Ns compared with Sc str op

(Section 2.3.6.6.3)

Nimbostratus is distinguished from Stratocumulus stratiformis opacus (thick layer) by:

• Having no features and usually no discernible base (Stratocumulus has clearly defined elements (merged or separated) and a distinct lower surface)
• Falls of rain, snow or ice pellets (Stratocumulus has infrequent weak falls of rain, snow or snow pellets)