FAA Ground School Practice Test

If an unstable air mass is forced upward, what type of clouds can be expected?

1. Stratiform clouds

2. Clouds with considerable vertical development and associated turbulence

3. Stable layer clouds

4. Thin cirrus clouds

The correct answer is: Clouds with considerable vertical development and associated turbulence

When an unstable air mass is forced upward, it tends to rise rapidly, leading to the development of clouds with considerable vertical development. This upward force allows the warm air to continue rising, cooling as it ascends, which can result in condensation and cloud formation. The instability of the air mass typically leads to the formation of cumulonimbus clouds, which are characterized by significant vertical growth, and they are often associated with turbulence, thunderstorm activity, and even severe weather conditions. In contrast, stratiform clouds generally form in stable air conditions and do not exhibit much vertical development, leading to overcast skies with light precipitation. Stable layer clouds, by nature, are associated with stable air and are typically flat and layered, lacking the vertical motion that results in towering clouds. Thin cirrus clouds are high-altitude clouds that signal stable weather, and they do not exhibit the characteristics associated with an unstable air mass. Thus, the presence of considerable vertical development and turbulence is a definitive indicator of the behavior of unstable air forced upward, making this the correct choice.