Scattered thunderstorms affected southern Wisconsin Sunday and Sunday night as a warm front moved northward from Iowa and Illinois. Most of the thunderstorms remained below severe levels but did bring areas of heavy rainfall of 1 to 2 inches.
Warm, humid air then settled over southern Wisconsin by Monday. The warm air along with an approaching cold front set off several rounds of strong to severe thunderstorms over southern Wisconsin on Monday and Monday night. 2 inch hail occurred in Racine, Elkhorn, Fort Atkinson, Bohners Lake area near Burlington, Beloit and the northwest side of Milwaukee. Strong winds caused tree damage in Janesville, Beloit, the Dousman area and the Bohners Lake area.
Heavy rainfall was the main story across southern Wisconsin. Many areas received between 1 and 3 additional inches of rainfall on Monday with a few spots receiving around 5 inches including the National Weather Service office in Sullivan (4.96") and Whitewater (5.32").
The below graphics depict the 48 hour rainfall total across southern Wisconsin as well as all of Wisconsin:
Here is a two day rainfall estimate from the WSR-88D Doppler radar at the NWS office near Sullivan. The radar rainfall estimate also highlights southern and eastern Jefferson county, northeast Rock county and Waukesha county receiving the heaviest rainfall.
The below graphics show the 24 hour rainfall from 7 am Monday to 7 am Tuesday:
The below graphics show the 24 hour rainfall from 7 am Sunday to 7 am Monday:
Here are several images of the large hail that occurred across southern Wisconsin on Monday:
National Weather Service - Milwaukee/Sullivan