Rain at Chicago changes to snow late Friday
The next in this series of fast-moving weather systems of Pacific origin arrives Friday afternoon with temperatures in the upper 30s and a good chance of rain.
Unlike its predecessors which developed after they passed east of Chicago, this system gains strength as it exits Iowa and tracks across northern Illinois. Updated computer models suggest upper-level dynamics will be strong enough to generate colder air in the lower 5,000 feet of the atmosphere—enough to change rain into snow here Friday night despite above-freezing temperatures at the surface.
As a result, wet snow may accumulate an inch of two on grassy or colder surfaces. The best of the snow crosses central Wisconsin with 6 inches of snow possible.
Thereafter, rain is likely with future frontal passages. By next Thursday, the mild pattern will begin to break down, and temperatures will plummet back toward normal.