Alert archive / Nebraska / Mesoscale Discussions in 2018

Mesoscale Discussion 545

May 27, 20187 counties in Nebraska; Fall River County, South Dakota; 6 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at May 27, 2018, 4:42 PM MDT for 7 counties in Nebraska; Fall River County, South Dakota; 6 counties in Wyoming. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: May 27, 2018, 4:42 PM MDT (22:42 UTC)
Expired: May 27, 2018, 6:15 PM MDT
In force: 93 min
Issued by: the Storm Prediction Center

Counties Banner County, NE, Box Butte County, NE, Dawes County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sioux County, NE, Fall River County, SD, Converse County, WY, Goshen County, WY, Laramie County, WY, Natrona County, WY, Niobrara County, WY, Platte County, WY

The radar

The Cheyenne radar (KCYS), 127 km from the middle of the area, began a volume at 22:43 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 126May 27, 5:25 PM MDT

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 10.7 hours before the alert went out and 300 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: 4365 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 105 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 27, 12:05 PM MDT	Severe Thunderstorm Watch	SPC	Banner, Box Butte, Cheyenne, Dawes, Kimball, Morrill and 2 more	9 hr
May 27, 1:13 PM MDT	Severe Thunderstorm Watch	SPC	Dundy, Hitchcock, Red Willow	7 hr
May 27, 2:40 PM MDT	Severe Thunderstorm Watch	SPC	Arthur, Chase, Cherry, Deuel, Frontier, Garden and 10 more	6 hr
May 27, 4:30 PM MDT	Mesoscale Discussion	SPC	Dundy	2 hr
May 27, 5:41 PM MDT	Mesoscale Discussion	SPC	Arthur, Chase, Cherry, Deuel, Frontier, Garden and 10 more	94 min
May 26, 9:13 PM MDT	Mesoscale Discussion	SPC	Harding, Perkins	2 hr
May 27, 5:06 PM MDT	Mesoscale Discussion	SPC	Bennett, Buffalo, Butte, Corson, Custer, Dewey and 22 more	84 min
May 27, 5:27 PM MDT	Severe Thunderstorm Watch	SPC	Bennett, Butte, Custer, Dewey, Fall River, Haakon and 16 more	6 hr
May 27, 11:36 AM MDT	Mesoscale Discussion	SPC	Albany, Carbon, Converse, Fremont, Hot Springs, Johnson and 4 more	2 hr
May 27, 2:25 PM MDT	Mesoscale Discussion	SPC	Albany, Carbon, Converse, Fremont, Goshen, Laramie and 2 more	2 hr

Nearby

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