Clouds Formation

+ Species Stratus nebulosus (St neb): A featureless veil of stratus sometimes producing light drizzle.
+ Species Stratus fractus (St fra): A ragged broken up sheet of stratus that often forms in precipitation falling from a higher cloud deck. This species may also result from a continuous sheet of stratus becoming broken up by the wind.
• Moderate vertical (Family D1)
Family D1 clouds have low to middle bases anywhere from near surface to about 10,000 ft (3,000 m) and therefore do not fit very well into the conventional height ranges of low, middle, and high. This group continues the pattern of comprising one cumuliform and one stratiform-category genus. Cumulus usually forms in the low altitude range but bases may rise into the lower part of the middle range during conditions of very low relative humidity. Nimbostratus normally forms from altostratus in the middle altitude range but the base typically subsides into the low range during precipitation.