Northwest wind flow across the Great lakes region kept the area dry and cool over the weekend. High temperatures recorded at O’Hare International Airport averaged 10 degrees below normal for the two weekend days, with readings more typical of mid-May. Another day of sub-normal temperatures is slated for Monday, before winds aloft shift to a west-to-east orientation. This change is to allow a lobe of heat and humidity to surge into the Midwest. Tuesday will be the transition day, with light winds, and temperatures trending closer to normal for late June. Increasing southwest winds are to lock in by midweek, sending temperatures to near 90 degrees by Thursday. Clusters of drenching thunderstorms may occur in the tropical air later this week.