Visualization of the Polar Jet Stream

The polar jet stream, depicted above, is a fast-moving belt of westerly winds that traverses the lower layers of the atmosphere. The jet is created by the convergence of cold air masses descending from the Arctic and rising warm air from the tropics. It’s strongest during the winter when the temperature
difference between warm and cold air in the Northern Hemisphere is at its highest. (NASA Scientific Visualization Studio, © National Aeronautics and Space Administration)