First, this would be a good time to remind you that I don't know what the heck I'm talking about. By that I mean, I have no meteorological training, other than what I've picked up. What I can do for you, though, is aggregate the opinions of the many real mets who frequent message boards and forum across the Internet and also illustrate through maps available on public web sites what is going on.
Having said that, there is much interest in the met community about this potential system for a couple of reasons:
1) It's a possible Christmas snow which is exciting to most everybody
2) There is higher than normal uncertainty with how the models are depicting the current pattern.
Right now the best way to describe the propsect of a Christmas snow is that there are pieces to the puzzle laying on a table -- the question is, will they get put together?
Right now, all of the pieces are shown in all of the models -- but none of them have the puzzle complete --- the Euro develops the storm too late, offshore, but has cold air in place. The UK model is better on precip but iffy on temps. And the GFS, well, it's just all over the place -- no storm at all one run, then too warm, then too suppressed.
There is an excellent chance we get a big fat nothing from this system or a cold rain, or a passing flurry.
But for now, the best I can tell you is this: We can't rule out a White Christmas. And to be able to say that on Dec. 20 is reason for optimism.
Chances of White Christmas: 1 in 40 (down from 1 in 30)
Reasoning: Continued model uncertainty and the failure of any one model to latch on to a strong, snowy solution.