Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 1643

July 13, 200420 counties in Illinois; Benton County, Newton County, Warren County, Indiana; 10 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Jul 13, 2004, 10:32 AM CDT for 20 counties in Illinois; Benton County, Newton County, Warren County, Indiana; 10 counties in Iowa. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued: Jul 13, 2004, 10:32 AM CDT (15:32 UTC)
Expired: Jul 13, 2004, 12:30 PM CDT
In force: 118 min
Issued by: the Storm Prediction Center

All 33 counties

Cedar County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Linn County, IA, Muscatine County, IA, Scott County, IA, Bureau County, IL, Carroll County, IL, Ford County, IL, Grundy County, IL, Henry County, IL, Iroquois County, IL, Kankakee County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, Mercer County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Whiteside County, IL, Will County, IL, Woodford County, IL, Benton County, IN, Newton County, IN, Warren County, IN

The radar

The Quad Cities radar (KDVN), 92 km from the middle of the area, began a volume at 15:34 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 619Jul 13, 10:55 AM CDT

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 3.5 hours before the alert went out and 86 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: 415 J/kg
Mixed-layer CIN: -335 J/kg
Mixed-layer LCL: 2160 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 184 m²/s²
0-3 km storm-relative helicity: 180 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 13, 10:55 AM CDT	Tornado Watch	SPC	Boone, Bureau, Carroll, DeKalb, Ford, Fulton and 27 more	6 hr
Jul 13, 1:39 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, DeKalb, Ford, Fulton and 27 more	66 min
Jul 13, 2:30 PM CDT	Mesoscale Discussion	SPC	Champaign, Clark, Coles, Crawford, Cumberland, Douglas and 6 more	2 hr
Jul 13, 3:30 PM CDT	Tornado Watch	SPC	Bond, Champaign, Christian, Clark, Clay, Coles and 23 more	7 hr
Jul 13, 5:00 PM CDT	Mesoscale Discussion	SPC	Bond, Christian, Clay, Crawford, Cumberland, Edwards and 15 more	2 hr
Jul 13, 5:50 PM CDT	Severe Thunderstorm Watch	SPC	Clay, Edwards, Gallatin, Hamilton, Hardin, Jefferson and 7 more	6 hr
Jul 12, 9:15 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Audubon, Boone, Buena Vista, Calhoun and 32 more	7 hr
Jul 12, 9:19 PM CDT	Mesoscale Discussion	SPC	Clay, Dickinson, Emmet, Hancock, Kossuth, Lyon and 5 more	116 min
Jul 12, 11:19 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Cass, Decatur, Fremont, Mills and 6 more	116 min
Jul 12, 11:52 PM CDT	Mesoscale Discussion	SPC	Cherokee, Dickinson, Lyon, O'Brien, Osceola, Plymouth and 1 more	53 min
Jul 13, 12:55 AM CDT	Severe Thunderstorm Watch	SPC	Adair, Audubon, Benton, Black Hawk, Boone, Bremer and 52 more	6 hr
Jul 13, 4:21 AM CDT	Mesoscale Discussion	SPC	Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 22 more	54 min
Jul 13, 2:25 PM CDT	Severe Thunderstorm Watch	SPC	Fremont, Harrison, Mills, Monona, Pottawattamie, Shelby	6 hr

Nearby

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