The chance for rain is still present for the weekend, but widespread and prolonged rain chances appear to be trending down for Friday and Saturday. A cold front will pass through southern Wisconsin and northern Illinois early Friday morning. High pressure located over the southeast has really scoured out most of the moisture in the atmosphere, leading to a dry frontal passage on Friday.
That cold front will then turn into a stationary boundary as high pressure moves in from the Plains Saturday morning. Surface winds will shift around to the northeast, pulling in a drier air mass into Great Lakes. The strength of the high will work to push the stationary boundary south into southern Illinois during the afternoon. The dry air north of the boundary will limit initially limit the amount of moisture in that atmosphere, keeping most of the rain to the south. Winds will be chilly, however, under the cloud cover and this will hold temperatures in the mid 40s for the afternoon. There still remains a slight chance for a few showers on Saturday as the southern portion of the Stateline will be close to the northern fringe of the precipitation. Along the northern edge, there may be just enough dry air to promote evaporative cooling, causing a few snowflakes to mix in along I-88. That scenario appear to be low, though.
Low pressure will lift northeast along the front, pushing it a little further north Saturday night and Sunday. This will allow the chance for rain to return through the morning Sunday.