Alert archive / South Dakota / Tornado Warnings in 2021

Tornado Warning 17, NWS Sioux Falls, SD

October 9, 2021Aurora County, Jerauld County, South Dakota

NWS Sioux Falls, SD issued this tornado warning at Oct 9, 2021, 3:56 PM CDT for Aurora County, Jerauld County, South Dakota. It was in force for 34 min. 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: Oct 9, 2021, 3:56 PM CDT (20:56 UTC)
Expired: Oct 9, 2021, 4:30 PM CDT
In force: 34 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.75 in

Counties Aurora County, SD, Jerauld County, SD

The radar

The Sioux Falls radar (KFSD), 150 km from the middle of the area, began a volume at 20:56 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
Oct 9, 3:56 PM CDT	HAIL 1.75	11 Sw Wessington Spring, SD	TIME ESTIMATED BY RADAR. SPOTTER REPORTED LARGE HAIL, STRONG WINDS, BUT NO OTHER DAMAGE.

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

The watch it was issued in

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

Issued	Product	Office	Lasted
Oct 9, 2:56 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 8.9 hours before the alert went out and 96 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: 4 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 713 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 97 m²/s²
0-3 km storm-relative helicity: 200 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

358 
WFUS53 KFSD 092056
TORFSD
SDC003-073-092130-
/O.NEW.KFSD.TO.W.0017.211009T2056Z-211009T2130Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
356 PM CDT Sat Oct 9 2021

The National Weather Service in Sioux Falls has issued a

* Tornado Warning for...
  North central Aurora County in south central South Dakota...
  Central Jerauld County in central South Dakota...

* Until 430 PM CDT.
    
* At 356 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 8 miles southwest of Wessington Springs, or 20 miles
  northwest of Plankinton, moving northeast at 35 mph.

  HAZARD...Tornado and golf ball size hail.

  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...
  Wessington Springs around 410 PM CDT.
  Lane around 420 PM CDT.

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 4407 9833 4405 9834 4390 9870 4398 9879
      4419 9848
TIME...MOT...LOC 2056Z 231DEG 30KT 4399 9867 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.75 IN

$$

SG

2 follow-up statements

288 
WWUS53 KFSD 092106
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
406 PM CDT Sat Oct 9 2021

SDC003-092115-
/O.CAN.KFSD.TO.W.0017.000000T0000Z-211009T2130Z/
Aurora SD-
406 PM CDT Sat Oct 9 2021

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

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
south central, central and east central South Dakota.

LAT...LON 4393 9862 4403 9872 4419 9848 4407 9833
      4405 9834
TIME...MOT...LOC 2105Z 230DEG 29KT 4404 9859 

$$

SDC073-092130-
/O.CON.KFSD.TO.W.0017.000000T0000Z-211009T2130Z/
Jerauld SD-
406 PM CDT Sat Oct 9 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR EASTERN
JERAULD COUNTY...
    
At 405 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Wessington Springs, or 22 miles north of Plankinton,
moving northeast at 35 mph.

HAZARD...Tornado and golf ball size hail.

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...
  Wessington Springs around 410 PM CDT.

Other locations in the path of this tornadic thunderstorm include
Lane.

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 4393 9862 4403 9872 4419 9848 4407 9833
      4405 9834
TIME...MOT...LOC 2105Z 230DEG 29KT 4404 9859 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.75 IN

$$

SG

251 
WWUS53 KFSD 092127
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
427 PM CDT Sat Oct 9 2021

SDC073-092134-
/O.EXP.KFSD.TO.W.0017.000000T0000Z-211009T2130Z/
Jerauld SD-
427 PM CDT Sat Oct 9 2021

...THE TORNADO WARNING FOR EASTERN JERAULD COUNTY WILL EXPIRE AT 430
PM CDT...
    
The tornado threat has diminished and the Tornado Warning will be 
allowed to expire. However, large hail and damaging winds remain 
likely and a Severe Thunderstorm Warning remains in effect for the 
area.  

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
south central, central and east central South Dakota.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Sioux Falls.

Remember, a Severe Thunderstorm Warning still remains in effect for
eastern Jerauld County until 515 PM CDT.

LAT...LON 4393 9862 4403 9872 4419 9848 4407 9833
      4405 9834
TIME...MOT...LOC 2124Z 231DEG 30KT 4414 9842 

$$

SG

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 9, 3:39 PM CDT	Severe Thunderstorm Warning	FSD	Aurora, Beadle, Brule, Jerauld	51 min
Oct 9, 4:23 PM CDT	Severe Thunderstorm Warning	FSD	Beadle, Jerauld, Kingsbury, Sanborn	52 min
Oct 9, 5:08 PM CDT	Severe Thunderstorm Warning	FSD	Beadle, Kingsbury	52 min
Oct 9, 5:53 PM CDT	Severe Thunderstorm Warning	FSD	Kingsbury	27 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.