'Gust front' deflects line of severe weather heading toward Chicago, pushing storms north
A tornado watch was still in effect until 11 p.m. Friday for Cook County and northern Illinois, but the severe weather mainly stayed northwest of the Chicago area thanks to a line of cool, dense air that broke the storms up. Saturday’s will see a 50% chance of rain.
A pedestrian walks on an island surrounded by flood water on La Salle Street and North DuSable Lake Shore Drive in Lincoln Park on Friday. Rains overnight Thursday and early Friday left some roads impassable. Despite a severe weather watch for Chicago on Friday evening, the severe weather passed to the north, offering some relief.
Pat Nabong/Sun-Times
Severe thunderstorms mostly missed the Chicago area Friday night despite a tornado watch issued for Cook County and many surrounding counties.
The tornado watch remained in effect until 11 p.m., but a gust front, a line of cool, dense air that leads a thunderstorm, jumped ahead of the storm line, causing the thunderstorms to break apart, with the most severe weather staying northwest of Chicago, near the Rockford area, National Weather Service meteorologist Scott Baker said.
“A lot of times when [a gust front] develops and pushes out ahead of the storms, any of the storms behind it will fall apart pretty quickly,” Baker said. “Once you see that, that’s where you start to watch for any additional developments, and we’ve been watching ... and nothing’s forming on that line.”
Some showers and light storms, along with gusty winds up to 40 mph, could enter the area overnight. Saturday is forecast for a 50% chance of rain and a high of 88 degrees, but the weather service’s storm prediction center calls for a level one risk for severe storms, on a scale of one to five, Baker said.
The winds have also triggered a special marine warning for Lake Michigan through Friday night and potentially into Saturday, causing high waves and possible dangerous conditions for small watercraft, according to the weather service.
Sunday is forecast to be sunny and clear with a high of 85, according to ABC7 meteorologist Cheryl Scott.
City officials issued a water overflow alert for Chicago, warning residents to reduce water use during and after Friday’s rainfall to help prevent flooding and protect water quality.
It follows a rainy Thursday night and early Friday during which a semi-trailer ran off the Dan Ryan Expressway, standing water collected on some city streets and viaducts, and roughly 30 calls were made to the Chicago Fire Department for reports of flooded basements.
Around 4:30 a.m. Friday, a semi-trailer was going north on Interstate 94 near 63rd Street on the city’s South Side when it ran off the roadway due to hydroplaning, blocking two traffic lanes, Illinois State Police said. Lanes were shut down about 4:30 a.m. and reopened an hour later.
More than 2 inches of rain was measured Friday at O’Hare Airport and 1.3 inches fell at Midway Airport, according to the weather service. Boone and Winnebago counties saw roughly 3 to 4 inches of rain, with one private weather station in Loves Park north of Rockford reporting nearly 6 inches.
At least six Chicago Department of Water Management crews were working Friday on a flooded street under the La Salle bridge on DuSable Lake Shore Drive.
Kristopher Williams walked through the tunnel after getting out of an Uber to get to North Avenue Beach from the other side of the bridge.
“I’ve never seen streets flooded like this before,” Williams said.
Despite no flood watches or warnings issued in Chicago, Baker said there’s nearly always a chance of small flooding in the city when it rains.
“With urban areas, you can get typical ponding of water here and there,” he said. “So, just stay alert overnight for potential ponding of water in areas that typically see that when there’s excess rainfall, excess water, but we’re not anticipating anything at this time in terms of flash flooding.”