Alert archive / Wisconsin / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 291
The Storm Prediction Center issued this severe thunderstorm watch at May 12, 2011, 1:41 PM CDT for 56 counties in Wisconsin. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 12, 2011, 1:41 PM CDT (18:41 UTC)
- Expired
- May 12, 2011, 7:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 56 counties
Adams County, WI, Brown County, WI, Calumet County, WI, Chippewa County, WI, Clark County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Door County, WI, Eau Claire County, WI, Fond du Lac County, WI, Forest County, WI, Grant County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jackson County, WI, Jefferson County, WI, Juneau County, WI, Kenosha County, WI, Kewaunee County, WI, La Crosse County, WI, Lafayette County, WI, Langlade County, WI, Lincoln County, WI, Manitowoc County, WI, Marathon County, WI, Marinette County, WI, Marquette County, WI, Menominee County, WI, Milwaukee County, WI, Monroe County, WI, Oconto County, WI, Oneida County, WI, Outagamie County, WI, Ozaukee County, WI, Portage County, WI, Price County, WI, Racine County, WI, Richland County, WI, Rock County, WI, Rusk County, WI, Sauk County, WI, Shawano County, WI, Sheboygan County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI
The radar
The Green Bay radar (KGRB), 133 km from the middle of the area, began a volume at 18:46 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
- 60%
Warnings issued inside it
9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 12, 2:33 PM CDT | Severe Thunderstorm Warning | MKX | Marquette | 14 min |
| May 12, 3:32 PM CDT | Severe Thunderstorm Warning | GRB | Portage, Waupaca | 43 min |
| May 12, 3:35 PM CDT | Severe Thunderstorm Warning | MKX | Marquette | 40 min |
| May 12, 4:13 PM CDT | Severe Thunderstorm Warning | GRB | Outagamie, Shawano, Waupaca | 62 min |
| May 12, 4:55 PM CDT | Severe Thunderstorm Warning | GRB | Marathon | 50 min |
| May 12, 5:12 PM CDT | Severe Thunderstorm Warning | MKX | Kenosha, Walworth | 48 min |
| May 12, 5:15 PM CDT | Severe Thunderstorm Warning | GRB | Langlade, Lincoln | 45 min |
| May 12, 5:16 PM CDT | Severe Thunderstorm Warning | GRB | Outagamie | 40 min |
| May 12, 6:11 PM CDT | Severe Thunderstorm Warning | GRB | Forest, Marinette | 49 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, 6.7 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.
- Mixed-layer CAPE
- 122 J/kg
- Mixed-layer CIN
- -257 J/kg
- Mixed-layer LCL
- 929 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 79 m²/s²
- 0-3 km storm-relative helicity
- 130 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 12, 1:08 PM CDT | Mesoscale Discussion | SPC | Adams, Calumet, Chippewa, Clark, Columbia, Dane and 28 more | 67 min |
| May 12, 6:16 PM CDT | Mesoscale Discussion | SPC | Brown, Calumet, Clark, Forest, Langlade, Lincoln and 12 more | 29 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.