A nice explanation of why this winter is so unusual

Remarkably dry and warm winter due to record extreme jet stream configuration
[Via Dr. Jeff Masters’ WunderBlog]

Flowers are sprouting in January in New Hampshire, the Sierra Mountains in California are nearly snow-free, and lakes in much of Michigan still have not frozen. It’s 2012, and the new year is ringing in another ridiculously wacky winter for the U.S. In Fargo, North Dakota yesterday, the mercury soared to 55°F, breaking a 1908 record for warmest January day in recorded history. More than 99% of North Dakota had no snow on the ground this morning, and over 95% of the country that normally has snow at this time of year had below-average snow cover. High temperatures in Nebraska yesterday were in the 60s, more than 30° above average. Storm activity has been almost nil over the past week over the entire U.S., with the jet stream bottled up far to the north in Canada. It has been remarkable to look at the radar displayday after day and see virtually no echoes, and it is very likely that this has been the driest first week of January in U.S. recorded history. Portions of northern New England, the Upper Midwest, and the mountains of the Western U.S. that are normally under a foot of more of snow by now have no snow, or just a dusting of less than an inch. Approximately half of the U.S. had temperatures at least 5°F above average during the month of December, with portions of North Dakota and Minnesota seeing temperatures 9°F above average. The strangely warm and dry start to winter is not limited to the U.S–all of continental Europe experienced well above-average temperatures during December.

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Even with a La Nina that should bring colder and wetter weather, the Atlantic is having effects to drive a warmer and drier one. SOme of the most extreme data readings ever have been seen so far.

Cold Arctic air simply can not make it down into the States. It is very likely that the rest of the winter will bring few storms and little moisture for much of the country. This could make for a very dry Spring.