Dynamic weather system brings storm threat, blizzard conditions in less than 24 hours

 11PM HEADLINE UPDATE: Green and Rock Counties in Southern Wisconsin were upgraded to a Winter Storm Warning, while Walworth County was converted over to a Winter Weather Advisory. Higher snowfall accumulations will be expected further West, leading to more significant winter impacts. Blowing and drifting snow remains a concern across the map, regardless of how much snow actually falls.

Dynamic weather system brings storm threat, blizzard conditions in less than 24 hours Sunday into Monday: General impacts of this system remain unchanged, but the headlines have been updated, including a BLIZZARD WARNING for Northwestern Illinois. Below is a timeline highlighting the precipitation types and winds expected through the duration of this storm system.

It is still looking like we will see rain and a few storms through the morning and afternoon on Sunday, with an isolated severe risk for a storm or two to produce wind gusts in excess of 60 mph. Outside of storms, winds will be gusting between 30-40 mph through the afternoon.

Sunday afternoon and evening will begin the transition over to freezing precipitation, and it will be a rather quick transition. We may see a period of heavy sleet during this time as well. Northwestern parts of the area may flip over to sleet as early as 5PM, while further South and East don't change over until 7-8PM.

Everyone is fully in the snow machine by 10PM-12AM, with some very heavy snow shortly after snow begins through early Monday morning. North-Northwest wind gusts during this time will be increasing further, pushing near 40-50 mph at times, and possibly higher for some of the Western counties. That will significantly reduce visibility, likely below a mile and at times, below a half mile. Near white-out conditions possible. The worst time for travel will be between 10PM-6AM Monday.

Snow showers will ease up through mid-day Monday, ending by late afternoon or evening. Blowing and drifting snow will remain a concern into the afternoon as winds remain strong gradually shifting to the NW at 40-50 mph.

Jo Daiviess, Stephenson, Carroll, and Whiteside Counties in NW Illinois have been upgraded to a BLIZZARD WARNING that will run Sunday evening through Monday afternoon. Southern Wisconsin and North-Central Illinois remain under the WINTER STORM WATCH that also runs Sunday into Monday (times vary).

Most of the area will see between 2-6" of snow, with the higher end of those totals North and West of Rockford. But even 2" of snow will blow and drift around significantly with these winds, so we continue to emphasize impacts over totals. Open roads may become hazardous to impassable Sunday night through Monday morning, so be sure to plan travel around that potential. The Monday morning commute will likely be significantly impacted. Continue to stay tuned for updates throughout the day tomorrow and stay safe everyone!