Alert archive / Illinois / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 147, NWS Chicago, IL

July 23, 2017Kankakee County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 23, 2017, 6:29 PM CDT for Kankakee County, Illinois. It was in force for 31 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: Jul 23, 2017, 6:29 PM CDT (23:29 UTC)
Expired: Jul 23, 2017, 7:00 PM CDT
In force: 31 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Kankakee County, IL

The radar

The Chicago radar (KLOT), 55 km from the middle of the area, began a volume at 23:29 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, 11.5 hours before the alert went out and 126 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: 2427 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 562 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 6 m²/s²
0-3 km storm-relative helicity: 8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

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 Jul 23, 6:13 PM CDT, 16 minutes earlier.

Area forecast discussion, Jul 23, 6:13 PM CDT, 16 minutes before

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Hazardous weather outlook, Jul 23, 3:13 PM CDT, 3 hours 16 minutes before

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In the hours before

Local storm report, Jul 23, 5:42 PM CDT, 47 minutes before

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Local storm report, Jul 23, 6:00 PM CDT, 29 minutes before

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Special weather statement, Jul 23, 6:18 PM CDT, 11 minutes before

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Local storm report, Jul 23, 6:21 PM CDT, 8 minutes before

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Local storm report, Jul 23, 6:23 PM CDT, 6 minutes before

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Local storm report, Jul 23, 6:28 PM CDT, 1 minute 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
Jul 22, 9:49 PM CDT	River Flood Watch	LOT	Iroquois	63 hr
Jul 23, 2:17 PM CDT	Special Weather Statement	LOT	McHenry	13 min
Jul 23, 2:34 PM CDT	Special Weather Statement	LOT	Lake	26 min
Jul 23, 2:55 PM CDT	Beach Hazards Statement	LOT	Lake	31 hr
Jul 23, 3:12 PM CDT	Special Weather Statement	LOT	Ogle	33 min
Jul 23, 3:17 PM CDT	Special Weather Statement	LOT	Boone, McHenry	28 min
Jul 23, 3:42 PM CDT	Special Weather Statement	LOT	McHenry	33 min
Jul 23, 3:45 PM CDT	Severe Thunderstorm Warning	LOT	Boone, DeKalb, Kane, McHenry	45 min
Jul 23, 3:58 PM CDT	Special Marine Warning	LOT		62 min
Jul 23, 4:19 PM CDT	Areal Flood Advisory	LOT	Boone, Cook, DeKalb, DuPage, Kane, Lake and 1 more	4 hr
Jul 23, 4:31 PM CDT	Special Weather Statement	LOT	Kane	29 min
Jul 23, 4:33 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Kane	42 min
Jul 23, 4:52 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Kane, Kendall, Will	53 min
Jul 23, 5:28 PM CDT	Areal Flood Advisory	LOT	Cook, DuPage, Kane, Kendall, Will	4 hr
Jul 23, 5:42 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kendall, Will	37 min
Jul 23, 6:18 PM CDT	Special Weather Statement	LOT	Kankakee	27 min
Jul 23, 6:35 PM CDT	Severe Thunderstorm Warning	LOT	Ford, Iroquois, Kankakee	40 min
Jul 22, 9:46 PM CDT	River Flood Warning	LOT	Lake, Newton	5 days

Nearby

Severe Thunderstorm Warnings in Illinois, 2017 Every severe thunderstorm warning in 2017

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.