Old Doug
Posts: 8279
Joined: 5/12/2011 From: Atlanta, Georgia, US Status: offline
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quote:
ORIGINAL: khmark7 "experts" say that January will be better than December was....but it is a tough mindset right now with two months to go and we have already had more "winter" this last December than the last two years combined. A year ago, Europe was getting slammed with it. I think it's more the norm now that somebody is going to be getting it. As long as the jet stream pattern stays like it's been recently, I wouldn't count on January being much fun. West of the Rockies, the jet stream has been going "up" very high - in June, Alaska had temperatures in the 90s, and on December 7 it was 39°F and raining at the Prudhoe Bay airport (on the shore of the Arctic Ocean). The airport was built in 1968 and the 39° is the warmest December temperature since then. Jet streams form over the area with the largest temperature differential - in general, the area or front where the cold polar air meets warm equatorial air. The Polar Jet Stream is the strongest, with a secondary, weaker Subtropical Jet Stream forming around 30 degrees north latitude. In the past, large "domes" of heavy, cold air over the polar regions would keep the Polar Jet Stream moving faster, which gives it a "flatter" course and less deviations to the north and south. Now we have dramatically less polar sea ice, so more open water, more water getting warmed by the sun and giving heat back to the atmosphere. Now there's less temperature difference between the polar and temperate regions, and the Jet Stream slows down and gets pushed and pulled more by low and high pressure air masses, and it's deflected farther to the north and south. As the Arctic Ocean warms, there is some evidence (and a good bit of speculation) that the circulation of cold air will move from a polar orbit to one closer to Greenland (which would presumably still be ice-covered). Then you've got really cold water near Greenland and in the North Atlantic Ocean. Here comes the Gulf Stream and the North Atlantic Currents, bringing warm water up from the south.... If anything, I'd say things are going to get "more interesting," rather than less.
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