Flash Flood Warning 74, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
333 AM EST Thu Nov 12 2020

.SYNOPSIS...
A slow moving cold front is expected to move across the region
today providing a focus for additional showers and storms. The
front should move off to the east tonight, followed by dry air
moving in from the west on Friday. High pressure moving past to
the north should control our weather for most of the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Thursday: A leading shortwave trough exiting a broad
longwave 500 mb trough across the central CONUS will produce strong
upper divergence atop the forecast area thru this morning. The
mid and upper level support will be coupled with a slow-moving
cold front, which has already push into the NC mountains and will
continue to advance east thru the day. PWATs are still running at
record levels along and ahead of the front. And forecast soundings
show very deep warm cloud layers and unidirectional flow that
supports training convection. All this to say that the flood
threat is probably at its highest over the next 6-8 hours or so,
especially along and east of the Blue Ridge Escarpment. No changes
were made to the Flood Watch with this update, but some of the
counties in the western and central NC mountains may be able to be
canceled with the next update. As a frontal band of heavy showers
(and possibly some isolated embedded tstms) will set up over the
I-77 corridor right around daybreak. Guidance shows an additional
1-3", with locally higher amounts.

Around noon...the heaviest convection should begin to exit to our
east, with Union County, NC, being the last to clear out. Low-level
flow behind the front will be fairly weak, and forecast soundings
show low clouds stubbornly holding on thru the aftn. The exceptions
will be in the western mountains and the Upper Savannah Valley,
which could see more sunshine before sunset. Temps will be tricky,
as too many breaks in the clouds could allow temps to shoot
up several degrees warmer than the current forecast. For now,
think they will range from the lower 70s northeast to upper 70s
southwest. Dewpts will come down from the lower 70s to mid 60s,
so it will still feel fairly humid.

Tonight...dry air continues to filter in from the west, but
low-level moisture lingers. It could be a good fog night for some
areas, but high pressure building in from the west and T.C. Eta
tracking along the GA/SC coast will keep a pressure gradient
atop the area. So still think it will be more of a low stratus
deck that forms with patchy fog, rather than widespread dense
fog tonight. Temps will start falling like usual around sunset,
but may not get below our record high minimums at any of our
climate sites before midnight. Lows will be mainly in the 50s,
still about 14-18 deg above normal.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 138 AM EST Thursday: Autumn is on track to return to the
western Carolinas and northeast Georgia for the weekend. The
moisture gradient should be across the fcst area at daybreak Friday
and is expected to push east during the day with a modest WNW flow
at 850mb, ushering in the dry air associated with high pressure to
our west. A flat upper ridge will carry that surface high past to
the north through Saturday, giving us a classic autumn day with
temperatures right around normal. The high will migrate off the
Mid-Atlantic coast Saturday night, with some weak moisture return by
daybreak Sunday. Think the guidance is a little premature suggesting
that some upslope light precip might develop around daybreak Sunday
near the Escarpment. Prefer to keep the fcst dry for now.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 321 AM EST Thursday: A broad upper trof moving east across
the Plains will push a cold front in our direction on Sunday, but
forcing and moisture return looks minimal. Guidance was generally
accepted with a chance of showers ramping up over the mtns/foothills
through the afternoon. The front should move quickly through the
region given such a low amplitude upper pattern, so we dry out
again Sunday night as the upper trof axis moves past. After that,
high pressure will build in from the west and dominate through
Tuesday, before a dry reinforcing front moves through followed
by the next surface high building in from the NW for the rest of
the period. Temperatures will be on the order of a category below
normal for most of the period.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: A slow-moving cold front is interacting
with a very moist, tropical air mass across the area to start
the 06z TAFs. Periods of heavy rain showers and isolated tstms
possible at all sites thru 12z, then a gradual shift from west to
east from 12-18z time frame. Drying takes over after 18z, but not
enough to scour out the low cigs, which look to remain generally
IFR to MVFR. The low cigs will likely persist tonight as well, with
guidance showing LIFR possible east of the mountains overnight. The
frontal passage will bring winds around from a light S/SW to N/NE,
clearing KCLT around 17z. There is some hint in the guidance that
winds may become light enough to allow fog to form, but overall,
it looks mostly like a stratus event tonight.

Outlook: Dry high pressure will finally build in Friday, scouring
out the low clouds and any fog that's around Friday morning,
bringing back mostly VFR conditions thru the weekend.

Confidence Table...

            08-14Z        14-20Z        20-02Z        02-06Z
KCLT       High  81%     High  81%     Med   78%     High  81%
KGSP       Med   78%     Med   70%     High  87%     Med   64%
KAVL       Med   79%     Med   74%     Med   78%     High  84%
KHKY       High  80%     Med   67%     Med   70%     Med   71%
KGMU       Med   78%     Med   70%     High  85%     Low   52%
KAND       Med   78%     Med   74%     High  86%     Med   66%

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

&&

.CLIMATE...
              MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      77 1890     35 1968     56 1929     16 1894
                            1934
   KCLT      81 1989     43 1894     61 1915     24 1894
   KGSP      81 1989     43 1968     58 1935     19 1913

RECORDS FOR 11-13

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      75 1964     32 1906     58 1929     13 1911
                1958
                1938
   KCLT      81 1931     40 1920     63 1879     21 2013
   KGSP      81 1909     40 1920     61 1929     20 1906

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Flood Watch through this evening for GAZ010.
NC...Flood Watch through this evening for NCZ033-035>037-048>053-
     056>059-062>065-068>072-082-501>510.
SC...Flood Watch through this evening for SCZ001>003-005>009-
     012>014.

&&

SYNOPSIS...PM
NEAR TERM...ARK
SHORT TERM...PM
LONG TERM...PM
AVIATION...ARK
CLIMATE...

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
547 AM EST Thu Nov 12 2020

NCZ033-035>037-049-050-053-056-057-064-065-068>072-082-501>510-
SCZ003-006>009-012>014-131100-
Avery-Alexander-Iredell-Davie-Yancey-Mitchell-Buncombe-Catawba-Rowan-
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-
Greenville Mountains-Greater Greenville-Spartanburg-Cherokee-York-
Laurens-Union SC-Chester-
547 AM EST Thu Nov 12 2020

...FLOOD WATCH IN EFFECT THROUGH THIS EVENING...

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

.DAY ONE...Today and tonight.

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

   Flood Watch.

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

Hazardous weather is not 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.

GAZ010-017-018-026-NCZ048-051-052-058-059-062-063-SCZ001-002-004-005-
131100-
Rabun-Habersham-Stephens-Franklin-Madison-Swain-Haywood-Graham-
Northern Jackson-Macon-Southern Jackson-Oconee Mountains-
Pickens Mountains-Greater Oconee-Greater Pickens-
547 AM EST Thu Nov 12 2020

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

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

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

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ028-029-SCZ010-011-019-131100-
Hart-Elbert-Anderson-Abbeville-Greenwood-
547 AM EST Thu Nov 12 2020

This Hazardous Weather Outlook is for northeast Georgia and upstate
South Carolina.

.DAY ONE...Today and tonight.

Showers and a few thunderstorms are expected this morning. The main
threats will be heavy rain that may result in localized flash
flooding, and a few cloud-to-ground lightning strikes. The showers
and storms should move to the east by early afternoon.

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

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
452 AM EST THU NOV 12 2020

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

0447 AM     FLASH FLOOD      4 NNW PATTERSON         36.04N 81.60W
11/12/2020                   CALDWELL           NC   COUNTY OFFICIAL

            HEAVY RAINFALL CREATED A LANDSLIDE 30 FEET WIDE AND 2
            FEET DEEP. THE LANDSLIDE HAS COVERED AND CLOSED KIRBY
            MOUNTAIN ROAD NEAR HIGHWAY 321. SEVERAL OTHER ROADS
            ACROSS THE COUNTY HAVE ALSO BEEN CLOSED DUE TO FLOODING.

&&

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
631 AM EST Thu Nov 12 2020

SCZ012-013-121230-
Laurens SC-Union SC-
631 AM EST Thu Nov 12 2020

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN LAURENS AND UNION
COUNTIES UNTIL 730 AM EST...

At 630 AM EST, Doppler radar was tracking a strong thunderstorm 13
miles southeast of Laurens, or 5 miles northeast of Cross Hill,
moving northeast at 25 mph.

Locations to be impacted include...
Union, Clinton, Monarch Mill, Joanna, Buffalo, Jonesville, Cross
Hill, Carlisle, Rose Hill State Park and Lake Greenwood.

Wind gusts up to 40 mph and very heavy rainfall rates up to 2 inches
per hour will be possible in these areas. If the rain continues, a
Flood Warning may be issued for all or part of the area.

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 3428 8205 3460 8185 3484 8178 3491 8171
      3490 8165 3488 8163 3489 8159 3486 8148
      3483 8146 3482 8149 3476 8146 3473 8149
      3472 8146 3460 8142 3449 8147 3445 8154
      3453 8164 3437 8178 3430 8190 3421 8194
TIME...MOT...LOC 1130Z 212DEG 21KT 3434 8190

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