"The NAO is one of the oldest known world weather patterns, as some of the earliest descriptions of it were from seafaring Scandinavians several centuries ago.
"Surface temperatures over the NH are likely to be warmer now than at any other time over the past millennium, and a substantial fraction of this most recent warming is linked to the behavior of the NAO, in particular a trend in its winter index from large amplitude anomalies of one phase in the 1960s to large amplitude anomalies of the opposite phase since the early 1980s.
"That the ocean may play an active role in determining the evolution of the NAO is also one pathway by which some limited predictability might exist. New statistical analyses have revealed patterns in North Atlantic SSTs that precede specific phases of the NAO by 6-9 months, a link that likely involves the remarkable tendency of the extratropical ocean to preserve its thermal state throughout the year."
Expected release date: early DEC
Overview (.pdf) here.