Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
302 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 235 PM: Convection continues to favor the NC Mountains and
Foothills along with a smaller area over the NW Piedmont and the
eastern CLT Metro. Convection currently isolated elsewhere. Expect
the convection to fill in across the rest of the area but remain low
end scattered at best. Atmos is still very unstable with high DCAPE
values, especially outside of the mountains. With light shear in
place, don't expect any organized severe storms, but isolated
damaging wind gusts are quite possible. Isolated flood 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 /19Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Convection developing across the area with
better coverage across the mountains. Enough current coverage and
chance through the afternoon for VCTS and TEMPO for TSRA at all
sites but KCLT. Convection is developing east of KCLT, so convection
may need to be added during the scheduled updates. Convection
dissipates during the evening. Looks like another good night for
mountain valley fog. MVFR fog 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...

            19-01Z        01-07Z        07-13Z        13-18Z
KCLT       High 100%     High 100%     High  96%     High  96%
KGSP       High 100%     High 100%     High  96%     High  96%
KAVL       High 100%     High  93%     Med   60%     High  92%
KHKY       High 100%     High 100%     High  90%     High  96%
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...RWH
SHORT TERM...JMP
LONG TERM...JMP
AVIATION...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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1208 PM EDT FRI AUG 31 2018

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

1005 PM     TSTM WND DMG     2 SSE CHINA GROVE       35.54N 80.56W
08/30/2018                   ROWAN              NC   TRAINED SPOTTER

            TRAINED SPOTTER REPORTED NUMEROUS TREES DOWN ON
            DAUGHERTY RD. TIME ESTIMATED FROM RADAR.

&&

JMP

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

NCZ082-311945-
Union NC-
321 PM EDT FRI AUG 31 2018

...A STRONG THUNDERSTORM WILL IMPACT WESTERN UNION COUNTY UNTIL 345
PM EDT...

At 321 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles southwest of Monroe, or over Mineral Springs, moving north at
10 mph.

Locations to be impacted include...
Monroe, Indian Trail, Weddington, Wesley Chapel, Waxhaw, Lake Park,
Mineral Springs, Hemby Bridge, Stallings and Marvin.

Wind gusts up to 40 mph, half inch 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 3490 8052 3485 8070 3501 8081 3513 8060
      3499 8052
TIME...MOT...LOC 1921Z 159DEG 9KT 3494 8066

MOORE