Alert archive / Nebraska / Mesoscale Discussions in 2014

Mesoscale Discussion 1590

August 20, 20144 states

The Storm Prediction Center issued this mesoscale discussion at Aug 20, 2014, 9:07 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 20, 2014, 9:07 PM CDT (02:07 UTC)
Expired: Aug 20, 2014, 11:30 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 40 counties

Lyon County, IA, Plymouth County, IA, Sioux County, IA, Rock County, MN, Antelope County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Cedar County, NE, Custer County, NE, Dixon County, NE, Garfield County, NE, Greeley County, NE, Holt County, NE, Knox County, NE, Loup County, NE, Madison County, NE, Pierce County, NE, Rock County, NE, Sherman County, NE, Valley County, NE, Wayne County, NE, Wheeler County, NE, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Hanson County, SD, Hutchinson County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Sanborn County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 181 km from the middle of the area, began a volume at 02:09 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, 2.1 hours before the alert went out and 240 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: 1531 J/kg
Mixed-layer CIN: -100 J/kg
Mixed-layer LCL: 2021 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 91 m²/s²
0-3 km storm-relative helicity: 162 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 21, 3:58 AM CDT	Mesoscale Discussion	SPC	Dickinson, Emmet, Osceola	92 min
Aug 21, 5:15 AM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Cerro Gordo, Chickasaw, Clayton, Fayette, Floyd and 6 more	5 hr
Aug 21, 9:04 AM CDT	Mesoscale Discussion	SPC	Allamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 31 more	86 min
Aug 21, 12:29 AM CDT	Mesoscale Discussion	SPC	Benton, Big Stone, Blue Earth, Brown, Carver, Chippewa and 32 more	2 hr
Aug 21, 1:00 AM CDT	Severe Thunderstorm Watch	SPC	Blue Earth, Brown, Carver, Chippewa, Douglas, Faribault and 22 more	6 hr
Aug 21, 5:43 PM CDT	Mesoscale Discussion	SPC	Adams, Clay, Fillmore, Franklin, Gage, Jefferson and 6 more	2 hr
Aug 20, 7:53 PM CDT	Mesoscale Discussion	SPC	Campbell, Corson, Dewey, Edmunds, Faulk, Haakon and 11 more	97 min

Nearby

Mesoscale Discussions in Nebraska, 2014 Mesoscale Discussions in South Dakota, 2014 Mesoscale Discussions in Iowa, 2014 Every mesoscale discussion in 2014

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.