From the National Weather Service-The combination of nearby deepening low pressure, a warm front, and a passing cold front will increase the chance for strong to severe thunderstorms across southern Wisconsin Tuesday afternoon and evening. The Storm Prediction Center in Norman Oklahoma has placed southern Wisconsin in a Marginal Risk for Severe Thunderstorms on Tuesday, with a Slight Risk along the Illinois border. The slight risk area includes the Janesville, Kenosha, and Racine areas. Highs are forecasted to be in the upper 50s inland, low 50s near the lake.
A Marginal Risk means there is an isolated risk severe thunderstorms could develop. A Slight Risk has a higher risk for severe thunderstorms developing (see chart just below). The primary severe weather risk on Tuesday is large hail to around 1 inch. An isolated tornado is also possible in far southern Wisconsin along the Illinois border should better instability develop.
Make sure to keep and eye on the weather tomorrow and bring an umbrella