The National Weather Service has issued a winter storm warning beginning at 7 p.m. Friday evening until 1 p.m. Saturday afternoon for Allegheny County.
A winter storm warning means that snow, sleet or ice will make travel hazardous or impossible.
The warning is in effect for counties along the Interstate 70 corridor due to forecast predictions for a wintry mix of freezing rain, sleet and snow on Friday night, the weather service said.
The weather service said a cold front sweeping through the area would generate a quarter-inch of ice and snow accumulations of 1 to 4 inches tonight and Saturday morning.
Hazardous travel conditions are expected because of slick roads, the weather service said.
Motorists should be prepared for snow-covered road and limited visibility. Report snow accumulations to the National Weather Service by calling 1-877-633-6772.