Alert archive / South Carolina / Flash Flood Warnings in 2021

Flash Flood Warning 1, NWS Columbia, SC

June 20, 20216 counties in South Carolina

NWS Columbia, SC issued this flash flood warning at Jun 20, 2021, 4:04 PM EDT for 6 counties in South Carolina. It was in force for 3 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: Jun 20, 2021, 4:04 PM EDT (20:04 UTC)
Expired: Jun 20, 2021, 7:15 PM EDT
In force: 3 hr
Issued by: NWS Columbia, SC
Area: Storm-based polygon
Flood severity: None

Counties Calhoun County, SC, Fairfield County, SC, Kershaw County, SC, Lexington County, SC, Newberry County, SC, Richland County, SC

The radar

The Columbia radar (KCAE), 20 km from the middle of the area, began a volume at 20:06 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

Time	Report	Where	Remark
Jun 20, 4:41 PM EDT	FLOOD	2 Wnw Forest Acres, SC	SC HIGHWAY PATROL REPORTS FLOODED ROADWAY AT TWO NOTCH ROAD AND WINDOVER STREET.
Jun 20, 4:55 PM EDT	HEAVY RAIN 0.95	4 Ene Chapin, SC	RCWINDS MESONET DATA AT SPRING HILL MEASURED 0.95 INCHES OF RAIN IN JUST 25 MIN FROM 4:30 PM TO 4:55 PM. THIS LOCATION HAS MEASURED A TOTAL OF 3.94 INCHES OF RAIN SINCE MIDNIGHT, WITH 1.74 INCHES FALLING WITHIN AN 85 MIN PERIOD.

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

The nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 8.1 hours before the alert went out and 173 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1312 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 848 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 199 m²/s²
0-3 km storm-relative helicity: 209 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.2

Open this sounding in Storm Lab

The text

As transmitted.

022 
WGUS52 KCAE 202004
FFWCAE
SCC017-039-055-063-071-079-202315-
/O.NEW.KCAE.FF.W.0001.210620T2004Z-210620T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Columbia SC
404 PM EDT Sun Jun 20 2021

The National Weather Service in Columbia has issued a

* Flash Flood Warning for...
  Northwestern Calhoun County in central South Carolina...
  Southern Fairfield County in central South Carolina...
  West Central Kershaw County in central South Carolina...
  Central Lexington County in central South Carolina...
  Southeastern Newberry County in central South Carolina...
  Western Richland County in central South Carolina...

* Until 715 PM EDT.

* At 404 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. Additional rainfall amounts of 1 to 2 inches are possible in 
  the warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  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...
  Columbia, Lexington, West Columbia, Cayce, Irmo, Forest Acres, 
  Winnsboro, Springdale, St. Andrews, Highway 6 at Lake Murray Dam, 
  Oak Grove, Dentsville, Red Bank, VC Summer Nuclear Station, South 
  Congaree, Pine Ridge, Elgin, Arcadia Lakes, Harbison State Forest 
  and Columbia International University.

This includes the following highways...
	Interstate 126 between mile markers 0 and 3.
	Interstate 20 in South Carolina between mile markers 49 and 81.
	Interstate 77 between mile markers 0 and 38.
	Interstate 26 between mile markers 87 and 122.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Most flooding deaths occur in vehicles. Never drive through a 
flooded roadway or around barricades. Turn around, don't drown.

&&

LAT...LON 3442 8128 3432 8069 3383 8102 3384 8104
      3396 8152

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

AWP

1 follow-up statement

390 
WGUS72 KCAE 202306
FFSCAE

Flash Flood Statement
National Weather Service Columbia SC
706 PM EDT Sun Jun 20 2021

SCC017-039-055-063-071-079-202316-
/O.EXP.KCAE.FF.W.0001.000000T0000Z-210620T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Calhoun SC-Fairfield SC-Kershaw SC-Lexington SC-Newberry SC-Richland
SC-
706 PM EDT Sun Jun 20 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 715 PM EDT THIS EVENING FOR 
NORTHWESTERN CALHOUN, SOUTHERN FAIRFIELD, WEST CENTRAL KERSHAW, 
CENTRAL LEXINGTON, SOUTHEASTERN NEWBERRY AND WESTERN RICHLAND 
COUNTIES...

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

LAT...LON 3442 8128 3432 8069 3383 8102 3384 8104
      3396 8152

$$

CRL

The office that day

Everything else NWS Columbia, SC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 20, 2:03 AM EDT	Flash Flood Watch	CAE	Aiken, Bamberg, Barnwell, Calhoun, Chesterfield, Clarendon and 12 more	17 hr
Jun 20, 1:18 PM EDT	Special Weather Statement	CAE	Edgefield	42 min
Jun 20, 1:35 PM EDT	Special Weather Statement	CAE	Aiken	25 min
Jun 20, 1:52 PM EDT	Areal Flood Advisory	CAE	Aiken, Fairfield, Kershaw, Lexington, Newberry, Richland	113 min
Jun 20, 2:18 PM EDT	Special Weather Statement	CAE	Aiken	27 min
Jun 20, 2:25 PM EDT	Tornado Warning	CAE	Aiken, Lexington, Saluda	35 min
Jun 20, 3:13 PM EDT	Special Weather Statement	CAE	Calhoun, Lexington	47 min
Jun 20, 3:33 PM EDT	Areal Flood Advisory	CAE	Aiken, Fairfield, Kershaw, Lexington, Newberry, Richland and 1 more	117 min
Jun 20, 3:49 PM EDT	Special Weather Statement	CAE	Lexington, Richland	26 min
Jun 20, 4:16 PM EDT	Special Weather Statement	CAE	Richland	44 min
Jun 20, 4:34 PM EDT	Special Weather Statement	CAE	Calhoun, Orangeburg	41 min
Jun 20, 5:03 PM EDT	Special Weather Statement	CAE	Kershaw	27 min
Jun 20, 5:10 PM EDT	Areal Flood Advisory	CAE	Fairfield, Kershaw, Lancaster	3 hr
Jun 20, 5:29 PM EDT	Special Weather Statement	CAE	Clarendon, Lee, Sumter	46 min
Jun 20, 5:35 PM EDT	Special Weather Statement	CAE	Kershaw, Lancaster	55 min
Jun 20, 6:06 PM EDT	Areal Flood Advisory	CAE	Chesterfield, Kershaw, Lancaster	3 hr
Jun 20, 6:31 PM EDT	Special Weather Statement	CAE	Chesterfield	59 min

Nearby

Flash Flood Warnings in South Carolina, 2021 Every 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.