Private Pilot Private Exam

An almond or lens-shaped cloud that appears stationary may contain winds of 50 knots or more and is referred to as...

1. A cumulonimbus cloud

2. A lenticular cloud

3. A stratocumulus cloud

4. A cirrus cloud

The correct answer is: A lenticular cloud

A lens-shaped cloud that appears stationary and can indicate strong winds is known as a lenticular cloud. These clouds form when moist air flows over a mountain or a similar obstruction, creating a wave pattern in the atmosphere. As the air rises and cools, it condenses into the almond or lens shape. The presence of wind speeds of 50 knots or more associated with lenticular clouds is significant because it warns pilots of the potential for severe turbulence in the vicinity. In contrast, cumulonimbus clouds are indicative of thunderstorms and turbulent conditions but are not necessarily stationary or lens-shaped. Stratocumulus clouds are low, lumpy clouds and do not have the dynamic formations and wind characteristics of lenticular clouds. Cirrus clouds are high-altitude clouds that are thin and wispy, and, while they can indicate atmospheric turbulence, do not have the same implications regarding strong winds under an almond or lens shape. Thus, the defining features of lenticular clouds align perfectly with the characteristics mentioned in the question.