Rain with areas of fog should spread from Virginia to New Jersey Monday or Monday night then spread into New England for Tuesday. From the mountains of northeastern Pennsylvania into the interior of New England this could at least start as snow or ice. The GFS for 1 AM New Year's Day looks interesting. See the map below. Whether or not this storm develops and where it will snow or rain cannot be precisely predicted two weeks in advance using these models.
This map is a spaghetti plot showing the upper air currents predicted by members of last night's GFS ensembles. In looking at each line, you see variations, but they all show the idea of major trough centered east of the middle of the country on Christmas Eve.
Any storm in the Northeast could be disruptive for travel, whether it turns out to be rain and fog or snow and ice. If a strong storm develops, the best chance for snow on Wednesday will be over the central or northern Great Lakes region. This map is last night's GFS operational solution for 7 p.m. ET Christmas Eve.
The map below shows the low pressure area and cold front now moving into the East. Looking at the temperatures, truly cold air is well behind the cold front. This is in line with the idea that the front itself is the leading edge of the change to colder conditions.
The satellite picture shows a deck of clouds all the way along I-80 from Nebraska to New Jersey with few holes along the way. However, nobody in the cloud zone is having any substantial precipitation. There was some spotty freezing drizzle this morning.
My back yard in the middle of Pennsylvania looked like a winter wonderland this morning as shown in the photo below. In many areas from western and central New York south into Pennsylvania, snow and ice patches on the roads made it a potential blunderland for motorists.