(12:30PM - 11/24/18) Evening model data that has come in the past few hours is in fairly good agreement on track and intensity of the upcoming snowstorm, and with heavy snowfall totals likely. Most models are on the northern side of the envelope, but short term analysis would suggest the southern solutions is the way to go. For now will side with a southern-middle solution.
With that said, a swath of accumulating snow is still expected across much of Northern and portions of Central Illinois Sunday morning through Monday morning. Within this general axis of snow, a narrow corridor of 9-15" will be likely. This axis will likely be across Northern Illinois, from in the vicinity of the Quad Cities to around DeKalb to around Waukegan.
One thing you might notice by reading this update is Monday morning is now being mentioned. One of the changes that has been increasing each cycle of model guidance is the storm lasting longer, on into Monday morning for some areas. This slowing trend may continue, which could lead to falling snow still occurring for some areas during the Monday morning rush period, including the Chicago area.
In addition to the expected snowfall, winds will be an issue as well. As the storm passes through the area, winds will increase on the north and northwest side of the storm system. Wind gusts of 30-45mph will be likely across portions of Northern and Central Illinois Sunday afternoon into Monday morning. Wind gusts may reach around 50mph in Chicago near Lake Michigan as well. This will likely lead to blizzard conditions at times for some areas.