Chicago faces first round of severe storms Wednesday as 2nd round prompts flash flood warning

Chicago was hit Wednesday by the first of what could be two rounds of severe weather driven by rising temperatures, according to the National Weather Service.

Those afternoon storms knocked down trees and left hundreds of thousands of homes without power — and more storms were on the way.

The entire Chicago metro area was under severe thunderstorm warnings until about 5 p.m. Wednesday. The first line hit the Western suburbs around 3 p.m. With it came rain and 70 mph wind gusts, the weather service said. Another round of storms could hit later Wednesday night, according to the weather service.

While a tornado threat couldn’t be ruled out closer to Chicago Wednesday — a warning had been issued for Joliet, Cresthill and Shorewood around 3:20 p.m. — NWS meteorologist Kevin Birk said damaging winds were a much more likely threat, bringing “considerable damage” to “trees, mobile homes, roofs and outbuildings.”

The Sun-Times confirmed downed branches in suburban Oak Park, as well as trees down in Jackson Park and debris damaging overhead wires near 75th Street and Stony Island Avenue. Other social media posts indicated more downed branches and felled trees in Belmont Cragin, Lincoln Park and Little Village.

In an email to constituents Wednesday night, Ald. Matt O’Shea (19th) said there were more than 100 reports of downed trees and about 6,000 households and businesses without power across the Beverly, Morgan Park and Mount Greenwood neighborhoods.

The storms were also moving at 45mph, according to the weather service, meaning they have less of a chance to dump large amounts of rain, Birk said.

“This line is moving pretty quick,” said NWS meteorologist Kevin Birk. “So the main story is damaging wind gusts.”

But another round of storms was set to hit the area later Wednesday night, with flash flood warnings being issued for much of the metro area until 3 a.m. Thursday.

The second wave was expected to be slower, and with the increased humidity, had the potential to drop significantly more rain — up to an inch or two an hour. The Wednesday afternoon storms had dropped half an inch of rain in the hardest hit areas, according to the weather service.

ComEd had been preparing for the damage the storms could cause, and subsequent outages. About 290,000 customers were experiencing outages by 5 p.m., though crews had restored power to about 40,000 customers by 8:30 p.m., ahead of the second wave.

“We’ve been closely monitoring these weather conditions and are fully prepared to respond quickly and restore service for customers who may be impacted,” said David Perez, executive vice president and COO of ComEd, said in a statement. “Our crews will work safely around the clock to ensure any outage our customers experience is brief.”

Shortly before 10 p.m., Red Line trains began bypassing the 87th/Dan Ryan station because it had lost power, according to a CTA service alert.

Earlier, the CTA reported significant delays on the Orange Line, which trains standing on both inbound and outbound trains to Midway International Airport. Service also was interrupted on the Pink and Green lines due to signal problems at the Ashland station, according to the CTA.

The Rock Island Metra line was also temporarily stopped due to a power outage, other trains were delayed due to high winds, per service alerts issued Wednesday afternoon. Milwaukee District North Metra train wasn’t operating beyond Glenview after a tree fell on the tracks.

A ground stop was ordered at O’Hare International Airport during the first wave of storms, contributing to the day’s 474 cancellations and average delay time of about an hour. Midway saw 13 cancellations, with an average delay time of nearly 70 minutes Wednesday.

On Thursday, the area is slated to see another round of storms coming later in the afternoon and into the evening — and those storms have the potential to be even stronger than Wednesday. Birk said the rising temperatures — with highs Wednesday reaching up to 89 degrees and staying in the high 80s until Friday — were strengthening the storms, which carried more significant tornado risks.

Birk’s rule of thumb for staying safe amid the storms: “If you hear thunder, go indoors or take shelter.”

Thursday’s storms “will have the potential for strong wind gusts and tornado threats,” he added. “The storms feed off the warm and humid air mass.”

Contributing: Tyler Pasciak LaRiviere