Chicago’s temperatures will be running well above normal through Friday, but the bottom drops out by the weekend. Daily highs approach 70 degrees today, then climb into the lower 70s Wednesday through Friday. They won’t be records – daily records are in the 80s from today through the 24th of October—but after the cloudy, chilly and wet weather that prevailed here through much of September, the coming spell of mild and dry days represents a change that many will consider welcome.
A powerful autumn storm with its center over Minnesota develops by Friday, then moves slowly toward the northeast to just north of Lake Superior on Monday. Cold air sweeps southeast around the storm center, arriving in Chicago late Friday. Snow will occur across the upper Midwest (but not here).