Severe Thunderstorm Warning 322, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
522 PM EDT Fri Aug 31 2018

.SYNOPSIS...
A strong upper-level ridge will dominate the eastern United States
through the entire period, resulting in above-normal temperatures
and reduced precip chances outside of the mountains.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 500 PM: The best convective coverage continues in
the higher instability region near the I-77 corridor late this
afternoon, with sbCAPE values running 2000 to 3000 J/kg
coincident with elevated DCAPE values. A secondary maximum of
coverage will continue over the NC mountains in weak terrain
forcing. Convection is currently isolated elsewhere. Expect the
convection to fill in slightly across the rest of the area on
outflows, but remain low end scattered at best. With light shear
in place, don't expect any organized severe storms, but
isolated damaging wind gusts are quite possible. An isolated
flooding threat continues as well with high PW values and slowly
moving storms. The southerly storm motion is also a concern as
storms may move across the same areas, especially in the higher
terrain. The convection should diminish this evening with the
loss of heating.

The weakness in the upper pattern is erased Saturday as upper
ridging builds west over the Southeast CONUS. This means less short
wave energy rotating over the area. This should also bring an end to
the steeper lapse rates we've seen the past couple of days. That
said, instability and high moisture levels continue keeping diurnal
convection in the forecast. Coverage should be similar to the past
couple of days with highest chance over the mountains and lowest
chance over NE GA and the western Upstate.

Lows tonight and highs Saturday will be a few degrees above normal.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 245 PM Fri: Since the previous issuance, there has been very
little change to the overall forecasted pattern through the end
of the extended period Saturday morning during what is thankfully
a benign pattern for this time of year.  The upper-level ridge,
which has been largely absent across the eastern ConUS all summer,
will retrograde slightly west and and amplify Sunday into Monday
Its presence should induce subsidence warming as indicated by
forecast profiles (700-800mb cap) which should provide enough
inhibition to limit most diurnal convective coverage to the
climatologically favorable ridge tops.  With negligible steering
flow and PWs in the 75th-90th percentile for this time of year,
any pulse convection will be capable of producing heavy rainfall.
Strong downburst winds will also be possible as the convection
collapses.  Max temperatures will be generally 2-5 degrees above
normal with min temps 4-7 degrees above normal.  Dewpoints outside
of the mountains will stagnate around 70 with very little mixing
to reduce humidity values during the afternoon.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 245 PM Fri: As mentioned above, the overall pattern will
persist through the end of the extended on Saturday morning
with the heat ridge peaking mid-week over the Mid-Atlantic.
Slight convective chances will persist, with the highest
chances remaining over the ridge tops as subsidence should limit
convection over the Pidemont.  Little change to total moisture
content through the period will mean the threat for isolated
heavy rainfall will also persist given the slow-moving activity.
Temperatures will remain above-normal through mid-week; however,
flow will become more northeasterly around the southern extent of
the high pressure heading into late week which may advect slightly
cooler air into the region as the upper-ridge starts to break
down somewhat.  Any sensible weather changes will be very modest
with max temperatures returning to near normal, low temperatures
remaining above normal, and PoPs largely unchanged.

&&

.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Thunderstorms with gusty winds will be
persistent around KCLT through at least 23Z and the TAF has been
updated accordingly for G35kt during this period. Coverage will be
fairly spotty at the other TAF sites, with KAVL and KHKY most at
risk. The convection should dissipate during the later evening
hours. Looks like another favorable night for mountain valley fog.
MVFR fog is possible at KHKY/KAND toward morning. Once the fog burns
off, cumulus develops for Saturday afternoon. Light S to SW wind
this afternoon becomes light and variable this evening. Light SW
wind for Saturday.

Outlook: Scattered diurnal showers and thunderstorms are expected
each afternoon Sunday through Tuesday. Areas of fog and low stratus
can also be expected each morning, primarily in the mtn valleys.

Confidence Table...

            21-03z        03-09Z        09-15Z        15-18Z
KCLT       High 100%     High 100%     High  91%     High 100%
KGSP       High 100%     High 100%     High  91%     High 100%
KAVL       High 100%     High  83%     Low   49%     High 100%
KHKY       High 100%     High 100%     High  83%     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 and ensemble forecasts
are available at the following link:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

SYNOPSIS...JMP
NEAR TERM...HG/RWH
SHORT TERM...JMP
LONG TERM...JMP
AVIATION...HG/RWH

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
403 AM EDT Fri Aug 31 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-010815-
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-
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-Chester-Greenwood-
403 AM EDT Fri Aug 31 2018

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

.DAY ONE...Today and tonight.

Scattered thunderstorms are in the forecast today and tonight. The
storms will be most widespread during the afternoon and early
evening. Cloud-to-ground lightning is possible with any of these
thunderstorms, along with torrential rainfall. A few of the storms
could also produce severe weather, in the form of damaging wind.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Wimberley

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
604 PM EDT FRI AUG 31 2018

SCZ009-312230-
York SC-
604 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL YORK COUNTY UNTIL 630 PM
EDT...

At 604 PM EDT, Doppler radar was tracking a strong thunderstorm near
York, moving north at 5 mph.

Locations to be impacted include...
York, Mcconnells and Newport.

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.

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 3489 8112 3487 8124 3492 8132 3506 8133
      3506 8110
TIME...MOT...LOC 2204Z 187DEG 5KT 3498 8122

MOORE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
625 PM EDT FRI AUG 31 2018

NCZ056-312300-
Catawba NC-
625 PM EDT FRI AUG 31 2018

...STRONG THUNDERSTORMS WILL IMPACT CATAWBA COUNTY UNTIL 700 PM
EDT...

At 624 PM EDT, Doppler radar was tracking a strong thunderstorm 4
miles south of Hickory, or near Mountain View, moving north at 10
mph. Another strong storm was located northeast of Maiden, also
moving north at 10 mph.

Locations to be impacted include...
Hickory, Newton, St. Stephens, Conover, Longview, Maiden, Claremont,
Catawba, Mountain View and Lake Hickory.

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.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio and tv
stations, as well as local cable tv outlets for additional
information and possible warnings from the National Weather Service.

&&

LAT...LON 3582 8118 3576 8109 3573 8107 3571 8106
      3555 8107 3556 8121 3561 8136 3572 8140
      3576 8137 3577 8135 3578 8136 3580 8134
      3580 8130 3581 8125
TIME...MOT...LOC 2224Z 172DEG 7KT 3568 8133

MOORE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
635 PM EDT FRI AUG 31 2018

NCZ504-312300-
Greater Burke NC-
635 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN BURKE COUNTY UNTIL
700 PM EDT...

At 635 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles east of Morganton, or near Rutherford College, moving north at
10 mph.

Locations to be impacted include...
Valdese, Icard, Drexel, Connelly Springs, Rutherford College, Lake
Rhodhiss and Pleasant Grove.

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.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio and tv
stations, as well as local cable tv outlets for additional
information and possible warnings from the National Weather Service.

&&

LAT...LON 3577 8144 3563 8148 3563 8158 3578 8165
      3578 8153 3579 8145
TIME...MOT...LOC 2235Z 172DEG 7KT 3569 8153

MOORE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
643 PM EDT FRI AUG 31 2018

NCZ068-070-312315-
Gaston NC-Cleveland NC-
643 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CLEVELAND AND
WESTERN GASTON COUNTIES UNTIL 715 PM EDT...

At 642 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles east of Shelby, or near Kings Mountain, moving north at 5 mph.
Another strong storm was developing near Cherryville...also moving
slowly north.

Locations to be impacted include...
Kings Mountain, Cherryville, Bessemer City, Waco, Crowders Mountain
State Park and Grover.

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.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio and tv
stations, as well as local cable tv outlets for additional
information and possible warnings from the National Weather Service.

&&

LAT...LON 3542 8134 3541 8133 3530 8126 3516 8131
      3517 8145 3537 8150 3542 8145
TIME...MOT...LOC 2242Z 172DEG 6KT 3525 8138

MOORE

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