Severe Thunderstorm Warning 178, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
242 PM EDT Sat Aug 10 2019

.SYNOPSIS...
Isolated to scattered mainly afternoon and evening showers and
thunderstorms are expected through the weekend. Rainfall chances
slowly increase through mid week, with hot and humid conditions
persisting through the period.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 225 PM: A cold frontal zone bisects the region, aiding
in moisture convergence. This was partly responsible for the
widespread mid to high level cloud cover which blanketed much
of the region this morning. With that cloud cover continuing
to dissipate, destabilization is getting underway across the
CWFA. Discrete cells are now widely scattered along the higher
terrain, with a couple cells having now popped up across the GA/SC
zones. Relatively fast flow aloft, surrounding the East Coast upper
trough, is expected to lead the mtn activity to propagate into the
Piedmont, though the likelihood of upscale growth appears small,
so coverage should remain scattered at best. Convection should
trend downward this evening, with potential waning latest in our
southeast, nearest the juicier dewpoints on the warm side of the
front. Despite a moist layer roughly 800-600 mb, dry air higher
aloft and moderately high cloud bases will bring a risk of an
isolated severe microburst. SPC included some of our area in the
Marginal Risk on the updated Day 1 outlook, though coverage of
any severe wx may still not be enough to meet the usual threshold.

The upper levels will continue to dry tonight as the front sags
slightly further south. The dominant synoptic feature then becomes
an area of high pressure migrating across the Ohio Valley and toward
the Mid-Atlantic coast, effectively forming a weak wedge. Min temps
will be about a category above normal with moisture continuing
to pool near the front. Patchy mountain valley fog is possible
again. The sfc high will bring a northeasterly flow over much of
the Piedmont, along with a minor subsidence inversion. The net
result is that deep convection should be confined to parts of
the east-facing Blue Ridge. However, highs are still progged to
be just above normal, though dewpoints will be able to mix out a
bit more than those today.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 217 PM EDT Saturday: Not much in the new guidance to change
our minds about the forecast for the early part of next week. Sfc
high pressure passing by to our north Sunday night will ride the
ridge and move offshore on Monday. A weak easterly upslope flow
should provide enough moisture to allow convection to break a
capping inversion over the mtns in the afternoon, so a chance
looks good there, but the cap over the wrn Piedmont still looks
too formidable. The eastern zones were kept dry. Temps will be
above normal, but not to the point where we should have to be
concerned with a Heat Advisory. That might not be the case for
Tuesday as the weak easterly flow at low levels is replaced by
w/sw flow ahead of an approaching upper wave/sfc front. Downslope
east of the mtns will add a few degrees to high temps, so mid-90s
are a good bet east of the Blue Ridge. Right now, the area with a
Heat Index above 105 is small and limited to the lower Piedmont
of SC, but this could easily change with only slightly higher
dewpoints. Expect scattered deep convection mainly over the mtns
again, but the mid/upper forcing and better instability will be
kept on the west side of the mountains closer to the approaching sfc
front through late in the period, so precip prob was kept at 30 pct
at best near the TN line, and only in the slight chance range east.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 2 PM EDT Saturday: Starting Tuesday evening with models in
good agreement with the 500mb pattern showing a ridge centered over
New Mexico and nearly zonal flow over the East. A weak cold front
will be dropping south from the Ohio Valley.  This slow moving cold
front will provide lift along with the moisture flux to the south of
the front for increased coverage of showers and thunderstorms.
Expect scattered to numerous coverage for the NC mountains Tuesday
evening. Instability will be best on Wednesday ahead of the front
with CAPE values 1500 to 2500. The coverage of convection on
Wednesday should be numerous across the forecast area. Shear will be
weak with wind from 700mb down to the surface mainly 15 kts or less.
The front is forecast to becoming stationary just south of our area
during the last half of the week. Models agree on keeping areas near
the front active with weak lows moving along or lingering on the
front. A strong shortwave passing over the Plains next weekend may
get close to our area toward the end of the weekend. Temperatures
will be 2 to 5 degrees above normal Wednesday then cooling Max Temps
to 2 to3 degrees below normal by the end of the week. Min temps will
be near or just above normal late in the week.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Main concern this aftn is for SHRA/TSRA,
with chances a bit better than climatology due to a weak cold
front sitting over the area. Chances at the NC sites warrant
a TEMPO. Wind gust potential is high enough to warrant a VRB
gust mention in the KAVL/KHKY TAFs. Following the dissolution
of the diurnal activity, a fairly quiet night is expected, with
some patchy fog possible in the mtn valleys (and KAVL) and in the
Upstate south of I-85. Relatively dry high pressure will build in
on NE winds on Sunday, with the resulting subsidence suppressing
most convection. Some MVFR to low VFR level cu are expected to
break out in the morning hours beneath the inversion.

Outlook: Typical late summer convection returns next week, with
brief flight restrictions possible in any stronger storm or heavy
downpour. Overnight and morning fog will be possible each day
across mountain valleys. Otherwise, expect VFR.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High  94%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High  84%     High  95%
KHKY       High 100%     High 100%     High 100%     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...DEO
NEAR TERM...Wimberley
SHORT TERM...PM
LONG TERM...DEO
AVIATION...Wimberley

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
508 AM EDT Sat Aug 10 2019

GAZ010-017-NCZ033-035-048>053-058-059-062>065-501>507-509-110915-
Rabun-Habersham-Avery-Alexander-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-
508 AM EDT Sat Aug 10 2019

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

.DAY ONE...Today and tonight.

Isolated to scattered thunderstorms are expected this afternoon and
evening. Cloud-to-ground lightning, brief heavy rain, and gusty winds
will be possible.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ018-026-028-029-NCZ036-037-056-057-068>072-082-508-510-SCZ001>014-
019-110915-
Stephens-Franklin-Hart-Elbert-Iredell-Davie-Catawba-Rowan-Cleveland-
Lincoln-Gaston-Mecklenburg-Cabarrus-Union-Greater Rutherford-
Eastern Polk-Oconee Mountains-Pickens Mountains-Greenville Mountains-
Greater Oconee-Greater Pickens-Greater Greenville-Spartanburg-
Cherokee-York-Anderson-Abbeville-Laurens-Chester-Greenwood-
508 AM EDT Sat Aug 10 2019

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

.DAY ONE...Today and tonight.

Isolated thunderstorms will be possible this afternoon and evening.
Cloud-to-ground lightning, brief heavy rain, and gusty winds will be
possible.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

A hot and humid airmass will move across the area Monday through
Wednesday. Heat index values are expected to be in the 100 to 105
degree range each afternoon, with a few locations experiencing
dangerous heat index values above 105 degrees. Extreme caution
should be used when participating in outdoor activity.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
244 PM EDT Sat Aug 10 2019

NCZ065-509-510-SCZ003-007-101915-
Henderson NC-Polk Mountains NC-Eastern Polk NC-
Greenville Mountains SC-Spartanburg SC-
244 PM EDT Sat Aug 10 2019

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN HENDERSON...POLK...
NORTHEASTERN GREENVILLE AND NORTHWESTERN SPARTANBURG COUNTIES UNTIL
315 PM EDT...

At 244 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles east of Hendersonville, or near Saluda, moving east at 20 mph.

Locations to be impacted include...
Columbus, Landrum, Tryon, Saluda, Flat Rock, Mill Spring, Tuxedo,
Glassy Mountain, Lake Adger and Dana.

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.

&&

LAT...LON 3522 8246 3539 8238 3532 8204 3506 8223
TIME...MOT...LOC 1844Z 291DEG 18KT 3528 8234

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
254 PM EDT Sat Aug 10 2019

NCZ504>508-101930-
Greater Rutherford NC-McDowell Mountains NC-Greater Burke NC-
Rutherford Mountains NC-Eastern McDowell NC-
254 PM EDT Sat Aug 10 2019

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN MCDOWELL...NORTH
CENTRAL RUTHERFORD AND SOUTHWESTERN BURKE COUNTIES UNTIL 330 PM
EDT...

At 254 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles southwest of Marion, moving southeast at 15 mph.

Locations to be impacted include...
Marion, Sugar Hill, Thermal City, Pleasant Gardens, Glenwood, Fero,
Dysartsville, Union Mills and Shingle Hollow.

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.

&&

LAT...LON 3554 8218 3571 8209 3564 8177 3539 8191
TIME...MOT...LOC 1854Z 294DEG 12KT 3560 8206

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
304 PM EDT Sat Aug 10 2019

SCZ012-019-101930-
Laurens SC-Greenwood SC-
304 PM EDT Sat Aug 10 2019

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN LAURENS AND
NORTHWESTERN GREENWOOD COUNTIES UNTIL 330 PM EDT...

At 304 PM EDT, Doppler radar was tracking a strong thunderstorm 13
miles southwest of Laurens, or near Ware Shoals, moving east at 15
mph.

Locations to be impacted include...
Ware Shoals, Cokesbury, Waterloo, Shoals Junction, Lake Greenwood,
Hodges, Cross Hill, Coronaca and Mountville.

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.

&&

LAT...LON 3433 8232 3433 8233 3435 8232 3441 8225
      3442 8226 3443 8226 3444 8228 3445 8228
      3450 8226 3445 8193 3419 8204
TIME...MOT...LOC 1904Z 289DEG 12KT 3439 8221

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
340 PM EDT Sat Aug 10 2019

NCZ506-508-102015-
Greater Rutherford NC-Eastern McDowell NC-
340 PM EDT Sat Aug 10 2019

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN MCDOWELL AND
CENTRAL RUTHERFORD COUNTIES UNTIL 415 PM EDT...

At 340 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles north of Rutherfordton, moving southeast at 15 mph.

Locations to be impacted include...
Forest City, Rutherfordton, Spindale, Ellenboro, Bostic, Shingle
Hollow, Green Hill, Thermal City, Sunshine and Union Mills.

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.

&&

LAT...LON 3538 8170 3536 8170 3522 8196 3524 8197
      3525 8196 3526 8198 3527 8199 3547 8211
      3558 8193
TIME...MOT...LOC 1940Z 325DEG 13KT 3547 8198

HG