Alert archive / Illinois / Mesoscale Discussions in 2007

Mesoscale Discussion 403

March 31, 200743 counties in Illinois; 13 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2007, 7:25 PM CDT for 43 counties in Illinois; 13 counties in Wisconsin. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: Mar 31, 2007, 7:25 PM CDT (00:25 UTC)
Expired: Mar 31, 2007, 8:30 PM CDT
In force: 65 min
Issued by: the Storm Prediction Center

All 56 counties

Boone County, IL, Bureau County, IL, Carroll County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, DeKalb County, IL, DeWitt County, IL, Douglas County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McHenry County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Moultrie County, IL, Ogle County, IL, Peoria County, IL, Piatt County, IL, Putnam County, IL, Sangamon County, IL, Scott County, IL, Shelby County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Whiteside County, IL, Winnebago County, IL, Woodford County, IL, Columbia County, WI, Crawford County, WI, Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Lafayette County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Vernon County, WI, Walworth County, WI

The radar

The Quad Cities radar (KDVN), 79 km from the middle of the area, began a volume at 00:26 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.

Tornado Watch 103Mar 31, 8:35 PM CDT

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.4 hours before the alert went out and 174 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: 389 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 844 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 158 m²/s²
0-3 km storm-relative helicity: 177 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.6

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
Mar 31, 7:10 PM CDT	Mesoscale Discussion	SPC	Alexander, Hardin, Johnson, Massac, Pope, Pulaski and 3 more	65 min
Mar 31, 8:33 PM CDT	Tornado Watch	SPC	Cook, DuPage, Iroquois, Kankakee, Lake, Vermilion and 1 more	3 hr
Mar 31, 9:17 PM CDT	Mesoscale Discussion	SPC	Bond, Boone, Champaign, Christian, Clinton, Coles and 36 more	58 min

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.