Pileus Cap Clouds
These are a unique type of lenticular cloud that forms above cumulus or cumulonimbus clouds. Due to a strong updraft within the parent cumulus cloud, it pushes upper level winds into cooler areas of the atmosphere--just like a mountain peak. Water in the air reaches its dew point and condenses. These clouds are symbols of severe weather in many cases. They indicate that the parent cloud is very unstable, contains a strong updraft, has a lot of available moisture and is growing rapidly.