Alert archive / Wisconsin / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 86

April 3, 201115 counties in Illinois; Lake County, Porter County, Indiana; 20 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Apr 3, 2011, 8:54 PM CDT for 15 counties in Illinois; Lake County, Porter County, Indiana; 20 counties in Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Apr 3, 2011, 8:54 PM CDT (01:54 UTC)
Expired: Apr 4, 2011, 2:22 AM CDT
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 37 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Will County, IL, Winnebago County, IL, Lake County, IN, Porter County, IN, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Marquette County, WI, Milwaukee County, WI, Ozaukee County, WI, Racine County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 55 km from the middle of the area, began a volume at 01:54 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 20%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

15 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Apr 3, 9:11 PM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle	49 min
Apr 3, 9:14 PM CDT	Severe Thunderstorm Warning	MKX	Dane	46 min
Apr 3, 9:44 PM CDT	Severe Thunderstorm Warning	MKX	Columbia, Dane, Dodge, Jefferson	46 min
Apr 3, 9:50 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb	40 min
Apr 3, 9:50 PM CDT	Severe Thunderstorm Warning	MKX	Lafayette	25 min
Apr 3, 10:06 PM CDT	Severe Thunderstorm Warning	MKX	Green, Lafayette	24 min
Apr 3, 10:09 PM CDT	Severe Thunderstorm Warning	MKX	Columbia, Dane, Sauk	36 min
Apr 3, 10:11 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kendall, LaSalle	64 min
Apr 3, 10:18 PM CDT	Severe Thunderstorm Warning	MKX	Dodge, Fond du Lac	42 min
Apr 3, 10:23 PM CDT	Severe Thunderstorm Warning	MKX	Dane, Green, Rock	35 min
Apr 3, 10:45 PM CDT	Severe Thunderstorm Warning	MKX	Jefferson	26 min
Apr 3, 11:04 PM CDT	Severe Thunderstorm Warning	MKX	Dodge, Washington	41 min
Apr 3, 11:09 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Will	42 min
Apr 3, 11:23 PM CDT	Severe Thunderstorm Warning	MKX	Ozaukee, Sheboygan, Washington	52 min
Apr 3, 11:54 PM CDT	Severe Thunderstorm Warning	MKX	Sauk	23 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.9 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: 1790 J/kg
Mixed-layer CIN: -85 J/kg
Mixed-layer LCL: 1684 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 119 m²/s²
0-3 km storm-relative helicity: 168 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 5.9

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 3, 7:44 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Fulton, Hancock, Henderson and 16 more	61 min
Apr 3, 8:11 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Brown, Calhoun, Cass, Fulton, Greene and 12 more	6 hr
Apr 3, 10:23 PM CDT	Mesoscale Discussion	SPC	Boone, Carroll, Cook, DeKalb, DuPage, Jo Daviess and 10 more	67 min
Apr 3, 10:50 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Cass, Fulton, Hancock, McDonough and 4 more	85 min
Apr 4, 1:29 AM CDT	Mesoscale Discussion	SPC	Adams, Bond, Brown, Calhoun, Cass, Christian and 31 more	91 min
Apr 4, 1:53 AM CDT	Mesoscale Discussion	SPC	Cook, DuPage, Grundy, Kane, Kendall, Lake and 2 more	97 min
Apr 4, 4:20 AM CDT	Mesoscale Discussion	SPC	Clark, Clay, Crawford, Effingham, Jasper, Lawrence and 2 more	25 min
Apr 4, 6:53 AM CDT	Mesoscale Discussion	SPC	Hardin, Lawrence, Wabash	2 hr
Apr 4, 7:22 AM CDT	Tornado Watch	SPC	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	7 hr
Apr 4, 4:30 AM CDT	Severe Thunderstorm Watch	SPC	Adams, Allen, Bartholomew, Blackford, Boone, Brown and 39 more	8 hr
Apr 4, 11:34 AM CDT	Tornado Watch	SPC	Clark, Crawford, Floyd, Harrison, Jefferson, Orange and 3 more	5 hr
Apr 4, 11:50 AM CDT	Mesoscale Discussion	SPC	Dearborn, Decatur, Franklin, Jennings, Ohio, Ripley and 1 more	25 min

Nearby

Severe Thunderstorm Watches in Wisconsin, 2011 Severe Thunderstorm Watches in Illinois, 2011 Severe Thunderstorm Watches in Indiana, 2011 Every severe thunderstorm watch in 2011

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.