Warm, moisture-laden southwest winds pushed Chicago-area temperatures into the upper 70s and lower 80s Saturday afternoon while dew points jumped well into the 60s. The approach of an upper-air disturbance and cold front from the west was enough to destabilize the atmosphere, triggering widespread showers and thunderstorms. A severe thunderstorm watch was posted south of Interstate 80, and severe storms developed in Will, Kankakee and Iroquois counties and spread into northwest Indiana. Wind was the primary culprit, with trees and power lines down in Lake and Porter counties in Indiana, with wind gusts to 70 mph reported in Valparaiso and Lowell.
A secondary cold front, assisted by a strong, reinforcing upper-air cold surge, will hit here Sunday, with high temperatures topping out about 15 degrees lower than Saturday. Beginning in the predawn hours Sunday, strong northerly winds will draw cloudiness and scattered showers across the area. Cool high pressure will persist Monday, followed by an extended period of fair skies and a slow warming trend the remainder of the week ahead.
