Alert archive / Iowa / Mesoscale Discussions in 2007

Mesoscale Discussion 871

May 23, 200730 counties in Iowa; 9 counties in Minnesota; 15 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 23, 2007, 5:24 PM CDT for 30 counties in Iowa; 9 counties in Minnesota; 15 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 23, 2007, 5:24 PM CDT (22:24 UTC)
Expired: May 23, 2007, 7:30 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 54 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Boone County, IA, Butler County, IA, Carroll County, IA, Cass County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clarke County, IA, Dallas County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Howard County, IA, Madison County, IA, Mitchell County, IA, Polk County, IA, Ringgold County, IA, Story County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Webster County, IA, Worth County, IA, Wright County, IA, Dodge County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Mower County, MN, Olmsted County, MN, Steele County, MN, Wabasha County, MN, Winona County, MN, Ashland County, WI, Barron County, WI, Bayfield County, WI, Buffalo County, WI, Chippewa County, WI, Dunn County, WI, Eau Claire County, WI, Iron County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Rusk County, WI, Saint Croix County, WI, Sawyer County, WI, Washburn County, WI

The radar

The La Crosse radar (KARX), 99 km from the middle of the area, began a volume at 22:27 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

Minneapolis, MN (KMPX), launched 12:00Z, 10.4 hours before the alert went out and 171 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: 84 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 811 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 141 m²/s²
0-3 km storm-relative helicity: 164 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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.

Issued	Product	Office	Counties	Lasted
May 23, 12:30 PM CDT	Mesoscale Discussion	SPC	Adair, Allamakee, Audubon, Benton, Black Hawk, Boone and 45 more	3 hr
May 23, 1:27 PM CDT	Severe Thunderstorm Watch	SPC	Fremont, Mills, Montgomery, Page	7 hr
May 23, 2:58 PM CDT	Severe Thunderstorm Watch	SPC	Chickasaw, Floyd, Howard, Mitchell	6 hr
May 23, 3:11 PM CDT	Mesoscale Discussion	SPC	Fremont, Page	94 min
May 23, 3:11 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Appanoose, Audubon, Black Hawk, Boone and 43 more	6 hr
May 23, 5:19 PM CDT	Mesoscale Discussion	SPC	Fremont, Mills, Montgomery, Page, Pottawattamie	86 min
May 22, 7:50 PM CDT	Mesoscale Discussion	SPC	Big Stone, Chippewa, Lac qui Parle, Lincoln, Pipestone, Swift and 2 more	85 min

Nearby

Mesoscale Discussions in Iowa, 2007 Mesoscale Discussions in Wisconsin, 2007 Mesoscale Discussions in Minnesota, 2007 Every mesoscale discussion in 2007

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.