Alert archive / Illinois / Mesoscale Discussions in 2005

Mesoscale Discussion 1808

July 21, 200550 counties in Illinois; 14 counties in Iowa; 5 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2005, 6:27 AM CDT for 50 counties in Illinois; 14 counties in Iowa; 5 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 21, 2005, 6:27 AM CDT (11:27 UTC)
Expired: Jul 21, 2005, 8:30 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 69 counties

Cedar County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cass County, IL, Champaign County, IL, DeKalb County, IL, DeWitt County, IL, Douglas County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Jo Daviess County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Moultrie County, IL, Ogle County, IL, Peoria County, IL, Piatt County, IL, Putnam County, IL, Rock Island County, IL, Sangamon County, IL, Schuyler County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Green County, WI, Kenosha County, WI, Lafayette County, WI, Rock County, WI, Walworth County, WI

The radar

The Quad Cities radar (KDVN), 89 km from the middle of the area, began a volume at 11:26 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.

Severe Thunderstorm Watch 655Jul 21, 8:50 AM CDT

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 11.5 hours before the alert went out and 85 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, 5:28 AM CDT	Mesoscale Discussion	SPC	Jo Daviess, Mercer, Rock Island	92 min
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 Illinois, 2005 Mesoscale Discussions in Iowa, 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.