Alert archive / Illinois / Mesoscale Discussions in 2007

Mesoscale Discussion 1850

August 22, 200734 counties in Illinois; 17 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Aug 22, 2007, 3:17 PM CDT for 34 counties in Illinois; 17 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 22, 2007, 3:17 PM CDT (20:17 UTC)
Expired: Aug 22, 2007, 5:45 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 51 counties

Boone County, IL, Bureau County, IL, Carroll County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Henry 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, Marshall County, IL, Mason County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Ogle County, IL, Peoria County, IL, Putnam 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, Columbia County, WI, Dane County, WI, Dodge County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI

The radar

The Quad Cities radar (KDVN), 109 km from the middle of the area, began a volume at 20:18 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 12:00Z, 8.3 hours before the alert went out and 103 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: 284 J/kg
Mixed-layer CIN: -437 J/kg
Mixed-layer LCL: 1242 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 87 m²/s²
0-3 km storm-relative helicity: 119 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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
Aug 21, 10:49 PM CDT	Mesoscale Discussion	SPC	Carroll, Jo Daviess, Stephenson, Whiteside	86 min
Aug 22, 2:13 AM CDT	Mesoscale Discussion	SPC	Boone, Jo Daviess, Lake, McHenry, Stephenson, Winnebago	62 min
Aug 22, 4:53 AM CDT	Mesoscale Discussion	SPC	Kankakee, Will	67 min
Aug 21, 8:14 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Buffalo, Clark, Crawford, Grant, Jackson and 6 more	8 hr
Aug 22, 12:09 AM CDT	Severe Thunderstorm Watch	SPC	Columbia, Dane, Dodge, Fond du Lac, Green, Green Lake and 11 more	3 hr

Nearby

Mesoscale Discussions in Illinois, 2007 Mesoscale Discussions in Wisconsin, 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.