Jet stream is apparently "moving" north and scientist believe global warming is causing this.

Jet stream, America's storm maker, moving slowly northward

WASHINGTON - The jet stream — America's stormy weather maker — is creeping northward and weakening, new research shows. That potentially means less rain in the already dry South and Southwest and more storms in the North.

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From 1979 to 2001, the Northern Hemisphere's jet stream moved northward on average at a rate of about 1.25 miles a year, according to the paper published Friday in the journal Geophysical Research Letters. The authors suspect global warming is the cause, but have yet to prove it.

The jet stream is a high-speed, constantly shifting river of air about 30,000 feet above the ground that guides storm systems and cool air around the globe. And when it moves away from a region, high pressure and clear skies predominate.

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Climate models have long predicted that with global warming, the world's jet streams would move that way, so it makes sense to think that's what happening, Caldeira said. However, proving it is a rigorous process, using complex computer models to factor in all sorts of possibilities. That has not been done yet.


http://news.yahoo.com/s/ap/20080417/ap_on_sc/jet_stream


now lets look at a four day Jet Stream Prediction in reality: