CAT can be caused by which factors?

CAT can be caused by which factors?

• A. Jet streams
• B. Jet streams, unstable air, convective lifting currents, and wind shears
• C. Mountain waves
• D. Thunderstorm downdrafts

Answer: (B)

Clear air turbulence occurs in air that looks calm and cloud-free, so it’s driven by conditions in the wind and stability of the upper atmosphere rather than visible weather. The main contributors are jet streams, where wind speeds change rapidly with altitude, creating strong wind shear that can shake an aircraft. Add in unstable air, which tends to rise and mix vertically, and convective lifting currents (thermals or shallow convection) that promote vertical motion even without clouds. Wind shear between different layers or air masses also stirs the air and leads to turbulence. This combination—jet streams, unstable air, convective lifting, and wind shear—covers the primary ways CAT develops. Jet streams alone or mountain waves can cause turbulence, but they’re not as comprehensive a description as including all the listed factors. Thunderstorm downdrafts involve visible weather and are not categorized as CAT in clear-air conditions.

Clear air turbulence occurs in air that looks calm and cloud-free, so it’s driven by conditions in the wind and stability of the upper atmosphere rather than visible weather. The main contributors are jet streams, where wind speeds change rapidly with altitude, creating strong wind shear that can shake an aircraft. Add in unstable air, which tends to rise and mix vertically, and convective lifting currents (thermals or shallow convection) that promote vertical motion even without clouds. Wind shear between different layers or air masses also stirs the air and leads to turbulence.

This combination—jet streams, unstable air, convective lifting, and wind shear—covers the primary ways CAT develops. Jet streams alone or mountain waves can cause turbulence, but they’re not as comprehensive a description as including all the listed factors. Thunderstorm downdrafts involve visible weather and are not categorized as CAT in clear-air conditions.