Alert archive / South Dakota / Mesoscale Discussions in 2013

Mesoscale Discussion 1713

August 13, 201310 counties in South Dakota; Crook County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Aug 13, 2013, 2:51 PM MDT for 10 counties in South Dakota; Crook County, Wyoming. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Aug 13, 2013, 2:51 PM MDT (20:51 UTC)
Expired: Aug 13, 2013, 4:15 PM MDT
In force: 84 min
Issued by: the Storm Prediction Center

Counties Bennett County, SD, Butte County, SD, Custer County, SD, Haakon County, SD, Jackson County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Crook County, WY

The radar

The Rapid City radar (KUDX), 15 km from the middle of the area, began a volume at 20:53 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 12:00Z, 8.9 hours before the alert went out and 21 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: 1268 J/kg
Mixed-layer CIN: -38 J/kg
Mixed-layer LCL: 601 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -54 m²/s²
0-3 km storm-relative helicity: -5 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 13, 12:36 PM MDT	Mesoscale Discussion	SPC	Butte, Custer, Haakon, Harding, Jackson, Lawrence and 3 more	2 hr
Aug 13, 1:17 PM MDT	Severe Thunderstorm Watch	SPC	Bennett, Butte, Custer, Fall River, Haakon, Harding and 8 more	8 hr
Aug 13, 4:45 PM MDT	Mesoscale Discussion	SPC	Bennett, Custer, Fall River, Haakon, Jackson, Jones and 7 more	90 min
Aug 13, 2:05 PM MDT	Mesoscale Discussion	SPC	Laramie	115 min

Nearby

Mesoscale Discussions in South Dakota, 2013 Mesoscale Discussions in Wyoming, 2013 Every mesoscale discussion in 2013

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.