The 83-degree high observed at O’Hare airport Monday afternoon marked the seventh consecutive day of above-normal temperatures. It was also the warmest Sept. 29 since 2002. The August-level warmth was well shy of the 99-degree record for the date, which was set in 1953. Just before 6 p.m. Monday, a cold front passed O’Hare, shifting the wind to the northeast and essentially bringing a change of seasons in about two hours’ time. The temperature was still a balmy 81 degrees at 5 p.m., but had slipped to 60 by 7 p.m. Temperatures are forecast to rebound following a chilly Tuesday. By midweek, increasing south winds will bring warmer, more humid air to the Midwest. This will set the stage for a period of showers and thunderstorms, which may arrive as early as Wednesday night. Current forecasts suggest the area will likely receive its first significant rainfall in three weeks.
