(10:30AM - 4/18/21) A storm system is expected to move through the region on Tuesday, bringing an accumulating snowfall to the heart of the state.
A storm system will eject out from the Plains Monday night, then moving northeastward through the Mid-Mississippi Valley on Tuesday, and then into the Great Lakes by Wednesday morning. Model guidance continues to be in some disagreement regarding the track and strength of this storm system, and thus also differ in placement and amounts of snowfall. Have taken a middle ground approach on placement of snowfall axis for the first snowfall forecast, and went on lower end for snowfall amounts.
As a cold front pushes southward across Northern Illinois on Monday, a bit of frontogenetic precipitation is likely behind the front Monday afternoon through Monday night across Northern Illinois. This precipitation will likely be a mix of rain and snow. The main focus will be on Tuesday... An area of snow will spread across portions of Northern and Central Illinois, Tuesday early morning through Tuesday early night. Snow will be of varying intensity during this time, though generally being light to moderate. Given it is mid-late April and temperatures will be marginal, greatest snowfall impacts and accumulations will be on colder surfaces, such as grass.
Snowfall totals of 1-3" are across Central Illinois, with amounts tapering north and south of this main axis.
Below is the snow forecast for this event.