Description & Characteristics. The ‘nebulosus’ cloud species is found in only cirrostratus and stratus cloud types. It is one of only two species that’s associated with stratus clouds (other being fractus) as well as cirrostratus clouds (other being fibratus). Translated from latin meaning nebulous, their cloud abbreviations can be respectively written as ‘Cs neb’ and ‘St neb’. For a cloud to be classified as nebulosus, there has to be zero sign of detail in the cloud.
Low-level fog is a great example of stratus nebulosus. It’s just a sheet of gray sitting above the ground. Very dense fog can be classified as stratus nebulosus opacus, which translates to a stratus cloud that has no detail and is dark enough to block out the sun. Stratus nebulosus clouds are commonly paired with cloud varieties opacus (opaque) and translucidus (see-through) and can produce precipitation (praecipitatio cloud feature) on occasion.
Cirrostratus nebulosus clouds are just the opposite of fog. It’s a high level cloud blanket that’s neither wispy, curly, or fibrous in appearance. It’s just a high-altitude vapor layer cloud. Because they’re made of ice crystals, cirrostratus nebulosus clouds are capable of producing sun halos and on the rare occasion, moon halos. Cirrostratus nebulosus clouds can be paired with cloud varieties undulatus (wavelike, undulating) and duplicatus (multilayered) on occasion.
The nebulosus cloud species is common, and more commonly found in stratus cloud formations relative to cirrostratus clouds, though it can depend on where you’re located. It can also be difficult to make out cirrostratus nebulosus clouds, especially if the cloud is high in altitude and/or very thin.