St neb op compared with Ns

(Section 2.3.8.6.4)

Stratus nebulosus opacus (thick) closely resembles Nimbostratus and may very easily be confused with it. It is distinguished from Nimbostratus by:

• Having a more clearly defined and more uniform base than Nimbostratus
• Having a “dry” appearance, contrasting to the “wet” appearance of Nimbostratus
• Producing only weak falls of drizzle, snow or snow grains (whereas Nimbostratus nearly always produces rain, snow or ice pellets)
• Not usually being preceded by other clouds of the low and middle levels (Nimbostratus nearly always succeeds other clouds, usually of the middle level, or develops from a pre-existing cloud)