The Chicago area’s most impressive early May stretch of mild days in six years yields to the chilliest air mass in 10 days Friday. The temperature downturn is temporary and comes on the heels of four consecutive above normal days—the most in early May here since 2000. A 4,000+ mile long band of north/northeast winds, extending from northern Greenland south to Texas, is a major factor in delivering Friday’s late season chill.
Sun-obscuring clouds and a wind trajectory off Lake Michigan preserve the lower temperatures by inhibiting warming. That there’s an easterly component to the wind is little surprise. Some form of easterly wind blows here 53% of the time in May, more than in any other month of the year.
The cool air’s arrival Thursday in the Deep South contributed to violent thunderstorms. Hail 4.25” in diameter pounded Mertzon and Baird—both in Texas.
-Tom Skilling
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
