Noun
nimbostratus (plural nimbostrati)
(meteorology) According to the World Meteorological Organization, a mid-level, principal cloud type, generally formless and dark grey in colour, which forms from altostratus occurring in layers at the middle altitude of the troposphere (usually above 2400 metres). Nimbostratus usually brings precipitation as the mid-level clouds thicken and subside into the low level of the troposphere. Frontal or cyclonic lift can also carry the top of a deep nimbostratus layer into the high levels of the troposphere. Also classified or characterized as multi-level; abbreviated Ns.
Mid-level altostratus and multi-level nimbostratus always have a flat or diffuse appearance and are therefore not subdivided into species. Source: Internet
There is no stratiform type in this group because by definition, even very thick stratiform clouds cannot have towering vertical structure, although nimbostratus may be accompanied by embedded towering cumuliform or cumulonimbiform types. Source: Internet
The stratiform group is cross-classified into the genera cirrostratus (high-étage), altostratus (middle-étage), stratus (low-étage), and nimbostratus (multi-étage). Source: Internet
This cloud often forms under a precipitating deck of altostratus or high-based nimbostratus associated with a well-developed warm front, slow-moving cold front, or low-pressure area. Source: Internet
Virga is a feature seen with clouds producing precipitation that evaporates before reaching the ground, these being of the genera cirrocumulus, altocumulus, altostratus, nimbostratus, stratocumulus, cumulus, and cumulonimbus. Source: Internet
Widespread opaque altostratus can produce light continuous or intermittent precipitation. citation Precipitation commonly becomes heavier and more widespread if it thickens into nimbostratus. Source: Internet