Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 2076

August 28, 201129 counties in Iowa; 23 counties in Nebraska; 4 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2011, 10:41 AM CDT for 29 counties in Iowa; 23 counties in Nebraska; 4 counties in South Dakota. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Aug 28, 2011, 10:41 AM CDT (15:41 UTC)
Expired: Aug 28, 2011, 12:15 PM CDT
In force: 94 min
Issued by: the Storm Prediction Center

All 56 counties

Audubon County, IA, Boone County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Fremont County, IA, Greene County, IA, Guthrie County, IA, Harrison County, IA, Ida County, IA, Lyon County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Pocahontas County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Webster County, IA, Woodbury County, IA, Antelope County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Otoe County, NE, Pierce County, NE, Platte County, NE, Sarpy County, NE, Saunders County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Clay County, SD, Lincoln County, SD, Union County, SD, Yankton County, SD

The radar

The Omaha radar (KOAX), 98 km from the middle of the area, began a volume at 15:42 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

Omaha, NE (KOAX), launched 12:00Z, 3.7 hours before the alert went out and 98 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: 1560 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 118 m²/s²
0-3 km storm-relative helicity: 218 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.7

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 28, 8:00 AM CDT	Severe Thunderstorm Watch	SPC	Audubon, Boone, Buena Vista, Calhoun, Carroll, Cass and 27 more	5 hr
Aug 28, 5:16 AM CDT	Mesoscale Discussion	SPC	Boyd, Keya Paha, Knox	2 hr
Aug 28, 2:09 AM CDT	Mesoscale Discussion	SPC	Brown, Campbell, Corson, Dewey, Edmunds, Faulk and 5 more	66 min

Nearby

Mesoscale Discussions in Iowa, 2011 Mesoscale Discussions in Nebraska, 2011 Mesoscale Discussions in South Dakota, 2011 Every mesoscale discussion in 2011

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.