Snow was falling in much of northwestern Pennsylvania, with more than one foot forecast in some areas by late Tuesday and rain expected to turn to snow in Pittsburgh and points further south as temperatures were expected to fall throughout the day.
The National Weather Service has issued a lake-effect snow warning for Erie County through 7 a.m. Wednesday. Three to six inches of snow should fall Monday with an additional foot falling through Tuesday.
In New Castle, about 45 miles northwest of Pittsburgh, snow was falling before dawn Monday, and four to six inches was expected by the end of the day.
Much of southwestern Pennsylvania was experiencing rain early Monday, but falling temperatures were expected to change that to snow in time for Monday's evening rush hour.