What is a common characteristic of an unstable atmosphere?

In an unstable atmosphere, rapid vertical air motion is a defining characteristic. This occurs when warm air near the surface rises and cools, creating convection currents. As the warm air rises, it expands and eventually cools to the point where it condenses, forming clouds and potentially leading to significant weather phenomena like thunderstorms. This vertical motion is crucial for the development of instability, as it encourages air mixing and contributes to the formation of cumulonimbus clouds, which are often associated with severe weather.

Other characteristics, like higher cloud ceilings, steady winds, and increased cloud cover, do not inherently indicate instability. Higher cloud ceilings often correspond to stable conditions, where air tends to remain relatively calm. Steady, uniform winds are also typical of stable atmospheres, where temperature inversions may suppress vertical motion. Increased cloud cover can happen in both stable and unstable atmospheres, but it is the rapid vertical air motion that distinctly defines an unstable atmosphere.