Tuesday, November 17, 2009

Just one week away!

There is without question a pattern change taking place middle of next week. This change is one that favors cold and snowy weather, and I'll tell you why. The arctic oscillation has a positive and negative phase. The positive phase is when the stratosphere over the arctic is cooler than normal which allows for a strong polar jet stream, which keeps all that arctic air bottled up. Then the negative phase which has a warmer stratosphere which allows for the polar jet to weaken and cold air can pour south. Well right now the stratosphere over the arctic is flipping from cold to warm which indicates that we have some blocking starting to begin, and that winter is about to begin.

This is confirmation that the arctic oscillation (AO) with be going negative. And that is what allows for arctic air masses to invade the mid-latitudes.

Now I am a bit obsessed with atmospheric and oceanic oscillation patterns. And this is my favorite blocking pattern of all, the North Atlantic Oscillation (NAO). When it is positive it's typically warm and dry across the eastern US and Europe. But when it's negative it means colder and wetter weather for both, and in the winter it usually signals coastal storms with snow. If both the AO and NAO are negative at the same time it has winter written all over it. And look at the NAO chart:

Oh yeah. This is the start of winter, and I see snow making opportunities up and down the appalachians and even natural snow by next week. Finally.

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