The entire Chicago area has been upgraded to a winter storm warning ahead of a major winter system set to arrive just ahead of the holiday weekend. At the same time, one Indiana county was elevated to a blizzard warning as officials warn of "white out" conditions, power outages and measurable snow.
Porter County, Indiana will see a blizzard warning beginning at 3 p.m. CT Thursday and continuing until 6 a.m. Saturday. The National Weather Service noted that such a warning is not based on snowfall amounts, but instead on winds and visibility.
According to the warning, "falling and blowing snow will result in white out conditions with zero visibility at times, making travel extremely difficult, if not impossible."
Wind gusts of up to 55 mph could also lead to power outages and ice-covered roads are possible as temperatures "rapidly fall" late Thursday afternoon and into early Thursday evening. From Thursday night and into Friday, wind chills as low as 35 degrees below zero are likely.
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Meanwhile, a winter storm warning will begin at 9 a.m. Thursday in McHenry, DeKalb, Kane, LaSalle, Kendall and Grundy counties, according to the National Weather Service. The warning will take effect in Lake, DuPage, Kankakee, Cook and Will counties in Illinois at noon and in Lake, Newton and Jasper counties in northwest Indiana starting at 3 p.m. CT.
It will remain in effect across the area until 6 a.m. Saturday.
White out conditions and "zero visibility" are also possible with the warning across the Chicago area, "making travel extremely difficult."
Power outages, wind gusts of up to 50 mph, and wind chills as low as 35 degrees below zero are all possible.
While the current forecasted snow totals of three to six inches may not seem impressive, "it's not just the snow," NBC 5 Meteorologist Paul Deanno says.
The National Weather Service is warning travelers and motorists -- whether they're taking trip out of town or just down the road -- that travel conditions during the height of the storm could be potentially "life-threatening."
The storm comes amid one of the busiest travel times of the year. According to AAA, 113 million Americans -- 5.8 million in Illinois -- are expected to travel 50 miles or more between Dec. 23 and Jan. 2. Wednesday and Thursday alone, the Illinois Tollway estimating that 1.7 million vehicles are expected to use the tollway system.
And according to the Chicago Department of Aviation, approximately 2.9 million air travelers are expected to pass through O'Hare and Midway International Airports between Dec. 21 and Jan. 2.
What Are Blizzard Conditions?
According to NBC 5 Storm Team, a specific set of conditions must be met in order for a weather pattern to be considered a blizzard. They include snow or blowing snow, wind gusts of at least 35 miles-per-hour, and visibility of a quarter-mile or less.
All three of those conditions must be present for at least three hours for a storm to be labeled a blizzard, NBC 5 meteorologists report.
According to NWS, the snowiest Christmas on record for the Chicago area took place in 1950, when the city say just over five inches of snow.
