Alert archive / North Carolina / Flash Flood Warnings in 2020

Flash Flood Warning 71, NWS Greenville-Spartanburg, SC

November 12, 20208 counties in North Carolina

NWS Greenville-Spartanburg, SC issued this flash flood warning at Nov 12, 2020, 5:49 AM EST for 8 counties in North Carolina. It was in force for 5 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Nov 12, 2020, 5:49 AM EST (10:49 UTC)
Expired
Nov 12, 2020, 11:00 AM EST
In force
5 hr
Issued by
NWS Greenville-Spartanburg, SC
Area
Storm-based polygon
Flood severity
None

Counties Catawba County, NC, Cleveland County, NC, Davie County, NC, Gaston County, NC, Iredell County, NC, Lincoln County, NC, Mecklenburg County, NC, Rowan County, NC

The radar

The Greer radar (KGSP), 117 km from the middle of the area, began a volume at 10:52 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Nov 12, 8:30 AM ESTFLASH FLOODStatesville, NCREPORTS OF MULTIPLE FLOODED ROADS ACROSS THE COUNTY.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this flash flood warning; the first came 161 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 10.8 hours before the alert went out and 132 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Greensboro/Hi Pt, NC at 00:00Z on 2020-11-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 497 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Greensboro/Hi Pt, NC at 00:00Z on 2020-11-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 119 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
497 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
638 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
119 m²/s²
0-3 km storm-relative helicity
146 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.6

Open this sounding in Storm Lab

The text

As transmitted.

051 
WGUS52 KGSP 121049
FFWGSP
NCC035-045-059-071-097-109-119-159-121400-
/O.NEW.KGSP.FF.W.0071.201112T1049Z-201112T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
549 AM EST Thu Nov 12 2020

The National Weather Service in Greenville-Spartanburg has issued a

* Flash Flood Warning for...
  Eastern Catawba County in the piedmont of North Carolina...
  Southeastern Cleveland County in the piedmont of North Carolina...
  West Central Davie County in the piedmont of North Carolina...
  Gaston County in the piedmont of North Carolina...
  Iredell County in the piedmont of North Carolina...
  Lincoln County in the piedmont of North Carolina...
  Northwestern Mecklenburg County in the piedmont of North Carolina...
  Northwestern Rowan County in the piedmont of North Carolina...

* Until 900 AM EST.

* At 549 AM EST, Doppler radar indicated heavy rain across the 
  warned area. Between 1 and 2 inches of rain have fallen. Flash 
  flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* * Some locations that will experience flash flooding include...
  Gastonia, Huntersville, Statesville, Shelby, Newton, Lincolnton, 
  Cornelius, Mooresville, Kings Mountain, Mt Holly, Davidson, 
  Belmont, Conover, Cherryville, Bessemer City, South Gastonia, 
  Dallas, Maiden, Stanley and Cramerton.

Due to recent heavy rainfall and high stream levels, flooding 
conditions will be easier to reach with new rainfall amounts around 
2 inches.

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, country roads, farmland, and other low lying 
spots.

&&

LAT...LON 3545 8128 3551 8139 3593 8094 3586 8059
      3515 8114 3519 8167

FLASH FLOOD...RADAR INDICATED

$$

Krentz
1 follow-up statement
688 
WGUS52 KGSP 121327
FFWGSP
NCC035-045-059-071-097-109-119-159-121600-
/O.EXT.KGSP.FF.W.0071.000000T0000Z-201112T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
827 AM EST Thu Nov 12 2020

The National Weather Service in Greenville-Spartanburg has extended 
the

* Flash Flood Warning for...
  Eastern Catawba County in the piedmont of North Carolina...
  Southeastern Cleveland County in the piedmont of North Carolina...
  West Central Davie County in the piedmont of North Carolina...
  Gaston County in the piedmont of North Carolina...
  Iredell County in the piedmont of North Carolina...
  Lincoln County in the piedmont of North Carolina...
  Northwestern Mecklenburg County in the piedmont of North Carolina...
  Northwestern Rowan County in the piedmont of North Carolina...

* Until 1100 AM EST.

* At 827 AM EST, After widespread storm total rainfall amounts of 3 
  to 4 inches with locally higher amounts, excessive runoff will 
  continue this morning all across the warned area.  Numerous roads 
  remained flooded and motorists are urged to use caution while 
  traveling this morning!

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Emergency management.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Gastonia, Huntersville, Statesville, Shelby, Newton, Lincolnton, 
  Cornelius, Mooresville, Kings Mountain, Mt Holly, Davidson, 
  Belmont, Conover, Cherryville, Bessemer City, South Gastonia, 
  Dallas, Maiden, Stanley and Cramerton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3545 8128 3551 8139 3593 8094 3586 8059
      3515 8114 3519 8167

FLASH FLOOD...OBSERVED

$$

CSH

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Greenville-Spartanburg, SC wrote its last area forecast discussion before this flash flood warning went out at Nov 12, 3:33 AM EST, 2 hours 16 minutes earlier.

Area forecast discussion, Nov 12, 3:33 AM EST, 2 hours 16 minutes before
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, Nov 12, 5:47 AM EST, 2 minutes before
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.

In the hours before

Special weather statement, Nov 12, 12:01 AM EST, 5 hours 48 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1201 AM EST Thu Nov 12 2020

GAZ010-017-NCZ062-120545-
Rabun GA-Habersham GA-Macon NC-
1201 AM EST Thu Nov 12 2020

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT NORTH CENTRAL
HABERSHAM...RABUN AND SOUTHEASTERN MACON COUNTIES UNTIL 1245 AM
EST...

At 1200 AM EST, Doppler radar was tracking a thunderstorm with
torrential rainfall 6 miles northwest of Clayton, or 4 miles
northwest of Black Rock Mountain State Park, moving northeast at 30
mph.

Locations to be impacted include...
Clayton, Franklin, Highlands, Mountain City, Tiger, Dillard, Sky
Valley, Lake Burton, Black Rock Mountain State Park and Scaly
Mountain.

Very heavy rainfall rates up to 2 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3488 8366 3490 8363 3491 8363 3492 8360
      3494 8360 3495 8355 3499 8355 3500 8348
      3500 8352 3502 8352 3504 8355 3518 8342
      3508 8316 3506 8317 3504 8313 3502 8313
      3473 8357 3481 8366
TIME...MOT...LOC 0500Z 227DEG 27KT 3494 8348

KRENTZ
Local storm report, Nov 12, 4:52 AM EST, 57 minutes before
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

The office that day

Everything else NWS Greenville-Spartanburg, SC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 11, 7:08 PM ESTAreal Flood AdvisoryGSPDavie3 hr
Nov 11, 8:45 PM ESTSpecial Weather StatementGSPCleveland45 min
Nov 11, 9:15 PM ESTAreal Flood AdvisoryGSPCleveland3 hr
Nov 11, 9:50 PM ESTAreal Flood AdvisoryGSPCleveland, Gaston, Lincoln3 hr
Nov 12, 12:01 AM ESTSpecial Weather StatementGSPMacon44 min
Nov 12, 12:46 AM ESTAreal Flood AdvisoryGSPMacon3 hr
Nov 12, 3:12 AM ESTFlash Flood WarningGSPCaldwell112 min
Nov 12, 3:22 AM ESTAreal Flood AdvisoryGSPAlexander, Burke, Caldwell, Catawba, Cleveland, Henderson and 3 more3 hr
Nov 12, 3:45 AM ESTFlash Flood WarningGSPAlexander, Burke, Caldwell8 hr
Nov 12, 4:17 AM ESTFlash Flood WarningGSPAlexander, Burke, Caldwell, Catawba, Iredell, Lincoln6 hr
Nov 12, 5:04 AM ESTAreal Flood WarningGSPCaldwell5 hr
Nov 12, 5:14 AM ESTFlash Flood WarningGSPCleveland, Gaston, Lincoln, Polk, Rutherford3 hr
Nov 12, 6:14 AM ESTFlash Flood Warning EmergencyCatastrophic damage threatGSPCatawba14 hr
Nov 12, 6:36 AM ESTFlash Flood Warning Considerable damage threatGSPDavie, Rowan4 hr
Nov 12, 7:40 AM ESTFlash Flood WarningGSPCabarrus, Gaston, Mecklenburg10 hr
Nov 12, 8:02 AM ESTFlash Flood Warning Considerable damage threatGSPCabarrus10 hr
Nov 12, 9:30 AM ESTAreal Flood WarningGSPDavie, Iredell24 hr
Nov 12, 9:46 AM ESTFlash Flood WarningGSPCabarrus, Mecklenburg, Union4 hr
Nov 12, 10:05 AM ESTAreal Flood WarningGSPCaldwell10 hr
Nov 12, 10:14 AM ESTAreal Flood WarningGSPAlexander11 hr
Nov 12, 10:21 AM ESTAreal Flood WarningGSPIredell, Rowan12 hr
Nov 12, 10:31 AM ESTAreal Flood WarningGSPGaston, Lincoln12 hr
Nov 12, 10:46 AM ESTAreal Flood WarningGSPBurke6 hr
Nov 12, 11:32 AM ESTAreal Flood WarningGSPCatawba9 hr
Nov 12, 12:09 PM ESTRiver Flood WarningGSPDavie, Rowan39 hr
Nov 12, 1:02 PM ESTRiver Flood AdvisoryGSPCleveland23 hr
Nov 12, 1:57 PM ESTAreal Flood WarningGSPUnion9 hr
Nov 12, 5:51 PM ESTAreal Flood WarningGSPMecklenburg5 hr
Nov 12, 6:13 PM ESTAreal Flood WarningGSPCabarrus30 hr

Nearby

Flash Flood Warnings in North Carolina, 2020Every flash flood warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.