Forecasters are warning of a serious threat for EF-2+ tornadoes in Lake and McHenry counties Thursday after additional thunderstorms knocked down power lines and trees across the area, causing power outages Wednesday.
The National Weather Service (NWS) said a strong storm system will bring a threat for two or more rounds of severe weather on Thursday.
Cooler and much less humid conditions will follow on Friday.
Another cold front will bring showers and scattered thunderstorms late in the day on Saturday into Saturday evening, followed by a cool and breezy Sunday.
The NWS ranked the Chicagoland area at a three out of five scale for tornado threat and for damaging winds.
Forecasters say some tornadoes may be strong, EF-2 or greater, and winds could gust 60-80 mph, with hail two inches or greater in diameter. Flash flooding may be significant locally.
The threat for strong EF-2+ tornadoes is across northern Illinois and southern Wisconsin, most likely between 4-8 p.m. with the highest threat in Lake, McHenry, Winnebago and Boone counties, as well as other parts of the Chicagoland area.
“Take tornado warnings seriously, and have multiple ways to get warning information today,” forecasters said.
The threat of tornadoes will be highest if storms can “stay discrete, or by themselves.”
The main source of uncertainty is where the warm front will stall on Thursday evening. “It may be in northern Illinois or southern Wisconsin,” the NWS said.
Severe thunderstorms swept through northern Illinois on Wednesday afternoon into the evening, bringing heavy rain and high winds.
Severe storms began impacting the McHenry County area around 3 p.m. before moving into Lake County a short time later.
Fire departments across McHenry, Lake and Kane counties were kept busy responding to emergency calls regarding downed wires, downed poles and downed trees in roadways.
Ground stops were issued at Midway Airport and O’Hare Airport in Chicago around 3:45 p.m. due to the weather.
ComEd said the severe storms on Wednesday caused significant damage across the area, including downed poles and wires, leading to widespread customer interruptions.
“We know this is challenging and will restore service as safely and quickly as conditions allow,” ComEd said.
“Right now, more than 100 crews are working around the clock to safely and efficiently restore service after this unique storm brought widespread damage and challenging conditions across our service area, including downed power lines, broken poles, and fallen trees and large limbs impacting equipment,” ComEd said in a statement.
“We are also monitoring the potential for additional severe weather on Thursday, which could create further challenges as restoration work continues,” they added.
ComEd said they expect about 80% of outages to be restored by 1 p.m. on Saturday. “We understand how stressful this is and how deeply this disruption affects your day to day life, especially for those who rely on electricity to power critical medical devices. Please know we do not take that responsibility lightly.”
The City of Highland Park said Sheridan Road between Waverly Road and Forest Avenue was shut down in both directions due to a live wire down on Thursday morning. “As a reminder, do not attempt to move or drive over downed power lines.”
The Huntley Police Department said Wednesday afternoon that wires were down in the area of Mill Street and Dean Street. “Please use caution when driving in the area or consider using alternate routes.”
A large tree came down at Lynn Drive and Lagoon Drive in Hawthorn Woods, prompting police and public works to respond to clear it.
The Woodstock Fire/Rescue District said they responded to multiple weather-related incidents as the strong storms moved through the area on Wednesday.
“Crews are working to address downed trees, power lines, and other storm-related hazards. Please use caution if traveling and avoid areas where emergency personnel are operating. If you encounter a downed power line, stay away from it and anything it may be touching. Always assume downed wires are energized and dangerous, and report them to 911 immediately,” the fire district said.
The Lake County Sheriff’s Office said responders were kept busy last night — from sheriff’s deputies to 911 dispatchers to the Auxiliary Deputy Unit. One call involved a tree that fell down onto a Jeep in Lake County, blocking the roadway.
“They were keeping the community safe! Today is shaping up to be very similar. Keep your eye on the weather today!” the sheriff’s office said.
The Lake County Division of Transportation said Thursday morning that travel is slow across parts of the county due to downed power lines. “Please allow extra travel time and seek alternate routes if possible.”
ComEd said mid-morning on Thursday that 165,000 customers remained without power due to over 5,200 outages.