Alert archive / South Dakota / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 227, NWS Sioux Falls, SD

August 17, 20264 counties in South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 17, 2026, 8:49 PM CDT for 4 counties in South Dakota. It was in force for 26 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 17, 2026, 8:49 PM CDT (01:49 UTC)
Expired: Aug 17, 2026, 9:15 PM CDT
In force: 26 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Beadle County, SD, Kingsbury County, SD, Miner County, SD, Sanborn County, SD

The radar

The Sioux Falls radar (KFSD), 114 km from the middle of the area, began a volume at 01:51 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 nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 1.8 hours before the alert went out and 88 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: 1577 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 1675 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 52 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sioux Falls, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 17, 7:29 PM CDT, 1 hour 20 minutes earlier.

Area forecast discussion, Aug 17, 7:29 PM CDT, 1 hour 20 minutes before

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Hazardous weather outlook, Aug 17, 3:44 AM CDT, 17 hours 5 minutes before

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        The site you requested is temporarily down for maintenance or an unexpected outage.
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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 11:07 PM CDT	Severe Thunderstorm Warning	FSD	Charles Mix, Gregory	38 min
Aug 17, 11:40 PM CDT	Severe Thunderstorm Warning	FSD	Charles Mix, Douglas	38 min
Aug 17, 11:54 PM CDT	Severe Thunderstorm Warning	FSD	Charles Mix, Douglas, Hutchinson	22 min
Aug 18, 12:57 AM CDT	Severe Thunderstorm Warning	FSD	Aurora, Brule, Jerauld	33 min
Aug 18, 1:29 AM CDT	Severe Thunderstorm Warning	FSD	Aurora, Brule, Davison, Jerauld	31 min
Aug 18, 2:24 AM CDT	Severe Thunderstorm Warning	FSD	Brule, Charles Mix, Gregory	32 min
Aug 18, 5:39 PM CDT	Severe Thunderstorm Warning	FSD	Pipestone, Rock	36 min
Aug 18, 6:32 PM CDT	Severe Thunderstorm Warning	FSD	Nobles	43 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2026 Every severe thunderstorm warning in 2026

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.