(9:45PM - 4/18/21) A storm system is expected to move through the region on Tuesday, bringing a late season 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 and Ohio Valley on Tuesday, and then into the Eastern Great Lakes by Wednesday morning. Model guidance continues to be in some disagreement regarding the track and strength of this storm system, however a southern solution continues to be heavily favored...Thus, continues to be reflected in our forecast. No significant changes were needed with this update.
As a cold front pushes southward across Northern Illinois on Monday, some frontogenetic precipitation is likely behind the front Monday morning through Monday night across Northern and portions of Central Illinois. This precipitation will likely be in the form of rain, and perhaps a rain/snow mix. The main focus will be on Tuesday... An area of snow will spread across much of Northern and Central Illinois, early Tuesday 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 (Mild ground temps and sun angle of issue) and air 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.