What is a common cause of clear air turbulence?

Clear air turbulence is most commonly associated with the jet stream, which is a high-altitude, fast-moving air current found in the atmosphere. This phenomenon occurs when the jet stream has strong wind shear, meaning there is a significant difference in wind speed or direction over a short distance. As aircraft fly beneath or near these intense wind currents, they can encounter sudden changes in air movement, leading to bumpy conditions and turbulence.

The jet stream's influence can result in turbulence that is often unexpected, particularly since it typically occurs in clear skies away from other weather phenomena. This characteristic of clear air turbulence makes it notoriously difficult to predict and avoid, as pilots may not always be aware of its presence until they experience it firsthand. Understanding the role of the jet stream is crucial for both pilots and meteorologists when anticipating flight conditions.