New research has shown that the persistent cold weather suffered by much of the United States this winter may be a result of a changing jet stream pattern. A new study shows that the jet stream over Northern Europe and North America may be taking a longer, more meandering path as a result of a rapidly warming Arctic narrowing the differential between upper and middle latitudes, reports the BBC. Temperatures in the Arctic have been rising two to three times as rapidly as the rest of the globe, and as the difference in temperature between the Arctic and middle latitudes diminishes, the jet stream that separates them slows. That means that cold weather over North America tends to linger longer. It also means that warm weather is pushed further north and cold weather heads further South. Alaska and Scandinavia have had unusually warm winters this year, while southern U.S. cities like Atlanta have been struck by rare snowstorms and freezing weather.
      A jet stream is defined as a current of rapidly moving air that is usually several thousand miles long and
 wide, but is relatively thin. They are found in the upper levels of Earth's atmosphere at the troposphere -
 the boundary between the troposphere and stratosphere. Jet streams are important because they contribute
 to worldwide weather patterns and as such, they help meteorologists forecast weather based on their 
position. In addition, they are important to air travel because flying in or out of them can reduce flight time
 and fuel consumption.