Clouds associated with the departing low-pressure system will move off to the east Friday morning, leaving partly sunny skies across the Chicago area. The western Great Lakes continue to be positioned in the far-southern extremity of the nearly stationary huge cool high pressure air mass that actually dominates the central two-thirds of Canada. Thus easterly winds flowing over the chilly waters of Lake Michigan will greatly enhance the cooling impact here with readings along the Illinois/Indiana portion of the Lake Michigan shoreline in store for 40-degree temperatures through the weekend.
Clouds and rain will spread back over the Chicago area Saturday as another low-pressure system moves east out of the central plains, following a similar track to the just departed low pressure — up the Ohio River Valley — the track again held to our south by the persistently strong high pressure. An additional inch or more rainfall is likely to be recorded at many Chicago-area observation points by the time this second low pressure system tracks off to the east later Sunday.
Mild temperatures are expected to finally return here by Tuesday.
