There are no absolute correlations. There is no index that is always going to work out in the favored manner...not within a realm as a chaotic as the earth's atmosphere. There are too many other variables at play.
2007-2008 and 2014-2015 were great...hope we pull off another +NAO!
The frame of mind should not be "modoki, HUGE snows...or +NAO, see you next year.".....but rather, there is a modoki, so I like my chances"....or "The NAO will likely be positive, so there is less margin for error".