Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
959 AM EDT Wed Jun 9 2021

.SYNOPSIS...
The Bermuda high remains in place across the southeastern United
States today before retreating to the south and east tomorrow as an
upper-level low phases into a trough digging across the eastern
United States. Daily shower and thunderstorm chances will continue
today and tomorrow despite the breaking down of this ridge. Friday
into Saturday a cold front keeps shower and thunderstorm chances in
the forecast. Late this weekend into early next week shower and
thunderstorm chances decrease significantly despite a second cold
front approaching the area.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 950 AM Wednesday...Most of the denser fog has dissipated over
the past couple of hours as daytime heating ramps up, but a handful
of sites are still reporting reduced visby. Cloud cover has also
scattered out to some degree with patches of mostly clear sky now
evident on the visible satellite imagery.

Otherwise, slow and subtle changes to the upper pattern will occur
over the next 24 hours, as an old upper low drifts eastward across
the Midwest/upper OH Valley region and a weak upper ridge slides
underneath across the Deep South. This will gradually veer the low-
level flow around more SWLY today and start to wean us from the
Gulf moisture feed. Mid/upper forcing will be non-existent, so the
convective evolution today will trend back toward something more
climatological. Expect convection to be initiated over the higher
terrain this afternoon and eventually drift eastward off the Blue
Ridge late in the afternoon and out over the Piedmont/Upstate in the
early to middle evening. Precip prob will be concentrated over the
mtns/foothills through the today period and then over the western
Piedmont in the early part of the tonight period. Fcst soundings
show an uptick in the amount of sfc-based CAPE later today with
a bit less moisture in the boundary layer, so that might lead
to a better chance of a few pulse-type severe multicells. The PW
drops a bit, as does the warm cloud depth, so perhaps localized
flash flooding might be a bit less of a concern, although still
present. Temps should rebound a few degrees above climo with fewer
storms and more sun. Convection should linger into the late evening
over the east before dying off. Meanwhile, convection to the west
tonight might reach the western zones by daybreak Thursday. Temps
will remain seasonally mild.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 AM EDT Wednesday: A strong high pressure ridge will build
into the Southern Plains while an upper-level low phases into a
digging trough across the eastern United States. This upper-level
trough will suppress the western periphery of the Bermuda high
across the southeastern CONUS pushing the ridge off to the south and
east. Low-level flow will remain SW'ly and W'ly Thursday into Friday
afternoon despite the retreating ridge. The trough will progress
eastward throughout the short term period with the axis crossing the
CWA Friday evening into early Saturday morning. In response low-
level flow turns WNW'ly and NW'ly by Friday evening. The surface
frontal boundary associated with the upper-level trough will
gradually sink southward across the Mid-Atlantic states out of the
Ohio Valley, but should remain just to the north of the forecast
area at the end of the short term. This frontal boundary approaching
the CWA along with lingering Gulf moisture will keep a good chance
for showers and thunderstorms in the forecast. PWATs should remain
above climo Thursday into late Friday. With a plethora of moisture
remaining in place and previous rainfall the past few days, isolated
flash flooding remains possible. The Weather Prediction Center has
us in a marginal to slight risk for excessive rainfall Thursday.
Hydro issues remain the main concern with any convection that occurs
due to high warm cloud heights leading to heavy downpours. SBCAPE
from GFS and NAM soundings show values ranging from 500 to 1,000
J/kg on Thursday. Friday the GFS shows similar values but the NAM is
more bullish with values ranging from 1,000 to 1,500 J/kg. However,
with low shear values from the weak synoptic flow, severe wx chances
should remain minimal, although they will NOT be zero. An isolated
strong to severe storm cannot be ruled out during the short term
period. Low temps will be 5 to 10 degrees above normal with high
temps 1 to 3 degrees above normal.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 AM EDT Wednesday: The aforementioned upper-level trough
axis should be located just to the east of the CWA to start the
extended while the ridge of high pressure dominates across the SW
United States. PWATs will gradually decrease throughout the extended
period as the Bermuda high retreats south and east and as two FROPAs
track out of the NW leading to the overall decrease in moisture
content. This will result in dewpoints and cloud cover gradually
declining each day. The first cold front is expected to track
through the area Saturday. NW'ly flow can be expected ahead of the
front Saturday morning becoming N'ly and NE'ly Saturday afternoon
and evening as the front sinks southward across the Carolinas and NE
Georgia. Highs will be noticeably cooler due to this N'ly flow.
Shower and thunderstorm chances remain in place Saturday due to the
FROPA. Sunday chances will be considerably lower with only a slight
chance to chance for showers and thunderstorms as second cold front
approaches from the NW. Monday the cold front remains to our NW
tracking through the region early Tuesday. PoPs will be much lower
due to the decreased moisture content with the second FROPA. Highs
will gradually warm throughout the extended becoming above climo
Sunday into early next week.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Dealing with patchy LIFR ceiling with some
VLIFR visibility near bodies of water, along with other convective
debris clouds scattered across the region. In particular, LIFR
just to the south of KCLT threatens the terminal, but the wind has
been pushing it slowly away to the east. We remain under the plume
of deep sub-tropical moisture, but slightly drier air appears to
work in this morning, so the lowest cloud deck may scatter out a
little bit earlier, in the mid/late morning hours. The guidance
is suggesting a more climatological diurnal pattern for today, so
showers and storms would develop first over the mtns and not move
out across the Upstate and Piedmont until late in the afternoon or
early evening. Will handle this with PROB30s and TEMPOs for the
time being. Convective debris clouds will linger again Wednesday
evening, with the possibility of another early morning fog/low
cloud ceiling restriction at places where it rains today.

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...

            14-20Z        20-02Z        02-08Z        08-12Z
KCLT       High  95%     High 100%     High 100%     Med   76%
KGSP       High  94%     High 100%     High 100%     High  92%
KAVL       High 100%     High 100%     High  93%     High  87%
KHKY       High  93%     High 100%     High  81%     High  82%
KGMU       High  86%     High 100%     High 100%     High  92%
KAND       Med   79%     High 100%     High 100%     High  89%

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...JPT/PM
SHORT TERM...AP
LONG TERM...AP
AVIATION...JPT/PM

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

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