Storm Record · Dane, Dodge, Jefferson, Waukesha Counties
September 3, 2011: Straight-line wind across four counties
What the National Weather Service recorded
A residual surface boundary that extended from eastern Iowa across northern Illinois was the focus for thunderstorm development as a moderate southwest 850 mb jet pushed it north as a warm front. Upper divergence from the right entrance region of an upper jet maxmum provided additional lift. Moderate deep layer wind shear produced sustained updrafts to form thunderstorm clusters that evolved into short line segments as they reached southern Wisconsin. The severe thunderstorm lines produced damaging wind gusts in a swath from Iowa County along and either side of the I-94 corridor to Milwaukee and Ozaukee counties.
Source: NOAA Storm Events Database · episode 54990
Every report, in the Weather Service's words
Where It Hit
| Location | County | Hazard | Size | Report |
|---|---|---|---|---|
| Blue Mounds (5 SW) | Dane | Wind | 75 mph wind | Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 65 knots (75 mph) in an 8-mile wide swath from southwest of Blue Mounds to east of McFarland. The damaging winds downed numerous trees and power lines, with 1000 customers left without power in the Madison area. |
| Waterloo | Jefferson | Wind | 75 mph wind | Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 65 knots (75 mph) in a 3-mile wide swath from Waterloo to northeast of Ixonia. The damaging winds downed numerous trees and power lines. |
| Lake Mills | Jefferson | Wind | 75 mph wind | A trained spotter reported large tree branches blown down, an above ground pool blown into a neighbor's yard and lawn furniture tossed from severe thunderstorm wind gusts estimated at 65 knots (75 mph). |
| Oregon | Dane | Wind | 75 mph wind | A trained spotter reported numerous trees and power lines downed along a path from Oregon to northeast of Albion from damaging severe thunderstorm wind gusts estimated at 65 knots (75 mph). The winds tore some siding off a home in Oregon. Heavy rain caused ponding of water on area roadways, with water over the curb on some streets in Oregon. |
| Portland (2 N) | Dodge | Wind | 75 mph wind | Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 65 knots (75 mph) in a 4-mile wide swath from north of Portland to north of Ashippun. The damaging winds downed numerous trees and power lines. |
| Monterey | Waukesha | Wind | 64 mph wind | Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 56 knots (65 mph) that downed two trees and two power lines and numerous branches in the township of Oconomowoc. |
| Alderley | Dodge | Wind | 64 mph wind | Law enforcement officials reported trees downed from damaging severe thunderstorm wind gusts estimated at 56 knots (65 mph). |
| Marshall (2 NNW) | Dane | Wind | 64 mph wind | Law enforcement officers reported trees downed from severe thunderstorm wind gusts estimated at 56 knots (65 mph). |
| Cottage Grove | Dane | Wind | 58 mph wind | A trained spotter reported large tree branches downed from severe thunderstorm wind gusts estimated at 50 knots (58 mph). |
| Paoli (2 E) | Dane | Hail | 0.75" hail | A trained spotter reported hail near Paoli that was measured 3/4 of an inch in diameter that fell from strong to severe thunderstorms moving through Dane County during the early morning hours of of September 3rd. |
Service areas this storm touched