We only care about the NAO during the winter, so this historical series gives you a good idea of the long term values. NAO has been predominately in the +phase during the winter months over the last 50 years, with generally more instances of strongly positive episodes in winter compared to prior periods.
With the recent unfavorable trends in the Pacific patterns during winter, we might be phucked in the MA for awhile. Go north. None of this stuff matters much relative to cold and snow up in NH.