A strengthening low pressure system over the northern plains and a vigorous cold front brought widespread rain to south central and southeast Wisconsin on Wednesday and Wednesday evening. Most areas received between one half inch and one inch. The below image illustrates the 24 hour rainfall totals ending at 7 am Thursday morning.
The heaviest rainfall occurred in a narrow strip from eastern Walworth county and western Racine and Kenosha counties north through Waukesha and Washington counties into eastern Fond du Lac county. Much of this strip received one inch to one and one half inches. The heaviest rainfall of 1.54 inches was reported from a CoCoRahs observer located 1 mile east of Lake Geneva.
Other heavier amounts included 1.43" in East Troy, 1.32" in Pewaukee, 1.11" in Merton and 1.18" at Taycheedah. Here is the complete listing of rainfall from around the state. Twenty-four hour rainfall from across the entire state is illustrated below.
The combination of Wednesday's rainfall and the heavy rainfall from last weekend resulted in much of central and all of southern Wisconsin receiving between 1.5 and 4.5 inches. Total rainfall over the past six day across Wisconsin is illustrated below.