Prime objective of this lecture is to present on Precipitation in Warm Clouds. Cloud physics is the study of the physical processes that lead to the formation, growth and precipitation of atmospheric clouds. Warm clouds – clouds with only liquid water above 0oC. Two processes produce warm cloud precipitation: (1) Collision and (2) Coalescence. Collision – when cloud droplets collide with each other. Coalescence – when colliding cloud droplets stick together.