It's not going to amount to much this evening but coating type accumulations to the west of the city are certainly do-able in areas where heavier precipitation falls. Yes, Philadelphia, it's snowing this evening and you can believe in seeing a White Christmas Eve. It won't amount to much as precipitation is quickly scooting through the Delaware Valley, moving northeast thanks to a small disturbance in the atmosphere but it is snowing north and west of 295 as of 6 PM, with a mix zone below that before transitioning to rain along the coastline.
North and west of the city, snow is sticking on back roads in Chester and Montgomery Counties -- especially above Route 202. Precipitation is coming down pretty solidly and is able to counteract temperatures that are generally near or slightly above freezing.
What can we expect over the next couple of hours? Coating type accumulations possible on grass and cars in the city but roads should stay wet except in Mt. Airy, where it could try to coat in a few spots on pavement. North and west of the city should see anyone from a coating to an inch, generally with the inch type accumulations in the hills. Some spots will pick up a couple of inches farther north -- generally Poconos and along Blue Mountain -- but most of us north and west of the city should see a nice coating before this wraps up.
Precipitation may transition to sleet or freezing drizzle before ending, likely around or just after 9 PM from southwest to northeast. Temperatures will generally hold steady in the lower and middle 30's northwest of the city, with mid 30's common along I-95. Some slick spots are possible, especially in areas where snow tends to stick more easily on paved roads.