Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 582

May 7, 200415 counties in Illinois; 6 counties in Iowa; 6 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 7, 2004, 4:33 PM CDT for 15 counties in Illinois; 6 counties in Iowa; 6 counties in Wisconsin. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued
May 7, 2004, 4:33 PM CDT (21:33 UTC)
Expired
May 7, 2004, 6:00 PM CDT
In force
87 min
Issued by
the Storm Prediction Center
All 27 counties

Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Jackson County, IA, Jones County, IA, Boone County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL, Grant County, WI, Green County, WI, Iowa County, WI, Lafayette County, WI, Rock County, WI, Walworth County, WI

The radar

The Quad Cities radar (KDVN), 105 km from the middle of the area, began a volume at 21:37 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.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.6 hours before the alert went out and 101 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-pSkew-T log-p diagram, Davenport, at 12:00Z on 2004-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2004-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 96 square meters per square second.193958Sfc1 km3 km6 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
915 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
96 m²/s²
0-3 km storm-relative helicity
219 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

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.

IssuedProductOfficeCountiesLasted
May 6, 11:53 PM CDTMesoscale DiscussionSPCBureau, Carroll, DeKalb, Henry, Jo Daviess, Knox and 10 more97 min
May 7, 4:24 AM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 22 more96 min
May 7, 5:00 AM CDTSevere Thunderstorm WatchSPCBureau, Ford, Grundy, Iroquois, Kankakee, Kendall and 10 more4 hr
May 7, 6:38 AM CDTMesoscale DiscussionSPCBureau, Champaign, DeWitt, Ford, Grundy, Iroquois and 12 more97 min
May 7, 11:44 AM CDTMesoscale DiscussionSPCBureau, Carroll, DeKalb, DuPage, Grundy, Henry and 9 more2 hr
May 7, 5:25 PM CDTSevere Thunderstorm WatchSPCBoone, Carroll, Cook, DeKalb, DuPage, Jo Daviess and 6 more6 hr
May 7, 2:26 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Buena Vista, Calhoun, Carroll and 26 more3 hr

Nearby

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