Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
248 PM EDT Wed Jun 9 2021

.SYNOPSIS...
A moist southerly flow off of the Gulf of Mexico will continue into
the second half of the week. An upper level trough will set up over
the eastern states through the weekend as weak cold fronts drift
south across our region.  Expect scattered to numerous afternoon and
evening showers and thunderstorms into the start of the weekend
with somewhat drier conditions by late in the weekend and early
next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 235 PM Wednesday...Convection continues to fire up over the
higher terrain with some sct storms moving northward from CAE and
encroaching on our southernmost zones as well. Expect convection to
eventually drift eastward off the Blue Ridge later this afternoon
and out over the Piedmont/Upstate this evening.

Otherwise, the upper pattern will gradually modify thru the period
as an old upper low drifts eastward across the Midwest/upper OH Valley
region and weak upper ridging slides underneath it and across the Deep
South. This will continue to veer the low-lvl flow around to a more
SWLY direction today and gradually begin to wean our CWA from the gulf
moisture feed. Mid/upper-lvl forcing will be very weak thru the period,
so convective evolution will trend back toward a more climatological
pattern today and tomorrow. Expect convection to eventually drift
eastward off the Blue Ridge later this afternoon and out over the
Piedmont/Upstate this evening. The best convective coverage will be
concentrated over the mtns/foothills again this aftn/evening and
then over the western Piedmont later this evening. Fcst soundings
continue to show an uptick in the amount of sfc-based CAPE with
a bit less moisture in the boundary layer, so that might give us
a better chance for a few more pulse-type severe multicells. But,
localized flash flooding still remains the bigger concern. Convection
should linger well into tonight and possibly into the overnight,
before finally dying off. Low temps overnight will remain about a
category above normal. Highs tomorrow should top out near normal,
if not slightly above.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 130 PM Wed: A light SW to WSW'ly flow will continue thru Friday
on the periphery of a subtropical sfc ridge over the western
Atlantic. A slowly moving shortwave initially will be to our
northwest over the lower Ohio Valley; confluent flow downstream of
this feature will maintain a better-defined sfc high near New
England. The shortwave looks to be timed to enhance convective
initiation Friday, and its height falls will help lapse rates improve
slightly compared to the previous day. Thus, our PoPs will trend a
bit upward. Moist profiles appear to keep damaging wind risk on the
low side, though slow-moving storms producing torrential rainfall
will continue to pose a localized excessive rain threat.

As the wave continues to move east Friday night into Saturday, the
front will sag slowly southward across the CWA. This does not look to
induce any real airmass change for Saturday, but it will turn
925-700mb winds toward NW and allow some drying aloft. It will also
bring slightly lower sfc dewpoints. Accordingly, PWATs will end up
closer to a median value for mid-June, though still elevated; peak
diurnal PoPs fall back more into the chance range. We will trade some
of the flash flood threat for more microburst threat as the models
begin to bring higher DCAPE and sfc-midlevel delta-theta-E back to
the area.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 200 PM Wed: We will remain under a relatively dry northerly
flow regime Sunday following the departure of the front, and a
downward trend likely will continue in PWATs. Deep layer lapse rates
remain conducive to diurnal instability, though deeper mixing appears
to make initiation less likely overall. PoPs mostly peak in the
chance range on Sunday with temps about normal. The GFS depicts large
DCAPE greater than 1000 J/kg across the CWA, with marginal
sfc-midlevel delta-theta-E values around 20 K across much of the
area, still with weak 0-6km shear. Thus, a seasonable risk of
damaging microbursts could persist.

A stronger cold front should push south of the Great Lakes on Sunday,
at the leading edge of an appreciably drier continental airmass, and
beneath a deepening NE CONUS trough. Though there are some timing
differences in the deterministic global models, the general idea
appears to be that diurnal convection along the front will
effectively push it a bit farther south each afternoon/evening early
next week. The GFS is more aggressive than the ECMWF or Canadian GDPS
in depicting this; it actually shows deep convection being completely
suppressed over the CWA Monday within the drier post-frontal
environment, which seems like a little bit of a stretch in light of
the other models' solutions. The synoptic fropa looks most likely to
occur Tuesday or Tuesday night, timed with a vort lobe rotating
around the aforementioned trough, and thus don't want to go too low.
Nevertheless, in light of blended guidance, precip chances are being
lowered for Mon-Tue compared to our previous fcst: typical chance
range values for the mountains and slight-chance Piedmont on Monday,
and still mostly at least slight-chance Tuesday. Temps will trend
above normal. Partial thicknesses are rather high, and with downslope
flow and lack of a front on Monday, that looks to be the warmest day
with lower 90s across much of the Piedmont.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: We will remain under the plume of deep sub-
tropical moisture thru the taf period and beyond with restrictions
likely at most sites. Overall, the guidance continues to suggest
a more climatological diurnal pattern wrt convective activity this
aftn and evening, with showers and thunderstorms developing over
the higher terrain and then gradually spreading out across the
Upstate and Piedmont later this aftn/evening. This was handled
with VCTS at KGSP, KGMU, and KAND and TEMPOs for TSRA at KAVL and
KHKY for the aftn/evening. KCLT appears less likely to be impacted
by thunderstorms this aftn/evening, so I just have VCSH there.
Otherwise, convective debris clouds will linger again tonight
and into the overnight, with the likelihood of another round of
early morning fog/low cig restrictions at most sites, with the
best chance for denser fog over the mtn valleys including KAVL.

Outlook: Scattered to numerous diurnally-driven convection and
associated flight restrictions will continue thru much of the week.
Overnight/morning fog/low cigs are possible, especially over the
mtn valleys and locations that receive heavy precip.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High  99%     High  99%     High  85%     High  89%
KGSP       High 100%     High 100%     High  90%     High  87%
KAVL       High 100%     High  95%     High  82%     Med   77%
KHKY       High 100%     Med   79%     Med   78%     High  85%
KGMU       High 100%     High 100%     High  91%     High  85%
KAND       High 100%     High 100%     High  93%     High  88%

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...DEO
NEAR TERM...JPT
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...JPT

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
348 AM EDT Wed Jun 9 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-100800-
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-
348 AM EDT Wed Jun 9 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 showers and thunderstorms are likely again this afternoon
and evening. The main impacts that can be expected are cloud-to-
ground lightning, gusty winds, and heavy downpours. Localized
flooding is possible with any storms that produce high rainfall
rates.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
139 PM EDT Wed Jun 9 2021

NCZ053-065-091800-
Buncombe NC-Henderson NC-
139 PM EDT Wed Jun 9 2021

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT NORTHWESTERN
HENDERSON AND SOUTH CENTRAL BUNCOMBE COUNTIES UNTIL 200 PM EDT...

At 138 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 10 miles northwest of Hendersonville, or near
Asheville Airport, moving east at 10 mph.

Locations to be impacted include... Arden, Mills River, Fletcher,
Mountain Home, Blue Ridge Parkway between Mount Pisgah and The NC
Arboretum, Asheville Airport, Skyland, Bent Creek, and Biltmore
Forest.

Wind gusts up to 40 mph 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.

&&

LAT...LON 3537 8269 3550 8269 3553 8246 3534 8246
TIME...MOT...LOC 1738Z 269DEG 8KT 3543 8259

8

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
218 PM EDT Wed Jun 9 2021

NCZ048-049-053-091845-
Buncombe NC-Yancey NC-Madison NC-
218 PM EDT Wed Jun 9 2021

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL MADISON...
NORTHEASTERN BUNCOMBE AND SOUTHERN YANCEY COUNTIES UNTIL 245 PM
EDT...

At 218 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles north of Downtown Asheville, or 4 miles northeast of
Weaverville, moving northeast at 15 mph.

Locations to be impacted include...
Burnsville, Weaverville, B.R. Parkway-East Asheville To Craggy
Gardens, Mount Mitchell State Park, Mars Hill, B.R. Parkway-Craggy To
Little Switzerland, Busick, Barnardsville, Flat Creek and Swiss.

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 3579 8216 3579 8217 3578 8216 3577 8216
      3561 8247 3575 8262 3599 8237
TIME...MOT...LOC 1818Z 228DEG 11KT 3573 8248

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
247 PM EDT Wed Jun 9 2021

NCZ501-502-504-091915-
Caldwell Mountains NC-Greater Burke NC-Greater Caldwell NC-
247 PM EDT Wed Jun 9 2021

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT CENTRAL
CALDWELL AND CENTRAL BURKE COUNTIES UNTIL 315 PM EDT...

At 247 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 4 miles west of Lenoir, or near Gamewell, moving
east at 15 mph.

Locations to be impacted include...
Lenoir, Sawmills, Granite Falls, Gamewell, Hudson, Cajah's Mountain,
Cedar Rock, Kings Creek, Collettsville and Patterson.

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.

&&

LAT...LON 3579 8168 3596 8171 3605 8140 3579 8135
TIME...MOT...LOC 1847Z 260DEG 11KT 3589 8161

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
253 PM EDT Wed Jun 9 2021

SCZ019-091930-
Greenwood SC-
253 PM EDT Wed Jun 9 2021

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT SOUTHERN
GREENWOOD COUNTY UNTIL 330 PM EDT...

At 253 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 10 miles south of Greenwood, or 9 miles southwest
of Ninety Six Historic Site, moving east at 15 mph.

Locations to be impacted include...
Ninety Six, Lake Greenwood State Park, Greenwood State Park, Ninety
Six Historic Site, Bradley, Kirksey, Dyson, Callison, Epworth and
Promised Land.

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.

&&

LAT...LON 3398 8205 3399 8215 3397 8218 3399 8222
      3402 8224 3411 8226 3420 8194 3420 8193
      3409 8191 3409 8192 3404 8194 3400 8199
      3396 8201 3395 8205
TIME...MOT...LOC 1853Z 260DEG 11KT 3404 8213

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
306 PM EDT Wed Jun 9 2021

NCZ049-503-505-506-091930-
McDowell Mountains NC-Yancey NC-Burke Mountains NC-
Eastern McDowell NC-
306 PM EDT Wed Jun 9 2021

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT CENTRAL
MCDOWELL...SOUTHEASTERN YANCEY AND WEST CENTRAL BURKE COUNTIES UNTIL
330 PM EDT...

At 306 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 6 miles northwest of Marion, or 4 miles east of
B.R. Parkway-Little Switzerland To Linville, moving east at 10 mph.

Locations to be impacted include...
Marion, Lake James State Park, Lake James, B.R. Parkway-Little
Switzerland To Linville, Old Fort, B.R. Parkway-Craggy To Little
Switzerland, Nebo, Pleasant Gardens, Ashford and Woodlawn.

Wind gusts up to 45 mph, pea size hail 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.

&&

LAT...LON 3580 8189 3577 8193 3572 8187 3564 8185
      3564 8217 3582 8221 3584 8215 3582 8214
      3582 8212 3585 8210 3585 8205 3587 8203
      3588 8201 3587 8200 3589 8198 3591 8191
TIME...MOT...LOC 1906Z 260DEG 10KT 3575 8210

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
413 PM EDT Wed Jun 9 2021

NCZ035-056-502-504-092045-
Greater Burke NC-Greater Caldwell NC-Alexander NC-Catawba NC-
413 PM EDT Wed Jun 9 2021

...A THUNDERSTORM WITH INTENSE LIGHTNING AND TORRENTIAL RAINFALL WILL
IMPACT NORTHWESTERN CATAWBA...SOUTHWESTERN ALEXANDER...SOUTHEASTERN
CALDWELL AND EAST CENTRAL BURKE COUNTIES UNTIL 445 PM EDT...

At 413 PM EDT, Doppler radar was tracking a thunderstorm with intense
lightning and torrential rainfall 8 miles south of Lenoir, or near
Lake Rhodhiss, moving east at 10 mph.

Locations to be impacted include...
Hickory, Lenoir, St. Stephens, Longview, Sawmills, Granite Falls,
Valdese, Bethlehem, Hudson and Icard.

Wind gusts up to 40 mph and torrential rainfall rates up to 3 inches
per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

Frequent lightning is occurring with this storm. If outdoors, try to
get indoors or into a hard topped vehicle. Otherwise, stay away from
open areas and isolated high objects such as trees. When indoors,
stay away from windows and doors and avoid using wired electronic
devices. Do not take a shower or bath. Try to unplug unnecessary
appliances before the storm approaches.

&&

LAT...LON 3569 8158 3587 8158 3591 8127 3564 8127
TIME...MOT...LOC 2013Z 270DEG 10KT 3578 8149

RWH