A winter storm watch has been moved up for most northern Illinois counties to 9 a.m. Thursday through 6 a.m. Saturday, according to the National Weather Service, with more details coming into focus while the storm approaches.
The winter storm watch starts at 9 a.m. Thursday for Winnebago, Boone, McHenry, Ogle, Lee, DeKalb, Kane, La Salle, Kendall, Grundy and Livingston counties.
For DuPage, Cook, Lake and Will counties, the winter storm watch begins at noon.
Falling and blowing snow may result in whiteout conditions at times, making travel difficult, if not impossible, according to the National Weather Service. Power outages also are a possibility with wind gusts exceeding 55 mph during the height of the storm.
The watch extends from the Wisconsin border through the Chicago suburbs, as far south as Ford County and as far west as Lee County, including the entirety of northeastern Illinois.
Kevin Doom, meteorologist at the National Weather Service in Chicago, said snowfall predictions have varied anywhere from a foot to 2 to 3 inches. Regardless, the storm will be dangerous, because of the heavy wind gusts and dangerous wind chills.
“I want to emphasize it’s not the snow totals with this storm that are drawing the most concern, the snow totals are lower on the list of concerns,” Doom said. “The snow is going to be dry, powdery and blow, causing sometimes zero visibility.”
The worst conditions to travel will be Thursday evening into Saturday morning. Anyone looking to travel should try to do so Wednesday, prior to the storm, or may be able to travel Saturday, depending on conditions, but Doom expects blowing snow and dangerous temperatures still to be an issue throughout Saturday.
Here is the updated timing for the storm:
Snow begins to fall early Thursday morning. There are increasing chances of an initial accumulating snow into early Thursday afternoon, according to forecasters.
Road conditions will rapidly deteriorate from west to east on Thursday afternoon, before the afternoon work commute, as the snowfall increases, temperatures drop and winds increase.
Thursday night into Friday night
Dangerous blizzard-like conditions are most likely to occur during this time, with blowing snow throughout the entire area severely affecting travel, according to the weather service.
Strong winds may cause power outages due to falling tree limbs.
Temperatures will continue to plummet, with wind chills approaching 20 below zero. Wind chills of this magnitude can cause frostbite on exposed skin in as little as 30 minutes.
Saturday - Christmas Eve
The snow will likely be done, but the wind will not. There will be widespread blowing snow across the area, making Christmas Eve travel difficult throughout the day, if not impossible during the morning.
Temperatures will continue to be in the single digits, with the wind chill below zero.