Southwest winds gusting to near 30 mph on Saturday helped send temps soaring to the upper 40s across the Chicago area. Similar to last winter, such mild air has been the rule thus far this season. A wind shift to the northwest Saturday night has ushered polar air into the Midwest. This flow of much colder air is forecast to continue into midweek, resulting in a series of days featuring below normal temps. The city is expected to experience its coldest readings in nearly two years during this period. High temps on Monday are expected to hover near 10 above zero, with lows Monday night ranging from 5 above zero downtown, to 5 below in the outlying suburbs. As cold as this may feel, consider that Sunday marks the 27th anniversary of Chicago’s lowest temperature on record. On January 20, 1985 the mercury dipped to -27 degrees at O’Hare International Airport.