(11:45AM - 11/23/20) A storm system moving through the region the next few days will bring a period of snow to Northern Illinois, tonight through midday Tuesday.
An area of precipitation will develop across Nebraska, Kansas, Iowa and Missouri today, as warm air advection increases...associated with an incoming storm system. This area of precipitation will expand and steadily push northeastward...eventually spreading across portions of Central and much of Northern Illinois, tonight through midday Tuesday. With colder air in place as this precipitation moves through, much of the precipitation will fall as snow across Northern Illinois during this time-frame. A couple to several hour period of snow is likely across much of Northern Illinois tonight through late Tuesday morning. Beyond this time-frame, temperatures will warm a bit, allowing snow to change to rain and any snowfall accumulation to quickly melt. Snowfall totals will range from a dusting to 2" across much of Northern Illinois. Highest snowfall totals will be near the Illinois/Wisconsin border and in Northwest Illinois...where locally higher amounts will be possible. Across Central Illinois, precipitation will mainly be rain...but could flip to snow for a brief time late tonight or early Tuesday morning. Little to no snowfall accumulation is expected.
Below is the snowfall forecast for tonight through midday Tuesday.