The high temperature of 51 observed at O’Hare International Airport on Friday was the city’s mildest reading since November 5th, and our first above normal high since Halloween. The influx of warmer air came courtesy of south winds that gusted over 30 mph. Rain and clouds are to exit the area early Saturday, leaving skies partly sunny. Air arriving in the wake of the departing weather system is of Pacific origin. Temperatures in the 50s over the Plains on Friday, are due to arrive in Chicago Saturday. Low pressure is then forecast to organize over southwest Missouri by early Sunday. This system is expected to track to our south, allowing strong northeast winds to develop, drawing colder air into the region, and changing rain to snow by Sunday evening. Sub-freezing high temperatures are expected to follow through early next week.