Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 392

April 9, 201137 counties in Iowa; 28 counties in Nebraska; Clay County, Lincoln County, Union County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2011, 9:06 PM CDT for 37 counties in Iowa; 28 counties in Nebraska; Clay County, Lincoln County, Union County, South Dakota. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Apr 9, 2011, 9:06 PM CDT (02:06 UTC)
Expired
Apr 9, 2011, 10:00 PM CDT
In force
54 min
Issued by
the Storm Prediction Center
All 68 counties

Audubon 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, Emmet County, IA, Fremont County, IA, Greene County, IA, Guthrie County, IA, Hancock County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Lyon County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, O'Brien County, IA, Osceola County, IA, Page County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, 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, Hall County, NE, Hamilton County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Otoe County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, York County, NE, Clay County, SD, Lincoln County, SD, Union County, SD

The radar

The Omaha radar (KOAX), 51 km from the middle of the area, began a volume at 02:05 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, 2.1 hours before the alert went out and 51 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 2011-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3327 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 2011-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 270 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
3327 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
1533 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
270 m²/s²
0-3 km storm-relative helicity
403 m²/s²
Significant tornado parameter
3.7
Supercell composite
19.0

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
Apr 9, 7:42 PM CDTSevere Thunderstorm WatchSPCAllamakee, Chickasaw, Floyd, Howard, Mitchell, Winneshiek7 hr
Apr 9, 10:43 PM CDTMesoscale DiscussionSPCAllamakee, Black Hawk, Bremer, Buena Vista, Butler, Cerro Gordo and 25 more62 min
Apr 9, 11:01 PM CDTTornado WatchSPCAllamakee, Bremer, Buena Vista, Butler, Cerro Gordo, Cherokee and 19 more5 hr
Apr 10, 1:26 AM CDTMesoscale DiscussionSPCAllamakee, Buena Vista, Cerro Gordo, Chickasaw, Clay, Dickinson and 14 more64 min
Apr 10, 1:30 PM CDTMesoscale DiscussionSPCAllamakee, Buchanan, Clayton, Delaware, Dubuque, Fayette and 5 more2 hr
Apr 10, 3:19 PM CDTTornado Watch PDSSPCAllamakee, Clayton, Fayette, Howard, Winneshiek7 hr
Apr 10, 5:03 PM CDTMesoscale DiscussionSPCCedar, Clinton, Davis, Delaware, Des Moines, Dubuque and 12 more57 min
Apr 10, 6:05 PM CDTTornado WatchSPCClinton, Des Moines, Jackson, Lee, Louisa, Muscatine and 1 more7 hr
Apr 9, 7:47 PM CDTSevere Thunderstorm WatchSPCBrookings, Davison, Douglas, Hanson, Hutchinson, Kingsbury and 6 more3 hr

Nearby

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