All snow will be confined to the northern mountains where over 12 inches of snow is highly possible. But as you can see, heavy snowfall accumulations will reach all the way down into the NW half of Middlesex County and most of Worcester County through the Berkshires. (Where 6-12" of snow is possible). Inside 495, the warm Atlantic will likely warm the surface more quickly, limiting accumulations to 3" to as much as 6" (best chance for higher amounts further inland, while somewhere like Boston right on the shore gets more like 1-2", maybe 3").
I will post my final accumulation map tomorrow morning and have more detailed information about start and changeover times. Again, Merry Christmas to those who celebrate! We may be able to muster up another storm by the end of this weekend too. More on that potential snow later.