Here's MU's weather director's take on the upcoming pattern, and note what he says regarding the NAO:
The three primary features driving our weather pattern so far this month have been a persistent ridge of high pressure in the Bering Sea, a deep trough across western North America, and a lack of downstream blocking in the North Atlantic. Although I don't see the first two features changing much over the next 2-3 weeks, a blocking high pressure system has already returned to the North Atlantic over the past 24 hours and will slowly intensify and retrograde westward over the next 7-14 days. I'm not going to go into the meteorology behind why this blocking is returning (believe me, it would be a long dissertation!), but what it means for us is a transition back into a more typical winter pattern by late December and early January. However, it's vital to remember that the exact location of the blocking is key for our snow chances and that computer models often overdue the strength and westward extent of the blocking. If the blocking fails to center itself to the south and west of Greenland, then we'll be left with a pattern much like what we saw at the end of November: one featuring pseudo-cold (and still a few mild days) and weak, northern- branch storm systems or systems that try to cut into the Great Lakes region. Even if the blocking does become centered farther west, we'll still be fighting the effects of the Bering Sea ridge and deep trough in the western US, both of which try to force warmer air into the East. So, I think the prudent call at this point is to realize that any truly Arctic cold shots aren't in the cards until after the New Year and that "changeover" or "mixed-bag" precipitation events are most likely. Any snow events we do see are likely to remain light (on the order of a few inches or less), and specific details on any particular system will remain obscure beyond 4 or 5 days