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Two other jet streams in the Southern Hemisphere are also shifting poleward, the study found.
The northern jet stream "is the dominant thing that creates weather systems for the United States," said study co-author Ken Caldeira, a climate scientist at the Carnegie Institution of Washington in Stanford, Calif. "Bascially look south of where you are and that's probably a good guess of what your weather may be like in a few decades."
Earth has seen some highly unusual weather patterns over the past three years, and three new studies published this year point to Arctic sea loss as a potential important driver of some of these strange weather patterns. The record loss of sea ice the Arctic in recent years may be increasing winter cold surges and snowfall in Europe and North America, says a study by a research team led by Georgia Institute of Technology scientists Jiping Liu and Judith Curry. The paper, titled "Impact of declining Arctic sea ice on winter snowfall", was published on Feb. 27, 2012 in the online early edition of the journal Proceedings of the National Academy of Sciences.
Image source: Cryosphere Today
According to the post, the melt in 2007 was even more extreme than the most recent summer, but weather patterns have been affected nearly as much.
Summertime Arctic sea ice loss: 40% since 1980
The Arctic has seen a stunning amount of sea ice loss in recent years, due to melting and unfavorable winds that have pushed large amounts of ice out of the region. Forty percent of the sea ice was missing in September 2007, compared to September of 1980. ... The Georgia Tech study found that Arctic sea ice loss had caused a 20 - 60% weakening of the west-to-east belt of winds circling the pole in recent years, producing broader meanders in the jet stream that allowed it to get "stuck" in place 20 - 60% more often. When the jet stream gets stuck in place for a long period of time, we say a "blocking pattern" has set up. ... Such a blocking pattern began on January 26, 2012 and lasted until February 11, bringing and exceptionally cold and snowy conditions to much of Europe, which lay on the cold side of an elongated loop of the jet stream that got stuck in place. Conversely, most of North America and northern Siberia saw unusually warm temperatures during this period, since they were on the warm side of the jet stream.
This explains perfectly why the US had such a mild winter while Europe experienced record setting snow storms. If the Jet Stream acts as a sort of "fence" for air masses, and it gets stuck in position for extended periods of time, then anything on the "warm" side of the fence will remain warm, while anything on the 'cold' side will experience that end of the spectrum.
Two other studies link Arctic sea ice loss to atmospheric circulation changes
"The question is not whether sea ice loss is affecting the large-scale atmospheric circulation...it's how can it not?" That was the take-home message from Dr. Jennifer Francis of Rutgers University, in her talk "Evidence Linking Arctic Amplification to Extreme Weather in Mid-latitudes, presented at December's American Geophysical Union meeting in San Francisco. Dr. Francis presented new research that has just been published in the journal Geophysical Research Letters, which shows that Arctic sea ice loss may significantly affect the upper-level atmospheric circulation, slowing its winds and increasing its tendency to make contorted high-amplitude loops. High-amplitude loops in the upper level wind pattern (and associated jet stream) increases the probability of persistent weather patterns in the Northern Hemisphere, potentially leading to extreme weather due to longer-duration cold spells, snow events, heat waves, flooding events, and drought conditions. Dr. Francis describes her work in a March 5, 2012 post on the Yale environment360 web site.
Changes in the jet-stream, mean a complete change in weather patterns all over the world. The jet-stream that controls weather systems in the U.S. for example, the Northern jet-stream; is moving further north - along with the other jet-streams, that are also shifting.
Jet streams are important because synoptic scale disturbances tend to form in the regions of maximum jet stream wind speed and to propagate downstream along storm tracks that follow the jet axes [Holton, 1992]
Contrary to popular belief, the jet stream does not "cause" weather conditions of a certain type to occur. Its existence is instead the result of certain weather conditions (a large temperature contrast between two air masses).
Originally posted by Phage
reply to post by SonOfTheLawOfOne
Very strange weather occurrence for July 3rd.
Not really. Summer is the time for hailstorms. Higher temperatures=stronger convection=thunder and hail.