Alert archive / Illinois / Mesoscale Discussions in 2004
Mesoscale Discussion 1747
The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2004, 7:53 AM CDT for 7 counties in Illinois; 6 counties in Wisconsin. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 21, 2004, 7:53 AM CDT (12:53 UTC)
- Expired
- Jul 21, 2004, 10:00 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
Counties Boone County, IL, DuPage County, IL, Kane County, IL, Lake County, IL, McHenry County, IL, Stephenson County, IL, Winnebago County, IL, Columbia County, WI, Jefferson County, WI, Kenosha County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI
The radar
The Milwaukee radar (KMKX), 36 km from the middle of the area, began a volume at 12:53 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, 0.9 hours before the alert went out and 183 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.
- Mixed-layer CAPE
- 2834 J/kg
- Mixed-layer CIN
- -90 J/kg
- Mixed-layer LCL
- 865 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 106 m²/s²
- 0-3 km storm-relative helicity
- 128 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 9:03 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Champaign, Cook, DeKalb and 37 more | 117 min |
| Jul 21, 9:35 AM CDT | Severe Thunderstorm Watch | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 26 more | 5 hr |
| Jul 21, 10:18 AM CDT | Mesoscale Discussion | SPC | Bureau, Cook, DeKalb, DuPage, Ford, Grundy and 14 more | 87 min |
| Jul 21, 1:01 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 25 more | 89 min |
| Jul 21, 2:35 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Bureau, Cook, DeKalb, DeWitt, DuPage and 20 more | 6 hr |
| Jul 21, 5:09 PM CDT | Mesoscale Discussion | SPC | Bureau, DeWitt, Ford, Grundy, Iroquois, Kankakee and 13 more | 36 min |
| Jul 21, 6:20 PM CDT | Mesoscale Discussion | SPC | Clark, Coles, Edgar, Vermilion | 25 min |
Nearby
Mesoscale Discussions in Illinois, 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.