It appeared to be a very late transfer which brought in much warmer air compared to the CMC. considering the 6z didn't have it all, just ran the thing up west of the apps, I wouldn't be surprised on the 18z if it transferred farther south, allowing more ice/snow a little farther south and east. But only a guessing game on that part.
In terms of the temp profiles, I feel like the CMC may be a bit too warm, that is a much considerable stronger HP to the north compared to the December storm(I believe?). Verbatim, it should at some point show a better push of cold air. Or if it just pushes down a bit south faster, it'll be game on for many.
Edit* FV3 also has a better placement for the HP compared to the CMC, which is why I don't really buy the Miller B option it's showing.