Alert archive / Illinois / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 76, NWS Chicago, IL

June 22, 2015Boone County, Ogle County, Winnebago County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jun 22, 2015, 9:47 AM CDT for Boone County, Ogle County, Winnebago County, Illinois. It was in force for 58 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 22, 2015, 9:47 AM CDT (14:47 UTC)
Expired: Jun 22, 2015, 10:45 AM CDT
In force: 58 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 80.0 mph

Counties Boone County, IL, Ogle County, IL, Winnebago County, IL

The radar

The Milwaukee radar (KMKX), 93 km from the middle of the area, began a volume at 14:50 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 22, 9:39 AM CDT	Severe Thunderstorm Watch	SPC	3 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 2.8 hours before the alert went out and 134 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: 1240 J/kg
Mixed-layer CIN: -232 J/kg
Mixed-layer LCL: 853 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 66 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

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 Jun 22, 9:15 AM CDT, 32 minutes earlier.

Area forecast discussion, Jun 22, 9:15 AM CDT, 32 minutes before

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Hazardous weather outlook, Jun 22, 4:43 AM CDT, 5 hours 4 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 21, 7:57 PM CDT	River Flood Advisory	LOT	Grundy	25 hr
Jun 22, 9:46 AM CDT	Special Marine Warning	LOT		3 hr
Jun 22, 10:05 AM CDT	River Flood Advisory	LOT	Winnebago	7 days
Jun 22, 10:43 AM CDT	Special Weather Statement	LOT	Lee, Ogle	47 min
Jun 22, 10:57 AM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Lee, Ogle	33 min
Jun 22, 11:14 AM CDT	Severe Thunderstorm Warning	LOT	DeKalb, LaSalle, Lee	46 min
Jun 22, 11:29 AM CDT	Special Weather Statement	LOT	DeKalb	31 min
Jun 22, 11:52 AM CDT	Special Weather Statement	LOT	LaSalle	23 min
Jun 22, 4:28 PM CDT	Gale Warning	LOT		3 hr
Jun 22, 4:28 PM CDT	Small Craft Advisory	LOT		6 hr

Nearby

Severe Thunderstorm Warnings in Illinois, 2015 Every severe thunderstorm warning in 2015

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.