Temperatures across much of the metro area returned to the 80s after a 6-day hiatus that included 5 straight days of below normal readings. Officially, the high of 82, and low of 62 observed at O’Hare International Airport on Wednesday was 6 degrees above normal, and marked the start of a warm spell that is forecast to persist into early next week. Though some spots may reach 90 degrees over the upcoming weekend, this warm period will not be as intense as what the area experienced during the opening days of September, and humidity levels will be much more tolerable. Our abnormal warmth is not arriving from the tropics, but is forming overhead. Areas from the southern Plains to the Great Lakes will be under a building dome of subsiding, warm air wedged between a large buckle in the jet stream over the West, and hurricane Florence over the Southeast. This pattern is expected remain in place through Monday.