Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
249 PM EDT Tue Jun 8 2021

.SYNOPSIS...
Southerly flow between an upper-level low to our west and Bermuda
high pressure in the Atlantic will act to provide moisture from the
Gulf of Mexico leading to daily shower and thunderstorm chances
through mid week. Despite the breaking down of the Bermuda high by
late week, shower and thunderstorm chances will continue into the
weekend as a frontal boundary over the Ohio Valley slowly sinks
southward interacting with the Gulf moisture across the forecast
area.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 225 PM Tuesday: The latest RADAR mosaic is showing increased
convective activity over the higher terrain and especially along the
NC/TN border. This trend will likely continue thru the rest of the
afternoon and into the evening, however sct showers and thunderstorms
could develop pretty much anywhere over the CWA within the very humid
airmass. Temps will remain mild overnight/early tomorrow, with lows
about a category above normal for early June.

Otherwise, the upper low to our west will continue to open up
and lift NE to the Midwest/lower Ohio Valley region tonight and
tomorrow. Deep subtropical moisture will continue to stream over
the region, but with the low-lvl flow becoming a bit more SWLY
over time. Thus, the forecast will change little for the rest of
the period and into the short-term. Extensive cloud cover will
keep the deeper convection in check until the early afternoon,
when breaks in the cloud cover will allow for destabilization
and the quick development of more showers and thunderstorms by
the mid/late afternoon again tomorrow. An isolated severe storm
cannot be ruled out, but greater threat continues to be locally
heavy rain due to the deep warm cloud layer, very high PW, and
a tendency toward training thunderstorms. At this point, a Flash
Flood Watch does not appear warranted, but the possibility of
isolated/localized flash flooding remains significant. Temps
will likely climb a few degrees above climatology tomorrow.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 2pm EDT Tuesday: Southeast CONUS mid-level trough remains west
of the GSP areas through Friday, but it makes gradual eastward
progress, with central axis reaching the Southern Appalachians
Friday evening. Surface trough with frontal boundary ahead of upper
system remains east of the mountains, and is far enough east by
Friday to bring the winds to a more northwesterly direction over the
mountains , but this will have little impact on dewpoints as in-
place moisture extends a considerable distance to the northwest.
Upper winds are somewhat mild with the slow-moving trough, but
gradually increase through Thursday as it makes its eastward
progress, reaching perhaps 20kts.  Somewhat tropical airmass will
also have modest CAPE at best, typically reaching MLCAPE levels of
500 to 1000 j/kg each afternoon.  Moisture and CAPE will be better
in the foothills and piedmont than the mountains, with a possibility
of a few severe wind reports.  The mountains are expected to have
much better shower coverage and pose more of an isolated flooding
threat in areas receiving repeated thunderstorms.  Chances for rain
are around 80% Thursday and Friday afternoon in the mountains, and
50% or so elsewhere.

Relatively mild synoptic conditions and dewpoints in the upper 60s
will give low temperatures 10 degrees or so above normal, with highs
5 or so degrees above normal.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 2pm EDT Tuesday: Weak Southeast CONUS upper trough finally
passes the region on Saturday with frontal zone ahead of it moving
out into the Atlantic, and winds northerly to northeasterly on
Saturday over the GSP area.  This will drop dewpoints several
degrees on Saturday, and break the previous pattern of afternoon
thunder each day. While a few stray showers may still be around on
Saturday, Sunday and Monday will have much lower chances for any
rain.  Clouds begin to clear on Saturday which, combined with a
ridging trend, will give warmer temps on Sunday and Monday.  EC
model fairly quickly brings in a new substantial shortwave that
disrupts the ridging trend, while the GFS declines to do this and
is, thus, warmer early next week.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: The moist pattern will continue thru the taf
period with sct showers and thunderstorms expected this aftn/evening
and again tomorrow aftn/evening. MVFR cloud decks continue to linger
at several sites with low-end VFR elsewhere. Still expecting more sites
to go VFR over the next few hours, but it will be hit or miss across
the fcst area. Convective coverage will continue to expand across the
region, however the latest CAM runs suggest that the better coverage
will be relegated to our higher terrain and northern Upstate. As such,
I have a TEMPO for TSRA at KAVL until 23z and just a VCTS for the other
taf sites for the remainder of the aftn/evening. Showers may linger
into the overnight, so I kept a VCSH going after the VCTS ends. In
addition, more low clouds will likely redevelop overnight and into
tomorrow morning, with most sites expected to see IFR and possibly
LIFR thru mid-morning. Otherwise, winds will be light and continue
to favor a SLY to SWLY direction thru the taf period.

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

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High  89%     High 100%     Med   78%     High  90%
KGSP       High  88%     High  98%     High  80%     High  89%
KAVL       High  99%     High  99%     Med   68%     High  84%
KHKY       High  98%     High 100%     High  87%     High  86%
KGMU       High  83%     High  97%     Med   77%     High  89%
KAND       High  83%     High  91%     Med   75%     High  94%

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...SCW
NEAR TERM...JPT
SHORT TERM...WJM
LONG TERM...WJM
AVIATION...JPT

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
337 AM EDT Tue Jun 8 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-090745-
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-
337 AM EDT Tue Jun 8 2021

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

.DAY ONE...Today and tonight.

Shower and thunderstorm chances return again today. The main impacts
are cloud-to-ground lightning and heavy downpours. Any slow moving
storms could produce locally heavy rainfall leading to isolated
flooding issues.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
341 PM EDT Tue Jun 8 2021

NCZ049-050-505-082015-
McDowell Mountains NC-Yancey NC-Mitchell NC-
341 PM EDT Tue Jun 8 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL MCDOWELL...
SOUTHEASTERN MITCHELL AND EAST CENTRAL YANCEY COUNTIES UNTIL 415 PM
EDT...

At 341 PM EDT, Doppler radar was tracking a strong thunderstorm 4
miles southwest of Spruce Pine. This storm was nearly stationary.

Locations to be impacted include...
Spruce Pine, B.R. Parkway-Little Switzerland To Linville, B.R.
Parkway-Craggy To Little Switzerland, Bandana, North Cove, Micaville,
Celo, Little Switzerland, Woodlawn and Busick.

Wind gusts up to 40 mph and pea size hail 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.

&&

LAT...LON 3601 8204 3599 8206 3595 8204 3591 8199
      3583 8194 3582 8196 3582 8197 3581 8199
      3579 8197 3577 8219 3594 8226 3605 8206
TIME...MOT...LOC 1941Z 249DEG 4KT 3588 8215

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
401 PM EDT Tue Jun 8 2021

NCZ052-059-063-082030-
Haywood NC-Southern Jackson NC-Northern Jackson NC-
401 PM EDT Tue Jun 8 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN JACKSON AND SOUTH
CENTRAL HAYWOOD COUNTIES UNTIL 430 PM EDT...

At 400 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles southeast of Sylva, or 5 miles southwest of B.R. Parkway-Balsam
Gap To Black Balsam Area. This storm was nearly stationary.

Locations to be impacted include...
Waynesville, B.R. Parkway-Black Balsam To Mount Pisgah, B.R.
Parkway-Balsam Gap To Black Balsam Area, Black Balsam Area,
Tuckasegee, Wolf Mountain and Sunburst.

Wind gusts up to 40 mph and pea size hail 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.

This storm 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 3548 8296 3531 8289 3531 8290 3529 8292
      3526 8292 3522 8294 3522 8295 3521 8296
      3520 8310 3536 8318
TIME...MOT...LOC 2000Z 249DEG 4KT 3531 8306

RWH