Near-record low humidity here, downpours hit California
The static electricity had to be near a maximum in Chicago yesterday afternoon as the relative humidity officially dropped to 17 percent at O’Hare Airport. This was the second driest February day in Chicago since 1900 (humidity records are unreliable before that time) and tied for the ninth driest all-time. Continental-source high pressure centered over southern Illinois was responsible for this rare occurrence.
Meanwhile, Californians were bracing for just the opposite—a strong low pressure system slamming into the West Coast. High wind warnings (50-70 m.p.h.) were posted for the west slopes of the Sierra Nevada Mountains along with winter storm warnings projecting as much as 6 feet of new snow above 8,000 feet and a foot or more at lower elevations. Downpours of an inch per hour were forecast for some areas with flash flood warnings up for most of the state, and mudslides were expected in recent burn areas in southwest California.
--Paul Dailey, WGN Weather Center Meteorologist