What Is the Jet Stream?
Several miles above our heads in the top part of the stratosphere, winds can blow up to 300 miles an hour. These winds are called the “jet stream.” The swift winds blow steadily around the earth, much like great rivers of rushing air.
Pilots have discovered that when the jet stream is going their way, their planes can sometimes “hitch a ride” on the stream and cut down on the flying time of a trip.
We can’t feel the jet stream winds down here on the earth’s surface, but our weather can be greatly changed by them as they rush along, far above the clouds. These slim strips of strong winds can push air masses around.
Jets streams play a key role in determining the weather because they usually separate colder air and warmer air. Jet streams generally push air masses around, moving weather systems to new areas and even causing them to stall if they have moved too far away.
While they are typically used as one of the factors in predicting weather, jet streams don’t generally follow a straight path — the patterns are called peaks and troughs — so they can shift, causing some to point at the poor forecasting skills of meteorologists.
Climatologists say that changes in the jet streams are closely tied to global warming, especially the polar jet streams, because there is a great deal of evidence that the North and South poles are warming faster than the remainder of the planet.
When the jets streams are warmer, their ups and downs become more extreme, bringing different types of weather to areas that are not accustomed to climate variations. If the jet stream dips south, for example, it takes the colder air masses with it.