Alert archive / Illinois / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 108, NWS Chicago, IL

May 31, 2004LaSalle County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at May 31, 2004, 3:01 AM CDT for LaSalle County, Illinois. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 31, 2004, 3:01 AM CDT (08:01 UTC)
Expired: May 31, 2004, 3:30 AM CDT
In force: 29 min
Issued by: NWS Chicago, IL
Area: Counties, with a storm outline in the text

County LaSalle County, IL

The radar

The Chicago radar (KLOT), 73 km from the middle of the area, began a volume at 08:02 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

Lincoln, IL (KILX), launched 00:00Z, 8.0 hours before the alert went out and 135 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: 7 J/kg
Mixed-layer CIN: -270 J/kg
Mixed-layer LCL: 845 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: -89 m²/s²
0-3 km storm-relative helicity: -31 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Chicago, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at May 31, 3:00 AM CDT, 1 minute earlier.

Area forecast discussion, May 31, 3:00 AM CDT, 1 minute before

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Hazardous weather outlook, May 30, 10:30 PM CDT, 4 hours 31 minutes before

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The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 30, 7:04 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Lake	56 min
May 30, 7:09 PM CDT	Severe Thunderstorm Warning	LOT	Kankakee, Will	51 min
May 30, 7:16 PM CDT	Flash Flood Warning	LOT	Cook, DuPage, Grundy, Kane, Kankakee, Kendall and 3 more	119 min
May 30, 7:16 PM CDT	Severe Thunderstorm Warning	LOT	McHenry	44 min
May 31, 4:11 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Ogle	49 min
May 31, 4:13 PM CDT	Severe Thunderstorm Warning	LOT	Lee	47 min
May 31, 4:41 PM CDT	Severe Thunderstorm Warning	LOT	Kane	34 min
May 31, 5:00 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Kendall, Lee	45 min
May 31, 5:46 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Will	44 min
May 30, 7:03 PM CDT	Flash Flood Warning	LOT	Jasper, Newton	117 min
May 30, 7:14 PM CDT	Tornado Warning	LOT	Jasper	46 min
May 30, 7:20 PM CDT	Severe Thunderstorm Warning	LOT	Benton	40 min
May 30, 7:28 PM CDT	Flash Flood Warning	LOT	Benton, Jasper, Lake, Newton, Porter	2 hr
May 30, 7:41 PM CDT	Severe Thunderstorm Warning	LOT	Lake, Porter	49 min
May 30, 8:00 PM CDT	Severe Thunderstorm Warning	LOT	Jasper	30 min
May 31, 6:15 PM CDT	Severe Thunderstorm Warning	LOT	Lake, Porter	45 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2004 Every severe thunderstorm warning 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.