Alert archive / Iowa / Mesoscale Discussions in 2005

Mesoscale Discussion 1807

July 21, 20054 states

The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2005, 5:28 AM CDT for 4 states. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: Jul 21, 2005, 5:28 AM CDT (10:28 UTC)
Expired: Jul 21, 2005, 7:00 AM CDT
In force: 92 min
Issued by: the Storm Prediction Center

All 46 counties

Allamakee County, IA, Benton County, IA, Bremer County, IA, Buchanan County, IA, Cedar County, IA, Chickasaw County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Henry County, IA, Howard County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Mitchell County, IA, Muscatine County, IA, Scott County, IA, Washington County, IA, Winneshiek County, IA, Jo Daviess County, IL, Mercer County, IL, Rock Island County, IL, Dodge County, MN, Fillmore County, MN, Goodhue County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Steele County, MN, Wabasha County, MN, Winona County, MN, Buffalo County, WI, Crawford County, WI, Grant County, WI, Iowa County, WI, La Crosse County, WI, Lafayette County, WI, Monroe County, WI, Richland County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 132 km from the middle of the area, began a volume at 10:31 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 00:00Z, 10.5 hours before the alert went out and 154 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: 3277 J/kg
Mixed-layer CIN: -20 J/kg
Mixed-layer LCL: 1271 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 71 m²/s²
0-3 km storm-relative helicity: 225 m²/s²
Significant tornado parameter: 1.6
Supercell composite: 13.2

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
Jul 21, 6:27 AM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cass, Champaign, DeKalb and 44 more	2 hr
Jul 21, 8:50 AM CDT	Severe Thunderstorm Watch	SPC	Boone, Cook, DeKalb, DuPage, Grundy, Kane and 9 more	4 hr
Jul 21, 10:27 AM CDT	Mesoscale Discussion	SPC	Cook, DuPage, Kankakee, Lake, Will	33 min
Jul 21, 3:15 PM CDT	Severe Thunderstorm Watch	SPC	Champaign, Christian, Coles, Douglas, Edgar, Ford and 5 more	6 hr
Jul 21, 5:33 PM CDT	Mesoscale Discussion	SPC	Champaign, Christian, Coles, Douglas, Edgar, Ford and 5 more	87 min
Jul 20, 10:10 PM CDT	Severe Thunderstorm Watch	SPC	Monona, Plymouth, Woodbury	4 hr
Jul 21, 1:17 AM CDT	Mesoscale Discussion	SPC	Adair, Audubon, Benton, Black Hawk, Boone, Bremer and 43 more	58 min
Jul 21, 4:05 AM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 10 more	5 hr

Nearby

Mesoscale Discussions in Iowa, 2005 Mesoscale Discussions in Minnesota, 2005 Mesoscale Discussions in Wisconsin, 2005 Every mesoscale discussion in 2005

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.