Jet Stream and Climate Change?

They're called Rossby waves and are not uncommon to dip that far south in winter. Looking at the weather charts I'd say that it'll be much warmer in Florida in few hours as the cold won't last long. http://www.weatheroffice.gc.ca/data/analysis/saj_1...

EDIT: Mikira, the jet stream that is sitting over Florida is the Polar Jet, for the purpose of this discussion it does no more that show the demarcation line where two air masses meet. Those lucky enough to be south of the jet enjoy warm air and those north of the jet freeze. Due to uneven heating and cooling of the earth's surface areas of high and low pressure areas form. Over Canada and Siberia when the lakes freeze cold air from the upper troposphere begins to descend forming large continental high pressure regions and is what makes these two regions so horridly cold in winter. As these highs are formed atmospheric circulation pushes them south forming the bulges in the jet stream called Rossby Waves and the earth's rotation moves them in an easterly direction. If the pressures are high enough, these bulges can push further south than is typical for this time of year bringing cold air as far south as Florida.

So in short, the polar jet in winter forecasting is a handy indicator of synoptic scale weather, but jet streams themselves have little impact on synoptic weather. It’s the air masses they are associated with that bring the weather over large areas. Where these two air masses of cold/dry and warm/moist air air masses meet is often where the snow occcurs

When it comes to climate, jets are a handy indicator of climate change, as we can watch their geographical position over long periods of time. Brief dips into Florida mean nothing. Were I live, we traditionally would spend most of the winter north of the jet, but for the past ten years, our time spent north of the jet has been reduced considerably resulting in warmer winters.

Essentially it is what I was talking about when I posted this http://ca.answers.yahoo.com/question/index;_ylt=Aj...

General Circulation Models (GCM's) are a very rudimentary stab at attempting to model Earths climate. It is an undisputed fact that they lack the sophistication to partition the amount of energy that is associated with the often touted term natural climate variability. The Pacific Decadal Oscillation PDO and the North Atlantic Oscillation NAO play a very important part in distributing heat across latitudes and are linked to many of the climatic changes that we have experienced over the last century. The process of unraveling the natural variation from the human induced climate variation is currently not possible with the methods currently employed.

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I don't know much about this subject, but it strikes me that if the jet stream has any sort of significant effect on climate change, the pertinent question to ask is what's causing changes in the jet stream over time.

Scientists HAVE studied this. The general view is that the jet streams will shift toward the poles.

This has implications for both temperature and precipitation, for storms tend to occur on the boundary of the jet stream. Here's one good article.

http://www.usatoday.com/weather/climate/2006-05-25...