It’s the ice-ing on the cake.
After the lowest temperatures in three decades hit Chicago during a brutal cold snap last week — and a rebound to the 50s for a day — the city could see its first ice storm in nine years.
The ice storm warning issued by the National Weather Service for much of the Chicago area took effect at 6 p.m. It extends until 6 a.m. Wednesday, but weather service meteorologists said late Tuesday that they expect the ice storm to peter off earlier than expected in the overnight hours.
Meteorologists predicted the storm would move through the Chicago metro area late Tuesday night, bringing treacherous road conditions with widespread precipitation from 11 p.m. to midnight.
Though the storm will have mostly moved on by the Wednesday morning commute, the weather service warned drivers to give themselves extra time to navigate potentially slick roads.
Significant icing was expected from freezing rain, with ice accumulations of one-tenth to four-tenths of an inch expected to make travel dangerous. Many suburban schools and libraries were closing early Tuesday and opening late Wednesday because of the storm, according to the Emergency Closing Center.
The storm was expected to hit northwest, far north and far west suburbs by about 6 p.m. and move into the city, near west suburbs and most of Will County by 7 p.m., hitting the Southeast Side and far south suburbs by about 8 p.m., according to the weather service.
Chicagoans may want to avoid roads entirely during the height of the storm and prepare for potential power outages, Castro said. Snapped power lines and falling tree branches are possible as ice accumulates.
“Thankfully we’re not looking at really strong winds with this,” Castro said. “But trees could be weighed down and come down onto power lines.”
Castro recommended having an emergency supply kit in your vehicle at all times.
“If the roads do get really bad tonight, always check road conditions before driving,” Castro said. “Consider putting off nonessential travel. That goes with any winter weather.”
Far northwest suburbs are likely to see prolonged accumulation as evening temperatures remain in the mid-20s, Castro said. But the downtown area could see temperatures in the low 30s later Tuesday night, which will help cut down on the ice accumulation.
“There’s good reason to think that the suburbs could fare worse,” Castro said. “Even in terms of the ice accumulation that we’re forecasting, we have higher overall ice accumulation in the suburbs.”
The downtown area could see one-tenth to two-tenths of an inch of ice accumulation, while areas farther north and west could see a range of a quarter of an inch to four-tenths of an inch of ice, Castro said.
The last ice storm warning was issued 3,328 days ago, said Castro, making this the first warning issued in more than nine years.
“Actual ice storm warnings are uncommon,” Castro said.
The storms occur when there’s a unique interaction between warm air riding up over colder air, the meteorologist said.
But after the ice melts Wednesday, Chicago will move again toward colder conditions.
More rain is possible Wednesday and Thursday, but by Friday highs are expected to hover in the teens, according to the weather service.
Chicago Tribune’s Tom Palmer contributed.
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