The words nimbostratus and cumulonimbus both have “nimbus” as part of the word. The nimbus portion of the word means “rain producing”. Thus, these clouds are rain producing clouds. The term “cumulo” indicates a vertically developed cloud. These are the clouds produced by convective uplift due to parcels of air rising from positive buoyancy. The rain from these clouds tends to be heavier and of shorter duration. Thus, the word “cumulonimbus” is a rain producing vertically developed cloud. The term “stratus” indicates a sheet-like or horizontal cloud. These clouds are produced by a generally lifting of saturated air (not convective lifting but rather dynamic lifting). Examples of processes that can produce dynamic lifting include frontal lifting, low level warm air advection lifting, topographic lifting and upper level divergence. The word “nimbostratus” means rain producing clouds from horizontally layered clouds. |