UPDATE: Evening Commute Could Be Snowstorm's Worst Time

A Winter Storm Warning will be in effect from 9 a.m. Wednesday to 4 a.m. Thursday in the Chicago area, with wet, heavy snow forecast for areas south and east of Chicago.

The evening commute could be terrible and dangerous based on the forecast.

The brunt of the snowstorm is expected to land east of Interstate 57 and into northwest Indiana, according to forecast models, but the rest of the Chicago area is not likely to escape unscathed.

The area from Chicago southwest to Pontiac is right on the line of heavy snow or no snow, according to the NWS, and as such, the confidence in the forecast is not high. The northwest flank of this band will feature a very sharp snowfall gradient, possibly going from 6 to 12 inches of snow to little or now snow in the span of just 15 to 20 miles.

Best estimates at this point are that heavy, wet snow accumulations up to 7 inches will likely land south of Interstate 80 in eastern Will County and southwestern Cook County. The North Shore and western suburbs could see 2 to 4 inches.

At O’Hare and Midway, 340 flights and 15 flights, respectively, have been cancelled as of 6 a.m. Wednesday due to the approaching storm.

Here is the latest update from the National Weather Service:

While this remains a complex forecast and uncertainty exists on the exact location of the heavy snow bands on Wednesday, confidence continues to increase that heavy snow will occur for a long enough duration in the afternoon and early evening, combined with strong winds, to cause major impacts. This includes during the evening commute when some of the heaviest snowfall rates may exist and the strongest wind speeds.

The combination of snow and winds will result in hazardous to dangerous travel conditions, as well as possibly power outages. Wind whipped snow will likely cause visibility to drop to near zero at times in portions of the warning area, especially in parts of Lake and Porter Counties in northwest Indiana. It is quite possible a Blizzard Warning will be needed for this area by morning.

This will be a HIGH IMPACT event especially during the late afternoon and early evening commute within the Winter Storm Warning area. Consider cancelling non-essential travel within this area during the mid-late afternoon into evening.

» CHECK CHICAGO-AREA SCHOOL CLOSINGS

Strong northerly winds are likely to gust up to 45 mph across the Chicago area, too. And in regions where the snow is falling, this could create blizzard conditions of wind-whipped snow, reducing visibility and making for dangerous travel conditions at the height of the storm, according to the National Weather Service.

A Lakeshore Flood Advisory also will be in effect from 9 a.m. Wednesday until 9 p.m. Thursday. Northerly gales could cause waves of 10 to 14 feet in lakeshore areas.

After Wednesday

• Thursday: A 30 percent chance of snow before noon. Mostly cloudy, with a high near 34. Breezy, with a north northwest wind 20 to 25 mph, with gusts as high as 35 mph. At night, mostly cloudy, with a low around 24. Blustery, with a northwest wind 15 to 20 mph, with gusts as high as 25 mph.
• Friday: Partly sunny, with a high near 33.
• Saturday: Sunny, with a high near 48.

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