Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 1584

July 9, 200416 counties in Illinois; 4 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2004, 4:26 PM CDT for 16 counties in Illinois; 4 counties in Iowa. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Jul 9, 2004, 4:26 PM CDT (21:26 UTC)
Expired: Jul 9, 2004, 6:00 PM CDT
In force: 94 min
Issued by: the Storm Prediction Center

Counties Des Moines County, IA, Lee County, IA, Louisa County, IA, Muscatine County, IA, Fulton County, IL, Hancock County, IL, Henderson County, IL, Knox County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Mercer County, IL, Peoria County, IL, Schuyler County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 92 km from the middle of the area, began a volume at 21:29 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, 9.4 hours before the alert went out and 126 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: 198 J/kg
Mixed-layer CIN: -326 J/kg
Mixed-layer LCL: 790 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 174 m²/s²
0-3 km storm-relative helicity: 208 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.5

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 9, 2:15 PM CDT	Mesoscale Discussion	SPC	Grundy, Iroquois, Kankakee, Will	2 hr
Jul 9, 12:45 AM CDT	Severe Thunderstorm Watch	SPC	Fremont, Mills, Montgomery, Page	4 hr

Nearby

Mesoscale Discussions in Illinois, 2004 Mesoscale Discussions in Iowa, 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.