PDO theorists say the phenomenon explains the "la ni˝as" of the past two winters, which begin when cold Pacific waters wash up on the shores of Central America. For the current year, meteorological predictions fall in line with this theory, as February forecasts call for an unusually cold and wet stretch for the northern states of the U.S., and warm, dry weather down south. But New Yorkers shouldn't buy that new down comforter just yet. The entire PDO theory is still fairly new (scientists first proposed it three years ago), and not even its supporters are fully convinced. So we can keep talking about the weather all we want, and there's still nothing we can do about it.
For those bundled-up northeasterners suffering from frostbitten noses: Get used to it, there could be decades more of winters just like this. NASA scientists believe the recent spate of unusual North American weather from last year's droughts and hurricanes up through the current manic hot-and-cold spells in the northeast U.S. will be with us for the next 20 to 30 years, due to a condition known as Pacific Decadal Oscillation (PDO). Some researchers believe that two years ago we began entering the cool portion of a cycle in which the Pacific Ocean waters alternate between warm and cool periods for decades at a stretch. During the cool phase, waters around the Asian edge of the ocean become abnormally warm and the waters off the western U.S. cool off, while the conditions are reversed during the warm phase. According to this theory, we've been in a warm phase for the past two decades. The PDO affects weather conditions across the globe, but has the strongest impact in North America.