With glimpses of sunlight and temperatures in the low 30s, Wednesday -- the astronomical start of winter -- is shaping up to be just another chilly December day in Chicago.
Call it the calm before the storm.
A significant winter storm headed to the Midwest with dangerously cold temperatures, strong wind gusts, snow accumulation and blizzard-like conditions is on its way, and predicted to hit parts of the Chicago area slightly earlier than expected, NBC 5 Storm Team says.
And 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.
As timing of the storm continues to shift, here's what we know right now about the winter storm watch in Chicago's forecast.
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Wednesday
According to NBC 5 Storm Team, Wednesday will remain quiet and mainly dry, with moderate temperatures in the low 30s. Overnight however, snowflakes are expected to begin falling, and temperatures are expected to drop.
Thursday
A winter weather watch alert originally set for Thursday evening is now set to go into effect in some areas of Chicago -- McHenry, DeKalb, Kane, LaSalle, Kendall and Grundy -- Thursday morning, according to the National Weather Service.
According to the alert, blizzard conditions are possible, and dangerous travel is likely, thanks to winds gusting as high as 55 miles-per-hour at times. While total accumulation of two to five inches of snow is possible, the potential for ice, river jams, and strong, blowing snow from strong winds is expected to make road conditions dangerous.
Things will "rapidly" worsen heading into Thursday afternoon, with snow growing more widespread and becoming stronger, the NWS says. At that time, a winter storm watch for Lake, DuPage, Kankakee, Cook and Will counties in Illinois, and Lake, Porter, Newton and Jasper counties in northwest Indiana will go into effect.
The alert warns that "falling and blowing snow may result in white-out conditions with zero visibility at times, making travel extremely difficult, if not impossible."
"Power outages will also be possible as a result of strong damaging wind gusts to 55 mph," it states.
Icy roads could add to the hazardous conditions as temperatures rapidly fall. "Dangerously cold wind chills as low as 25 to 35 below zero are likely Thursday night through Friday night," the NWS alert says. "Wind chills of this magnitude can cause frostbite on exposed skin in as little as 20 minutes."
The intense winter storm is expected to be widespread by the evening hours. This marks the time when it could could generate blizzard conditions and is expected to "severely" impact travel.
Friday
Major impacts are expected from the snowstorm throughout the day Friday.
Expect heavy snow, strong and damaging winds, difficult or near-impossible travel conditions and dangerously cold temperatures and wind chills.
Wind chill readings are expected to drop near -30 as early as Friday morning.
The winter storm watch is slated to continue through late Friday evening as the storm and potentially "blizzard-like" conditions hold strong.
Forecasts are unclear as to how much snow may actually fall as snow but the snow is expected to begin subsiding overnight.
Early predictions so far indicate the Chicago area could see between three and eight inches of snow, with higher totals possible, especially in northwest Indiana. Some locations could also see lower totals.
Christmas Eve and Christmas Day
Snow begins to lighten early Saturday morning, but hazardous travel conditions are slated to continue through the weekend as dangerous cold continues.
Minimum wind chills of -20 to -30 degrees are expected with highs in the single digits and low teens. Lake effect snow showers are also possible in parts of northwest Indiana, according to the NBC 5 Storm Team.
Difficult and impossible travel conditions could linger, particularly in the morning hours Saturday, as blowing and drifting snow remains a concern.
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.
