what are the visual signs of cloud decay and dissolution in a Cumulus cloud?

Answer 1

Ragged edges are the main clue. They signify a dry atmosphere, which causes the water droplets forming the cloud to evaporate. Cumulus clouds that are building will have mainly sharp edges, and you may see cirrus-type hoods over the tops, if they are building rapidly. These hoods are created by pressure as both the cloud mass and the air with it rises rapidly in the atmosphere. The same phenomenon can be seen on the forward surfaces of the space shuttle as it climbs through moist air and even on forward surfaces of aircraft in flight (as well as behind the wingtips).