Meteorologists and forecasters have been closely watching a system for the past few days that will bring messy winter weather to the Stateline. Now that the system has moved on shore into the Pacific Northwest, we are getting a better look at the path of this storm, and the impact to the area.
First, breaking down the Watches, Warnings, and Advisories for the Stateline. A Winter Storm Warning is in place for Jo Daviess, Stephenson, Winnebago, Boone, McHenry, Green, Rock, and Walworth counties beginning at 6pm tonight for all counties except for McHenry and Walworth, their Warning will go into effect at 9pm. The Winter Storm Warning will continue through 9am Tuesday morning. This is where the highest snow totals are forecast.
A Winter Weather Advisory will go into effect at 6pm tonight for Carroll, Whiteside, Ogle, Lee, and DeKalb counties and will expire at 9am Tuesday. This is the region where the mix will last a little longer and snow totals are forecast to be a little less.
Breaking down the system, there are a couple factors in place. First, is an incoming cold front that will come through mainly dry this afternoon. It will switch our breezy southwest winds to the north, clouds will increase, and colder air will be pulled in. The front will then stall just south of I-80 tonight and an area of low pressure will then track near the front as well. This system will then allows the winter weather to move in after dinner time tonight. A winter mix will begin to spread east from the Mississippi around 6pm but will impact most of the Stateline around 8/9pm tonight. It will be tough for this to accumulate at first with warmer ground temperatures. Freezing rain, sleet, and snow all possible at first. After midnight the winter mix turns to snow, then looking through the early morning hours the snowfall rates will begin to pick up and start to accumulate. Winds will also be strong overnight into Tuesday morning and will allow the snow to be blown around, reducing visibility.
From Rockford and areas north, a heavier band of snow looks to set up and this is where we will see some of the higher totals. Though this is the most difficult portion on the forecast, because it is a little too soon to have high confidence in where exactly this band will set up. Within the band of heavier snow expect snow totals around 3-5inches but locally higher amounts will also be seen. South of Rockford, in areas with the Winter Weather Advisory, the winter mix will linger a bit longer before switching to snow, and thus snow totals will be less in this area. Generally 2-3" is a better bet for this area. Though despite getting a bit less snow south of Rockford, it will still be a messy commute tomorrow, you will want to leave a lot of extra time if you have to travel tomorrow morning.
Possible hazards tomorrow morning will include; blowing snow and reduced visibility, and snow covered and slick roads.
The good news is, the snow doesn't look to last all day. Most of the snow will be out around noon, though light snow is still possible through the late afternoon.
Details with this forecast will change, so make sure to stop by later, we'll make sure to keep you updated on the latest forecast.