Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
747 PM EDT Tue Jul 27 2021

.SYNOPSIS...
A weak stationary front from west to east across our region will
slowly dissipate into mid week. Hot and dry high pressure will
prevail from Wednesday until Friday when a cold front arrives from
the north. Expect mainly afternoon showers and thunderstorms during
the weekend. Another cold front should arrive from the north to
start next week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 635 PM EDT Tuesday: Several thunderstorms, a few strong to
severe, were ongoing across mainly the Upstate and the foothills
of NC. The thunderstorm activity should continue for the next hour
or two, mainly along outflow boundaries, using up the remaining
buoyancy of roughly 2000-3000 muCAPE where storms have not yet
developed. Won't rule out another severe wind producing downburst
or two, with dCAPE in the environment above 800 J/kg. Some of the
storms have been slow moving, so locally heavy rainfall can also
be expected owing to deep warm cloud depth leading to efficient
rain production.

Overnight, the upper levels experience significant drying,
paving the way for intense radiational cooling.  Thus, tomorrow
morning carries another chance of some fog or low stratus, though a
less-saturated boundary layer and somewhat steadier surface winds
should keep it becoming as dense or persistent as this morning's
event.  Instead, low clouds will scatter out within the first hour
or two after sunrise, giving way to clear, dry weather leading into
the late morning.  With this drying, CCLs will be considerably
higher tomorrow afternoon than they have been the last two days.
Although some convection isn't out of the question, fairly confident
it won't be as widespread or intense as we have seen in recent days.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 225 PM EDT Tuesday: the short-term forecast picks up at 00z
on Thursday with broad upper trofing centered over the NE CONUS
and steep upper ridging still in place over the rest of the CONUS.
This pattern is expected to persist thru the period and into the
extended. At the sfc, weak high pressure will be centered over our
area as the period begins late Wed/early Thurs with a moist frontal
bndy to our south. Another weak cold front will track out of the
Ohio Valley on Thursday and drop into our CWA late Thurs/into early
Friday. The front will be slow to move thru the fcst area, with most
of the latest guidance placing the bndy over our southern tier of
zones (or just south of them), as the period ends Friday evening.
As for the sensible fcst, broad subsidence should keep things dry
on Thursday with more typical summertime PoPs returning for Friday.
Temps will remain well-above climo thru the period with triple digit
heat indices likely across most of the lower terrain both days.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 205 PM EDT Tuesday: the extended forecast picks up at 00z
on Saturday with broad upper trofing centered over New England
and steep upper ridging still in place over the west. This pattern
is expected to persist through the period with the upper trof
amplifying again early next week and shifting at least slightly
west. At the sfc, a weak frontal bndy and associated lee trof will
be lingering somewhere just to our south as the period begins.
Most of the long-range guidance has the bndy lifting back to the
north gradually over the weekend. By early next week, broad high
pressure from Canada will push southward and move over the Great
Lakes as the period ends. This will likely provide some drying at
least across our northern zones, however the above-mentioned moist
bndy will persist just to our south and may shift back northward
as the period ends. Temps will start out just above climatology
on Sat, and cool to below climo by early next week.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Dealing with ongoing thunderstorms affecting
most terminals, including KCLT. Will not rule out more strong
variable wind gusts as storms have been seen producing strong
downbursts and very heavy rain. IFR/MVFR should be expected
in the heaviest cells. KAVL might be the only terminal in the
clear at this point. The convective activity should wane around
02Z or so, afterward we will have variable winds and extensive
convective debris clouds at the VFR level. If the debris clouds
can dissipate quickly and effectively, we may have another fog
problem in the pre-dawn hours. Chances are good that this will be
the case, and most terminals will feature an MVFR fog restriction by
daybreak. KAVL will probably go LIFR as patchy dense fog fills up
the valley overnight. The fog should lift quickly. By 12Z-13Z, all
terminals should become VFR with low chances of convective precip
during Wednesday. Wind will be N to NE through most of the day.

Outlook: Continued dry air influx suggests the lull in convective
activity will extend into Thursday, before a return to the usual
summertime pattern revives diurnal showers and storms on Friday.
This trend continues through the weekend.  Early morning fog and low
stratus will once again be possible each morning from Friday onward.

Confidence Table...

            23-05Z        05-11Z        11-17Z        17-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     Med   75%     Low   39%     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%     Med   75%     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/PM
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...PM

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
440 PM EDT Tue Jul 27 2021

GAZ010-017-NCZ033-048>053-058-059-062>065-501>507-509-282045-
Rabun-Habersham-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-Polk Mountains-
440 PM EDT Tue Jul 27 2021

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

.DAY ONE...Tonight.

Widespread showers and thunderstorms can be expected again this
afternoon into this evening. The main hazards are cloud-to-ground
lightning, heavy downpours leading to potential for flooding or
flash flooding, and the potential for isolated strong to severe
storms. Damaging wind gusts are possible with any storm that becomes
strong to severe.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ018-026-028-029-NCZ035>037-056-057-068>072-082-508-510-SCZ001>014-
019-282045-
Stephens-Franklin-Hart-Elbert-Alexander-Iredell-Davie-Catawba-Rowan-
Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union NC-
Greater Rutherford-Eastern Polk-Oconee Mountains-Pickens Mountains-
Greenville Mountains-Greater Oconee-Greater Pickens-
Greater Greenville-Spartanburg-Cherokee-York-Anderson-Abbeville-
Laurens-Union SC-Chester-Greenwood-
440 PM EDT Tue Jul 27 2021

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

.DAY ONE...Tonight.

Widespread showers and thunderstorms can be expected again this
afternoon into this evening. The main hazards are cloud-to-ground
lightning, heavy downpours leading to potential for flooding or
flash flooding, and the potential for isolated strong to severe
storms. Damaging wind gusts are possible with any storm that becomes
strong to severe.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Heat indicies will climb into the low hundreds Wednesday through
Friday due to temperatures in the mid to upper 90s combined with high
humidity. These will be the warmest heat index conditions seen so far
this year, which could cause stress to those working in the heat or
without access to air conditioning.

.SPOTTER INFORMATION STATEMENT...

None.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
740 PM EDT TUE JUL 27 2021

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

0706 PM     TSTM WND DMG     1 SSE MORGANTON         35.73N 81.69W
07/27/2021                   BURKE              NC   TRAINED SPOTTER

            TREE ON 3 CARS. TIME ESTIMATED FROM RADAR.

&&

WJM

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
759 PM EDT Tue Jul 27 2021

SCZ012-280030-
Laurens SC-
759 PM EDT Tue Jul 27 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL LAURENS COUNTY
UNTIL 830 PM EDT...

At 759 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles southeast of Laurens, or 6 miles southwest of Clinton. This
storm was nearly stationary.

Locations to be impacted include...
Joanna, Cross Hill, Waterloo, Lake Greenwood and Mountville.

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 3429 8208 3448 8205 3442 8181 3435 8182
      3435 8183 3432 8186 3430 8189 3429 8190
      3427 8205
TIME...MOT...LOC 2359Z 093DEG 4KT 3440 8192

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
828 PM EDT Tue Jul 27 2021

NCZ070-280100-
Gaston NC-
828 PM EDT Tue Jul 27 2021

...A STRONG THUNDERSTORM WILL IMPACT WESTERN GASTON COUNTY UNTIL 900
PM EDT...

At 827 PM EDT, Doppler radar was tracking a strong thunderstorm over
Gastonia, moving west at 10 mph.

Locations to be impacted include...
Gastonia, Bessemer City, South Gastonia, Dallas, Lowell, Ranlo,
Mcadenville, Crowders Mountain State Park, Cramerton and Crowders.

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 3518 8109 3516 8121 3516 8132 3517 8133
      3519 8132 3526 8132 3527 8133 3537 8136
      3530 8107
TIME...MOT...LOC 0027Z 095DEG 7KT 3525 8116

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
846 PM EDT Tue Jul 27 2021

SCZ012-019-280115-
Laurens SC-Greenwood SC-
846 PM EDT Tue Jul 27 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL LAURENS AND
EASTERN GREENWOOD COUNTIES UNTIL 915 PM EDT...

At 846 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles east of Greenwood, or over Lake Greenwood, moving west at 15
mph.

Locations to be impacted include...
Greenwood, Ninety Six, Cross Hill, Waterloo, Lake Greenwood State
Park, Lake Greenwood, Greenwood State Park, Ninety Six Historic Site,
Coronaca and Kirksey.

Wind gusts up to 40 mph and very heavy rainfall rates up to 2 inches
per hour 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 3397 8204 3398 8205 3399 8215 3397 8217
      3399 8222 3416 8212 3441 8215 3432 8185
      3430 8190 3424 8191 3421 8194 3418 8191
      3416 8191 3413 8187 3409 8192 3397 8201
      3396 8205
TIME...MOT...LOC 0046Z 088DEG 12KT 3424 8202

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
920 PM EDT Tue Jul 27 2021

SCZ002-003-005-006-280145-
Pickens Mountains SC-Greater Pickens SC-Greenville Mountains SC-
Greater Greenville SC-
920 PM EDT Tue Jul 27 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL GREENVILLE AND
NORTHEASTERN PICKENS COUNTIES UNTIL 945 PM EDT...

At 919 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles north of Easley, or near Slater-Marietta, moving southwest at
10 mph.

Locations to be impacted include...
Travelers Rest, Slater-Marietta and Dacusville.

Wind gusts up to 40 mph and very heavy rainfall rates up to 2 inches
per hour 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 3507 8250 3499 8241 3488 8251 3500 8263
TIME...MOT...LOC 0119Z 043DEG 8KT 3499 8253

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
949 PM EDT Tue Jul 27 2021

SCZ005-280215-
Greater Pickens SC-
949 PM EDT Tue Jul 27 2021

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL PICKENS COUNTY
UNTIL 1015 PM EDT...

At 949 PM EDT, Doppler radar was tracking a strong thunderstorm 4
miles north of Easley, moving southwest at 10 mph.

Locations to be impacted include...
Easley, Pickens and Dacusville.

Wind gusts up to 40 mph and very heavy rainfall rates up to 2 inches
per hour 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 3488 8276 3489 8274 3494 8262 3496 8256
      3491 8250 3489 8250 3476 8264
TIME...MOT...LOC 0149Z 045DEG 11KT 3489 8260

KRENTZ