Alert archive / Michigan / Mesoscale Discussions in 2004

Mesoscale Discussion 734

May 18, 2004Grundy County, Kankakee County, Will County, Illinois; 6 counties in Indiana; 12 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at May 18, 2004, 12:41 AM CDT for Grundy County, Kankakee County, Will County, Illinois; 6 counties in Indiana; 12 counties in Michigan. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 18, 2004, 12:41 AM CDT (05:41 UTC)
Expired: May 18, 2004, 2:45 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 21 counties

Grundy County, IL, Kankakee County, IL, Will County, IL, Elkhart County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Porter County, IN, Saint Joseph County, IN, Barry County, MI, Berrien County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Eaton County, MI, Hillsdale County, MI, Jackson County, MI, Kalamazoo County, MI, Saint Joseph County, MI, Van Buren County, MI, Washtenaw County, MI

The radar

The Chicago radar (KLOT), 88 km from the middle of the area, began a volume at 05:42 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 00:00Z, 5.7 hours before the alert went out and 289 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: 1036 J/kg
Mixed-layer CIN: -10 J/kg
Mixed-layer LCL: 1284 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 90 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.3

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
May 17, 7:15 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Carroll, DeKalb, Jo Daviess, Lee, McHenry and 6 more	5 hr
May 17, 11:37 PM CDT	Mesoscale Discussion	SPC	Bureau, Cook, DeKalb, DuPage, Grundy, Kane and 8 more	23 min
May 18, 10:26 AM CDT	Mesoscale Discussion	SPC	Bond, Brown, Bureau, Calhoun, Cass, Champaign and 38 more	3 hr
May 18, 12:00 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Bond, Brown, Calhoun, Cass, Champaign and 48 more	7 hr
May 18, 2:38 PM CDT	Mesoscale Discussion	SPC	Bond, Champaign, Christian, Clark, Clay, Clinton and 23 more	2 hr
May 18, 6:09 PM CDT	Mesoscale Discussion	SPC	Cass, Champaign, Christian, Clark, Clay, Coles and 27 more	96 min
May 18, 11:55 AM CDT	Mesoscale Discussion	SPC	Adams, Allen, Benton, Blackford, Boone, Carroll and 34 more	2 hr
May 18, 12:45 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Allen, Bartholomew, Benton, Blackford, Boone and 49 more	6 hr
May 18, 3:02 PM CDT	Mesoscale Discussion	SPC	Adams, Blackford, Boone, Carroll, Cass, Clinton and 15 more	118 min

Nearby

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