Editing Stratus cloud (section)

== Sub-forms ==

=== Species ===

[[Stratus nebulosus]] clouds appear as a featureless or nebulous veil or layer of stratus clouds with no distinctive features or structure.{{sfn|WMO|1975|p=43|loc=Description of Clouds}} They are found at low altitudes, and are a good sign of [[atmospheric stability]], which indicates continuous stable weather. Stratus nebulosus may produce light rain and drizzle or flakes of snow. '''Stratus fractus''' clouds on the other hand, appear with an irregular shape, and forms with a clearly fragmented or ragged appearance.{{sfn|WMO|1975|p=43|loc=Description of Clouds}} They mostly appear under the [[precipitation]] of major rain-bearing clouds; these are [[nimbostratus]] and [[cumulonimbus]] clouds, and are classified as types of [[Scud (cloud)|pannus cloud]]s. Stratus fractus can also form beside mountain slopes, without the presence of [[nimbus cloud]]s (clouds that precipitate), and their color can be from dark grey to almost white.

=== Opacity-based varieties ===
Stratus fractus are not divided into varieties, but stratus nebulosus on the other hand, are divided into two. The '''Stratus opacus''' variety appears as a nebulous or milky sheet of the nebulosus species, but are opaque enough to block the sun from view.{{sfn|WMO|1975|p=43|loc=Description of Clouds}} '''Stratus Translucidus''' is another variety of the nebulosus species. These clouds are considered more thin than the opacus variety because this cloud is rather translucent, allowing the position of the Sun or Moon to be observed from Earth's surface.

=== Pattern-based variety ===
Stratus clouds only have one pattern-based variety. This is the ''stratus undulatus'' variety. Mild [[wikt:undulation|undulations]] can be observed from this cloud, only associated by the nebulosus species. Though rare, this cloud formation is caused by disturbances on the gentle wind shear. Stratus undulatus clouds are more common on stratus stratocumulomutatus clouds where the wind is stronger as height increases.{{sfn|WMO|1975|p=43|loc=Description of Clouds}}
[[File:Stratus undulatus 1.jpg|thumb|Stratus undulatus clouds during a rainy day.]]

=== Genitus mother clouds ===
'''Stratus cumulogenitus''' clouds occur when the base of cumulus clouds spreads, creating a nebulous sheet of stratiform clouds. This can also occur on [[nimbostratus cloud]]s ('''stratus nimbostratogenitus''') and on [[cumulonimbus cloud]]s ('''stratus cumulonimbogenitus'''). Stratus fractus clouds can also form under the base of precipitation-bearing clouds and are classified as pannus clouds. Stratus clouds may also form from formation mechanisms that are not typical for the cloud type, for example, '''Stratus homogenitus''', which are stratus formed by human activity, '''Stratus cataractagenitus''', which are formed from the spray of [[waterfalls]], and '''Stratus silvagenitus''', which are formed by evaporation or [[evapotranspiration]] occurring in a forest.

=== Mutatus mother cloud ===
Stratus only has one mutatus mother cloud. '''Stratus stratocumulomutatus''' clouds occur when [[stratocumulus]] opacus patches fuse to create a stratiform layer.{{sfn|WMO|1975|p=43|loc=Description of Clouds}}

=== Accessory clouds and supplementary feature ===

Stratus clouds do not produce accessory clouds, but a supplementary feature '''praecipitatio''' is derived from [[Latin]], which means "[[precipitation]]". Stratus clouds are generally too low to produce virga, or rain shears that evaporate before reaching the ground, although higher stratus clouds can produce it.