Alert archive / Nebraska / Mesoscale Discussions in 2011

Mesoscale Discussion 1948

August 11, 20117 counties in Iowa; 19 counties in Nebraska; 6 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 11, 2011, 6:38 PM CDT for 7 counties in Iowa; 19 counties in Nebraska; 6 counties in South Dakota. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Aug 11, 2011, 6:38 PM CDT (23:38 UTC)
Expired: Aug 11, 2011, 8:15 PM CDT
In force: 97 min
Issued by: the Storm Prediction Center

All 32 counties

Cherokee County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Antelope County, NE, Boone County, NE, Burt County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Knox County, NE, Madison County, NE, Pierce County, NE, Platte County, NE, Saunders County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, Bon Homme County, SD, Clay County, SD, Lincoln County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Omaha radar (KOAX), 136 km from the middle of the area, began a volume at 23:41 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.

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 11.6 hours before the alert went out and 297 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: 192 J/kg
Mixed-layer CIN: -85 J/kg
Mixed-layer LCL: 1189 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.4

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 10, 7:50 PM CDT	Severe Thunderstorm Watch	SPC	Dundy, Hitchcock, Red Willow	3 hr
Aug 10, 10:10 PM CDT	Mesoscale Discussion	SPC	Arthur, Chase, Deuel, Dundy, Frontier, Hayes and 7 more	95 min
Aug 11, 4:15 PM CDT	Mesoscale Discussion	SPC	Arthur, Cherry, Garden, Grant, Hooker, Logan and 3 more	60 min
Aug 11, 4:38 PM CDT	Tornado Watch	SPC	Blaine, Boyd, Brown, Cherry, Custer, Garfield and 9 more	9 hr
Aug 11, 1:49 PM CDT	Mesoscale Discussion	SPC	Brown, Butte, Campbell, Corson, Dewey, Edmunds and 15 more	86 min
Aug 11, 3:05 PM CDT	Tornado Watch	SPC	Aurora, Beadle, Bennett, Bon Homme, Brule, Buffalo and 33 more	5 hr

Nearby

Mesoscale Discussions in Nebraska, 2011 Mesoscale Discussions in Iowa, 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.