Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
224 PM EDT Mon Jun 7 2021

.SYNOPSIS...
Daily shower and thunderstorm chances continue through the week as
an upper low meanders northeastward into the Great Lakes region
while the Bermuda High pumps Gulf moisture into the Southeast. Even
as this pattern breaks down late this week, showers and
thunderstorms will continue at least through Saturday.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 150 pm: Convection is blossoming across the forecast area
early this afternoon along the leading edge of deep moisture plume
extending from the Gulf of Mexico into the TN Valley and southern
Appalachians. Coverage should continue to increase as activity lifts
northeast across the CWA through the afternoon into early evening,
warranting 70-80 PoPs across much of the forecast area. Instability
is perhaps a bit higher than what was previously anticipated, while
shear values are at least approaching the moderate range, so there's
been a slight uptick in the chance for a pulse severe storm or two.
Meanwhile, slightly improved mean tropospheric flow is allowing for
better cell movement than during the past couple of days.
Nevertheless, the potential for training cells, continued very moist
conditions/warm rain processes, and increased overall convective
coverage than in previous days will result in a continued risk of
locally excessive rainfall. Convection should again steadily
diminish and/or move east of the forecast area this evening, with
token small PoPs retained through the overnight in light of the
moist environment. Min temps will again be several degrees above
climo.

In terms of the synoptic setup, just more of the same on Tuesday,
with upper low wobbling very slowly east across the central Conus,
and subtropical ridge east of the area supporting anomalously moist
conditions across the forecast area, although guidance indicates
some decrease in mean 1000-500 mb RH. Short term guidance also sets
up a weak surface trough across the forecast area, which could
provide a focus for diurnal convective initiation, in addition to
the usual terrain effects. Thus, another day of above-climo PoPs is
warranted, with 50-60% chances peaking during the late afternoon in
most locations. The threats for a brief pulse severe storm or two
and locally excessive rainfall will otherwise persist.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 145 PM EDT Monday: Midlevel ridging persists through Wednesday
before weakening on Thursday as the upper low previously situated
over the Ozarks meanders northeastward.  As it does so, it loses
much of its veracity and phases with a developing trough over
Canada, and with a fairly relaxed height gradient it will be tough
to get significant synoptic forcing. Meanwhile, at the surface,
southerly flow continues as a consequence of the stationary Bermuda
High over the west Atlantic. Late Thursday, the global models hint
that it will begin creeping southeastward, but this should not
hinder continued southerly flow from pumping Gulf moisture into the
low-levels.  So, where earlier in the week profiles look to be near-
saturated through much of the troposphere, midlevels will begin to
dry out starting Thursday as mid/upper flow veers more west-
southwesterly. The area of 2"+ PWATs will push eastward
following the best synoptic environment, and our CWA will see
slowly diminishing PWATs after Thursday morning.

Nonetheless, we'll be looking at rain chances through end of the
short term - scattered showers all day Wednesday and into Thursday,
with the potential once again for some afternoon pulse storms in the
presence of modest surface instability.  It's looking as though the
threat of heavy rain could continue into Thursday owing to
stationary storm cells, with PWATs lingering in the ~1.5" vicinity
and background winds struggling to pick up the pace.  Luckily, in
line with what we've seen thus far this week and this past weekend,
the flooding threat should remain highly localized.

Temps should climb from at- or slightly above-normal on Wednesday,
to at least 2-3 degrees above normal on Thursday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
As of 200 PM EDT Monday: On Friday, the trough over the northeastern
CONUS prompts development of a weak low pressure system over the
Ohio Valley.  The warm frontal boundary should keep well to our
north, though it should aid in maintaining PoPs late Friday and
early Saturday.  A weak attendant cold front pushes through the CWA
on Saturday, and flow at least briefly turns northwesterly.  The
approach of a second upper feature - a shortwave that attempts to
skirt the broader trough - complicates matters, potentially inducing
additional rainfall past Saturday.  Models remain in poor agreement,
however - with the GFS and ECMWF pushing for more rain, while the
CMC allows the shortwave to simply fade into the background flow as
dry, high pressure filters into the CWA on Sunday.  For now, have
kept chance PoPs in the grids through the end of the extended.

Highs should remain a degree or two above normal through Saturday.
They'll likely drop on Sunday behind Saturday's cold front, but
certainty is low for not on the details.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Convection is blossoming across the Terminal
Forecast Area this afternoon, and tempos for TSRA are warranted at
all sites. Coverage of convection should steadily diminish and/or
move east this evening, but coverage should remain high enough to
warrant VCSH through at least late evening. Statistical guidance is
in good agreement in developing widespread IFR, or even LIFR
conditions (primarily cigs) late tonight into early Tuesday, and
this trend is reflected in the latest forecast. Scattered convection
should begin firing by the end of this forecast cycle, and Prob30s
for TSRA are advertised at all sites during Tue afternoon.

Outlook: Scattered to numerous, mainly diurnal convective coverage
and associated restrictions persist through much of the week.
Morning fog/stratus are also possible, especially in the mountain
valleys.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High  93%     High  81%     High  85%
KGSP       High  97%     High  88%     Med   75%     High  87%
KAVL       High  91%     High  86%     Med   64%     Med   70%
KHKY       High 100%     High  95%     Med   73%     High  85%
KGMU       Med   69%     High  80%     High  83%     High  84%
KAND       Med   77%     High  87%     High  89%     High  92%

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...MPR
NEAR TERM...JDL
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...JDL

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
344 AM EDT Mon Jun 7 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-080745-
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-
344 AM EDT Mon Jun 7 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 can be expected again today. The
main impacts are cloud-to-ground lightning and heavy downpours.
Isolated flash flooding is possible with any slow moving storm that
produces locally heavy rainfall.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
236 PM EDT Mon Jun 7 2021

SCZ007-008-013-071900-
Cherokee SC-Union SC-Spartanburg SC-
236 PM EDT Mon Jun 7 2021

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL SPARTANBURG...
CHEROKEE AND NORTHWESTERN UNION COUNTIES UNTIL 300 PM EDT...

At 235 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles southeast of Spartanburg, or near Pacolet, moving northeast at
20 mph.

Locations to be impacted include...
Gaffney, Pacolet, Cowpens, Jonesville, Pacolet Mills, Croft State
Park, Cherokee Falls, Draytonville and Thicketty.

Wind gusts up to 40 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.

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 3477 8173 3487 8191 3518 8173 3518 8170
      3506 8146 3505 8145 3505 8147 3503 8149
      3502 8148
TIME...MOT...LOC 1835Z 212DEG 15KT 3488 8178

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
300 PM EDT Mon Jun 7 2021

NCZ056-068-069-502-504-508-071930-
Greater Rutherford NC-Cleveland NC-Lincoln NC-Greater Burke NC-
Greater Caldwell NC-Catawba NC-
300 PM EDT Mon Jun 7 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN CATAWBA...
NORTHEASTERN RUTHERFORD...NORTHWESTERN LINCOLN...SOUTHEASTERN
CALDWELL...NORTHWESTERN CLEVELAND AND SOUTHEASTERN BURKE COUNTIES
UNTIL 330 PM EDT...

At 300 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles south of Morganton, or near South Mountains State Park, moving
northeast at 30 mph.

Locations to be impacted include...
Hickory, Longview, Sawmills, Granite Falls, Valdese, Icard,
Hildebran, Connelly Springs, Rutherford College and Rhodhiss.

Wind gusts up to 40 mph, pea size hail 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 3544 8170 3560 8178 3587 8146 3556 8123
TIME...MOT...LOC 1900Z 231DEG 24KT 3558 8164

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
320 PM EDT Mon Jun 7 2021

SCZ007-071945-
Spartanburg SC-
320 PM EDT Mon Jun 7 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHERN SPARTANBURG COUNTY
UNTIL 345 PM EDT...

At 320 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles west of Spartanburg, or near Reidville, moving northeast at 15
mph.

Locations to be impacted include...
Spartanburg, Boiling Springs SC, Duncan, Lyman, Wellford, Inman,
Roebuck, Reidville, GSP Airport and Moore.

Wind gusts up to 35 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 3478 8213 3478 8215 3488 8223 3489 8222
      3495 8222 3512 8202 3490 8183 3476 8213
TIME...MOT...LOC 1920Z 234DEG 13KT 3490 8213

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
325 PM EDT Mon Jun 7 2021

NCZ035-056-502-504-072000-
Greater Burke NC-Greater Caldwell NC-Alexander NC-Catawba NC-
325 PM EDT Mon Jun 7 2021

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT CENTRAL
CATAWBA...WESTERN ALEXANDER...SOUTHEASTERN CALDWELL AND SOUTHEASTERN
BURKE COUNTIES UNTIL 400 PM EDT...

At 325 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 6 miles west of Hickory, or over Icard, moving
northeast at 30 mph.

Locations to be impacted include...
Hickory, Taylorsville, Newton, St. Stephens, Conover, Longview,
Sawmills, Granite Falls, Valdese and Bethlehem.

In addition to intense lightning, wind gusts up to 40 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.

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 3601 8125 3581 8108 3580 8108 3578 8111
      3577 8110 3577 8109 3575 8109 3560 8145
      3574 8159
TIME...MOT...LOC 1925Z 232DEG 25KT 3573 8145

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
331 PM EDT Mon Jun 7 2021

NCZ056-069-070-072000-
Gaston NC-Lincoln NC-Catawba NC-
331 PM EDT Mon Jun 7 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CATAWBA...LINCOLN
AND NORTHWESTERN GASTON COUNTIES UNTIL 400 PM EDT...

At 331 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles west of Lincolnton, moving northeast at 35 mph.

Locations to be impacted include...
Newton, Lincolnton, Cherryville, Maiden, Westport, Catawba, High
Shoals, Boger City, Iron Station and Denver.

Wind gusts up to 40 mph and very heavy rainfall rates up to 1 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 3571 8106 3571 8102 3551 8096 3550 8096
      3549 8095 3545 8094 3543 8096 3541 8096
      3538 8138 3554 8148 3575 8108
TIME...MOT...LOC 1931Z 243DEG 30KT 3550 8135

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
333 PM EDT Mon Jun 7 2021

NCZ068-070-SCZ008-009-072000-
Gaston NC-Cleveland NC-York SC-Cherokee SC-
333 PM EDT Mon Jun 7 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CLEVELAND...
GASTON...NORTHWESTERN YORK AND NORTHEASTERN CHEROKEE COUNTIES UNTIL
400 PM EDT...

At 333 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles east of Gaffney, or near Blacksburg, moving northeast at 20
mph.

Locations to be impacted include...
Gastonia, Kings Mountain, Mt Holly, Belmont, Cherryville, Bessemer
City, South Gastonia, Clover, Dallas and Stanley.

Wind gusts up to 40 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.

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 3535 8097 3534 8099 3533 8098 3527 8102
      3525 8101 3497 8144 3511 8159 3542 8139
      3542 8130 3535 8094
TIME...MOT...LOC 1933Z 225DEG 18KT 3511 8146

HG