Has anyone ever done correlation analysis between conditions in October/November and the resultant NAO state during DJF? I'm sure it's been done, and I'd be interested in reading if anyone has a link. It's hard to just cancel winter when there is some off-chance that we do have -NAO. While it has only occurred few times in the past 20 years, it's not theoretically impossible, right? It even happened during a Nina in 2010-2011.