Most of the shower and storm activity has been focused to the east and southeast much of Sunday afternoon, tied to an area of better instability across northern Illinois. However, a few isolated showers have developed Sunday afternoon and will continue as a cold front and low pressure system move closer to the Stateline.
The warm front that brought overnight storm activity to much of the area has lifted north into Wisconsin providing a better focus for storm development through much of the afternoon. Very little forcing will take place in the atmosphere overnight to really provide much for thunderstorms to develop on, so most of the night should remain dry.
As a surface low pressure system and cold front move closer to the area Monday afternoon, thunderstorm activity will become more widespread mid to late morning and afternoon. There remains a low risk for strong to severe storms over northern Illinois and southern Wisconsin Monday afternoon. Greatest concern would be mostly hail should any strong storm develop.