Flash Flood and Damaging Wind in North Carolina, August 6, 2020

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
736 PM EDT Thu Aug 6 2020

.SYNOPSIS...
Passing upper-level disturbances will produce greater than
typical coverage of showers and thunderstorms through Friday. A
return to more typical isolated to scattered summertime thunderstorm
activity is expected over the weekend as weak drying arrives from
the west. Moisture will gradually return late in the weekend through
the middle of next week to support a more active pattern once again.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 735 PM Thursday: Convective coverage will remain high across
the mountains and I-40 corridor this evening, with lower coverage
elsewhere. While a strong to severe storm is possible, flooding will
be a bigger threat as echoes train over the same areas, especially
where coverage is better.

Persistence will be the rule for the weather and the forecast of
the same for the next 24 hours as the upper trof axis remains in
place to our west. Just like last night, we may keep showery precip
around parts of the forecast area for the better part of the tonight
period before it finally wanes in the pre-dawn hours. On Friday,
more of the same. Looks to be a similar pattern to morning low
clouds and fog, which could delay onset outside of the mountains.
The fcst looks the same in terms of coverage that will go beyond
climo in the afternoon. The environment should be conducive to a few
pulse severe storms again as well, with sfc-based CAPE in the 2000 -
3000 J/kg range and sfc-delta Theta-e above 30 deg. Temps will be
near normal as well.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 1230 pm EDT Thursday: Deeper moisture and higher PWAT values
will be displaced off to our east this weekend as weak upper trough
axis translates east and fills.  Essentially, for the upcoming
weekend, wx conds are expected to be pretty typical of early August,
featuring a developing weaker flow regime, and seasonable humidity
levels.  Dirunally fired deeper convective chances will be close to
climo values with piedmont maximum apparent temperatures approaching
95 each day.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 100 pm EDT Thursday: Still expectimg a weak westerly flow
regime with embedded weak s/wv's rippling thru to exist atop the SE
CONUS to start off the work week.  PWAT progs starting on Monday
depict a moisting trend after a weekend featuring below climo values.
Despite limited Gulf moisture fetch, expecting a daily uptick in
diurnal PoPs for showers and thunderstorms each day.

PoPs may increase further above climo Wednesday and Thursday as
moisture begins to pool over the region as a frontal boundary lays
out across the Mid-Atlantic to the north. Anticipate plenty of lower
90s Piedmont to upper 80s mountain valley max temperatures each
afternoon, with mins a degree or so above climo through the period.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
At KCLT and Elsewhere: Thunderstorms continue near some TAF sites
and will develop near the others this evening, so have adjusted the
TEMPOs for this. Convection should begin winding down around
midnight and end overnight. That said, some showers could linger.
Otherwise, expect another round of MVFR to IFR cigs, with LIFR or
VLIFR possible in some locations. Vsby should generally be MVFR
outside of the mountains, but IFR possible. KAVL should have the
lowest vsby with LIFR likely and VLIFR possible. Expect another slow
improvement after daybreak with vsby improving quickly but cigs
slowly rising to VFR and/or scattering out around noon. Looks to be
a relatively quick start to convection over the mountains with a
slightly slower start elsewhere, so have adjusted PROB30s for that
scenario. Winds will be anywhere from SW to SE, except gusty in
storms, as outflow boundaries traverse the area. Light and variable
wind overnight. S to SW wind expected during the afternoon.

Outlook: Coverage of thunderstorms will be more isolated to
scattered during the afternoon and evening over the weekend. Morning
fog/stratus restrictions will also be possible, especially over
the usual mountain valleys. Diurnal storms will become more likely
again from Monday onward.

Confidence Table...

            23-05Z        05-11Z        11-17Z        17-18Z
KCLT       High 100%     High 100%     High  86%     High 100%
KGSP       High 100%     High 100%     Low   53%     High 100%
KAVL       High 100%     High  95%     Med   77%     High 100%
KHKY       High 100%     Med   79%     Med   68%     High 100%
KGMU       High 100%     High 100%     Low   48%     High 100%
KAND       High 100%     High 100%     Low   48%     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...CSH
NEAR TERM...PM/RWH
SHORT TERM...CSH
LONG TERM...CSH
AVIATION...RWH

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
408 AM EDT Thu Aug 6 2020

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-070815-
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-
408 AM EDT Thu Aug 6 2020

This Hazardous Weather Outlook is for northeast Georgia, Piedmont
North Carolina, western North Carolina and Upstate South Carolina.

.DAY ONE...Today and tonight.

Numerous thunderstorms are expected to develop across the region this
afternoon and evening, with the most widespread coverage likely
occurring across western North Carolina. Any of these thunderstorms
will be capable of producing dangerous lightning, gusty winds, and
torrential downpours. Some of these storms may become severe, with
damaging wind gusts being the primary threat. Any locations
repeatedly affected by thunderstorms over a short period of time will
be prone to localized flash flooding from the heavy rainfall.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
811 PM EDT Thu Aug 6 2020

NCZ053-065-070045-
Buncombe NC-Henderson NC-
811 PM EDT Thu Aug 6 2020

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL HENDERSON AND
SOUTHEASTERN BUNCOMBE COUNTIES UNTIL 845 PM EDT...

At 811 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles north of Hendersonville, or near Fairview In Buncombe County.
This storm was nearly stationary.

Locations to be impacted include...
Fairview In Buncombe County and Gerton.

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.

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 3542 8238 3543 8244 3553 8245 3551 8232
TIME...MOT...LOC 0011Z 199DEG 4KT 3547 8240

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
820 PM EDT Thu Aug 6 2020

NCZ036-056-057-069-070045-
Rowan NC-Iredell NC-Lincoln NC-Catawba NC-
820 PM EDT Thu Aug 6 2020

...STRONG THUNDERSTORMS WILL IMPACT SOUTHEASTERN CATAWBA...SOUTHERN
IREDELL...NORTHEASTERN LINCOLN AND ROWAN COUNTIES UNTIL 845 PM EDT...

At 818 PM EDT, Doppler radar was tracking a strong thunderstorms
between Hickory and Salisbury moving southeast at 25 mph.

Locations to be impacted include...
Salisbury, Newton, Lincolnton, Hickory, Statesville, Mooresville,
Conover, China Grove, Maiden and Spencer.

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.

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 3557 8021 3551 8080 3551 8091 3549 8094
      3546 8123 3572 8135 3580 8055 3578 8051
      3578 8048 3573 8045 3571 8032 3568 8033
      3567 8031 3563 8029 3561 8024
TIME...MOT...LOC 0018Z 324DEG 25KT 3559 8064

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
833 PM EDT Thu Aug 6 2020

NCZ035-056-068-069-501-502-504-508-070130-
Greater Rutherford NC-Caldwell Mountains NC-Cleveland NC-Lincoln NC-
Greater Burke NC-Greater Caldwell NC-Alexander NC-Catawba NC-
833 PM EDT Thu Aug 6 2020

...STRONG THUNDERSTORMS WILL IMPACT WESTERN CATAWBA...NORTHEASTERN
RUTHERFORD...WESTERN ALEXANDER...WESTERN LINCOLN...CALDWELL...CENTRAL
CLEVELAND AND BURKE COUNTIES UNTIL 930 PM EDT...

At 833 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 8 miles northwest of Lenoir to 6 miles east of
Forest City, and moving northeast at 35 mph.

Locations to be impacted include...
Lenoir, Morganton, Forest City, Hickory, Longview, Sawmills, Granite
Falls, Valdese, Gamewell and Hudson.

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.

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 3610 8152 3609 8145 3607 8144 3607 8141
      3604 8139 3604 8137 3600 8133 3602 8127
      3542 8141 3542 8146 3538 8142 3533 8143
      3532 8191 3612 8164 3612 8155
TIME...MOT...LOC 0033Z 245DEG 30KT 3600 8163 3531 8175

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
926 PM EDT Thu Aug 6 2020

GAZ017-070200-
Habersham GA-
926 PM EDT Thu Aug 6 2020

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN HABERSHAM COUNTY
UNTIL 1000 PM EDT...

At 926 PM EDT, Doppler radar was tracking a strong thunderstorm 4
miles southwest of Clarkesville, or near Demorest, moving east at 20
mph.

Locations to be impacted include...
Clarkesville, Cornelia, Baldwin, Demorest, Mount Airy, Alto, Raoul
and Hollywood.

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.

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 3462 8364 3463 8364 3469 8345 3457 8342
      3453 8344 3449 8351 3449 8355 3445 8358
      3444 8361 3453 8363 3454 8362 3455 8362
      3458 8364 3461 8365
TIME...MOT...LOC 0126Z 252DEG 16KT 3456 8356

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
933 PM EDT Thu Aug 6 2020

NCZ056-068-069-504-070200-
Cleveland NC-Lincoln NC-Greater Burke NC-Catawba NC-
933 PM EDT Thu Aug 6 2020

...STRONG THUNDERSTORMS WITH INTENSE LIGHTNING WILL IMPACT
SOUTHWESTERN CATAWBA...NORTHWESTERN LINCOLN...NORTH CENTRAL CLEVELAND
AND SOUTHEASTERN BURKE COUNTIES UNTIL 1000 PM EDT...

At 932 PM EDT, Doppler radar was tracking a cluster of strong thunderstorms
with intense lightning 13 miles southwest of Hickory, or 7 miles northeast
of Belwood, moving east at 10 mph.

Locations to be impacted include...
Maiden, Icard, Hildebran, Mountain View, Connelly Springs, Belwood,
Startown, Cooksville, Propst and Vale.

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...

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.

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 3544 8144 3557 8163 3576 8149 3560 8116
TIME...MOT...LOC 0132Z 251DEG 4KT 3557 8146

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1012 PM EDT Thu Aug 6 2020

NCZ036-068>072-508-070245-
Greater Rutherford NC-Gaston NC-Iredell NC-Cleveland NC-Lincoln NC-
Cabarrus NC-Mecklenburg NC-
1012 PM EDT Thu Aug 6 2020

...STRONG THUNDERSTORMS WILL IMPACT NORTHWESTERN CABARRUS...EAST
CENTRAL RUTHERFORD...SOUTH CENTRAL IREDELL...LINCOLN...NORTHWESTERN
MECKLENBURG...CENTRAL CLEVELAND AND NORTHERN GASTON COUNTIES UNTIL
1045 PM EDT...

At 1012 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 6 miles north of Huntersville to 11 miles
northwest of Shelby, and moving south at 10 mph.

Locations to be impacted include...
Huntersville, Shelby, Lincolnton, Cornelius, Davidson, Cherryville,
Stanley, Westport, Belwood and High Shoals.

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 3537 8069 3527 8171 3546 8177 3556 8079
TIME...MOT...LOC 0212Z 342DEG 7KT 3550 8081 3541 8167

KRENTZ