Severe Thunderstorm Warning 239, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
238 PM EDT Sun Jul 23 2017

.SYNOPSIS...
A cold front will become stationary from west to east across our
region through the middle of the week then dissipate.  This should
result in a little cooler temperature and better chances for rain
over the next few days.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 235 PM EDT Sunday: Convection will move off the Blue Ridge and
SE across the foothills and piedmont of the Carolinas and NE GA
through early evening. Some of these storms will be severe with
damaging downbursts the main threat but isolated large hail cannot
be ruled out. The NC Southern Piedmont and eastern Upstate look to
have the best chance of seeing severe storms given the movement of
the current broken line of severe storms. That said, there is plenty
of instability and DCAPE over NE GA and the western Upstate, so
those areas are vulnerable as well.

Convection diminishes this evening as the line moves SE of the area.
However, there will be more MCS convection moving into the NC
mountains overnight. The latest CAM guidance shows this convection
diminishing as it moves into the foothills and dissipating before
reaching the piedmont. Have followed these trends in the PoP
forecast. Mountain valley fog, some dense, is expected again and
locations outside of the mountains that receive rainfall may see
some as well. Lows will again be above normal but not quite as warm
as last night.

Convection redevelops Monday as outflow boundaries from the
overnight MCS move across the area. Coverage will be better along
and south of the I-85 corridor where the timing of the boundary
movement will coincide with the higher instability. North of the
corridor instability will be much less leading to only isolated
coverage at best. DCAPE and sfc delta theta-E values while still on
the high side, will not be as high as Sunday. Instability will reach
moderate levels but just barely. Therefore, the chance of severe
storms will be less but not non-existent. Highs will be in the lower
90s outside of the mountain, and while still humid, heat index
values should remain below 100.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 200 PM Sunday: A weak and nearly stationary cold front
will remain over central GA and SC Monday night into Tuesday,
immediately south of the CWFA. Aloft, we will remain somewhat
under the influence of the northeast CONUS trough, though
without significant embedded vorticity in play early in the
period. More abundant moisture will be present over the south,
near the front, which could increase cloud cover. But otherwise it
appears conditions will be close to climatology, with seasonably
modest instability and weak shear producing a small pulse severe
threat. Partial thicknesses change little from Monday, so max
temps should be similar.

Tuesday night, high pressure will shift into New England in the
wake of the upper trough. A weak upper low is shown to cut off
and remain over the Carolina coast, and allows enough vorticity
to persist over the area that isolated t-storms still could fire
overnight across mainly the Piedmont. The eastward push of the high
will bring cooler air south into the area, which virtually all
guidance indicates will knock max temps down to a couple degrees
below normal, in conjunction with increased cloud cover. Nonetheless
consensus SBCAPE values remain fairly large given still-elevated
sfc dewpoints and good lapse rates afforded by the upper low. PoPs
peak above climo and pulse threats return once again.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 145 PM Sunday: The medium range begins Wednesday evening with
a weak closed off 500mb low over the Carolinas and Georgia. As the
next northern stream shortwave crosses the Great Lakes on Thursday,
it kicks this weak low off to the east with the 500mb trough digging
over the East through the weekend. As the Great Lakes shortwave
moves to far eastern Canada, the associated cold front moves slowly
southeast. This front should be nearing the Ohio River early Friday.
As the front approaches from the north, frontal associated
convection will increase first across areas along and north of I-40
Friday afternoon and then spread across much of the rest of the area
Friday evening. The front becomes stationary west to east across our
region through the weekend. The eventual location of the axis of the
trough next weekend varies among the models. This axis location will
have significant influence on our weather. Also, mesoscale
convective systems are expected to develop near the Rockies or
northern Plains states and track southeast in the northwest 500mb
flow toward our region of the nation. Therefore, our weather will
remain unsettled through the weekend. Temperatures will be near
normal.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Line of convection developing across the NC
mountains and becoming strong to severe. Have gone pessimistic with
the TAFs in response and indicate VRB winds and TSRA in a TEMPO.
Storms could linger a while in the evening outside of the mountains
so have VFR VCTS in place. Guidance not very favorable for
restrictions outside of the mountain valleys overnight, so have
limited them to KAVL. That said, they will be possible as most
locations will receive rainfall. Scattered convection expected
Monday for all but KHKY. SW wind today becomes light overnight, then
W to SW for Monday.

Outlook: Increasing chances of convection expected through the
middle of next week ahead of a series of weakening cold fronts.
Overnight restrictions will continue in the mountain valleys with
chance increasing elsewhere.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High  92%     High  96%
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...RWH
SHORT TERM...Wimberley
LONG TERM...DEO
AVIATION...RWH

Hazardous Weather Outlook...CORRECTED
National Weather Service Greenville-Spartanburg SC
557 AM EDT Sun Jul 23 2017

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-241000-
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-
557 AM EDT Sun Jul 23 2017

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

.DAY ONE...Today and Tonight.

Scattered to numerous thunderstorms are expected to develop across
the area this afternoon into early evening. The air mass in place is
expected to become moderately to highly unstable. Therefore, many
of the storms may become severe, capable of producing damaging
wind gusts and large hail. This is in addition to the usual threat
of cloud- to-ground lightning and locally heavy rainfall. While
most of the activity will diminish after sunset, additional
thunderstorms may move into western North Carolina from Tennessee
and Virginia overnight, bringing a second round of thunderstorms
producing lightning and gusty winds.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

..Monday...No hazardous weather is expected at this time.
..Tuesday...No hazardous weather is expected at this time.
..Wednesday...No hazardous weather is expected at this time.
..Thursday...No hazardous weather is expected at this time.
..Friday...No hazardous weather is expected at this time.
..Saturday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
306 PM EDT SUN JUL 23 2017

SCZ014-231930-
Chester SC-
306 PM EDT SUN JUL 23 2017

...A STRONG THUNDERSTORM WILL IMPACT EASTERN CHESTER COUNTY UNTIL 330
PM EDT...

At 306 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles southeast of Chester, or 6 miles northeast of Blackstock,
moving southeast at 40 mph.

Locations to be impacted include...
Chester, Great Falls, Richburg, Blackstock, Fishing Creek Reservoir,
Chester State Park and Cornwell.

Wind gusts up to 45 mph and dime size hail will be possible in these
areas.

LAT...LON 3454 8088 3455 8097 3456 8119 3463 8128
      3479 8109 3466 8089 3463 8090 3462 8089
      3460 8089 3458 8088 3455 8087
TIME...MOT...LOC 1906Z 309DEG 36KT 3464 8111

KRENTZ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
307 PM EDT SUN JUL 23 2017

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

0250 PM     HAIL             ELLENBORO               35.33N 81.76W
07/23/2017  E1.00 INCH       RUTHERFORD         NC   PUBLIC

            QUARTER SIZED HAIL.

&&

OUTLAW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
316 PM EDT SUN JUL 23 2017

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

0144 PM     TSTM WND DMG     2 E FLETCHER            35.43N 82.47W
07/23/2017                   HENDERSON          NC   FIRE DEPT/RESCUE

            HOOPERS CREEK AREA HAS AT LEAST TWO TREES DOWN.

&&

OUTLAW

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
342 PM EDT SUN JUL 23 2017

SCZ007>009-013-014-232015-
York SC-Cherokee SC-Union SC-Chester SC-Spartanburg SC-
342 PM EDT SUN JUL 23 2017

...A CLUSTER OF THUNDERSTORMS WILL IMPACT WESTERN CHESTER...YORK...
SOUTHEASTERN SPARTANBURG...EASTERN CHEROKEE AND UNION COUNTIES UNTIL
415 PM EDT...

At 342 PM EDT, Doppler radar indicated a cluster of thunderstorms
along a line extending from 8 miles south of Rock Hill to 11 miles
west of Union, and moving southeast at 25 mph.

Locations to be impacted include...
Rock Hill, Union, York, Chester, Fort Mill, Tega Cay, Clover,
Newport, Lesslie and Monarch Mill.

Wind gusts up to 50 mph and dime 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.

These storms 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 3455 8166 3455 8171 3467 8193 3515 8148
      3510 8105 3506 8106 3504 8104 3509 8097
      3508 8091 3501 8091 3494 8086 3487 8088
      3476 8111 3457 8137 3457 8142 3452 8142
      3446 8153
TIME...MOT...LOC 1942Z 308DEG 28KT 3482 8101 3467 8181

KRENTZ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
346 PM EDT SUN JUL 23 2017

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

0226 PM     TSTM WND DMG     3 ENE LAKE LURE         35.46N 82.16W
07/23/2017                   RUTHERFORD         NC   911 CALL CENTER

            NUMEROUS TREES AND POWERLINES DOWN FROM LAKE LURE TO
            SHINGLE HOLLOW.

0238 PM     TSTM WND DMG     RUTHERFORDTON           35.36N 81.96W
07/23/2017                   RUTHERFORD         NC   911 CALL CENTER

            A TREE ON A HOUSE.

&&

OUTLAW

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
350 PM EDT SUN JUL 23 2017

NCZ082-232015-
Union NC-
350 PM EDT SUN JUL 23 2017

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN UNION COUNTY UNTIL
415 PM EDT...

At 350 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles east of Monroe, or near Marshville, moving east at 15 mph.

Locations to be impacted include...
Marshville and Sturdivants.

Wind gusts up to 50 mph and dime size hail will be possible in these
areas.

LAT...LON 3484 8032 3486 8046 3509 8039 3507 8029
TIME...MOT...LOC 1950Z 291DEG 12KT 3498 8035

KRENTZ