Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 1205

June 11, 200416 counties in Illinois; 8 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jun 11, 2004, 10:04 PM CDT for 16 counties in Illinois; 8 counties in Wisconsin. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Jun 11, 2004, 10:04 PM CDT (03:04 UTC)
Expired: Jun 11, 2004, 11:00 PM CDT
In force: 56 min
Issued by: the Storm Prediction Center

All 24 counties

Boone County, IL, Bureau County, IL, Carroll County, IL, DeKalb County, IL, Grundy County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Putnam County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL, Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Lafayette County, WI, Rock County, WI, Walworth County, WI

The radar

The Quad Cities radar (KDVN), 112 km from the middle of the area, began a volume at 03:06 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 444Jun 11, 11:00 PM CDT

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 3.1 hours before the alert went out and 262 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: 3388 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 1075 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 58 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.4

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
Jun 11, 9:35 PM CDT	Severe Thunderstorm Watch	SPC	Henderson, Mercer	4 hr
Jun 11, 11:00 PM CDT	Tornado Watch	SPC	Bureau, Carroll, DeKalb, DuPage, Ford, Grundy and 15 more	5 hr
Jun 12, 1:48 AM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 19 more	87 min
Jun 12, 3:08 AM CDT	Mesoscale Discussion	SPC	Cook, DeKalb, DuPage, Grundy, Iroquois, Kane and 7 more	97 min
Jun 12, 10:48 AM CDT	Mesoscale Discussion	SPC	Gallatin, Hardin, Massac, Pope	2 hr
Jun 12, 3:45 PM CDT	Severe Thunderstorm Watch	SPC	Henderson, Mercer, Rock Island, Warren	5 hr
Jun 12, 3:51 PM CDT	Mesoscale Discussion	SPC	Alexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 11 more	84 min
Jun 12, 4:15 PM CDT	Severe Thunderstorm Watch	SPC	Alexander, Gallatin, Hardin, Jackson, Johnson, Massac and 5 more	5 hr
Jun 12, 6:08 PM CDT	Mesoscale Discussion	SPC	Alexander, Gallatin, Hardin, Jackson, Johnson, Massac and 5 more	37 min
Jun 11, 7:57 PM CDT	Mesoscale Discussion	SPC	Adams, Barron, Buffalo, Chippewa, Clark, Crawford and 18 more	93 min

Nearby

Mesoscale Discussions in Illinois, 2004 Mesoscale Discussions in Wisconsin, 2004 Every mesoscale discussion in 2004

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.