The biggest weather news of this new year 2014 is, of course, the huge and hard-hitting cold wave during the first eight days of January. Questions have been asked in terms of how the cold wave should be interpreted in the climate change perspective. I put that question to my colleague Jeff Johnson, who is the Chief Science Officer for our parent company, Schneider Electric. Jeff is a co-author of a Schneider Electric "white paper" on climate change that was done last fall. His comments are interesting as they pertain to the extremes of weather features that have been so pronounced during the past several years.
"Yes the...extreme cold outbreak is a great example of the more volatile weather patterns that have been observed in recent years. Temperature anomalies with this outbreak, as well as another one that occurred in early December, produced temperatures that were 30-45 degrees Fahrenheit below normal. These types of departures are on the far end of observed anomalies.
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Both of the extreme cold episodes occurred when an upper (atmosphere) ridge (high pressure) built well to the north into the Alaska region. This highly-amplified ridge brought warm air to the north Pacific region, but on its eastern flank northerly jet stream winds drove cold air southward from the Arctic regions of Canada.
Extreme events like this have happened in the past, but we are seeing more of them. A possible cause that is being investigated is that greater warming in the Arctic regions of the globe is slowing the jet stream down in the far northern latitudes and causing more of these highly amplified patterns. Europe, Alaska and Russia experienced these abnormally cold periods in recent winters. This year North America is seeing them instead primarily due to the persistence of the ridge in the northern Pacific-Alaska area."
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