Hail and Damaging Wind in Wisconsin, September 1, 2000

Two clusters of severe thunderstorms moved east/southeast across south-central Wisconsin during the mid to late afternoon hours. Damaging straight-line winds downed large trees near Endeavor (Marquette Co.), and produced large hail elsewhere in Sauk and Columbia Counties. The second, and later, cluster of storms transformed into a single line about 10 to 15 miles wide as it moved through eastern Sauk, all of Columbia, and northern Dane County. As it propagated and developed to the southeast, cloud base rotation was noted by several spotters in southern Columbia County. Cloud-base rotation was also noted in an isolated storm over northern Dane County. However, the surface outflow coupled with a west-east orientated cold front which was sliding south. This frontal boundary pushed 10 miles south of the main updraft tower, thus robbing the storm of low-level vorticity needed to spin up a vortex at ground level. Mesocylcones were observed on the Milwaukee/Sullivan WSR-88D Doppler radar.