The center of cool high pressure will pass overhead Friday to the east. Then winds will pick up — gradually shifting to the southwest Friday night — flowing up the backside of the departing high pressure. Pacific-origin air will ride a steady west-southwest flow bringing mild air into the Midwest and western Great Lakes, the leading edge reaching the Chicago area Saturday. Because of the heavy snow cover south of Chicago and in northwest Indiana, there will be a wide range in Saturday’s high temperatures — from the middle 50s over bare ground west of Chicago to the lower/middle 40s over the melting but still solid snowpack.
If Sunday’s high temperatures rise into the lower 60s as forecast, the record for Feb. 28, 61 degrees in 1895, will be in jeopardy. A cool front is expected to swing through from the west later Sunday afternoon with temperatures beginning a slow downhill slide into the 30s with a good chance of snow by the middle of next week.
