Alert archive / South Carolina / Flash Flood Warnings in 2021

Flash Flood Warning 14, NWS Greenville-Spartanburg, SC

August 16, 2021Oconee County, South Carolina

NWS Greenville-Spartanburg, SC issued this flash flood warning at Aug 16, 2021, 10:12 AM EDT for Oconee County, South Carolina. It was in force for 3 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
Aug 16, 2021, 10:12 AM EDT (14:12 UTC)
Expired
Aug 16, 2021, 1:15 PM EDT
In force
3 hr
Issued by
NWS Greenville-Spartanburg, SC
Area
Storm-based polygon
Flood severity
None

County Oconee County, SC

The radar

The Greer radar (KGSP), 74 km from the middle of the area, began a volume at 14:13 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 16, 11:00 AM EDTFLASH FLOOD6 Se Walhalla, SCKEOWEE SCHOOL ROAD CLOSED DUE TO FLOODING. EVENT TIME ESTIMATED.

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

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 2.2 hours before the alert went out and 216 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, Peachtre/Fal Fld, GA at 12:00Z on 2021-08-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 86 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Peachtre/Fal Fld, GA at 12:00Z on 2021-08-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 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
86 J/kg
Mixed-layer CIN
-80 J/kg
Mixed-layer LCL
1005 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

337 
WGUS52 KGSP 161412
FFWGSP
SCC073-161800-
/O.NEW.KGSP.FF.W.0014.210816T1412Z-210816T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
1012 AM EDT Mon Aug 16 2021

The National Weather Service in Greenville-Spartanburg has issued a

* Flash Flood Warning for...
  Northeastern Oconee County in upstate South Carolina...

* Until 200 PM EDT.

* At 1012 AM EDT, Doppler radar and gage reports were indicating 
  scattered areas of very heavy showers lingering within the warned 
  area.  Isolated rainfall totals may be as high as 5 inches today.  
  A few areas of stream and road flooding have been received from 
  around Salem and points south, especially near Lake Keowee.


  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Seneca, Walhalla, Salem, Lake Keowee, Oconee State Park, Devils 
  Fork State Park, Lake Jocassee, Lake Hartwell and Bad Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3493 8312 3494 8311 3494 8312 3500 8309
      3505 8291 3500 8295 3497 8295 3495 8292
      3473 8290 3462 8297 3462 8301 3475 8313
      3488 8310

FLASH FLOOD...RADAR INDICATED

$$

CSH
2 follow-up statements
812 
WGUS72 KGSP 161520
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
1120 AM EDT Mon Aug 16 2021

SCC073-161800-
/O.CON.KGSP.FF.W.0014.000000T0000Z-210816T1800Z/
/00000.U.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Oconee SC-
1120 AM EDT Mon Aug 16 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 2 PM EDT THIS 
AFTERNOON FOR NORTHEASTERN OCONEE COUNTY...

At 1120 AM EDT, Doppler radar indicated that the heavy shower threat 
had diminished but locally excessive runoff will linger from around 
Salem to Seneca and along the Jocassee and Keowee Lake shores. If 
appreciable showers do not redevelop, this warning will likely be 
cancelled early.



HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

LAT...LON 3496 8300 3498 8301 3499 8304 3500 8309
      3505 8291 3500 8295 3497 8295 3495 8292
      3473 8290 3462 8297 3462 8301 3470 8308
      3478 8302 3490 8300

FLASH FLOOD...RADAR INDICATED

$$

CSH
449 
WGUS72 KGSP 161715
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
115 PM EDT Mon Aug 16 2021

SCC073-161725-
/O.CAN.KGSP.FF.W.0014.000000T0000Z-210816T1800Z/
/00000.U.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Oconee SC-
115 PM EDT Mon Aug 16 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN OCONEE COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 3496 8300 3498 8301 3499 8304 3500 8309
      3505 8291 3500 8295 3497 8295 3495 8292
      3473 8290 3462 8297 3462 8301 3470 8308
      3478 8302 3490 8300

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 16, 8:33 AM EDTSpecial Weather StatementGSPOconee42 min
Aug 16, 9:23 AM EDTSpecial Weather StatementGSPOconee52 min
Aug 16, 2:20 PM EDTFlash Flood WatchGSPAbbeville, Anderson, Greenwood, Laurens40 hr
Aug 16, 3:46 PM EDTSpecial Weather StatementGSPCherokee, York59 min
Aug 16, 6:53 PM EDTAreal Flood AdvisoryGSPOconee3 hr

Nearby

Flash Flood Warnings in South Carolina, 2021Every flash flood warning in 2021

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.