1. The Jetstream By: C Weaver

2. What is the Jetstream? The Jetstream is a narrow, variable band of very strong, predominantly westerly air currents encircling the globe several miles above the earth. There are typically two or three jet streams in each of the northern and southern hemispheres.

3. About the Jetstream In the Jetstream winds can travel up to and even greater than 100 miles per hour. Jetstreams flow from west to east in the upper portion of the troposphere.

4. How It Works During the Northern Hemisphere summer, easterly jets can form in tropical regions, typically in a region where dry air encounters more humid air at high altitudes. Low-level jets also are typical of various regions such as the central United States.