Alert archive / North Carolina / Flash Flood Warnings in 2020

Flash Flood Warning 45, NWS Greenville-Spartanburg, SC

August 15, 2020Catawba County, North Carolina

NWS Greenville-Spartanburg, SC issued this flash flood warning at Aug 15, 2020, 12:19 AM EDT for Catawba County, North Carolina. It was in force for 6 hr. 2 reports 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
Aug 15, 2020, 12:19 AM EDT (04:19 UTC)
Expired
Aug 15, 2020, 6:15 AM EDT
In force
6 hr
Issued by
NWS Greenville-Spartanburg, SC
Area
Storm-based polygon
Flood severity
None

County Catawba County, NC

The radar

The Greer radar (KGSP), 133 km from the middle of the area, began a volume at 04:18 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
Aug 15, 3:16 AM EDTFLASH FLOOD1 N Conover, NCLYLE CREEK FLOODED AN APARTMENT COMPLEX ON COUNTY HOME ROAD IN CONOVER. ALSO, HWY 16 WAS CLOSED DUE TO FLOOD WATERS NORTH OF CONOVER.
Aug 15, 3:20 AM EDTFLASH FLOOD2 Ne Claremont, NCLYLE CREEK FLOODING FORCED THE CLOSURE OF THE ROAD AT THE INTERSECTION OF BUNKERHILL SCHOOL ROAD AND DEAL ROAD.

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 3 storm reports to this flash flood warning; the first came 149 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, 4.3 hours before the alert went out and 122 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 2020-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 754 joules per kilogram.LCLEL10008507005003002001001 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 2020-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 53 square meters per square second.1939Sfc1 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
754 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
787 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
53 m²/s²
0-3 km storm-relative helicity
49 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

255 
WGUS52 KGSP 150419
FFWGSP
NCC035-150815-
/O.NEW.KGSP.FF.W.0045.200815T0419Z-200815T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
1219 AM EDT Sat Aug 15 2020

The National Weather Service in Greenville-Spartanburg has issued a

* Flash Flood Warning for...
  North central Catawba County in the Piedmont of North Carolina...

* Until 415 AM EDT.

* At 1213 AM EDT, Lyle Creek at Section House Rd had exceeded flood 
  stage following earlier heavy rain across the warned area. Up to 
  three inches of rain have already fallen, and additional heavy 
  rain may occur overnight. Flash flooding is ongoing or expected to 
  begin shortly. County Home Road near 13th Street Northwest, north 
  of Conover, is likely to flood.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  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 flooding include...
  Conover, Claremont, St. Stephens, Oxford and Hickory. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, country roads, as well as farmland, drainages, 
and other low-lying areas. Do not drive across flooded roads. Turn 
around, don't drown.

When it is safe to do so, please report flood waters or landslides
flowing over roads or threatening property to the National Weather
Service by calling toll free, 1, 800, 2 6 7, 8 1 0 1, by posting on
our Facebook page, or via Twitter using hashtag NWSGSP. Your message
should describe the event and the specific location where it
occurred, including roadways, nearby cross streets, stream names and
other landmarks.

&&

LAT...LON 3572 8109 3570 8119 3571 8126 3574 8131
      3579 8122 3579 8119

FLASH FLOOD...RADAR INDICATED

$$

08
3 follow-up statements
413 
WGUS72 KGSP 150609
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
209 AM EDT Sat Aug 15 2020

NCC035-150815-
/O.CON.KGSP.FF.W.0045.000000T0000Z-200815T0815Z/
/00000.U.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Catawba NC-
209 AM EDT Sat Aug 15 2020

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 AM EDT EARLY THIS 
MORNING FOR NORTH CENTRAL CATAWBA COUNTY...

At 209 AM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Lyle 
Creek at Section House Rd had receded but is rising again as heavy 
rainfall has returned to the area. County Home Road near 13th Street 
Northwest, north of Conover, is likely to flood.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Doppler radar and automated gauges.

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...
  Hickory, St. Stephens, Conover, Claremont and Oxford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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.

&&

LAT...LON 3572 8109 3570 8119 3571 8126 3574 8131
      3579 8122 3579 8119

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

RWH
276 
WGUS52 KGSP 150804
FFWGSP
NCC035-151015-
/O.EXT.KGSP.FF.W.0045.000000T0000Z-200815T1015Z/
/00000.U.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
404 AM EDT Sat Aug 15 2020

The National Weather Service in Greenville-Spartanburg has extended 
the

* Flash Flood Warning for...
  North Central Catawba County in the piedmont of North Carolina...

* Until 615 AM EDT.

* At 404 AM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain have diminished across the 
  warned area. However, additional rainfall will move across the 
  area. Flash flooding is ongoing along Lyle Creek.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar and automated gauges.

  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...
  Hickory, St. Stephens, Conover, Claremont and Oxford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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.

&&

LAT...LON 3572 8109 3570 8119 3571 8126 3574 8131
      3579 8122 3579 8119

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

RWH
754 
WGUS72 KGSP 151007
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
607 AM EDT Sat Aug 15 2020

NCC035-151017-
/O.EXP.KGSP.FF.W.0045.000000T0000Z-200815T1015Z/
/00000.U.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Catawba NC-
607 AM EDT Sat Aug 15 2020

...FLASH FLOOD WARNING WILL EXPIRE AT 615 AM EDT THIS MORNING FOR 
NORTH CENTRAL CATAWBA COUNTY...

The heavy rain has ended and flood waters are receding. Flooding is 
no longer expected to pose a threat. However, high water levels 
continue across portions of the area. Please continue to heed 
remaining road closures.

A Flash Flood Watch remains in effect until 1200 AM EDT Sunday for 
portions of piedmont North Carolina and western North Carolina.

LAT...LON 3572 8109 3570 8119 3571 8126 3574 8131
      3579 8122 3579 8119

$$

RWH

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 Aug 14, 7:51 PM EDT, 4 hours 28 minutes earlier.

Area forecast discussion, Aug 14, 7:51 PM EDT, 4 hours 28 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
751 PM EDT Fri Aug 14 2020

.SYNOPSIS...
Numerous to widespread showers and thunderstorms are expected
through Saturday with highs slightly below normal. Thunderstorm
chances diminish Sunday then slowly increase through the week. Highs
will be around normal through the first part of the week then fall
below normal.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 740 pm EDT Friday: Water vapor imagery shows the base of a
digging trough steadily advancing eastward across western Tennessee
this evening, with better forced convective coverage developing
upstream across Alabama and Georgia. Coverage has been sparser and
weaker across the western Carolinas and northeast Georgia thus far,
and what outflows exist at present do not look terribly robust. PoPs
have thus been shaved a bit in Piedmont sections, but with continued
likely coverage across the higher terrain and the NC foothills for
ongoing showers and embedded thunderstorms. It's quite possible that
the region will still experience an uptick tonight as the upstream
coverage arrives from the southwest later this evening, but SBCAPE
values will start trending down soon and there may not be good
instability to get coverage back up above the high scattered range.
Will keep the best overnight PoPs in southwest mountain sections,
closer to the deeper moisture and forcing and where upslope flow
will be best. Will likely allow the Flash Flood Watch to expire on
schedule at midnight, with just about any location possibly seeing
localized flooding with any training showers overnight.

PoPs will ramp up a bit sooner than typical diurnal trends indicate
on Saturday, as upper DPVA and jet energy begins to push east into
the area. The best 2+ inch precipitable water values of the event
will occur on Saturday, and the deep forcing, abundant moisture and
slightly improved lapse rates should yield more coverage, stronger
storms, and a slight uptick in the hydro threat with any training
cells. A new Flash Flood Watch could be needed at some point
Saturday where antecedent rainfall conditions are the wettest
(mainly western NC). Expect mild and muggy conditions overnight, and
then below climo maxes Saturday afternoon given all the cloud cover.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 200 PM EDT Friday: The mid level trof will be pulling east of
the area by Saturday night. We should have some showers and storms
in the evening, but they will move east of the area leaving a dry
overnight period.  As the trof moves east, a drier air mass will
move into the area for Sunday and Monday as northwest mid level flow
develops. There will be a small chance of a shower or storm each day
but conditions should be quiet overall.

Highs both days will be near climo. Slightly lower dewpoints will
make conditions relatively comfortable for mid August.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 200 PM EDT Friday: Another mid level trof is expected to
develop to our west for the middle to latter part of next week. This
should act to pull deeper moisture back into the area leading to a
more active, mainly diurnal, convective pattern. The increased cloud
cover and rainfall should keep high temperatures in check and a few
degrees below climo through the period.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and Elsewhere: Convection chances will be best this
evening from KAVL to KHKY, but with a sharp gradient to lower
chances across the Upstate TAF sites and KCLT, where mainly VCSH or
VCTS is warranted through early overnight. Abundant moisture should
yield another round of low clouds and fog, with IFR to LIFR
conditions mainly from KAVL to KHKY, but with MVFR likely at the
other sites, including KCLT, and a window of IFR possible as well.
Restrictions will be slow to lift through noon, and insolation will
be limited by abundant clouds through the afternoon hours. Expect
mainly afternoon VFR conditions but with MVFR to IFR possible in any
heavy downpours. The best convective chances will be during the
afternoon and evening hours as the upper trough makes a push into
the region. Expect very slow drying to begin from the west right
around the end of the TAF period, but with low-level moisture
persisting. Light and variable winds will be mainly S to SW with any
mixing tonight through Saturday, except NW at times in the French
Broad Valley tonight. Winds will be briefly gusty near any
thunderstorms.

Outlook: Slightly less thunderstorm coverage is expected Sunday and
Monday compared to recent days, but perhaps still slightly above
normal as low-level moisture continues. 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.

Confidence Table...

            00-06Z        06-12Z        12-18Z        18-00Z
KCLT       High  97%     Med   78%     Med   69%     High  96%
KGSP       High  98%     Med   71%     Med   73%     High  88%
KAVL       Med   74%     Low   58%     Med   78%     Med   75%
KHKY       High  90%     Med   62%     Med   65%     Med   78%
KGMU       High  98%     Med   70%     Med   68%     High  90%
KAND       High  98%     Med   78%     Med   79%     High  94%

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...HG
SHORT TERM...SCW
LONG TERM...SCW
AVIATION...HG
Hazardous weather outlook, Aug 14, 10:10 PM EDT, 2 hours 9 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
1010 PM EDT Fri Aug 14 2020

GAZ010-017-018-026-028-029-NCZ048>053-058-059-062>065-068>072-082-
507>510-SCZ001>014-019-160215-
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-
1010 PM EDT Fri Aug 14 2020

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

.DAY ONE...Tonight.

Numerous showers and thunderstorms will continue to develop across
the region through the overnight 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...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ033-035>037-056-057-501>506-160215-
Avery-Alexander-Iredell-Davie-Catawba-Rowan-Caldwell Mountains-
Greater Caldwell-Burke Mountains-Greater Burke-McDowell Mountains-
Eastern McDowell-
1010 PM EDT Fri Aug 14 2020

...FLASH FLOOD WATCH IN EFFECT THROUGH SATURDAY EVENING...

This Hazardous Weather Outlook is for the northwest Piedmont,
northern foothills, and Avery county in western North Carolina.

.DAY ONE...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.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

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

   Flash Flood Watch.

.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

In the hours before

Special weather statement, Aug 14, 10:47 PM EDT, 1 hour 32 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1047 PM EDT Fri Aug 14 2020

NCZ035-036-056-150400-
Iredell NC-Alexander NC-Catawba NC-
1047 PM EDT Fri Aug 14 2020

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT NORTHEASTERN
CATAWBA...SOUTHERN ALEXANDER AND NORTHWESTERN IREDELL COUNTIES UNTIL
MIDNIGHT EDT...

At 1046 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 6 miles northeast of Hickory, or near St.
Stephens, moving east at 5 mph.

Locations to be impacted include...
Newton, Hickory, St. Stephens, Conover, Bethlehem, Stony Point,
Claremont, Catawba, Lookout Shoals Lake and Lake Hickory.

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 3568 8130 3585 8130 3594 8100 3570 8099
TIME...MOT...LOC 0246Z 256DEG 6KT 3579 8122

08

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 14, 10:47 PM EDTSpecial Weather StatementGSPAlexander73 min
Aug 15, 12:56 AM EDTFlash Flood WarningGSPBurke, Caldwell6 hr
Aug 15, 2:19 AM EDTFlash Flood Warning EmergencyGSPAlexander, Burke, Caldwell, Catawba4 hr
Aug 15, 4:29 AM EDTAreal Flood AdvisoryGSPAlexander, Catawba5 hr
Aug 15, 10:48 AM EDTRiver Flood AdvisoryGSPHenderson, Transylvania8 hr
Aug 15, 3:09 PM EDTSpecial Weather StatementGSPUnion36 min
Aug 15, 4:04 PM EDTSpecial Weather StatementGSPPolk, Rutherford26 min
Aug 15, 4:28 PM EDTFlash Flood WarningGSPAlexander, Burke, Caldwell, Catawba, Iredell2 hr
Aug 15, 4:33 PM EDTSpecial Weather StatementGSPCleveland27 min
Aug 15, 4:50 PM EDTFlash Flood WarningGSPMecklenburg, Union3 hr
Aug 15, 5:57 PM EDTSpecial Weather StatementGSPIredell33 min
Aug 15, 6:10 PM EDTFlash Flood WarningGSPCatawba, Davie, Iredell, Rowan2 hr
Aug 15, 7:43 PM EDTSpecial Weather StatementGSPCabarrus, Mecklenburg32 min

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.