Flooding and Hail in Wisconsin, June 28, 1999

Deep tropical moisture, pooled near a frontal boundary, resulted in two separate rounds of thunderstorms across southcentral and southeast Wisconsin. The 1st round consisted primarily of heavy rains and urban/small stream flooding. The 2nd round consisted of primarily large hail and heavy rains, although a wet microburst did generate powerful winds which levelled some large trees in Packwaukee (Marquette Co.) and Green Lake (Green Lake Co.).In the couple hours just after 0000CST, small clusters of thunderstorms, moving slowly east at 15 mph, dumped heavy rains in scattered areas. Estimated rainfall totals based on WSR-88 Doppler radar were in the 1 to 2 inch range within 1 to 1.5 hours. The result was urban street flooding in Janesville (Rock Co.), Delavan (Walworth Co.), and Silver Lake (Kenosha Co.). Water was reported to be 4 to 8 inches deep on some roads. During the afternoon hours it was the same story when urban flooding was reported in Madison and Marshall (Dane Co.), and in the city of Milwaukee (Milwaukee Co.). At the NWS Forecast office 3SE of Sullivan (Jefferson Co.), 1.14 inches fell in 20 minutes! A total of 1.14 inches fell in 1 hour in Wauwatosa (Milwaukee Co.), and 1.42 inches in 30 minutes near the intersection of Capitol Drive and the Milwaukee River north of downtown Milwaukee.