Alert archive / Illinois / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 98, NWS Chicago, IL

August 1, 2014DeKalb County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Aug 1, 2014, 6:50 PM CDT for DeKalb County, Illinois. It was in force for 25 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: Aug 1, 2014, 6:50 PM CDT (23:50 UTC)
Expired: Aug 1, 2014, 7:15 PM CDT
In force: 25 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

County DeKalb County, IL

The radar

The Chicago radar (KLOT), 65 km from the middle of the area, began a volume at 23:51 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 12:00Z, 11.8 hours before the alert went out and 194 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: 203 J/kg
Mixed-layer CIN: -52 J/kg
Mixed-layer LCL: 1337 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 27 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 Aug 1, 6:17 PM CDT, 33 minutes earlier.

Area forecast discussion, Aug 1, 6:17 PM CDT, 33 minutes before

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Hazardous weather outlook, Aug 1, 3:47 PM CDT, 3 hours 3 minutes before

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In the hours before

Local storm report, Aug 1, 5:26 PM CDT, 1 hour 24 minutes before

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Local storm report, Aug 1, 5:33 PM CDT, 1 hour 17 minutes before

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Special weather statement, Aug 1, 5:44 PM CDT, 1 hour 6 minutes before

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Special weather statement, Aug 1, 6:18 PM CDT, 32 minutes before

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Local storm report, Aug 1, 6:44 PM CDT, 6 minutes before

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Special weather statement, Aug 1, 6:47 PM CDT, 3 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
Aug 1, 6:01 AM CDT	Areal Flood Advisory	LOT	Will	3 hr
Aug 1, 6:17 AM CDT	Areal Flood Advisory	LOT	LaSalle	3 hr
Aug 1, 11:54 AM CDT	Special Weather Statement	LOT	Cook	51 min
Aug 1, 2:02 PM CDT	Areal Flood Advisory	LOT	Cook	4 hr
Aug 1, 2:21 PM CDT	Special Weather Statement	LOT	Kane	39 min
Aug 1, 2:24 PM CDT	Special Weather Statement	LOT	Cook	51 min
Aug 1, 4:15 PM CDT	Special Weather Statement	LOT	DuPage	15 min
Aug 1, 4:35 PM CDT	Special Weather Statement	LOT	Livingston	25 min
Aug 1, 4:43 PM CDT	Special Weather Statement	LOT	DuPage	32 min
Aug 1, 4:59 PM CDT	Areal Flood Advisory	LOT	DuPage	3 hr
Aug 1, 5:22 PM CDT	Special Weather Statement	LOT	Will	23 min
Aug 1, 5:44 PM CDT	Special Weather Statement	LOT	DeKalb	31 min
Aug 1, 5:56 PM CDT	Areal Flood Advisory	LOT	Kankakee, Will	4 hr
Aug 1, 6:18 PM CDT	Special Weather Statement	LOT	DeKalb	27 min
Aug 1, 6:41 PM CDT	Areal Flood Advisory	LOT	DeKalb	4 hr
Aug 1, 6:47 PM CDT	Special Weather Statement	LOT	DeKalb	28 min
Aug 1, 1:52 PM CDT	Areal Flood Advisory	LOT	Jasper, Porter	6 hr
Aug 1, 2:43 PM CDT	Areal Flood Advisory	LOT	Lake, Porter	4 hr

Nearby

Severe Thunderstorm Warnings in Illinois, 2014 Every severe thunderstorm warning in 2014

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.