Alert archive / South Dakota / Tornado Warnings in 2021

Tornado Warning 6, NWS Rapid City, SD

May 23, 2021Custer County, Pennington County, South Dakota

NWS Rapid City, SD issued this tornado warning at May 23, 2021, 4:14 PM MDT for Custer County, Pennington County, South Dakota. It was in force for 13 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: May 23, 2021, 4:14 PM MDT (22:14 UTC)
Expired: May 23, 2021, 4:27 PM MDT
In force: 13 min
Issued by: NWS Rapid City, SD
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Custer County, SD, Pennington County, SD

The radar

The Rapid City radar (KUDX), 59 km from the middle of the area, began a volume at 22:14 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
May 23, 1:50 PM MDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 10.2 hours before the alert went out and 52 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 549 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 271 m²/s²
0-3 km storm-relative helicity: 339 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

095 
WFUS53 KUNR 232214
TORUNR
SDC033-103-232245-
/O.NEW.KUNR.TO.W.0006.210523T2214Z-210523T2245Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Rapid City SD
414 PM MDT Sun May 23 2021

The National Weather Service in Rapid City has issued a

* Tornado Warning for...
  North central Custer County in southwestern South Dakota...
  Western Pennington County in west central South Dakota...

* Until 445 PM MDT.

* At 413 PM MDT, severe thunderstorms capable of producing both
  tornadoes and extensive straight line wind damage were located over
  northwestern Custer State Park, or 6 miles northeast of Custer,
  moving northeast at 35 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.

* These dangerous storms will be near...
  Keystone around 420 PM MDT.
  Hayward, Keystone Wye and Sheridan Lake around 425 PM MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4378 10348 4383 10357 4400 10349 4388 10328
TIME...MOT...LOC 2213Z 222DEG 31KT 4383 10349 

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

$$

Carstens

2 follow-up statements

474 
WWUS53 KUNR 232222
SVSUNR

Severe Weather Statement
National Weather Service Rapid City SD
422 PM MDT Sun May 23 2021

SDC033-232231-
/O.CAN.KUNR.TO.W.0006.000000T0000Z-210523T2245Z/
Custer SD-
422 PM MDT Sun May 23 2021

...THE TORNADO WARNING FOR NORTH CENTRAL CUSTER COUNTY IS
CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 900 PM MDT for west central
South Dakota.

LAT...LON 4386 10338 4386 10356 4400 10349 4388 10328
TIME...MOT...LOC 2221Z 222DEG 31KT 4389 10342 

$$

SDC103-232245-
/O.CON.KUNR.TO.W.0006.000000T0000Z-210523T2245Z/
Pennington SD-
422 PM MDT Sun May 23 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 445 PM MDT FOR WESTERN
PENNINGTON COUNTY...

At 421 PM MDT, a severe squall line capable of producing both
tornadoes and extensive straight line wind damage was located over
Keystone, or 8 miles southeast of Hill City, moving northeast at 35
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.

These dangerous storms will be near...
  Hayward and Sheridan Lake around 425 PM MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4386 10338 4386 10356 4400 10349 4388 10328
TIME...MOT...LOC 2221Z 222DEG 31KT 4389 10342 

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

$$

Carstens

008 
WWUS53 KUNR 232227
SVSUNR

Severe Weather Statement
National Weather Service Rapid City SD
427 PM MDT Sun May 23 2021

SDC103-232237-
/O.CAN.KUNR.TO.W.0006.000000T0000Z-210523T2245Z/
Pennington SD-
427 PM MDT Sun May 23 2021

...THE TORNADO WARNING FOR WESTERN PENNINGTON COUNTY IS CANCELLED...
    
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, large hail and damaging winds remain likely and a
Severe Thunderstorm Warning remains in effect for the area.

A Tornado Watch remains in effect until 900 PM MDT for west central
South Dakota.

LAT...LON 4386 10338 4386 10356 4400 10349 4388 10328
TIME...MOT...LOC 2224Z 222DEG 31KT 4393 10337 

$$

Carstens

The office that day

Everything else NWS Rapid City, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 23, 3:20 AM MDT	Special Weather Statement	UNR	Oglala Lakota	40 min
May 23, 4:57 AM MDT	Special Weather Statement	UNR	Meade	33 min
May 23, 5:23 AM MDT	Special Weather Statement	UNR	Jackson	37 min
May 23, 1:40 PM MDT	Special Weather Statement	UNR	Fall River	35 min
May 23, 2:00 PM MDT	Special Weather Statement	UNR	Custer	30 min
May 23, 2:02 PM MDT	Special Weather Statement	UNR	Meade	28 min
May 23, 2:16 PM MDT	Special Weather Statement	UNR	Pennington	29 min
May 23, 2:45 PM MDT	Tornado Warning	UNR	Meade	30 min
May 23, 3:13 PM MDT	Tornado Warning	UNR	Meade, Perkins	47 min
May 23, 3:34 PM MDT	Special Weather Statement	UNR	Fall River	26 min
May 23, 3:53 PM MDT	Severe Thunderstorm Warning	UNR	Custer	37 min
May 23, 3:58 PM MDT	Tornado Warning	UNR	Perkins	47 min
May 23, 3:59 PM MDT	Tornado Warning	UNR	Custer	31 min
May 23, 4:26 PM MDT	Severe Thunderstorm Warning	UNR	Custer, Lawrence, Meade, Pennington	49 min
May 23, 4:26 PM MDT	Severe Thunderstorm Warning	UNR	Butte, Meade, Pennington	33 min
May 23, 5:04 PM MDT	Severe Thunderstorm Warning	UNR	Butte, Meade, Pennington	30 min
May 23, 5:35 PM MDT	Special Weather Statement	UNR	Perkins	40 min
May 23, 5:53 PM MDT	Severe Thunderstorm Warning	UNR	Haakon, Meade, Pennington, Ziebach	67 min

Nearby

Tornado Warnings in South Dakota, 2021 Every tornado warning in 2021 Tornadoes 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.