Wednesday, October 1, 2014

Arctic Oscillation Set to Tank

As a follow up to some of my earlier posts this week about the coming cold shot this weekend. It is supported by the Arctic Oscillation going into its negative phase. What does this mean? In simple terms it means high pressure develops over the Arctic which weakens the polar vortex which results in the jet stream allowing cold air to funnel south. In its opposite phase pressures are much lower over the arctic and the cold air stays locked up which results in more of a westerly pacific flow of air over our country. Here is a diagram to help explain...


 Models are forecasting this to go very negative as seen by the red lines...


This results in a pattern looking like this for late this week early next week...

Notice all the reds over the arctic, this is the high pressure i am talking about. As the diagram above showed look at the result with a big trough forming over our area. The big question is will the winter hold a similar pattern. Find out the answer to that question when my Winter 2015 Outlook comes on on October 15th. 




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