Alert archive / Illinois / Tornado Warnings in 2008

Tornado Warning 27, NWS Chicago, IL

June 13, 2008Boone County, McHenry County, Illinois

NWS Chicago, IL issued this tornado warning at Jun 13, 2008, 12:27 AM CDT for Boone County, McHenry County, Illinois. It was in force for 48 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: Jun 13, 2008, 12:27 AM CDT (05:27 UTC)
Expired: Jun 13, 2008, 1:15 AM CDT
In force: 48 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon

Counties Boone County, IL, McHenry County, IL

The radar

The Milwaukee radar (KMKX), 72 km from the middle of the area, began a volume at 05:30 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
Jun 12, 7:48 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 5.5 hours before the alert went out and 173 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: 3526 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 947 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 192 m²/s²
0-3 km storm-relative helicity: 304 m²/s²
Significant tornado parameter: 5.4
Supercell composite: 26.7

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this tornado 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 tornado warning went out at Jun 12, 6:38 PM CDT, 5 hours 49 minutes earlier.

Area forecast discussion, Jun 12, 6:38 PM CDT, 5 hours 49 minutes before

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Hazardous weather outlook, Jun 12, 5:28 PM CDT, 6 hours 59 minutes before

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In the hours before

Local storm report, Jun 13, 12:12 AM CDT, 15 minutes before

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Local storm report, Jun 13, 12:18 AM CDT, 9 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
Jun 12, 11:07 PM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle	38 min
Jun 12, 11:37 PM CDT	Severe Thunderstorm Warning	LOT	LaSalle, Lee, Ogle	53 min
Jun 12, 11:47 PM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle, Winnebago	43 min
Jun 12, 11:59 PM CDT	Severe Thunderstorm Warning	LOT	Boone, DeKalb, Grundy, Kane, Kendall, LaSalle and 1 more	61 min
Jun 13, 12:06 AM CDT	Special Marine Warning	LOT		114 min
Jun 13, 12:31 AM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Lake, Will	59 min
Jun 13, 1:55 AM CDT	Special Marine Warning	LOT		62 min
Jun 13, 3:37 AM CDT	Special Marine Warning	LOT		83 min
Jun 13, 1:15 PM CDT	Flash Flood Warning	LOT	Benton	4 hr

Nearby

Tornado Warnings in Illinois, 2008 Every tornado warning in 2008 Tornadoes in 2008

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.