After sunset on a clear evening the atmosphere cools down. The stable air in an inversion acts like a nearly solid object and allows the air above it to flow rapidly past the inversion like wind blowing over water. Differences in air pressure on either side of the developing low-level jet help to concentrate the flow of air into a corridor or stream less than several hundred miles wide. Winds in the stream can flow at speeds of 60 mph or more.
Mountain ranges can further enhance low-level jet stream winds.
Nighttime, low-level jet streams are marked by a rapid change in wind speed with height. The sudden shift in wind can catch late-night fliers by surprise and be hazardous to landing aircraft. And low-level jet streams can form other hazards for pilots. When strong winds blow across a body water waves form. The atmosphere reacts in a similar manner forming waves of air on the edges of the inversion layer called turbulence.