Alert archive / Nebraska / Mesoscale Discussions in 2018

Mesoscale Discussion 449

May 17, 2018Sedgwick County, Colorado; 17 counties in Nebraska; 10 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 17, 2018, 9:03 PM MDT for Sedgwick County, Colorado; 17 counties in Nebraska; 10 counties in South Dakota. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: May 17, 2018, 9:03 PM MDT (03:03 UTC)
Expired: May 17, 2018, 11:00 PM MDT
In force: 117 min
Issued by: the Storm Prediction Center

All 28 counties

Sedgwick County, CO, Arthur County, NE, Blaine County, NE, Brown County, NE, Cherry County, NE, Cheyenne County, NE, Deuel County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Keith County, NE, Keya Paha County, NE, Lincoln County, NE, Logan County, NE, McPherson County, NE, Perkins County, NE, Rock County, NE, Thomas County, NE, Bennett County, SD, Hughes County, SD, Hyde County, SD, Jones County, SD, Lyman County, SD, Mellette County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD

The radar

The North Platte radar (KLNX), 89 km from the middle of the area, began a volume at 03:06 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

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 3.1 hours before the alert went out and 175 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: 1242 J/kg
Mixed-layer CIN: -26 J/kg
Mixed-layer LCL: 2392 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: 220 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.7

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	Logan, Phillips, Sedgwick	58 min
May 18, 1:43 PM MDT	Mesoscale Discussion	SPC	Baca, Bent, Kiowa, Prowers	2 hr
May 18, 3:02 PM MDT	Severe Thunderstorm Watch	SPC	Baca, Bent, Cheyenne, Crowley, El Paso, Huerfano and 6 more	7 hr
May 18, 3:06 PM MDT	Mesoscale Discussion	SPC	Adams, Arapahoe, Boulder, Broomfield, Denver, Jefferson and 4 more	114 min
May 18, 1:50 PM MDT	Mesoscale Discussion	SPC	Scotts Bluff, Sioux	115 min
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 Nebraska, 2018 Mesoscale Discussions in South Dakota, 2018 Mesoscale Discussions in Colorado, 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.