Alert archive / Wisconsin / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 661
The Storm Prediction Center issued this severe thunderstorm watch at Jul 18, 2011, 6:18 PM CDT for 20 counties in Wisconsin. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 18, 2011, 6:18 PM CDT (23:18 UTC)
- Expired
- Jul 18, 2011, 9:35 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties 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), 73 km from the middle of the area, began a volume at 23:19 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
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 18, 7:03 PM CDT | Severe Thunderstorm Warning | MKX | Fond du Lac | 42 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
Green Bay/Straub, WI (KGRB), launched 12:00Z, 11.3 hours before the alert went out and 159 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.
- Mixed-layer CAPE
- 3928 J/kg
- Mixed-layer CIN
- -31 J/kg
- Mixed-layer LCL
- 613 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 106 m²/s²
- 0-3 km storm-relative helicity
- 111 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 9.7
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 17, 7:22 PM CDT | Severe Thunderstorm Watch | SPC | Brown, Calumet, Door, Florence, Forest, Kewaunee and 17 more | 4 hr |
| Jul 17, 9:24 PM CDT | Mesoscale Discussion | SPC | Door, Florence, Forest, Kewaunee, Langlade, Lincoln and 9 more | 66 min |
| Jul 17, 11:06 PM CDT | Mesoscale Discussion | SPC | Calumet, Fond du Lac, Kewaunee, Manitowoc, Sheboygan | 54 min |
| Jul 18, 6:30 AM CDT | Mesoscale Discussion | SPC | Adams, Clark, Columbia, Crawford, Dane, Dodge and 25 more | 2 hr |
| Jul 18, 8:05 AM CDT | Severe Thunderstorm Watch | SPC | Adams, Brown, Buffalo, Calumet, Clark, Columbia and 32 more | 4 hr |
| Jul 18, 9:54 AM CDT | Mesoscale Discussion | SPC | Manitowoc, Sheboygan | 96 min |
| Jul 18, 2:06 PM CDT | Mesoscale Discussion | SPC | Barron, Brown, Chippewa, Clark, Dunn, Eau Claire and 17 more | 84 min |
| Jul 18, 2:26 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Brown, Calumet, Chippewa, Clark, Door and 28 more | 7 hr |
| Jul 18, 5:42 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calumet, Chippewa, Clark, Eau Claire and 21 more | 63 min |
Nearby
Severe Thunderstorm Watches in Wisconsin, 2011Every 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.