The 64 at MDT just after midnight sounds accurate. I remember being worried about being screwed out of a white Christmas because of how warm it got Christmas Eve and then we got a bunch of snow in Pittsburgh on Christmas Day.
So what do we have here? Christmas 2021 has a solid chance to be warmer in many parts of PA than:
Friday and Saturday of Easter weekend
Mother’s Day
2 out of the 3 days of Memorial Day weekend
Thanksgiving
The other thing that’s mildly interesting is how far out of agreement the GFS is on Monday. GFS suggests wintry precip, everything else puts PA firmly in the warm sector.