Flash Flood Warning 50, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
252 PM EDT Sat Aug 15 2020

.SYNOPSIS...
Showers and thunderstorms will diminish overnight tonight.
Thunderstorm chances will return to more typical levels for Sunday
and Monday, then increase through the week as an upper level trough
becomes well established. Highs will be around normal through the
first part of the week then fall below normal.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 245 PM EDT Saturday: A Flash Flood Watch remains in effect for
portions of North Carolina through tonight.

With upper troughing moving overhead the western fringes of the
Southeast and developing sfc feature near the area, showers and
thunderstorms continue to blossom in coverage as they move from SW
to ENE across the FA ahead of an approaching front as seen from
latest radar imagery, with a noticeable uptick in lightning over the
past hour. Rainfall rates through much of the morning hours were
fairly light in nature, but latest precip rates indicate an
increasing trend with even local rivers/streams slowly beginning to
respond. While gusty winds cannot be entirely ruled out in stronger
storms, the primary threat will be heavy downpours and flooding
through this evening with plenty of available forcing and moisture
in place (PWATs around 2 inches) and already saturated soils given
recent rainfall. Isolated flash flooding will be possible, but
confidence is low given decent storm motion. Current temperatures
range from the low to mid 70s to lower 80s attm, with variations
expected given rain-cooled air in many locations.

Expect activity to wane tonight with lingering light showers
possible overnight as the sfc low and trailing cold front slowly
push through the area and upper troughing moves overhead. While
patchy fog will be possible given light winds and saturated soils,
expect low stratus to be the main concern overnight per latest fcst
soundings. Guidance continues to suggest low clouds lingering
through mid Sunday morning at the latest as drier air gradually
makes it's way into the area with NW flow. Min temps will drop to
around normal.

Despite the slow infiltration of drier air in the wake of the
exiting system, lingering available moisture and instability will
warrant the potential for isolated convection once again Sunday.
Otherwise, expect a mixture of sunshine and clouds with max
temperatures falling a few degrees short of normal.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 2pm EDT Saturday:  Weather Monday and Tuesday is largely the
result of a longwave trough over the eastern CONUS, with a southern
extent over the GSP CWA.  This far south, dynamical factors are
somewhat weak, but a frontal boundary is expected to pass through
the area from northwest to southeast on Monday, with an enhanced
chance for precipitation as it passes, and a reduction behind it as
moisture is reduced.  Showers on Monday may be more confined to
piedmont areas where the front may better interact with moisture,
while on Tuesday, what showers that manage to form will be more
likely over the mountains where elevated surface heating has a
better chance of breaking the cap. MLCAPE will be weak on Monday
behind the previous front, and confined to piedmont areas, by
Tuesday afternoon behind the next front, it will be even weaker at
below 400 j/kg.  Longwave pattern is expected to help temperatures
to remain just below climo, and notably below recent weeks.  With
still weak dynamics at play, surface features are poorly defined,
and winds are expected to remain light, outside of outflows from
storms.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
As of 2pm EDT Saturday:  Longwave eastern trough gives way
Wednesday/Thursday as northern extent pulls out, being replaced by
some ridging east of the continent and, relevant to GSP, a shortwave
trough over the Southern Mississippi basin.  This trough will help
to maintain and increase moisture back up to sub-tropical levels,
and keep a chance for afternoon thunderstorms in the forecast for
Wednesday onward. GFS surface forecast gains 4 degrees in dewpoint
on Wednesday, regaining the moisture lost on Tuesday. The GFS model
brings the southwest shortwave across the area earlier than the EC,
with Saturday afternoon being a respite from afternoon
thunderstorms, if it is correct. Seasonally weak synoptic features
will lead to near normal temperatures and light winds through the
extended forecast.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
At KCLT and Elsewhere: Expect scattered to widespread showers and
thunderstorms to continue across the area through the rest of today
and into this evening, which will bring periods of flight
restrictions to TAF sites due to heavy downpours/patchy fog and
lowered cigs, as noted by TEMPO groups. Expect a majority of the
activity to wane into tonight, with a few lingering showers possible
overnight. While patchy fog will be possible especially given
saturated soils, latest fcst soundings continue to suggest low cigs
to be the primary concern for some TAF sites with MVFR/IFR/possible
LIFR overnight. Cigs may be gradual to lift Sunday morning, thus
have kept with VFR/MVFR trend. Winds will remain light overall, with
brief gusty winds possible in any stronger storms.

Outlook: Isolated to widely scattered tstms expected Sunday and
Monday. An uptick in thunderstorm coverage is then likely Tuesday
through Wednesday. Fog and low stratus restrictions will be possible
each morning, especially over the usual mountain valleys. Otherwise
expect VFR.

Confidence Table...

            19-01Z        01-07Z        07-13Z        13-18Z
KCLT       High  99%     Med   79%     Med   74%     Med   79%
KGSP       High  94%     High  97%     Med   76%     Med   78%
KAVL       High  91%     High  81%     Low   46%     High  80%
KHKY       Med   69%     Low   53%     Med   69%     Med   74%
KGMU       High  95%     High  99%     Med   70%     Med   75%
KAND       High  95%     High 100%     Med   67%     Med   72%

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...Flash Flood Watch until midnight EDT tonight for NCZ033-
     035>037-056-057-501>506.
SC...None.

&&

SYNOPSIS...DEO
NEAR TERM...12
SHORT TERM...WJM
LONG TERM...WJM
AVIATION...12

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
336 PM EDT Sat Aug 15 2020

GAZ010-017-018-026-028-029-NCZ048>053-058-059-062>065-068>072-082-
507>510-SCZ001>014-019-161945-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Madison-Yancey-
Mitchell-Swain-Haywood-Buncombe-Graham-Northern Jackson-Macon-
Southern Jackson-Transylvania-Henderson-Cleveland-Lincoln-Gaston-
Mecklenburg-Cabarrus-Union NC-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-
336 PM EDT Sat Aug 15 2020

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

.DAY ONE...This afternoon and tonight.

Widespread showers and thunderstorms will continue to develop across
the region through the evening hours. The primary threats with these
storms will be cloud-to-ground lightning and locally heavy rainfall.
The storms and heavy rain showers will occasionally become
stationary, posing a threat of excessive rainfall and flash flooding,
especially in locations that have received heavy rainfall over the
past few days.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ033-035>037-056-057-501>506-161945-
Avery-Alexander-Iredell-Davie-Catawba-Rowan-Caldwell Mountains-
Greater Caldwell-Burke Mountains-Greater Burke-McDowell Mountains-
Eastern McDowell-
336 PM EDT Sat Aug 15 2020

...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT EDT TONIGHT...

This Hazardous Weather Outlook is for piedmont North Carolina and
western North Carolina.

.DAY ONE...This afternoon and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

 Flash Flood Watch.

Widespread thunderstorms can produce cloud-to-
ground lightning and occasional gusty winds.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

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.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
423 PM EDT Sat Aug 15 2020

GAZ029-SCZ006-010>012-019-152100-
Elbert GA-Laurens SC-Anderson SC-Abbeville SC-Greenwood SC-
Greater Greenville SC-
423 PM EDT Sat Aug 15 2020

...STRONG THUNDERSTORMS WILL IMPACT SOUTHEASTERN ELBERT...WESTERN
LAURENS...SOUTHEASTERN GREENVILLE...SOUTHEASTERN ANDERSON...ABBEVILLE
AND WESTERN GREENWOOD COUNTIES UNTIL 500 PM EDT...

At 423 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 13 miles east of Anderson to 13 miles north of
Washington, and moving east at 30 mph.

Locations to be impacted include...
Abbeville, Belton, Honea Path, Ware Shoals, Calhoun Falls, Due West,
Gray Court, Donalds, Cokesbury and Hodges.

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 3398 8261 3397 8264 3399 8265 3398 8267
      3457 8251 3469 8205 3401 8225 3397 8231
      3406 8233 3406 8244 3408 8248 3407 8250
      3407 8253 3401 8260 3399 8258 3396 8257
TIME...MOT...LOC 2023Z 253DEG 26KT 3459 8243 3391 8265

KRENTZ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
433 PM EDT SAT AUG 15 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0300 PM     DEBRIS FLOW            4 NE BAT CAVE           35.50N 82.24W
08/15/2020                   BUNCOMBE           NC   911 CALL CENTER

            911 CALL CENTER AND SOCIAL MEDIA REPORTED LANDSLIDE ON
            ROCK CREEK RD. OVER HALF OF THE ROADWAY WASHED AWAY.

&&

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
433 PM EDT Sat Aug 15 2020

NCZ068-508-152100-
Greater Rutherford NC-Cleveland NC-
433 PM EDT Sat Aug 15 2020

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN RUTHERFORD AND
SOUTHWESTERN CLEVELAND COUNTIES UNTIL 500 PM EDT...

At 433 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles east of Forest City, or near Ellenboro, moving east at 15 mph.

Locations to be impacted include...
Shelby, Forest City, Boiling Springs NC, Lawndale, Patterson Springs,
Fallston, Polkville, Ellenboro, Lattimore and Mooresboro.

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 3526 8189 3544 8180 3547 8150 3522 8151
TIME...MOT...LOC 2033Z 271DEG 15KT 3536 8171

KRENTZ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
454 PM EDT SAT AUG 15 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0420 PM     FLASH FLOOD      2 S DREXEL              35.74N 81.61W
08/15/2020                   BURKE              NC   BROADCAST MEDIA

            BROADCAST MEDIA REPORTED FLASH FLOOD ON THE
            INTERSECTION OF DREXEL AND COOK RD. DEBRIS BEING SWEPT ONTO THE
            ROADWAY FROM RUNNING WATER.

&&

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
459 PM EDT Sat Aug 15 2020

SCZ006-007-010>012-019-152130-
Laurens SC-Anderson SC-Abbeville SC-Greenwood SC-Spartanburg SC-
Greater Greenville SC-
459 PM EDT Sat Aug 15 2020

...STRONG THUNDERSTORMS WILL IMPACT LAURENS...SOUTHEASTERN
GREENVILLE...SOUTH CENTRAL SPARTANBURG...EAST CENTRAL ANDERSON...
EASTERN ABBEVILLE AND GREENWOOD COUNTIES UNTIL 530 PM EDT...

At 459 PM EDT, Doppler radar indicated strong thunderstorms along a
line extending from 13 miles west of Laurens to 8 miles south of
Abbeville, and moving east at 25 mph.

Locations to be impacted include...
Greenwood, Laurens, Abbeville, Honea Path, Ware Shoals, Ninety Six,
Due West, Gray Court, Cross Hill and Donalds.

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 3398 8205 3399 8210 3399 8215 3397 8218
      3399 8221 3402 8224 3397 8231 3406 8233
      3406 8244 3408 8247 3459 8238 3470 8185
      3422 8193 3421 8194 3419 8193 3402 8196
      3397 8201 3397 8204
TIME...MOT...LOC 2059Z 264DEG 20KT 3453 8227 3406 8235

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
504 PM EDT Sat Aug 15 2020

NCZ068-SCZ006>009-013-152130-
Cleveland NC-York SC-Cherokee SC-Union SC-Spartanburg SC-
Greater Greenville SC-
504 PM EDT Sat Aug 15 2020

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN CLEVELAND...EAST
CENTRAL GREENVILLE...SOUTHWESTERN YORK...SPARTANBURG...CHEROKEE AND
NORTHERN UNION COUNTIES UNTIL 530 PM EDT...

At 504 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles west of Spartanburg, or near Duncan, moving east at 25 mph.

Locations to be impacted include...
Spartanburg, Gaffney, Greer, Five Forks, Boiling Springs SC, Duncan,
Lyman, Pacolet, Cowpens and Wellford.

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.

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 3508 8222 3518 8177 3527 8145 3482 8143
      3482 8149 3479 8146 3476 8146 3476 8212
      3478 8215 3476 8216 3476 8227
TIME...MOT...LOC 2104Z 263DEG 20KT 3491 8210

KRENTZ