Alert archive / South Carolina / Tornado Warnings in 2020

Tornado Warning 28, NWS Columbia, SC

September 17, 2020Clarendon County, Sumter County, South Carolina

NWS Columbia, SC issued this tornado warning at Sep 17, 2020, 3:02 PM EDT for Clarendon County, Sumter County, South Carolina. It was in force for 28 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 17, 2020, 3:02 PM EDT (19:02 UTC)
Expired: Sep 17, 2020, 3:30 PM EDT
In force: 28 min
Issued by: NWS Columbia, SC
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Clarendon County, SC, Sumter County, SC

The radar

The Columbia radar (KCAE), 107 km from the middle of the area, began a volume at 19:02 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Sep 17, 10:20 AM EDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 7.0 hours before the alert went out and 108 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: 1154 J/kg
Mixed-layer CIN: -13 J/kg
Mixed-layer LCL: 652 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 188 m²/s²
0-3 km storm-relative helicity: 261 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 5.7

Open this sounding in Storm Lab

The text

As transmitted.

193 
WFUS52 KCAE 171902
TORCAE
SCC027-085-171930-
/O.NEW.KCAE.TO.W.0028.200917T1902Z-200917T1930Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Columbia SC
302 PM EDT Thu Sep 17 2020

The National Weather Service in Columbia has issued a

* Tornado Warning for...
  Northeastern Clarendon County in central South Carolina...
  Eastern Sumter County in central South Carolina...

* Until 330 PM EDT.
    
* At 302 PM EDT, a severe thunderstorm capable of producing a tornado
  was located 7 miles east of Alcolu, or 8 miles east of Manning,
  moving northeast at 30 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Woods Bay State Park around 330 PM EDT.

Other locations impacted by this tornadic thunderstorm include
Turbeville and Shiloh.

This includes Interstate 95 between mile markers 144 and 146.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! If you are outdoors, in a mobile home, or in a
vehicle, move to an interior room or closet on the lowest floor of a
sturdy building immediately.

&&

LAT...LON 3382 7992 3381 7995 3377 7999 3375 7999
      3370 8007 3373 8015 3404 7999 3402 7996
      3401 7991 3399 7989 3395 7998 3388 7994
      3389 7988
TIME...MOT...LOC 1902Z 213DEG 26KT 3374 8008 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$
awp

1 follow-up statement

422 
WWUS52 KCAE 171923
SVSCAE

Severe Weather Statement
National Weather Service Columbia SC
323 PM EDT Thu Sep 17 2020

SCC027-085-171931-
/O.EXP.KCAE.TO.W.0028.000000T0000Z-200917T1930Z/
Clarendon SC-Sumter SC-
323 PM EDT Thu Sep 17 2020

...THE TORNADO WARNING FOR NORTHEASTERN CLARENDON AND EASTERN SUMTER
COUNTIES WILL EXPIRE AT 330 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning will be allowed to expire.

A Tornado Watch remains in effect until 600 PM EDT for central South
Carolina.

Remember, a Severe Thunderstorm Warning still remains in effect for
Eastern Clarendon County until 345 PM.

LAT...LON 3382 7992 3381 7995 3377 7999 3375 7999
      3370 8007 3373 8015 3404 7999 3402 7996
      3401 7991 3399 7989 3395 7998 3388 7994
      3389 7988
TIME...MOT...LOC 1921Z 213DEG 26KT 3385 8000 

$$

awp

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 16, 11:22 PM EDT	River Flood Advisory	CAE	Lexington, Richland	46 hr
Sep 17, 7:56 AM EDT	Tornado Warning	CAE	Richland, Sumter	34 min
Sep 17, 8:09 AM EDT	Tornado Warning Tornado observed	CAE	Calhoun, Richland, Sumter	21 min
Sep 17, 8:30 AM EDT	Flash Flood Warning	CAE	Aiken, Edgefield, McCormick	3 hr
Sep 17, 9:22 AM EDT	Flash Flood Warning	CAE	Aiken, Barnwell, Edgefield, McCormick, Newberry, Saluda	3 hr
Sep 17, 9:33 AM EDT	Tornado Warning	CAE	Calhoun, Orangeburg	27 min
Sep 17, 9:46 AM EDT	River Flood Warning	CAE	Calhoun, Lexington, Richland	35 hr
Sep 17, 9:46 AM EDT	River Flood Warning	CAE	Calhoun, Richland	3 days
Sep 17, 9:46 AM EDT	River Flood Warning	CAE	Edgefield, McCormick	12 hr
Sep 17, 10:00 AM EDT	Tornado Warning	CAE	Calhoun, Clarendon, Orangeburg	45 min
Sep 17, 10:28 AM EDT	Flash Flood Warning	CAE	Bamberg, Calhoun, Clarendon, Orangeburg, Richland, Sumter	3 hr
Sep 17, 10:38 AM EDT	Flash Flood Warning	CAE	Aiken, Bamberg, Barnwell, Calhoun, Fairfield, Kershaw and 6 more	3 hr
Sep 17, 10:44 AM EDT	Tornado Warning	CAE	Clarendon, Sumter	46 min
Sep 17, 11:01 AM EDT	Tornado Warning	CAE	Clarendon, Sumter	29 min
Sep 17, 11:27 AM EDT	Tornado Warning	CAE	Lee, Sumter	48 min
Sep 17, 11:44 AM EDT	Tornado Warning	CAE	Calhoun, Clarendon, Orangeburg, Sumter	46 min
Sep 17, 12:06 PM EDT	Flash Flood Warning	CAE	Clarendon, Kershaw, Lee, Richland, Sumter	3 hr
Sep 17, 12:39 PM EDT	Tornado Warning	CAE	Clarendon, Sumter	33 min
Sep 17, 12:56 PM EDT	Tornado Warning	CAE	Calhoun, Clarendon, Orangeburg	36 min
Sep 17, 1:11 PM EDT	Tornado Warning	CAE	Sumter	49 min
Sep 17, 1:34 PM EDT	Flash Flood Warning	CAE	Calhoun, Clarendon, Orangeburg, Richland, Sumter	3 hr
Sep 17, 2:37 PM EDT	Severe Thunderstorm Warning	CAE	Lee, Sumter	23 min
Sep 17, 2:52 PM EDT	Severe Thunderstorm Warning	CAE	Clarendon	40 min
Sep 17, 3:19 PM EDT	Flash Flood Warning	CAE	Clarendon, Lee, Sumter	3 hr
Sep 17, 5:45 PM EDT	Areal Flood Advisory	CAE	Clarendon, Orangeburg, Sumter	60 min
Sep 17, 6:08 PM EDT	Special Weather Statement	CAE	Clarendon	22 min

Nearby

Tornado Warnings in South Carolina, 2020 Every tornado warning in 2020 Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.