Jet streams are relatively narrow corridors or very strong winds within the atmosphere. The most prominent jet stream is located directly above the polar front in the upper troposphere between the mid-latitude and the polar troposphere. Because of its close association with the polar front this jet stream is known as the polar front jet stream (Williams).
The polar jet stream is not well defined around the globe. However where surface temperature gradients are steep, where the polar front is well defined, jet stream winds are stronger. These segments of strong winds are known as jet streak. The strongest jet streaks develop along the east cost of America. The jet streaks are most predominate in this area because of the contrast in temperature between snow covered land and the ocean. Over theses areas the jet streak can get as high as 350 km per hour. The average jet streak is 160km in width, two or three km thick, and several hundred kilometers in length (Haby).
Jet streams form at the boundaries of adjacent air masses with differences in temperature. Because of earths rotation the streams flow west to east in both the Northern Hemisphere and the Southern Hemisphere due to the Coriolis effect. The Coriolis effect is deflection of a moving object in a rotating frame of reference (Jet).
The location of the jet stream is extremely important data for airlines. In the United States and Canada, for example, the time needed to fly east across the continent can be decreased by about 30 minutes if an airplane can fly with the jet stream, or increased by about the same amount if it must fly west against it. On international flights, the difference is even greater, and it is often actually faster and cheaper flying eastbound along the jet...