Alert archive / South Carolina / Flash Flood Warnings in 2021

Flash Flood Warning 18, NWS Greenville-Spartanburg, SC

August 17, 2021Oconee County, South Carolina

NWS Greenville-Spartanburg, SC issued this flash flood warning at Aug 17, 2021, 12:30 PM EDT for Oconee County, South Carolina. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 17, 2021, 12:30 PM EDT (16:30 UTC)
Expired
Aug 17, 2021, 5:30 PM EDT
In force
5 hr
Issued by
NWS Greenville-Spartanburg, SC
Area
Storm-based polygon
Flood severity
None

County Oconee County, SC

The radar

The Greer radar (KGSP), 78 km from the middle of the area, began a volume at 16:28 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.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 4.5 hours before the alert went out and 206 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 2021-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 259 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 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 2021-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 square meters per square second.193958Sfc1 km3 km6 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
259 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
461 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
197 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.8

Open this sounding in Storm Lab

The text

As transmitted.

145 
WGUS52 KGSP 171630
FFWGSP
SCC073-171930-
/O.NEW.KGSP.FF.W.0018.210817T1630Z-210817T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
1230 PM EDT Tue Aug 17 2021

The National Weather Service in Greenville-Spartanburg has issued a

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

* Until 330 PM EDT.

* At 1230 PM EDT, Doppler radar and automated rain gauges indicated 
  that new rainfall totals since midnight have averaged around 2 
  inches countywide.  An additional inch or two rain is expected 
  this afternoon.  With very wet conditions persisting renewed flash 
  flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar and automated gauges.

  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, Westminster, Salem, Oconee State Park, Lake 
  Keowee, Devils Fork State Park, Lake Jocassee, Lake Hartwell, 
  Tallulah Gorge State Park, Mountain Rest, Long Creek and Bad Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

When it is safe to do so, please report flooding or landslides 
threatening roads or property to the National Weather Service 
Greenville-Spartanburg 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 specific location where 
impacts occurred and the depth of flooding observed.

&&

LAT...LON 3505 8292 3499 8295 3494 8292 3479 8289
      3474 8291 3472 8287 3465 8284 3459 8288
      3458 8292 3462 8301 3473 8316 3474 8323
      3468 8331 3469 8334 3473 8335 3476 8332
      3479 8331 3491 8318 3494 8311 3500 8310

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$
1 follow-up statement
000 
WGUS52 KGSP 171842
FFWGSP
SCC073-172130-
/O.EXT.KGSP.FF.W.0018.000000T0000Z-210817T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
242 PM EDT Tue Aug 17 2021

The National Weather Service in Greenville-Spartanburg has extended 
the

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

* Until 530 PM EDT.

* At 242 PM EDT, After a widespread 2 to 3 inch rainfall today, 
  additional rounds of heavy showers will threaten Oconee County 
  through late afternoon. This will maintain the likihood of locally 
  excessive runoff and high water conditions across a large portion 
  of the county.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar and automated gauges.

  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, Westminster, Salem, Oconee State Park, Lake 
  Keowee, Devils Fork State Park, Lake Jocassee, Lake Hartwell, 
  Tallulah Gorge State Park, Mountain Rest, Long Creek and Bad Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

When it is safe to do so, please report flooding or landslides 
threatening roads or property to the National Weather Service 
Greenville-Spartanburg 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 specific location where 
impacts occurred and the depth of flooding observed.

&&

LAT...LON 3505 8292 3499 8295 3494 8292 3479 8289
      3474 8291 3472 8287 3465 8284 3459 8288
      3458 8292 3462 8301 3473 8316 3474 8323
      3468 8331 3469 8334 3473 8335 3476 8332
      3479 8331 3491 8318 3494 8311 3500 8310

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 11:47 AM EDTTornado WarningGSPOconee13 min
Aug 17, 12:30 PM EDTTornado WarningGSPOconee, Pickens23 min
Aug 17, 12:59 PM EDTTornado WarningGSPAnderson, Pickens23 min
Aug 17, 1:20 PM EDTTornado WarningGSPPickens25 min
Aug 17, 2:03 PM EDTFlash Flood WarningGSPGreenville, Pickens5 hr
Aug 17, 2:14 PM EDTTornado WarningGSPGreenwood, Laurens33 min
Aug 17, 2:52 PM EDTTornado WarningGSPGreenville26 min
Aug 17, 3:01 PM EDTTornado Warning Tornado observedGSPGreenville18 min
Aug 17, 3:25 PM EDTSpecial Weather StatementGSPSpartanburg35 min
Aug 17, 3:26 PM EDTSpecial Weather StatementGSPOconee34 min
Aug 17, 4:34 PM EDTSpecial Weather StatementGSPAbbeville, Anderson, Pickens26 min
Aug 17, 5:08 PM EDTTornado WarningGSPAnderson, Greenville, Pickens52 min
Aug 17, 5:10 PM EDTTornado WarningGSPAbbeville, Greenville, Greenwood, Laurens50 min
Aug 17, 5:11 PM EDTTornado WarningGSPAbbeville, Greenwood, Laurens49 min
Aug 17, 5:33 PM EDTTornado WarningGSPAnderson, Greenville, Spartanburg42 min
Aug 17, 5:37 PM EDTTornado WarningGSPChester, York38 min
Aug 17, 5:57 PM EDTTornado WarningGSPGreenville, Laurens, Spartanburg48 min
Aug 17, 5:58 PM EDTTornado WarningGSPGreenwood, Laurens47 min
Aug 17, 6:15 PM EDTTornado WarningGSPLaurens, Spartanburg, Union45 min
Aug 17, 6:16 PM EDTFlash Flood WarningGSPGreenville, Pickens, Spartanburg3 hr
Aug 17, 6:42 PM EDTTornado WarningGSPSpartanburg48 min
Aug 17, 6:46 PM EDTTornado WarningGSPCherokee, Spartanburg44 min
Aug 17, 6:51 PM EDTTornado WarningGSPLaurens, Spartanburg, Union39 min
Aug 17, 7:59 PM EDTTornado WarningGSPCherokee, Spartanburg46 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.