Alert archive / Wyoming / Mesoscale Discussions in 2018

Mesoscale Discussion 451

May 18, 2018Scotts Bluff County, Sioux County, Nebraska; Custer County, Fall River County, Lawrence County, South Dakota; 10 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at May 18, 2018, 1:50 PM MDT for Scotts Bluff County, Sioux County, Nebraska; Custer County, Fall River County, Lawrence County, South Dakota; 10 counties in Wyoming. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: May 18, 2018, 1:50 PM MDT (19:50 UTC)
Expired: May 18, 2018, 3:45 PM MDT
In force: 115 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Scotts Bluff County, NE, Sioux County, NE, Custer County, SD, Fall River County, SD, Lawrence County, SD, Albany County, WY, Campbell County, WY, Converse County, WY, Goshen County, WY, Johnson County, WY, Laramie County, WY, Natrona County, WY, Niobrara County, WY, Platte County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 207 km from the middle of the area, began a volume at 19:52 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, 7.8 hours before the alert went out and 200 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1315 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: -16 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, 6:47 PM MDT	Mesoscale Discussion	SPC	Arthur, Banner, Box Butte, Cheyenne, Dawes, Deuel and 9 more	58 min
May 17, 9:03 PM MDT	Mesoscale Discussion	SPC	Arthur, Blaine, Brown, Cherry, Cheyenne, Deuel and 11 more	117 min
May 18, 3:02 PM MDT	Severe Thunderstorm Watch	SPC	Dundy, Hitchcock, Red Willow	7 hr
May 18, 5:04 PM MDT	Mesoscale Discussion	SPC	Banner, Box Butte, Dawes, Morrill, Scotts Bluff, Sioux	86 min
May 18, 5:27 PM MDT	Mesoscale Discussion	SPC	Dundy, Hitchcock, Red Willow	63 min
May 17, 7:11 PM MDT	Mesoscale Discussion	SPC	Bennett, Buffalo, Dewey, Edmunds, Fall River, Faulk and 17 more	64 min

Nearby

Mesoscale Discussions in Wyoming, 2018 Mesoscale Discussions in South Dakota, 2018 Mesoscale Discussions in Nebraska, 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.