Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 2097

September 2, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Sep 2, 2011, 2:41 PM CDT for 4 states. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Sep 2, 2011, 2:41 PM CDT (19:41 UTC)
Expired: Sep 2, 2011, 4:15 PM CDT
In force: 94 min
Issued by: the Storm Prediction Center

All 103 counties

Adair County, IA, Adams County, IA, Allamakee County, IA, Audubon County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cedar County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clarke County, IA, Clayton County, IA, Clinton County, IA, Crawford County, IA, Dallas County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Fremont County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Mills County, IA, Monona County, IA, Monroe County, IA, Montgomery County, IA, Muscatine County, IA, Pocahontas County, IA, Polk County, IA, Pottawattamie County, IA, Poweshiek County, IA, Sac County, IA, Scott County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Webster County, IA, Winneshiek County, IA, Wright County, IA, Boone County, IL, Carroll County, IL, Henry County, IL, Jo Daviess County, IL, Lee County, IL, Ogle County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL, Burt County, NE, Butler County, NE, Cass County, NE, Dodge County, NE, Douglas County, NE, Lancaster County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Washington County, NE, Crawford County, WI, Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Lafayette County, WI, Richland County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Des Moines radar (KDMX), 68 km from the middle of the area, began a volume at 19:41 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 nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 7.7 hours before the alert went out and 209 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: 1439 J/kg
Mixed-layer CIN: -303 J/kg
Mixed-layer LCL: 1897 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -77 m²/s²
0-3 km storm-relative helicity: -43 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

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.

Issued	Product	Office	Counties	Lasted
Sep 2, 3:27 AM CDT	Mesoscale Discussion	SPC	Buena Vista, Cerro Gordo, Clay, Emmet, Floyd, Hancock and 10 more	93 min
Sep 2, 3:48 AM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 15 more	6 hr
Sep 1, 8:57 PM CDT	Mesoscale Discussion	SPC	Burnett, Douglas	93 min
Sep 2, 7:29 AM CDT	Mesoscale Discussion	SPC	Adams, Calumet, Columbia, Dodge, Fond du Lac, Green Lake and 10 more	61 min
Sep 2, 7:50 AM CDT	Severe Thunderstorm Watch	SPC	Brown, Calumet, Columbia, Dodge, Door, Fond du Lac and 16 more	3 hr
Sep 2, 10:08 AM CDT	Mesoscale Discussion	SPC	Brown, Calumet, Door, Fond du Lac, Kewaunee, Manitowoc and 3 more	97 min

Nearby

Mesoscale Discussions in Iowa, 2011 Mesoscale Discussions in Wisconsin, 2011 Mesoscale Discussions in Illinois, 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.