Alert archive / Nebraska / Mesoscale Discussions in 2020

Mesoscale Discussion 643

May 20, 20204 states

The Storm Prediction Center issued this mesoscale discussion at May 20, 2020, 1:07 PM MDT for 4 states. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: May 20, 2020, 1:07 PM MDT (19:07 UTC)
Expired: May 20, 2020, 2:30 PM MDT
In force: 83 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch likely
Chance of a watch: 95%

All 22 counties

Logan County, CO, Weld County, CO, Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sioux County, NE, Butte County, SD, Custer County, SD, Fall River County, SD, Lawrence County, SD, Pennington County, SD, Converse County, WY, Crook County, WY, Goshen County, WY, Laramie County, WY, Niobrara County, WY, Platte County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 170 km from the middle of the area, began a volume at 19:07 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 195May 20, 2:20 PM MDT

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 7.1 hours before the alert went out and 163 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: 1415 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 10 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 20, 2:22 PM MDT	Severe Thunderstorm Watch	SPC	Logan, Morgan, Weld	8 hr
May 20, 2:51 PM MDT	Mesoscale Discussion	SPC	Baca, Bent, Cheyenne, Kiowa, Kit Carson, Prowers	114 min
May 20, 5:25 PM MDT	Mesoscale Discussion	SPC	Logan, Weld	95 min

Nearby

Mesoscale Discussions in Nebraska, 2020 Mesoscale Discussions in Wyoming, 2020 Mesoscale Discussions in South Dakota, 2020 Every mesoscale discussion 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.