Common Types of Clouds
Nimbus clouds
Nimbus clouds produces precipitation. Usually the precipitation
reaches the ground as rain, hail or snow. However, precipitation is not
a requirement. Falling precipitation may evaporate.
Cirrus clouds
Cirrus are characterized by thin, wisplike strands, often accompanied
by tufts, leading to their common (non-standard) name of mare's tail.
Sometimes these clouds are so extensive that they are virtually
indistinguishable from one another, forming a sheet of cirrus called
cirrostratus. Sometimes convection at high altitudes produces another
form of cirrus called cirrocumulus, a pattern of small cloud tufts which
include droplets of supercooled water.
Many cirrus clouds produce hair like filaments made of the heavier ice
crystals that precipitate from them. These "fall streaks", a form of
virga, often indicate the difference in the motion of air (wind shear)
between the upper part of the cirrus cloud and the air below it.
Sometimes the top of the cirrus cloud is moving rapidly above a slower
layer of air, or the streak is falling into a faster moving lower layer.
The directions of these winds can also vary.
Stratus Cloud
A stratus cloud is a cloud belonging to a class characterized by
horizontal layering with a uniform base, as opposed to convective clouds
that are as tall or taller than wide (these are termed cumulus clouds).
More specifically, the term stratus is used to describe flat, hazy,
featureless clouds of low altitude varying in color from dark gray to
nearly white. A "cloudy day" usually features a sky filled with stratus
clouds obscuring the disk of the sun. These clouds are essentially
above-ground fog formed either through the lifting of morning fog or
when cold air moves at low altitudes over a region.
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