Alert archive / South Dakota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 95, NWS Sioux Falls, SD

August 22, 2021Aurora County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 22, 2021, 7:21 PM CDT for Aurora County, South Dakota. It was in force for 24 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: Aug 22, 2021, 7:21 PM CDT (00:21 UTC)
Expired: Aug 22, 2021, 7:45 PM CDT
In force: 24 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

County Aurora County, SD

The radar

The Sioux Falls radar (KFSD), 140 km from the middle of the area, began a volume at 00:20 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
Aug 22, 3:36 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Aug 22, 6:31 PM CDT	Tornado Watch	SPC	3 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 0.4 hours before the alert went out and 117 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: 166 J/kg
Mixed-layer CIN: -152 J/kg
Mixed-layer LCL: 1323 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 245 m²/s²
0-3 km storm-relative helicity: 282 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.4

Open this sounding in Storm Lab

The text

As transmitted.

467 
WUUS53 KFSD 230021
SVRFSD
SDC003-230045-
/O.NEW.KFSD.SV.W.0095.210823T0021Z-210823T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
721 PM CDT Sun Aug 22 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Northeastern Aurora County in south central South Dakota...

* Until 745 PM CDT.

* At 721 PM CDT, a severe thunderstorm was located 9 miles west of
  Storla, or 11 miles north of Plankinton, moving east at 35 mph.

  HAZARD...60 mph wind gusts and half dollar size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* This severe thunderstorm will be near...
  Storla around 735 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Tornado Watch remains in effect for the warned area. Tornadoes can
develop quickly from severe thunderstorms. Although a tornado is not
immediately likely, if one is spotted, act quickly and move to a
place of safety inside a sturdy structure such as a basement or small
interior room.

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

&&

LAT...LON 4394 9833 4375 9832 4374 9833 4379 9867
      4394 9864
TIME...MOT...LOC 0021Z 268DEG 30KT 4387 9853 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Schumacher

2 follow-up statements

605 
WWUS53 KFSD 230034
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
734 PM CDT Sun Aug 22 2021

SDC003-230045-
/O.CON.KFSD.SV.W.0095.000000T0000Z-210823T0045Z/
Aurora SD-
734 PM CDT Sun Aug 22 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM CDT
FOR NORTHEASTERN AURORA COUNTY...

At 734 PM CDT, a severe thunderstorm was located over Storla, or 12
miles northeast of Plankinton, moving east at 35 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

This severe thunderstorm will remain over mainly rural areas of
northeastern Aurora County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A tornado watch remains in effect for the warned area. Tornadoes can
develop quickly from severe thunderstorms. Although a tornado is not
immediately likely, if one is spotted act quickly and move to a place
of safety inside a sturdy structure, such as a basement or small
interior room.

&&

LAT...LON 4394 9833 4375 9832 4376 9836 4379 9853
      4394 9851
TIME...MOT...LOC 0034Z 268DEG 30KT 4387 9838 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Schumacher

107 
WWUS53 KFSD 230046
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
746 PM CDT Sun Aug 22 2021

SDC003-230056-
/O.EXP.KFSD.SV.W.0095.000000T0000Z-210823T0045Z/
Aurora SD-
746 PM CDT Sun Aug 22 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN AURORA COUNTY HAS
EXPIRED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been allowed to expire.

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

LAT...LON 4394 9833 4375 9832 4376 9836 4379 9853
      4394 9851
TIME...MOT...LOC 0046Z 268DEG 30KT 4387 9825 

$$

Schumacher

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 22, 7:15 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Davison, Hanson, Miner, Sanborn	30 min
Aug 22, 7:31 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Davison, Sanborn	44 min
Aug 22, 8:06 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FSD	Davison, Hanson, Miner, Sanborn	39 min
Aug 22, 8:32 PM CDT	Severe Thunderstorm Warning	FSD	Hanson, McCook	43 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2021 Every severe thunderstorm 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.