Alert archive / South Dakota / Mesoscale Discussions in 2018

Mesoscale Discussion 445

May 17, 20184 states

The Storm Prediction Center issued this mesoscale discussion at May 17, 2018, 4:54 PM MDT for 4 states. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: May 17, 2018, 4:54 PM MDT (22:54 UTC)
Expired: May 17, 2018, 6:00 PM MDT
In force: 66 min
Issued by: the Storm Prediction Center

All 36 counties

Carter County, MT, Adams County, ND, Bowman County, ND, Dickey County, ND, Emmons County, ND, Grant County, ND, McIntosh County, ND, Sioux County, ND, Brown County, SD, Butte County, SD, Campbell County, SD, Corson County, SD, Custer County, SD, Day County, SD, Dewey County, SD, Edmunds County, SD, Fall River County, SD, Faulk County, SD, Haakon County, SD, Harding County, SD, Jackson County, SD, Lawrence County, SD, McPherson County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Potter County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD, Crook County, WY, Niobrara County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 124 km from the middle of the area, began a volume at 22:55 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 12:00Z, 10.9 hours before the alert went out and 131 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: 975 J/kg
Mixed-layer CIN: -186 J/kg
Mixed-layer LCL: 2104 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -27 m²/s²
0-3 km storm-relative helicity: -53 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 17, 12:58 PM MDT	Mesoscale Discussion	SPC	Carter	92 min
May 17, 1:23 PM MDT	Severe Thunderstorm Watch	SPC	Carter	10 hr
May 17, 2:47 PM MDT	Mesoscale Discussion	SPC	Dickey, Emmons, McIntosh	28 min
May 17, 3:03 PM MDT	Severe Thunderstorm Watch	SPC	Dickey, Emmons, McIntosh, Sioux	6 hr
May 17, 4:19 PM MDT	Mesoscale Discussion	SPC	Goshen, Laramie	116 min

Nearby

Mesoscale Discussions in South Dakota, 2018 Mesoscale Discussions in North Dakota, 2018 Mesoscale Discussions in Wyoming, 2018 Every mesoscale discussion in 2018

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.