In the city, the precipitation will likely change to rain by about 10 a.m., but out toward Reading and Allentown, the wintry threats could continue, with freezing rain joining in.
In Berks, Lehigh and Northampton Counties, "several inches of snow is possible Wednesday . . . followed by a period of sleet . . . then freezing rain," according to a National Weather Service notice. "The light freezing rain could persist into Thursday morning."
Bucks County might see morning rain and snow, followed by midday snow as things chill, then evening rain.
The predictions as to who will get what will likely change, said weather service meteorologist Kristin Kline.
"The models kind of differ on how much cold air will be around," she said.
Temperatures might not even reach freezing Tuesday night in Philadelphia, Delware County, and South Jersey, and the event could be primarily rain.
Even if a half-inch of snow falls in Philadelphia, it's not likely to stick to roads, Kline said.
The ground is likely to have too much residual warmth from Monday and Tuesday, she said.
Philadelphia and its nearby surburbs should also be fine for Thursday morning, since overnight lows are likely to stay above freezing.
Slick roads, but not power outages, might be a worry for Thursday morning in counties to the north.
Winds won't be high and any freezing rain is likely to be minimal, not enough to snap branches or wires, Kline said.
For more on the forecast, go to http://go.philly.com/weather.
Contact staff writer Peter Mucha at 215-854-4342 or pmucha@phillynews.com.