Alert archive / Iowa / Mesoscale Discussions in 2005

Mesoscale Discussion 1791

July 20, 200541 counties in Iowa; 17 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Jul 20, 2005, 3:23 AM CDT for 41 counties in Iowa; 17 counties in Minnesota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 20, 2005, 3:23 AM CDT (08:23 UTC)
Expired: Jul 20, 2005, 5:30 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 58 counties

Allamakee County, IA, Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Cerro Gordo County, IA, Cherokee County, IA, Chickasaw County, IA, Clay County, IA, Clayton County, IA, Delaware County, IA, Dickinson County, IA, Emmet County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Linn County, IA, Mitchell County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Pocahontas County, IA, Sac County, IA, Tama County, IA, Webster County, IA, Winnebago County, IA, Winneshiek County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Brown County, MN, Cottonwood County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Nicollet County, MN, Nobles County, MN, Redwood County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN

The radar

The Des Moines radar (KDMX), 168 km from the middle of the area, began a volume at 08:23 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 00:00Z, 8.4 hours before the alert went out and 181 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: 2127 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1273 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 154 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 7.0

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
Jul 19, 11:18 PM CDT	Mesoscale Discussion	SPC	Lyon, Sioux	87 min
Jul 20, 1:25 AM CDT	Severe Thunderstorm Watch	SPC	Buena Vista, Calhoun, Cherokee, Clay, Dickinson, Emmet and 12 more	6 hr
Jul 20, 5:55 AM CDT	Mesoscale Discussion	SPC	Allamakee, Audubon, Benton, Black Hawk, Boone, Bremer and 37 more	95 min
Jul 20, 11:26 AM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Boone, Carroll, Cass and 26 more	94 min
Jul 19, 10:43 PM CDT	Mesoscale Discussion	SPC	Marshall, Norman, Pennington, Polk, Red Lake	92 min
Jul 20, 1:28 AM CDT	Mesoscale Discussion	SPC	Beltrami, Cook, Koochiching, Lake, Saint Louis	32 min

Nearby

Mesoscale Discussions in Iowa, 2005 Mesoscale Discussions in Minnesota, 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.