Alert archive / South Dakota / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 331, NWS Rapid City, SD

July 31, 2020Perkins County, South Dakota

NWS Rapid City, SD issued this severe thunderstorm warning at Jul 31, 2020, 2:04 PM MDT for Perkins County, South Dakota. It was in force for 18 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 31, 2020, 2:04 PM MDT (20:04 UTC)
Expired
Jul 31, 2020, 2:22 PM MDT
In force
18 min
Issued by
NWS Rapid City, SD
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Perkins County, SD

The radar

The Rapid City radar (KUDX), 154 km from the middle of the area, began a volume at 20:06 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 12:00Z, 8.1 hours before the alert went out and 326 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-pSkew-T log-p diagram, Aberdeen, SD at 12:00Z on 2020-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Aberdeen, SD at 12:00Z on 2020-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1473 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 2:10 PM MDTSpecial Weather StatementUNRHarding50 min
Jul 31, 2:33 PM MDTSpecial Weather StatementUNRPerkins27 min
Jul 31, 2:47 PM MDTSpecial Weather StatementUNRHarding28 min
Jul 31, 2:49 PM MDTSpecial Weather StatementUNRPerkins26 min
Jul 31, 3:15 PM MDTSpecial Weather StatementUNRHarding45 min
Jul 31, 4:12 PM MDTSpecial Weather StatementUNRMeade48 min
Jul 31, 4:18 PM MDTSpecial Weather StatementUNRMeade42 min
Jul 31, 4:39 PM MDTSpecial Weather StatementUNRLawrence51 min
Jul 31, 4:42 PM MDTSpecial Weather StatementUNRZiebach48 min
Jul 31, 5:02 PM MDTSpecial Weather StatementUNRHaakon, Pennington58 min
Jul 31, 5:43 PM MDTSpecial Weather StatementUNRBennett, Jackson, Oglala Lakota47 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2020Every 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.