What cloud type generally indicates stable atmospheric conditions?

Stratus clouds are typically associated with stable atmospheric conditions. These clouds form in layers and often cover the sky like a blanket, resulting from gentle lifting in the atmosphere where air is relatively stable. This stability means that there is little vertical movement of air, which prevents the development of towering cloud structures typically associated with instability, such as cumulonimbus clouds.

In contrast, cumulonimbus clouds are indicative of unstable conditions, leading to significant vertical development and the potential for severe weather phenomena like thunderstorms. Cirrus clouds, although they appear high in the atmosphere, do not signify stability as they are also often associated with weather changes. Nimbus clouds, particularly in their usage as "nimbostratus," indicate a blanket of clouds bringing precipitation, which may arise in more stable conditions, but they do not exclusively signify atmospheric stability as stratus clouds do. Thus, stratus clouds are the best representation of stable atmospheric conditions.