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
408 PM 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>014-019-292015-
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-
408 PM 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...Tonight.

Scattered thunderstorms are likely to continue this 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...

Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.

MPR

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

NCZ057-072-282115-
Rowan NC-Cabarrus NC-
448 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN CABARRUS AND
SOUTHEASTERN ROWAN COUNTIES UNTIL 515 PM EDT...

At 448 PM EDT, Doppler radar was tracking a strong thunderstorm 4
miles northeast of Downtown Concord, moving northeast at 20 mph.

Locations to be impacted include...
Kannapolis, Downtown Concord, Salisbury, China Grove, Spencer,
Landis, Enochville, Granite Quarry, Rockwell and Mt Pleasant.

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 3550 8029 3538 8038 3534 8056 3551 8069
      3573 8040 3572 8038 3572 8034 3571 8033
      3568 8033 3567 8031 3563 8029 3563 8027
      3559 8021 3555 8021 3554 8020 3551 8018
TIME...MOT...LOC 2048Z 245DEG 19KT 3545 8054

HG

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

NCZ070-071-SCZ009-282115-
Gaston NC-Mecklenburg NC-York SC-
450 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT MECKLENBURG...SOUTHEASTERN
GASTON AND NORTHEASTERN YORK COUNTIES UNTIL 515 PM EDT...

At 450 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles southeast of Gastonia, or 4 miles northwest of Lake Wylie,
moving northeast at 25 mph.

Locations to be impacted include...
Uptown Charlotte, Huntersville, Gastonia, Central Charlotte,
Northeast Charlotte, Southwest Charlotte, East Charlotte, Northwest
Charlotte, Mint Hill and Mt Holly.

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 3519 8057 3502 8111 3517 8122 3550 8080
      3546 8077 3542 8075 3540 8077 3535 8069
      3527 8067 3524 8060
TIME...MOT...LOC 2050Z 240DEG 21KT 3514 8109

HG

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

NCZ071-072-082-282145-
Union NC-Cabarrus NC-Mecklenburg NC-
517 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHERN CABARRUS...SOUTHERN
MECKLENBURG AND NORTHERN UNION COUNTIES UNTIL 545 PM EDT...

At 517 PM EDT, Doppler radar was tracking a strong thunderstorm 5
miles north of Indian Land, or over Pineville, moving northeast at 55
mph.

Locations to be impacted include...
South Charlotte, Southwest Charlotte, East Charlotte, Matthews, Mint
Hill, Indian Trail, Weddington, Stallings, Pineville and Lake Park.

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 3519 8028 3499 8083 3511 8093 3507 8100
      3511 8103 3543 8044 3536 8039 3519 8051
      3518 8050 3516 8044 3517 8042 3517 8039
      3518 8037 3517 8036
TIME...MOT...LOC 2117Z 240DEG 49KT 3507 8089

HG

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

NCZ071-072-082-282215-
Union NC-Cabarrus NC-Mecklenburg NC-
544 PM EDT Fri May 28 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CABARRUS...
SOUTHEASTERN MECKLENBURG AND NORTHERN UNION COUNTIES UNTIL 615 PM
EDT...

At 544 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles northwest of Monroe, or over Lake Park, moving east at 35 mph.

Locations to be impacted include...
Monroe, Matthews, Mint Hill, Indian Trail, Stallings, Unionville,
Wesley Chapel, Lake Park, Hemby Bridge and Midland.

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 3501 8030 3499 8070 3517 8074 3534 8040
      3521 8048 3519 8051 3518 8050 3518 8048
      3517 8047 3516 8044 3517 8042 3516 8041
      3518 8037 3517 8036 3518 8031 3519 8030
      3519 8028
TIME...MOT...LOC 2144Z 261DEG 29KT 3510 8063

HG

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

NCZ051-058-282245-
Graham NC-Swain NC-
553 PM EDT Fri May 28 2021

...STRONG THUNDERSTORMS WILL IMPACT SWAIN AND GRAHAM COUNTIES UNTIL
645 PM EDT...

At 553 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 8 miles southeast of Maryville to 7 miles north
of Ducktown, and moving east at 30 mph.

Locations to be impacted include...
Bryson City, Robbinsville, Town Of Santeetlah, Smoky Mountains-Deep
Creek, Smoky Mountains-Fontana Area, Lake Santeetlah, Fontana Lake,
Fontana Village, Smoky Mountains-Twentymile Creek and Smoky
Mountains-Oconaluftee.

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 3537 8401 3541 8402 3552 8388 3553 8382
      3556 8377 3558 8360 3556 8350 3565 8335
      3565 8332 3557 8324 3547 8332 3547 8335
      3534 8342 3528 8367 3525 8373 3525 8385
      3522 8396 3523 8400 3531 8404 3535 8404
TIME...MOT...LOC 2153Z 259DEG 26KT 3569 8384 3514 8438

HG

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

NCZ048>052-282300-
Haywood NC-Yancey NC-Swain NC-Madison NC-Mitchell NC-
601 PM EDT Fri May 28 2021

...STRONG THUNDERSTORMS WILL IMPACT MADISON...NORTHEASTERN SWAIN...
NORTHERN MITCHELL...NORTHWESTERN HAYWOOD AND NORTHERN YANCEY COUNTIES
UNTIL 700 PM EDT...

At 601 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 10 miles east of Greeneville Tennessee to 7
miles southeast of Newport to 11 miles west of Gatlinburg, and
moving east at 35 mph.

Locations to be impacted include...
Burnsville, Marshall, Mars Hill, Hot Springs, Smoky Mountains-Balsam
Mountain, Smoky Mountains-Big Creek, Smoky Mountains-Cataloochee,
Smoky Mountains-Oconaluftee, Bakersville and Smoky
Mountains-Clingmans Dome.

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 3608 8207 3582 8243 3569 8281 3570 8285
      3565 8287 3548 8331 3557 8362 3556 8350
      3576 8316 3578 8299 3588 8290 3593 8292
      3593 8281 3600 8277 3606 8264 3603 8259
      3597 8261 3595 8256 3611 8237 3616 8222
TIME...MOT...LOC 2201Z 279DEG 31KT 3618 8264 3587 8312 3566 8369

HG