Alert archive / South Dakota / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 95, NWS Rapid City, SD

July 18, 2017Butte County, South Dakota

NWS Rapid City, SD issued this severe thunderstorm warning at Jul 18, 2017, 6:55 PM MDT for Butte County, South Dakota. It was in force for 65 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 18, 2017, 6:55 PM MDT (00:55 UTC)
Expired: Jul 18, 2017, 8:00 PM MDT
In force: 65 min
Issued by: NWS Rapid City, SD
Area: Storm-based polygon
Hail: 2.75 in
Wind: 70.0 mph

County Butte County, SD

The radar

The Rapid City radar (KUDX), 102 km from the middle of the area, began a volume at 00:55 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

Rapid City, SD (KRAP), launched 00:00Z, 0.9 hours before the alert went out and 105 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: 726 J/kg
Mixed-layer CIN: -72 J/kg
Mixed-layer LCL: 1891 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 161 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.8

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 Rapid City, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 18, 4:37 PM MDT, 2 hours 18 minutes earlier.

Area forecast discussion, Jul 18, 4:37 PM MDT, 2 hours 18 minutes before

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Hazardous weather outlook, Jul 18, 6:20 AM MDT, 12 hours 35 minutes before

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In the hours before

Special weather statement, Jul 18, 4:59 PM MDT, 1 hour 56 minutes before

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Special weather statement, Jul 18, 5:06 PM MDT, 1 hour 49 minutes before

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Local storm report, Jul 18, 5:27 PM MDT, 1 hour 28 minutes before

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Special weather statement, Jul 18, 6:11 PM MDT, 44 minutes before

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Local storm report, Jul 18, 6:29 PM MDT, 26 minutes before

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Local storm report, Jul 18, 6:49 PM MDT, 6 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 6:11 PM MDT	Special Weather Statement	UNR	Pennington	34 min
Jul 18, 7:37 PM MDT	Severe Thunderstorm Warning	UNR	Butte, Meade	53 min
Jul 18, 8:24 PM MDT	Severe Thunderstorm Warning	UNR	Meade, Pennington	66 min
Jul 18, 9:21 PM MDT	Severe Thunderstorm Warning	UNR	Haakon, Jackson, Pennington	25 min
Jul 19, 2:08 PM MDT	Special Weather Statement	UNR	Tripp	52 min
Jul 19, 2:30 PM MDT	Severe Thunderstorm Warning	UNR	Tripp	45 min
Jul 19, 3:56 PM MDT	Special Weather Statement	UNR	Todd	34 min
Jul 19, 4:08 PM MDT	Severe Thunderstorm Warning	UNR	Todd, Tripp	38 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2017 Every severe thunderstorm warning in 2017

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.