Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
245 PM EDT Fri May 28 2021

.SYNOPSIS...
A cold front will approach from the west this afternoon into this
evening increasing shower and thunderstorm chances for most of the
CWA. A few isolated strong to severe storms cannot be ruled out with
this front. Saturday isolated showers and thunderstorms are possible
behind the departing FROPA. Sunday into early next week high
pressure will return leading to drier and cooler conditions.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 226 PM: Shower coverage has gradually increased this afternoon
as we slowly destabilize under a deep southwesterly regime. The
latest mesoanalysis shows about 1000 J/kg of mixed-layer CAPE for
the convection to feed on. Expect this trend to continue, with
some of them developing into thunderstorms. There is no immediate
expectation of severe storms, but the Piedmont of the Carolinas
has dCAPE above 1000 J/kg, so we will have to watch for any icy
cores and stronger updrafts.

An upper trof dropping down over the Midwest and attendant short
wave moving over the lower OH Valley region this evening should
drive a sfc boundary into the region from the west overnight. A
vort lobe out ahead of the main trof axis, combined with some
weak upper divergence in the right entrance region of the jet,
should enhance the coverage of convection across the region mainly
this evening. The convection allowing models show the coverage
peaking during the evening hours from west to east. Of note is the
Marginal Risk from SPC that runs up to the I-85 corridor, which
is accepted on general principles because of a boundary moving in
at this time of year. The relative lack of sfc-based CAPE after
sunset, generally less than 500 J/kg, will be a limiting factor
for the severe chances. Overnight, the precip coverage will shift
eastward and taper off east of the mtns as the front moves east,
while precip prob remains fairly high along the TN border where
an upslope flow develops. The upslope flow is maintained through
Saturday as the upper system lifts to the upper OH Valley, keeping
a low level NW flow in play. Some shower/thunderstorm activity
should spill over the mtns in VA and make its way down into the
NW Piedmont of NC. At this time, think the convection will stay
N of metro Charlotte. High temps on Saturday should get knocked
down two categories compared to Friday.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 2:30 PM EDT Friday: An upper level positively tilted
trough will be approaching the CWA at the start of the short term
forecast period while the cold front is draped along the coast of
the Carolinas. This trough will track through the CWA throughout the
day Sunday lifting northeast out of the area by Sunday night while
the cold front continues tracking east offshore the Carolinas. This
trough could lead to a slight chance for isolated showers behind the
departing FROPA Saturday evening into Sunday afternoon from the NC
mtns into portions of the NC Piedmont. Otherwise high pressure will
build in behind the departing cold front Sunday into Monday leading
to much drier conditions and cooler temps while a low pressure
system tracks across the Southern Plains. High temps will return to
below normal Sunday thanks to N'ly and NW'ly flow at the sfc and
aloft.These cooler temps will be a much needed relief after seeing
highs in or near 90 for locations outside the mtns the last several
days. Highs will be closer to normal on Monday with upper 70s to mid
80s outside the mtns and low 70s to low 80s across the mtns. Higher
elevations may see slightly cooler highs for Monday.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 230 PM EDT Friday: High pressure will be in place across the
Mid-Atlantic states to start the extended. A low pressure system
located over the Southern Plains Tuesday will track northeastward
into the Midwest thoughout the extended period. Although this system
will remain to our north and west, the warm front associated with
the upper low will lead to southerly flow at the mid-levels as early
as Tuesday afternoon. This southerly flow is expected to strengthen
and dominate Wednesday into Friday allowing for moisture to increase
across the SE CONUS. In response, shower and thunderstorm chances
are expected to become widespread towards the second half of the
long term. Currently global models show the best coverage for shower
and thunderstorms Thursday into Friday. Depending on how models
handle this incoming low pressure system, we could finally see some
much needed measurable rainfall late next week. High temps will
remain near normal through the extended period.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere...An unstable pre-frontal air mass was
supporting the development of scattered showers...and eventually
scattered thunderstorms this afternoon. Deep mixing was allowing
for a SW breeze with occasional gusts at all terminals, and that
condition should persist until sunset. Coverage of showers and
thunderstorms will increase into the evening as a cold front
approaches from the west. Cloud bases outside the showers should
stay in the 040 to 060 range with a mid-level ceiling spreading
over the top through late afternoon. The main time period for more
concentrated shower/thunderstorm activity appears to begin around
22Z in the west and end around 04Z in the east. All terminals
get a 4hr TEMPO group to address the thunderstorm chances and
associated MVFR restrictions, then a PROB30 for lingering shower
chances over the eastern terminals into the early morning hours
on Saturday. The passage of the front will barely be noticed as
the wind direction does not change late tonight. As the front
crosses, a low cloud ceiling is likely over the mtns, but guidance
is inconsistent. Have kept an MVFR restriction at most terminals
to handle this. Prior guidance suggested a period of IFR in the
pre-dawn hours at KAVL. That could still certainly happen, but
the trend is away from that. Dry air moving in behind the front
should allow for VFR after 14Z or so on Saturday, with SW wind
maintained. Shower activity, and the possible low cloud ceiling,
is expected to stay in the mtns along the TN border, and perhaps
down across the NW Piedmont. For now, KCLT will be kept VFR.

Outlook: VFR conditions are anticipated through the weekend with
only sparse diurnal activity expected.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     High  83%     High  87%
KGSP       High 100%     High  99%     High  82%     High  88%
KAVL       High 100%     Med   74%     Low   56%     High  89%
KHKY       High 100%     Med   77%     High  81%     High 100%
KGMU       High 100%     High  99%     High  82%     High  86%
KAND       High 100%     High 100%     High  99%     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...AP
NEAR TERM...PM
SHORT TERM...AP
LONG TERM...AP
AVIATION...PM

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
431 AM EDT Fri May 28 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-290845-
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 NC-
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-Union SC-Chester-Greenwood-
431 AM EDT Fri May 28 2021

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 likely this afternoon and evening. The
main threats from these storms will be cloud-to-ground lightning and
strong to possibly damaging straight line winds.

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

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

JPT

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
304 PM EDT Fri May 28 2021

NCZ071-SCZ009-281930-
Mecklenburg NC-York SC-
304 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN MECKLENBURG AND
CENTRAL YORK COUNTIES UNTIL 330 PM EDT...

At 304 PM EDT, Doppler radar was tracking a strong thunderstorm over
York, moving east at 35 mph.

Locations to be impacted include...
Rock Hill, York, Fort Mill, Tega Cay, Newport, Steele Creek,
Carowinds, Lake Wylie, Clover and Southwest Charlotte.

Wind gusts up to 40 mph 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 3488 8128 3504 8136 3515 8110 3515 8107
      3514 8104 3514 8096 3509 8091 3503 8090
      3501 8091 3499 8089 3497 8088
TIME...MOT...LOC 1904Z 247DEG 29KT 3499 8124

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
308 PM EDT Fri May 28 2021

NCZ068>070-281945-
Gaston NC-Cleveland NC-Lincoln NC-
308 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT LINCOLN...EAST CENTRAL CLEVELAND
AND NORTHERN GASTON COUNTIES UNTIL 345 PM EDT...

At 308 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles northeast of Shelby, or near Cherryville, moving east at 35
mph.

Locations to be impacted include...
Lincolnton, Cherryville, Dallas, Stanley, High Shoals, Waco, Boger
City, Iron Station, Denver and Fallston.

Wind gusts up to 40 mph 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 3526 8143 3542 8151 3556 8121 3555 8103
      3539 8095 3538 8098 3537 8098 3536 8097
      3538 8096 3537 8095 3536 8096
TIME...MOT...LOC 1908Z 247DEG 29KT 3537 8139

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
321 PM EDT Fri May 28 2021

SCZ007-013-281945-
Union SC-Spartanburg SC-
321 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL SPARTANBURG AND
NORTHWESTERN UNION COUNTIES UNTIL 345 PM EDT...

At 320 PM EDT, Doppler radar was tracking a strong thunderstorm 14
miles southwest of Spartanburg, or near Woodruff, moving northeast at
35 mph.

Locations to be impacted include...
Spartanburg, Woodruff, Pacolet, Roebuck, Jonesville, Pacolet Mills,
Reidville, Croft State Park, Moore and USC Upstate.

Wind gusts up to 40 mph 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 3470 8207 3472 8207 3476 8211 3475 8212
      3478 8213 3478 8215 3480 8217 3480 8216
      3484 8220 3509 8186 3495 8176 3493 8176
      3493 8174 3480 8165 3467 8202
TIME...MOT...LOC 1920Z 236DEG 30KT 3477 8207

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
328 PM EDT Fri May 28 2021

NCZ070-071-SCZ009-282000-
Gaston NC-Mecklenburg NC-York SC-
328 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHERN MECKLENBURG...
SOUTHEASTERN GASTON AND NORTHEASTERN YORK COUNTIES UNTIL 400 PM
EDT...

At 328 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles north of Rock Hill, or near Lake Wylie, moving northeast at 35
mph.

Locations to be impacted include...
Uptown Charlotte, Central Charlotte, South Charlotte, Northeast
Charlotte, Southwest Charlotte, East Charlotte, Northwest Charlotte,
Mint Hill, Pineville and Tega Cay.

Wind gusts up to 40 mph 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.

Lake Wylie is in the path of this storm. Cloud to ground lightning
and gusty winds will create dangerous boating conditions.
Move to shore immediately.

&&

LAT...LON 3505 8088 3507 8090 3504 8090 3496 8109
      3511 8122 3538 8082 3516 8064
TIME...MOT...LOC 1928Z 236DEG 30KT 3508 8109

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
330 PM EDT Fri May 28 2021

SCZ003-005-006-010-282000-
Greater Pickens SC-Anderson SC-Greenville Mountains SC-
Greater Greenville SC-
330 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN GREENVILLE...NORTH
CENTRAL ANDERSON AND EAST CENTRAL PICKENS COUNTIES UNTIL 400 PM
EDT...

At 329 PM EDT, Doppler radar was tracking a strong thunderstorm near
Easley, moving east at 35 mph.

Locations to be impacted include...
Greenville Downtown, Easley, Pickens, Greenville Eastside, West
Greenville, Greer, Taylors, Berea, Welcome and Powdersville.

Wind gusts up to 40 mph 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 3470 8266 3487 8274 3508 8228 3496 8222
      3485 8223 3482 8218
TIME...MOT...LOC 1929Z 247DEG 31KT 3482 8262

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
339 PM EDT Fri May 28 2021

NCZ036-056-069>071-282015-
Gaston NC-Iredell NC-Lincoln NC-Mecklenburg NC-Catawba NC-
339 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CATAWBA...EASTERN
LINCOLN...SOUTH CENTRAL IREDELL...NORTHWESTERN MECKLENBURG AND
NORTHEASTERN GASTON COUNTIES UNTIL 415 PM EDT...

At 339 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles southeast of Lincolnton, or near High Shoals, moving northeast
at 40 mph.

Locations to be impacted include...
Huntersville, Gastonia, Lincolnton, Cornelius, Mooresville, Mt Holly,
Davidson, Dallas, Stanley and Ranlo.

Wind gusts up to 40 mph 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.

Lake Norman is in the path of this storm. Cloud to ground lightning
and gusty winds will create dangerous boating conditions.
Move to shore immediately.

&&

LAT...LON 3527 8119 3543 8128 3567 8085 3551 8077
      3551 8078 3549 8079 3542 8075 3540 8077
      3535 8070
TIME...MOT...LOC 1939Z 245DEG 35KT 3538 8116

HG