Alert archive / Illinois / Severe Thunderstorm Watches in 2005

Severe Thunderstorm Watch 655

July 21, 200515 counties in Illinois; 13 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Jul 21, 2005, 8:50 AM CDT for 15 counties in Illinois; 13 counties in Wisconsin. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jul 21, 2005, 8:50 AM CDT (13:50 UTC)
Expired: Jul 21, 2005, 1:00 PM CDT
In force: 4 hr
Issued by: the Storm Prediction Center

All 28 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Will County, IL, Winnebago County, IL, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green Lake County, WI, Jefferson County, WI, Kenosha County, WI, Marquette County, WI, Milwaukee County, WI, Rock County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 34 km from the middle of the area, began a volume at 13:53 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.

Warnings issued inside it

1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jul 21, 10:39 AM CDT	Severe Thunderstorm Warning	MKX	Milwaukee, Waukesha	54 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 1.8 hours before the alert went out and 200 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: 521 J/kg
Mixed-layer CIN: -294 J/kg
Mixed-layer LCL: 834 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 89 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

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, 6:27 AM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cass, Champaign, DeKalb and 44 more	2 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 21, 4:05 AM CDT	Severe Thunderstorm Watch	SPC	Buffalo, Crawford, Grant, La Crosse, Pepin, Pierce and 2 more	5 hr

Nearby

Severe Thunderstorm Watches in Illinois, 2005 Severe Thunderstorm Watches in Wisconsin, 2005 Every severe thunderstorm watch 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.