A winter weather advisory now is in effect for Pittsburgh and most of southwestern Pennsylvania.
The National Weather Service in Pittsburgh issued the advisory at 1:35 p.m. for the city and counties ranging from Armstrong, Lawrence, Butler and Beaver in the north to Greene and Washington in the southwest. Northern West Virginia and much of eastern Ohio is included in the advisory area, as are the lower elevations of Westmoreland and Fayette.
The advisory is in effect from 3 a.m. Friday to 7 p.m. Saturday. It calls for as much as 4 to 6 inches of snow and winds from the west at 15 to 25 mph with gust to 40 mph.
Widespread rain began falling in Pittsburgh around 1 p.m., and residents of the city and suburban areas are expected to see as much as 3/4 inch of liquid precipitation before it changes to snow late tonight.
National Weather Service meteorologist Lee Hendricks said there is a 100 percent chance of rain today with increasing winds. After midnight, little accumulation is expected initially, but snow showers could cause some slick spots for the morning commute, especially on bridges and overpasses, he said.
Drivers overnight also should watch for water that accumlates on roadways. With falling temperatures, it could cause some icy patches by morning.
In Pittsburgh, the weather service is calling for rain to change to snow around 1 a.m. Friday.
The City of Pittsburgh this afternoon declared a Phase 1 alert and said it expects 2 to 4 inches within city limits. Road crews will work 12-hour shifts if needed. The worst road conditions are expected from 6 a.m. to 9 p.m. Friday.
A winter storm warning is in effect from 11 a.m. Friday to 7 p.m. Saturday for the I-80 corridor north of Pittsburgh, including the counties of Mercer, Venango, Forest and Clarion. The Laurel Highlands also are under a winter storm warning, with the higher elevations of Westmoreland, Somerset and Fayette counties expected to get 8 to 14 inches of snow blown by winds gusting to 45 mph. The warning also extends to the ridges of West Virginia and western Maryland, including the Interstate 68 corridor. Preston and Tucker counties in West Virginia and Garrett County, Md., were among the areas hit hard by superstorm Sandy in late October.
Parts of northwest Ohio are under a winter storm watch and wind advisory from 7 p.m. today to 7 a.m. Friday. Less snow is expected in that area but winds may gust to 50 mph.
The website FlightAware reported more than 1,000 cancellations of U.S. flights as of early afternoon, with most of those concentrated in Chicago, Minneapolis and Kansas City.
Southwest Airlines canceled two scheduled Pittsburgh departures to Chicago this afternoon.
Jon Schmitz: email@example.com, 412-263-1868 and on Twitter @pgtraffic. Molly Born: firstname.lastname@example.org or 412-263-1944 or on Twitter @borntolede. First Published December 20, 2012 12:45 PM