Wednesday’s blustery winds, combined with the chilliest temperatures since last April, are likely to jar many Chicagoans. The cool air arrives on the heels of one of the warmest October opens on the books. A buckling jet stream, the product of the northward flood of mild air ahead of a powerful landfalling Pacific storm, has developed a ridge aloft. Steering winds riding up and over that ridge have tapped the pool of chilly air collecting over northern Canada’s increasingly snow- covered tundra, forcing it south into the Midwest.
Wednesday’s predicted 53° high—a reading more typical of early November than Oct. 10—represents this area’s biggest three-day October high temperature plunge in 10 years. It was only Monday that readings here surged to 87°. Not since readings tumbled from 82° to 49° in Chicago between Oct. 12-14, 1997 have daytime temps here lost so much ground so quickly.
-By Tom Skilling, WGN-TV Chief Meteorologist
