Alert archive / Nebraska / Mesoscale Discussions in 2011

Mesoscale Discussion 1894

August 7, 201116 counties in Iowa; 36 counties in Nebraska; 4 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 7, 2011, 10:28 PM CDT for 16 counties in Iowa; 36 counties in Nebraska; 4 counties in South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 7, 2011, 10:28 PM CDT (03:28 UTC)
Expired
Aug 8, 2011, 12:30 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 56 counties

Audubon County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cherokee County, IA, Crawford County, IA, Harrison County, IA, Ida County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, Plymouth County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Woodbury County, IA, Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Custer County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Howard County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, York County, NE, Bon Homme County, SD, Clay County, SD, Union County, SD, Yankton County, SD

The radar

The Omaha radar (KOAX), 133 km from the middle of the area, began a volume at 03:30 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

Omaha, NE (KOAX), launched 00:00Z, 3.5 hours before the alert went out and 133 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-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2011-08-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1873 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2011-08-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1873 J/kg
Mixed-layer CIN
-119 J/kg
Mixed-layer LCL
1289 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
93 m²/s²
Significant tornado parameter
0.2
Supercell composite
3.1

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.

IssuedProductOfficeCountiesLasted
Aug 7, 7:49 PM CDTSevere Thunderstorm WatchSPCIda, Woodbury7 hr
Aug 7, 11:34 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Audubon, Calhoun, Carroll, Cass and 15 more4 hr
Aug 8, 1:06 PM CDTMesoscale DiscussionSPCBenton, Cedar, Clinton, Des Moines, Dubuque, Henry and 11 more84 min
Aug 8, 2:41 AM CDTMesoscale DiscussionSPCAdams, Buffalo, Butler, Cass, Clay, Fillmore and 23 more34 min
Aug 8, 3:09 PM CDTMesoscale DiscussionSPCArthur, Blaine, Box Butte, Custer, Dawes, Garden and 11 more66 min
Aug 8, 4:52 PM CDTSevere Thunderstorm WatchSPCArthur, Box Butte, Chase, Cherry, Cheyenne, Dawes and 19 more6 hr
Aug 8, 6:27 PM CDTMesoscale DiscussionSPCArthur, Box Butte, Chase, Cheyenne, Dawes, Dawson and 21 more2 hr
Aug 8, 6:44 PM CDTSevere Thunderstorm WatchSPCDawson, Furnas, Gosper, Harlan, Phelps4 hr

Nearby

Mesoscale Discussions in Nebraska, 2011Mesoscale Discussions in Iowa, 2011Mesoscale Discussions in South Dakota, 2011Every 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.