June 4, 2005: Straight-line wind in Dane and Jefferson Counties

Three different rounds of severe weather occurred between the afternoon of June 4th and the evening of June 5th. The first round occurred just after noon on June 4th. Scattered severe thunderstorms produced areas of mainly damaging winds between 52 to 61 knots (60 and 70 mph). At 1225CST, a 20x20 foot section of Jefferson High School's roof was blown off in Jefferson County. Power lines were also reported down around 1230CST near Jefferson. Other scattered reports of tree damage with some power line damage were noted across Rock, Dane, Fond du Lac, and Kenosha counties. Synoptically, an area of low pressure tracked across eastern South Dakota on June 4th and into northern Minnesota by late evening on June 5th. A warm front surged north across South-Central and Southeast Wisconsin during the evening on June 4th, causing thunderstorms to develop. The warm front stalled for a bit during the early morning hours on June 5th, allowing another round to develop and head east across the area. Finally, the warm front pushed into northern Wisconsin, allowing warm and humid air to flood into the region, fueling the final round along the cold front by late afternoon or early evening on June 5th.