Monday, January 24, 2011

I May Regret This

For the second year in a row, the mid-Atlantic and Northeastern states are getting pummeled by "the worst winter in history". And, for the second year in a row, the Canadian Arctic is having the mildest winter in history. In both cases, the reason is a negative North Atlantic Oscillation (NAO). This despite the fact that 2009-2010 was an El Nino winter, and 2010-2011 is a La Nina winter. The NAO is overpowering the effects of ENSO, at least in the North Atlantic.

And maybe beyond. Here in the Northwest, in 2010, we experienced the warmest January on record. But it was an El Nino winter, after all. More surprising is our relatively normal winter this year, during the strongest La Nina event in more than 50 years. Before I go too hyperbolic, we've had a wetter-than-average winter, with snow in the mountains and flooding in the lowlands. But only a few stretches of below-freezing weather, and very little overnight frost.

Of course, now that I've said this out loud, we'll probably get pummeled ourselves next month since Winter doesn't officially end until February 21st.

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