlotte, Northwest Charlotte, Mint Hill, Fort Mill,
Pineville and Tega Cay.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

LAT...LON 3502 8086 3507 8090 3503 8090 3501 8091
      3500 8089 3496 8095 3508 8111 3515 8106
      3515 8102 3516 8100 3521 8101 3535 8090
      3517 8065
TIME...MOT...LOC 2133Z 221DEG 17KT 3508 8098

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
600 PM EDT Mon Jul 12 2021

NCZ071-072-122230-
Cabarrus NC-Mecklenburg NC-
600 PM EDT Mon Jul 12 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN CABARRUS AND
CENTRAL MECKLENBURG COUNTIES UNTIL 630 PM EDT...

At 559 PM EDT, Doppler radar was tracking a strong thunderstorm near
Uptown Charlotte, or near Freedom Park, moving northeast at 20 mph.

Locations to be impacted include...
Uptown Charlotte, Huntersville, Central Charlotte, Northeast
Charlotte, Southwest Charlotte, East Charlotte, Northwest Charlotte,
Harrisburg, Freedom Park and University City.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

LAT...LON 3506 8084 3518 8100 3519 8100 3545 8079
      3527 8054
TIME...MOT...LOC 2159Z 221DEG 18KT 3518 8087

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
633 PM EDT Mon Jul 12 2021

NCZ057-071-072-122315-
Rowan NC-Cabarrus NC-Mecklenburg NC-
633 PM EDT Mon Jul 12 2021

...A STRONG THUNDERSTORM WILL IMPACT CABARRUS...NORTHEASTERN
MECKLENBURG AND SOUTHWESTERN ROWAN COUNTIES UNTIL 715 PM EDT...

At 633 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles southwest of Downtown Concord, or over Charlotte Motor
Speedway, moving northeast at 25 mph.

Locations to be impacted include...
Kannapolis, Downtown Concord, Northeast Charlotte, West Concord,
Harrisburg, China Grove, Landis, Enochville, University City and
Charlotte Motor Speedway.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

LAT...LON 3523 8064 3534 8082 3551 8077 3551 8074
      3557 8075 3567 8072 3551 8033
TIME...MOT...LOC 2233Z 214DEG 25KT 3536 8069

KRENTZ