What does clear air turbulence (CAT) often relate to in terms of weather conditions?

Clear air turbulence (CAT) is closely associated with jet streams, which are fast flowing, narrow air currents found in the atmosphere. Jet streams exist at high altitudes, typically near the tropopause, and the turbulence associated with them occurs in clear air, outside of cloud formations. As the high-velocity air flows along the boundary between air masses of differing temperatures and densities, variations in speed and direction can create turbulent conditions that can impact aircraft flying through these areas.

This phenomenon can occur even in the absence of visible weather conditions like clouds or storms, making the turbulence particularly difficult to predict. Pilots and meteorologists pay close attention to jet stream patterns because their presence indicates potential for CAT, influencing flight planning and safety measures.