Alert archive / Michigan / Mesoscale Discussions in 2004

Mesoscale Discussion 732

May 17, 200414 counties in Illinois; 24 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at May 17, 2004, 11:37 PM CDT for 14 counties in Illinois; 24 counties in Michigan. It was in force for 23 min.

The area

The outline as issued.

The facts

Issued: May 17, 2004, 11:37 PM CDT (04:37 UTC)
Expired: May 18, 2004, 12:00 AM CDT
In force: 23 min
Issued by: the Storm Prediction Center

All 38 counties

Bureau County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Kane County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Marshall County, IL, Putnam County, IL, Stark County, IL, Will County, IL, Allegan County, MI, Arenac County, MI, Barry County, MI, Bay County, MI, Clare County, MI, Clinton County, MI, Gladwin County, MI, Gratiot County, MI, Ionia County, MI, Isabella County, MI, Kent County, MI, Lake County, MI, Mecosta County, MI, Midland County, MI, Missaukee County, MI, Montcalm County, MI, Muskegon County, MI, Newaygo County, MI, Ogemaw County, MI, Osceola County, MI, Ottawa County, MI, Roscommon County, MI, Saginaw County, MI, Van Buren County, MI

The radar

The Grand Rapids radar (KGRR), 84 km from the middle of the area, began a volume at 04:38 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

Green Bay/Straub, WI (KGRB), launched 00:00Z, 4.6 hours before the alert went out and 202 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: 938 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 968 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 3.0

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
May 17, 7:15 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Carroll, DeKalb, Jo Daviess, Lee, McHenry and 6 more	5 hr
May 18, 12:41 AM CDT	Mesoscale Discussion	SPC	Grundy, Kankakee, Will	2 hr
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

Nearby

Mesoscale Discussions in Michigan, 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.