Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
607 PM EDT Fri Jun 11 2021

.SYNOPSIS...
Daily afternoon and evening thunderstorms are expected through the
weekend, and with subtropical moisture lingering over the region,
they will pose a threat of localized flash flooding. A front will
settle across the region early next week, promoting a slight chance
for showers Monday and Tuesday. Hot and humid conditions can be
expected those days, but somewhat drier and cooler high pressure
will return by midweek.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 6pm EDT Friday: Showers and thunderstorms continue this
evening, more numerous in eastern areas and the mountains.
Expectations are for convection to continue for the next several
hours before a substantial decline. Localized flooding remains
the main concern, with chances for severe convection about as
limited as the previous few days.

An upper trough/associated speed maxima and attendant diffuse
frontal boundary will sag slowly across the area through the period.
The atmosphere will remain anomalously moist through the period,
with PWATs hovering around 1.8. This setup combined with a
moderately unstable air mass will allow convective coverage...
currently widely scattered at most...to increase throughout the
afternoon into the evening, with likely PoPs still seemingly
warranted across much of the forecast area. Heavy/locally excessive
rainfall remains the primary concern, especially across the
Tennessee border counties, where persistent W/NW upslope flow will
provide a favorable scenario for training cells and antecedent
conditions are wet owing to heavy rainfall over the past 24 hours.
Having said that, the flash flood threat remains too localized to
warrant a Flash Flood Watch at this time. One or two pulse severe
storms also remain possible into the evening, esp in the more
unstable air across the Piedmont. Convective coverage will diminish
through the evening, but persistent W/NW flow should result in
occasional showers developing near the TN border through the night.

With the upper trough positioned over the area tomorrow and the
diffuse frontal zone expected to sag into western NC, convection
should again blossom across the CWA Saturday afternoon, with likely
PoPs again advertised in all areas. In terms of hazards: more of the
same, with the threat of locally excessive rainfall persisting.
There may be a slight uptick in the threat of pulse severe storms,
particularly over the upper Savannah River Valley and Lakelands,
where guidance suggests an increase above the modest levels of
instability over that of the past several days. Temps will remain
around normal.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of midday Fri: As front continues to slowly sag south across SC/GA
Saturday night into Sunday morning, a weak coastal low is expected to
develop via the shortwave near the NC/SC coast. That development,
along with sfc high over the Mid-Atlantic, still looks to bring an
easterly component to the low-level flow, which leads multiple
guidance sources to show some continuing convection near the Blue
Ridge Escarpment into the night, in addition to what develops near
the front. The 12z HRRR and NAMNest however are not too excited by
this possibility, so will keep PoPs low; the concern would be for
possible anchoring of cells along the Escarpment in that scenario;
MBE vectors are very short as it is.

The weak easterly flow will continue into Sunday, but diminishing
and/or backing to a less upslope direction as the low drifts
offshore. The shortwave looks to be south and east of the CWA;
heights should rise as it is replaced by an extension of the deep
ridge over the Rockies/Plains. Dewpoints probably will be a tad lower
but still and most likely remaining in the 60s. Midlevel height rises
imply poor lapse rates above the PBL which, given lack of a trigger,
suggests PoPs close to climo. Still looking at a bit of a wildcard
with models depicting an unstable warm sector across the upper OH/TN
Valleys ahead of a seasonally respectable cold front.  Earlier runs
suggested that the resultant activity could impinge on our mountain
zones late Sunday or Sunday night, but this depiction has generally
diminished. Deep shear and weak forcing just don't look all that
supportive of an MCS threat. Profiles will be somewhat drier Sunday
than Saturday, so heavy rainfall potential may be slightly reduced
although soils may be wetter after still another day of storms, so
can't say we won't exactly be out of the flash-flood threat window.
Sfc-midlevel theta-e lapses will be a bit stronger, so pulse storm
wind damage threat may be a bit greater. Max temps will trend a
little warmer compared to Saturday, near to slightly above climo.

By Monday, the front appears to reach the CWA, as it picks up a
little bit of a boost from a shortwave approaching from the Great
Lakes and deepening the trough across the NE CONUS. With winds
turning northwesterly through much of the mid to upper levels, deep
drying does occur on the "cool" side of the front. Most of the models
depict a convergence zone across the Carolina/Georgia Piedmont, and
small PoPs will follow. Similar to the trend noted for Sunday, flood
threat may diminish a bit in lieu of improving microburst threat
where the drier air is able to work in. Downsloping and increasing
thicknesses still look to produce max temps in the lower 90s for much
of the Piedmont, but despite dewpoint pooling potentially keeping
values in the upper 60s there, heat index concerns are not expected.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 200 PM Fri: The drying trend will continue Monday night as cold
front continues to push south and east, and dewpoints/PWATs continue
to tumble across the CWA into Tuesday, looking likely to remain low
thru the remainder of the period. A shortwave will swing across the
area Tuesday on the periphery of a cutoff low over Quebec; the
combination of this feature and the front leads to model QPF response
mostly to our east, but we will maintain small PoPs over the eastern
half of the area. Above-normal temps persist in downsloping flow Tue.
Unmentionably low PoPs are fcst from Tue night to at least early
Friday as continental sfc high migrates across the eastern CONUS, and
max temps fall back to near normal. Various models depict a
tropical/subtropical low approaching the Gulf Coast late in the week,
but any moisture associated with it looks to affect our area after
the end of the period, if at all.

&&

.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Convection remains somewhat isolated across
the Terminal Forecast Area so far this afternoon, but the influence
of an upper trough just to our west will combine with moderate
instability to allow for steady expansion of coverage throughout the
afternoon, and tempos for TSRA are warranted at most sites into the
early evening hours. Convection will likely linger, although with
decreasing coverage past the tempo expiration, so those may need to
be extended by an hour or two at some point. After this evening, low
level moisture is expected to result in clouds filling in and
lowering, mainly at the NC terminals, with low MVFR or IFR cigs
expected at the NC terminals by sunrise. MVFR/possible IFR fog is
also expected in the mountain valleys. Convection should begin
redeveloping Sat afternoon, warranting Prob30s at all sites. SW
winds at 5-10 kts will continue at most sites through the afternoon,
before weakening and gradually turning toward the NE by the end of
the period, as a diffuse frontal boundary sags across the area.

Outlook: Modest drying moves in Sunday into next week. This will
result in less coverage of diurnal convection each day, such that
little in the way of convection is expected Tue and Wed. The
potential for overnight/morning fog/low cigs should become
increasingly confined to the mtn valleys next week.

Confidence Table...

            22-04Z        04-10Z        10-16Z        16-18Z
KCLT       High 100%     High 100%     Med   65%     High  89%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High  82%     Med   77%     High  83%
KHKY       High 100%     High 100%     Med   70%     High  86%
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 are available at
the following link:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

SYNOPSIS...Wimberley
NEAR TERM...JDL/WJM
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...JDL

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
331 AM EDT Fri Jun 11 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-120745-
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-
331 AM EDT Fri Jun 11 2021

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

.DAY ONE...Today and tonight.

Numerous to widespread showers and thunderstorms will develop across
the western Carolinas and northeast Georgia today, with the greatest
coverage during the afternoon and early evening hours. The
thunderstorms will have the potential to produce torrential
downpours in affected areas and localized flooding may develop in
any locations that see repeated thunderstorms in a short period of
time. The thunderstorms will also produce dangerous cloud-to-ground
lightning and gusty winds.

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

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

MPR

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
629 PM EDT Fri Jun 11 2021

NCZ056-068-069-504-506-508-510-SCZ007-008-112300-
Greater Rutherford NC-Cleveland NC-Lincoln NC-Greater Burke NC-
Eastern McDowell NC-Eastern Polk NC-Catawba NC-Cherokee SC-
Spartanburg SC-
629 PM EDT Fri Jun 11 2021

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL IMPACT SOUTHWESTERN
CATAWBA...SOUTHEASTERN MCDOWELL...RUTHERFORD...SOUTHEASTERN POLK...
WESTERN LINCOLN...WESTERN CLEVELAND...SOUTHERN BURKE...NORTHEASTERN
SPARTANBURG AND NORTHWESTERN CHEROKEE COUNTIES UNTIL 700 PM EDT...

At 629 PM EDT, Doppler radar indicated thunderstorms with torrential
rainfall along a line extending from 5 miles southwest of Hickory to
10 miles northeast of Forest City to 13 miles southeast of Columbus,
and moving southeast at 10 mph.

Locations to be impacted include...
Hickory, Spartanburg, Newton, Lincolnton, Forest City, Rutherfordton,
Morganton, Longview, Boiling Springs SC and Spindale.

Wind gusts up to 40 mph and very heavy rainfall rates up to 2 inches
per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.

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 3556 8107 3542 8135 3542 8145 3538 8142
      3527 8163 3481 8194 3512 8209 3569 8195
      3576 8134
TIME...MOT...LOC 2229Z 327DEG 11KT 3568 8138 3547 8178 3513 8202

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
635 PM EDT Fri Jun 11 2021

GAZ029-SCZ011-112300-
Elbert GA-Abbeville SC-
635 PM EDT Fri Jun 11 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN ELBERT AND
SOUTHEASTERN ABBEVILLE COUNTIES UNTIL 700 PM EDT...

At 635 PM EDT, Doppler radar was tracking a strong thunderstorm 14
miles southeast of Elberton, or near Lake Strom Thurmond, moving east
at 25 mph.

Locations to be impacted include...
Calhoun Falls, Nancy Hart State Park, Bobby Brown State Park, Lake
Strom Thurmond, Lake Russell, Broad River Campground, Fortsonia,
Richard B Russell Dam, Rice Town and Bobby Brown State Recreation
Area.

Wind gusts up to 45 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 3398 8261 3397 8264 3399 8265 3397 8278
      3399 8283 3398 8286 3403 8295 3417 8232
      3408 8231 3406 8236 3406 8244 3408 8248
      3407 8253 3401 8260 3396 8257
TIME...MOT...LOC 2235Z 262DEG 22KT 3401 8263

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
643 PM EDT Fri Jun 11 2021

SCZ002-003-005>008-112315-
Pickens Mountains SC-Greater Pickens SC-Cherokee SC-
Greenville Mountains SC-Spartanburg SC-Greater Greenville SC-
643 PM EDT Fri Jun 11 2021

...STRONG THUNDERSTORMS WILL IMPACT GREENVILLE...SPARTANBURG...
WESTERN CHEROKEE AND NORTHEASTERN PICKENS COUNTIES UNTIL 715 PM
EDT...

At 643 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 11 miles west of Gaffney to 10 miles northwest of
Spartanburg to 12 miles north of Greenville Downtown to 11 miles
south of Brevard, and moving south at 15 mph.

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

Wind gusts up to 45 mph and very heavy rainfall rates up to 2 inches
per hour 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.

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 3480 8247 3482 8248 3481 8251 3486 8278
      3508 8275 3510 8270 3513 8268 3512 8266
      3516 8255 3517 8243 3518 8178 3492 8164
      3491 8171 3489 8174 3480 8199 3478 8237
TIME...MOT...LOC 2243Z 348DEG 13KT 3512 8186 3505 8206 3503 8243 3507
8267

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
647 PM EDT Fri Jun 11 2021

NCZ035>037-056-057-069-112315-
Rowan NC-Davie NC-Iredell NC-Lincoln NC-Alexander NC-Catawba NC-
647 PM EDT Fri Jun 11 2021

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL IMPACT EASTERN
CATAWBA...NORTHWESTERN DAVIE...SOUTHEASTERN ALEXANDER...NORTHEASTERN
LINCOLN...IREDELL AND NORTHWESTERN ROWAN COUNTIES UNTIL 715 PM EDT...

At 647 PM EDT, Doppler radar indicated thunderstorms with torrential
rainfall along a line extending from 12 miles southwest of
Yadkinville to 4 miles southeast of Newton, and moving east at 15
mph.

Locations to be impacted include...
Statesville, Newton, Maiden, Westport, Troutman, Stony Point,
Claremont, Catawba, Harmony and Lake Norman.

Wind gusts up to 40 mph and very heavy rainfall rates up to 2 inches
per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.

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 3605 8050 3551 8088 3551 8091 3550 8093
      3547 8095 3546 8094 3558 8127 3606 8093
TIME...MOT...LOC 2247Z 282DEG 15KT 3605 8086 3563 8115

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
650 PM EDT Fri Jun 11 2021

SCZ019-112315-
Greenwood SC-
650 PM EDT Fri Jun 11 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN GREENWOOD COUNTY
UNTIL 715 PM EDT...

At 650 PM EDT, Doppler radar was tracking a strong thunderstorm 14
miles southeast of Greenwood, or 9 miles south of Ninety Six Historic
Site, moving east at 15 mph.

Locations to be impacted include...
Kirksey, Callison and Epworth.

Wind gusts up to 45 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 3398 8205 3399 8215 3397 8217 3398 8221
      3411 8208 3410 8190 3409 8192 3404 8194
      3400 8199 3396 8201 3395 8205
TIME...MOT...LOC 2250Z 282DEG 15KT 3401 8202

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
713 PM EDT Fri Jun 11 2021

NCZ036-037-056-057-069-071-072-112345-
Rowan NC-Davie NC-Iredell NC-Lincoln NC-Cabarrus NC-Mecklenburg NC-
Catawba NC-
713 PM EDT Fri Jun 11 2021

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL IMPACT NORTHWESTERN
CABARRUS...SOUTHEASTERN CATAWBA...DAVIE...NORTHEASTERN LINCOLN...
IREDELL...NORTH CENTRAL MECKLENBURG AND ROWAN COUNTIES UNTIL 745 PM
EDT...

At 713 PM EDT, Doppler radar indicated thunderstorms with torrential
rainfall along a line extending from 5 miles southwest of Yadkinville
to 10 miles northeast of Statesville to 12 miles southeast of Newton,
and moving southeast at 20 mph.

Locations to be impacted include...
Huntersville, Kannapolis, Salisbury, Statesville, Mocksville, West
Concord, Cornelius, Mooresville, Davidson and China Grove.

Wind gusts up to 40 mph and very heavy rainfall rates up to 2 inches
per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.

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 3531 8074 3557 8123 3590 8089 3605 8082
      3604 8049 3606 8046 3601 8042 3599 8042
      3596 8038 3589 8037 3588 8042 3586 8039
      3584 8039 3585 8042 3583 8043 3583 8049
      3581 8047 3579 8048 3573 8045 3572 8034
TIME...MOT...LOC 2313Z 293DEG 18KT 3606 8071 3587 8074 3557 8104

RWH