Editor's Note: We're tracking the winter storm all day. You can find the latest weather updates in our winter storm live blog here.
The entire Chicago area was under a winter storm warning Friday, with some counties already seeing heavy and wet "bursts" of snow as a powerful winter snowstorm began to take hold across all of Northeastern Illinois and Northwest Indiana.
"A snowy 24 hours is expected," NBC 5 Meteolrogist Alicia Roman said. As of 4:30 a.m. Friday, snow had already begun to fall at a fast clip, with more significant snowfall beginning to pile up to the west, in DuPage, Kendall, Grundy and LaSalle counties.
NBC 5 Meteorologist Kevin Jeanes reported thundersnow in LaSalle County, where the NBC 5 Storm Team's pinpoint radar captured flashes of lightning. In DeKalb County, on I-88 at Peace, an Illinois Tollway traffic camera showed the highway entirely covered in snow, with low visibility as more snowflakes fell.
MORE: School closures: More than 100 Chicago-area schools, libraries closed amid winter storm
"Take your time if you have to go somewhere," Roman said early Friday morning. "Roadways for some are already treacherous."
According to NBC 5 Traffic Reporter Kye Martin, traffic accidents and crashes had already begun to follow the storm's track, with multiple crashes reported to the west.
Friday afternoon and into the evening, another wave of accumulating snow and dangerous travel was expected.
With that round, areas north and northwest of Chicago are likely to see the biggest impacts, with up to 6 inches of additional accumulation still possible, combined with dangerous wind gusts of up to 45 mph.
As the snow continues to fall, here's a breakdown of the latest predicted snow timing, totals and more.
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Winter Storm Warnings
Winter storm warnings went into effect at 3 a.m. Friday for Lake, McHenry, DeKalb, Kane, DuPage and Central Cook Counties Illinois, as well as Northern LaPorte County in Indiana, and Kenosha County in Wisconsin.
That warning was expected to continue through 12 p.m. Saturday.
"Heavy snow, strong winds and dangerous conditions expected," the National Weather Service warned. "Total snow accumulations of 6 to 12 inches and wind gusts up to 45 mph expected."
"Travel could be very difficult to impossible, especially away from Lake Michigan," the NWS said, adding that the hazardous conditions were expected to impact both the morning and evening commutes."
In Lake, Porter, and Newton Counties in Indiana, and Kankakee County in Illinois, a winter weather advisory was in effect.
Around 9:30 a.m., LaSalle, Kendall Grundy, Southern Cook and Will Counties, were downgraded from a winter storm warning to a winter weather advisory.
In those parts, snow total accumulations were expected to be between 3-6 inches, as snow was expected to mix with rain at times. However, strong wind gusts of up to 45 miles per hour were expected in those parts as well, the NWS said.
'Treacherous commute this morning'
One of the largest threats the storm brings will be for travelers and commuters.
"Strongly consider postponing travel," a tweet from the NWS said early Friday. The tweet specifically pointed to areas across the Chicago area, away from Lake Michigan and west of I-90/94.
Snowfall rates of 1-2 inches per hour were expected to fall through 10 a.m., the NBC 5 Storm Team said, with winds gusting between 40 and 50 miles through the morning.
As the day goes on, the NWS warned travelers to expect "downright dangerous travel conditions" across much of the area, especially in Northern Illinois during the morning and evening commutes as the snow continues to ramp up.
Some small crashes were reported Friday morning across area road ways, with air travel also beginning to snarl.
As of 5:30 a.m., O'Hare issued a ground stop, with more than 700 flights canceled across O'Hare and Midway airports. That ground stop transitioned to a ground delay later Friday morning.
Storm Timing
"Bursts" of heavy snow to the west began occurring overnight and into Friday morning, especially in counties to the west. That was expected to continue through the morning commute, the NBC 5 Storm Team said.
Later Friday morning, locations south of Interstate I-80 and potentially near Lake Michigan are expected to see snow transition to rain, with precipitation across the area getting lighter before conditions worsen later in the day.
The precipitation is expected to pick back up around or after 2 p.m. as wind gusts of 30 mph, possibly even higher, kick in.
Heavy snow areawide is likely for the evening commute, though lower snowfall totals are likely along the Lakefront. The largest snowfall totals are expected to fall after 5 p.m. and into the overnight hours as temperatures continue to drop.
According to the NWS, near-zero visibility, snow covered roads and dangerous travel can be expected Friday night and overnight with winds expected to gust as high as 45 miles per hour.
Predicted snowfall totals
The latest snowfall predictions showed between 8 and 12 inches of snowfall by Saturday morning for the counties in the winter storm watch. Closer to the lake however, those totals are expected to be slightly lower, in the 6-10 inch range, Roman said.
"A foot of snow will be possible in some parts," Jeanes said.
To the southwest, 6-10 inches of snow could fall, with between 4 and 6 inches possible in Kankakee and Northwest Indiana.
By Saturday evening, the snow is expected to taper.
Wind chills will drop to -20 and -30 degrees Sunday through Wednesday, with 20-30 mph wind gusts expected. These temperatures will mark the coldest days seen in the city since the end of January 2019.
The NBC 5 Storm Team is tracking this forecast as it develops. Stay tuned for updates as each system approaches.
Latest information on the Chicago snowstorm
You can find our latest stories on the Chicago snowstorm below:
- Live snow radar map: Track weather near you as storm snarls Chicago area
- Snow totals: Latest snow totals in Chicago and Illinois as snowfall as continues
- Illinois winter road conditions: Buses rerouted, crashes reported and more
- Power outages: Tens of thousands of ComEd customers without power amid winter storm
- Flights canceled: Ground delay at O'Hare, thousands of flights canceled across Chicago airports
- School closures: More than 100 schools closed across Illinois
