Turbulence encountered in air where no clouds are present. This expression is commonly applied to high-level turbulence associated with wind shear (WS). CAT is often encountered in the vicinity of the jet stream. abbreviation: CAT Fr: turbulence en air clair
Name given to turbulence that may occur in perfectly clear air without any visual in warning in the form of clouds. It is often found in the vicinity of the jet stream where large shears in the horizontal and vertical are found, although this turbulence is not limited just to jet stream locale. Other areas where it may occur include near mountains, in closed lows aloft, and in regions of wind shear. May be referred to as CAT.
in aviation, sudden severe turbulence occurring in cloudless regions that causes violent buffeting of aircraft