What cause gentle consitent rain?
Gentle consistent rain usually is the product of nimbostratus clouds. They are normally associated with a board area of lift of nearly saturated air that can be caused by several different methods. First there has to be a good source of low level moisture. This is most often near oceans or very large lakes/seas but sometimes happens when very deep (say 5 thousand feet or more) low level moisture that previous has been moved over area by the approach of the system is slowly lifted. The lift mechanism is often the key. It has to be strong enough to vertically lift the air but the air must be stable enough to not continue to rise once it starts to precipitate. That would produce thunderstorms in that case. The lift can be mechanical. That is wind is pushing the moisture laden air up a slope. This is why you often seen this type of rain near the coasts with winds steadily blowing from the sea onto the land. The lift can be caused by the slow passage of a strong upper level system that is p
