Differences in the 12z NAM start off at noise level early in the run, but increased quickly by mid-run.
Main storm is definitely jumping north on this run.
A lot of guidance that is south of the GFS are still showing significant snowfall totals. I’m not saying it’ll be the case with this one, but there are many cases that would prove the first part of your comment wrong. .
Some of the positives we saw, such as with the 12z run, stepped back.
PV in Canada was further SW, along with associated area of confluence. Heights also steadily lower ahead of the main ejecting wave.