Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 573

May 7, 200428 counties in Illinois; 9 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at May 7, 2004, 4:24 AM CDT for 28 counties in Illinois; 9 counties in Iowa. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued
May 7, 2004, 4:24 AM CDT (09:24 UTC)
Expired
May 7, 2004, 6:00 AM CDT
In force
96 min
Issued by
the Storm Prediction Center
All 37 counties

Cedar County, IA, Clinton County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Washington County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McHenry County, IL, Mercer County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL

The radar

The Quad Cities radar (KDVN), 32 km from the middle of the area, began a volume at 09:25 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 00:00Z, 9.4 hours before the alert went out and 26 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 00:00Z on 2004-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2446 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 2004-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 square meters per square second.193958Sfc1 km3 km6 km9 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
2446 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
1583 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
217 m²/s²
Significant tornado parameter
0.8
Supercell composite
9.0

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.

IssuedProductOfficeCountiesLasted
May 6, 11:53 PM CDTMesoscale DiscussionSPCBureau, Carroll, DeKalb, Henry, Jo Daviess, Knox and 10 more97 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, 4:33 PM CDTMesoscale DiscussionSPCBoone, Carroll, Cook, DeKalb, DuPage, Jo Daviess and 9 more87 min
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, 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.