Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 2040

August 23, 201162 counties in Iowa; 5 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Aug 23, 2011, 12:45 AM CDT for 62 counties in Iowa; 5 counties in Minnesota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 23, 2011, 12:45 AM CDT (05:45 UTC)
Expired
Aug 23, 2011, 2:45 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 67 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cerro Gordo County, IA, Cherokee County, IA, Clarke County, IA, Clay County, IA, Crawford County, IA, Dallas County, IA, Decatur County, IA, Dickinson County, IA, Emmet County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Humboldt County, IA, Ida County, IA, Iowa County, IA, Jasper County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Kossuth County, IA, Linn County, IA, Lucas County, IA, Lyon County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Pocahontas County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Sac County, IA, Story County, IA, Tama County, IA, Union County, IA, Warren County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Cottonwood County, MN, Faribault County, MN, Jackson County, MN, Martin County, MN, Nobles County, MN

The radar

The Des Moines radar (KDMX), 74 km from the middle of the area, began a volume at 05:47 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, 5.8 hours before the alert went out and 211 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 2011-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3125 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 2011-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 square meters per square second.193958Sfc1 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
3125 J/kg
Mixed-layer CIN
-39 J/kg
Mixed-layer LCL
970 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
1.5
Supercell composite
8.3

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.

IssuedProductOfficeCountiesLasted
Aug 23, 3:00 AM CDTSevere Thunderstorm WatchSPCAllamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 24 more6 hr
Aug 23, 4:55 AM CDTMesoscale DiscussionSPCAllamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 23 more2 hr
Aug 23, 3:10 AM CDTMesoscale DiscussionSPCAnoka, Benton, Carver, Chippewa, Chisago, Hennepin and 21 more2 hr
Aug 23, 3:34 AM CDTSevere Thunderstorm WatchSPCAnoka, Benton, Blue Earth, Brown, Carver, Chippewa and 34 more4 hr

Nearby

Mesoscale Discussions in Iowa, 2011Mesoscale Discussions in Minnesota, 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.