FAA Ground School Practice Test

Moist, stable air flowing upslope can be expected to:

1. Produce cumulus clouds

2. Produce stratus type clouds

3. Lead to thunderstorms

4. Cause heavy rain

The correct answer is: Produce stratus type clouds

Moist, stable air flowing upslope is characteristic of conditions that promote the formation of stratus clouds. When stable air is forced to rise over terrain, it cools adiabatically. Since the air is stable, it does not rise rapidly or produce vertical development typical of cumulus clouds. Instead, as the moist air rises, it cools to its dew point and condenses gradually, resulting in the formation of layer-like cloud structures. Stratus clouds typically appear as uniform gray sheets that cover the sky, and they can produce light precipitation but are generally associated with less intense weather phenomena than cumulus clouds. While stable air can lead to other outcomes such as light rain or mist, the key feature here is how the stable air behaves when encountering upland features. This behavior aligns clearly with the expected outcome of stratus cloud formation rather than the turbulence and vertical development associated with cumulus clouds or the severity of thunderstorms.