(9:30AM - 12/28/21) A storm system moving through the region today will bring a period of accumulating snow across Northern Illinois, this morning through this evening.
A storm system will move from the Plains this morning, into the Northern Great Lakes by tonight. This storm system will bring a period of accumulating snow across Northern Illinois, this morning through late this afternoon and evening, before precipitation changes to rain and/or ends.
With this update we slightly raised expected snowfall totals across portions of Northwest Illinois, and adjusted the gradient on the southern end of the snowfall axis.
Precipitation spread into Central Illinois early this morning, in the form of rain and a mix. This activity will transition to all rain with time this morning, if it hasn't already. As precipitation pushes northeastward into Northern Illinois this morning, it is moving into colder air, allowing for a transition to snow. Snow will be likely across Northern Illinois for a several hour period of time, from this morning through late this afternoon and evening. As milder air works northward and the back-edge of the precipitation shield moves in, snow will change over to a bit of rain/drizzle and end late this afternoon and Tuesday evening.
Snowfall totals upwards of 1-3" is expected across much of Northeast and North-Central Illinois with this event, with 2-5" expected across much of Northwest Illinois. With temperatures hovering around freezing for this event, this will be a wet snow, which accumulates best of colder surfaces with some melting during the event. However, snow accumulation is expected on pavement surfaces as well, which could cause travel issues.
Below is the snowfall forecast for this event.