Just a few months ago, this winter was forecast to be warm, and so far that’s been generally true. But now let’s look more closely at that North Atlantic Oscillation, which has been known since 1770. When people notice that we seem “stuck in a pattern” -- either for good or for bad -- well, the NAO is that pattern. In 2010 and 11 the NAO was negative, and those winters were harsh and snowy. It was positive in 2000 and 2007, and we then had mild conditions.