Alert archive / Illinois / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 112, NWS Chicago, IL

July 10, 2017Grundy County, Kendall County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 10, 2017, 9:34 PM CDT for Grundy County, Kendall County, Illinois. It was in force for 41 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 10, 2017, 9:34 PM CDT (02:34 UTC)
Expired: Jul 10, 2017, 10:15 PM CDT
In force: 41 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Grundy County, IL, Kendall County, IL

The radar

The Chicago radar (KLOT), 34 km from the middle of the area, began a volume at 02:36 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 10, 3:58 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 2.6 hours before the alert went out and 144 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: 2755 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 1493 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 135 m²/s²
0-3 km storm-relative helicity: 236 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 14.2

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 10, 6:38 PM CDT, 2 hours 56 minutes earlier.

Area forecast discussion, Jul 10, 6:38 PM CDT, 2 hours 56 minutes before

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Hazardous weather outlook, Jul 10, 4:23 PM CDT, 5 hours 11 minutes before

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In the hours before

Special weather statement, Jul 10, 8:22 PM CDT, 1 hour 12 minutes before

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Local storm report, Jul 10, 8:48 PM CDT, 46 minutes before

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Local storm report, Jul 10, 8:58 PM CDT, 36 minutes before

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Local storm report, Jul 10, 9:01 PM CDT, 33 minutes before

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Special weather statement, Jul 10, 9:28 PM CDT, 6 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
Jul 10, 8:22 PM CDT	Special Weather Statement	LOT	LaSalle	38 min
Jul 10, 8:34 PM CDT	Severe Thunderstorm Warning	LOT	LaSalle	41 min
Jul 10, 9:28 PM CDT	Special Weather Statement	LOT	Kendall	32 min
Jul 11, 8:33 AM CDT	Special Weather Statement	LOT	Marshall	42 min
Jul 11, 8:41 AM CDT	Severe Thunderstorm Warning	LOT	LaSalle, Livingston	49 min
Jul 11, 9:18 AM CDT	River Flood Warning	LOT	Lake	14 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.