People in the Chicago area are used to a little wind. But on Tuesday and Wednesday, the gusts are expected to be so strong that a walk down Michigan Avenue could feel like a scene from “The Wizard of Oz.”
This storm is likely to be anything but magical — with wind gusts up to 60 mph and sustained winds of about 35 mph. The National Weather Service warned that the strong winds could cause major problems across the area, including falling tree limbs, structural damage, downed power lines and widespread power outages.
The massive storm, packing lightning and heavy downpours, was expected to begin its two-day sweep through the area in the predawn hours Tuesday, the result of a low-pressure system that the western Great Lakes and upper Midwest region has not experienced in decades.
“The storm system will be one of the most powerful we have seen in this part of the country in 70 years,” said Jim Allsopp, a meteorologist for the National Weather Service. “This is a big deal.”
Early-morning thunderstorms are expected to be followed by high winds throughout the day, possibly affecting both morning and evening commutes. The winds will taper off Tuesday night and pick up again Wednesday before the system moves out of the area that night, according to the weather service.
In preparation, residents were advised to park vehicles in the garage, secure all windows and doors and tie down garbage cans, barbecue grills and anything else that could blow away.
Chicago officials activated their “extreme weather plan,” which includes notifying city contractors and building managers to secure building equipment, cranes and scaffolding. The city said it was notifying public schools, hotels, universities and yacht clubs, and would take precautions at Navy Pier.
Tom Byrne, commissioner of Chicago’s Streets and Sanitation Department, said his workers were prepared to deal with a high number of downed trees. ComEd crews will work 16-hour shifts to respond to expected power outages, a spokesman said.
“The impact of these powerful storms could result in outages across ComEd’s entire northern service territory,” said Michael Guerra, a vice president.
Richard Edgeworth, chief of safety and security for the Chicago Department of Aviation, said both Midway Airport and O’Hare International Airport could experience delays, so travelers should call the airlines to confirm flights.
In River Forest, residents received recorded phone calls Monday advising them to stow away garden furniture and expect falling limbs and downed power lines. In Lombard, village officials cautioned residents that some school districts may suspend bus service if the winds create travel safety concerns.
Chicago harbors will officially close for the season on Sunday, and most boats have already been removed. But the Chicago Park District issued a notice to boaters to take necessary precautions.
The massive storm, expected to affect 13 states, is fueled by a jet stream that will also bring lower temperatures to the area over the next few days, though no snow is predicted.
The low-pressure system is moving northeast from Nebraska across the Midwest and is expected to continue into southern Canada, said WGN meteorologist Tom Skilling. At its most severe point, in northern Minnesota, record low pressure of 28.27 inches of mercury could develop, the equivalent of the pressure system of a Category 3 hurricane, Skilling said.
In Chicago, the barometric pressure could drop to 29.05, breaking the record of 29.11 for October, meteorologists said.
The weather service predicted that the storm will have the second-lowest pressure ever detected in the Great Lakes region. The Great Ohio Blizzard on Jan. 26, 1978, holds the No. 1 spot. This new storm’s pressure would be lower than that for the previous No. 2 Great Lakes event, the Armistice Day storm of Nov. 11, 1940. It would also surpass the storm on Nov. 10, 1975, that led to the sinking of the SS Edmund Fitzgerald on Lake Superior.
In some ways, the storm is the price Chicagoans will pay for the nice October weather, which has resulted in temperatures in the 70s, meteorologists said.
“The very cool air in the center of the country is doing battle with the warm air we’ve had here, and this leads to pressure variations and jet stream variations,” Skilling said. “Everything else flows from that.”
The jet stream, which produced pockets of 220 mph winds, forced air from ground level to rise quickly to fill the gaps, resulting in a drop in air pressure.
“In effect, the air is being pulled aloft, and the air around the storm has to rush in and fill in for it, creating strong winds across the area,” Skilling said.
After two days of severe and cooler weather, warmer temperatures are expected to return in time for trick-or-treaters. By Saturday, the forecast calls for partly sunny skies and breezy weather, with highs near 60. On Sunday, Halloween is expected to be warm with possible late showers.
Tribune reporter Liam Ford contributed to this report.
