Alert archive / South Dakota / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 138, NWS Sioux Falls, SD

July 17, 2020Hanson County, Hutchinson County, McCook County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 17, 2020, 8:59 AM CDT for Hanson County, Hutchinson County, McCook County, South Dakota. It was in force for 46 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: Jul 17, 2020, 8:59 AM CDT (13:59 UTC)
Expired: Jul 17, 2020, 9:45 AM CDT
In force: 46 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Hanson County, SD, Hutchinson County, SD, McCook County, SD

The radar

The Sioux Falls radar (KFSD), 73 km from the middle of the area, began a volume at 13:59 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

Minneapolis, MN (KMPX), launched 12:00Z, 2.0 hours before the alert went out and 352 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: 1028 J/kg
Mixed-layer CIN: -75 J/kg
Mixed-layer LCL: 924 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 145 m²/s²
0-3 km storm-relative helicity: 190 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 Jul 17, 6:32 AM CDT, 2 hours 27 minutes earlier.

Area forecast discussion, Jul 17, 6:32 AM CDT, 2 hours 27 minutes before

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Hazardous weather outlook, Jul 17, 5:29 AM CDT, 3 hours 30 minutes before

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In the hours before

Local storm report, Jul 17, 8:42 AM CDT, 17 minutes before

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Local storm report, Jul 17, 8:44 AM CDT, 15 minutes before

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Local storm report, Jul 17, 8:58 AM CDT, 1 minute before

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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
Jul 17, 4:05 AM CDT	Excessive Heat Watch	FSD	Bon Homme, Clay, Hanson, Hutchinson, Lincoln, McCook and 4 more	11 hr
Jul 17, 8:01 AM CDT	Severe Thunderstorm Warning	FSD	Bon Homme	29 min
Jul 17, 8:26 AM CDT	Severe Thunderstorm Warning	FSD	Bon Homme, Yankton	49 min
Jul 17, 2:36 PM CDT	Excessive Heat Warning	FSD	Bon Homme, Clay, Hutchinson, Lincoln, Minnehaha, Turner and 2 more	29 hr
Jul 17, 2:36 PM CDT	Heat Advisory	FSD	Brookings, Charles Mix, Davison, Douglas, Hanson, Lake and 4 more	25 hr

Nearby

Severe Thunderstorm Warnings in South Dakota, 2020 Every severe thunderstorm warning 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.