What began as freezing rain this morning may develop into snow showers later tonight. The National Weather Service issued a weather alert, warning of 1 to 4 inches of snow between 2 p.m. and 9 p.m., with northern Cook County seeing the heaviest accumulation. The advisory will last until midnight. 

The rain is expected to turn to snow beginning around 5 or 6 p.m.—"in time for the evening rush," the weather service said in the advisory. 

The heavy snowfall could reduce visibility to under a mile, the service warns. Drivers are also urged to use caution while driving in snowy weather, as road conditions are likely to become hazardous.