[Ref AC 00-6B 17.2.3.2, AC 00-30C 6.5]
What’s CAT (Clear Air Turbulence)?
Clear Air Turbulence (CAT) is a higher altitude turbulence phenomenon occurring (from 20,000 to 50,000 feet) in cloud-free regions associated with wind shear.
CAT can occur between the core of a jet stream and the surrounding air. It can often affect an aircraft without warning. CAT frequency and intensity are maximized during winter when jet streams are strongest.
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