[kleer-air] 
| atmospheric turbulence, sometimes severe, occurring in air devoid of clouds or other visible indicators that turbulence might be present. Abbreviation: CAT |
| clear-air turbulence (klîr'âr') Pronunciation Key
Atmospheric turbulence that occurs under tranquil and cloudless conditions at high altitudes near jet streams, mountain ranges, and developing storm systems. It subjects aircraft to strong updrafts and downdrafts. |