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.) 



) 



Codes 4 & 5 

 <- ALTOSTRATUS & ALTOCUMULUS 



M7: Any of the following cases: 



(a) Double-layered altocumulus, usually 

 opaque in parts, not increasing. 



(6) A thick (opaque) layer of altocumulus, 

 not increasing. 



(c) Altostratus and altocumulus both pre- 

 sent at the same or different levels. 



Type (a): Two layers of altocumulus, the 

 lower of which resembles a gray veil, often 

 hardly visible, lying at a level very little 

 lower in places and for a short time hiding 

 the cloudlets of the altocumulus sheet suffi- 

 ciently to give it the appearance of alto- 

 stratus. This double-layered altocumulus 

 is coded M7 only if the altocumulus is not 

 systematically increasing; otherwise it is 

 coded M5. 



T;y'P6 (^)- The under surface of opaque 

 altocumulus is marked by a more or less cor- 

 rugated or wave-like structure, sometimes 

 called wrinkled. 



H. O. 607 



350676 O — 56 13 



181 



