29. Altocumulus, or High Stratocumulus, at One Level Only, 3/3. 



In this case the clouds are more surely altocumulus. It appears 

 that the cloud sheet exists at one level only. The cloud masses 

 here are more nearly globular than in the preceding example. Shading 

 is plainly visible on the under surfaces of the thicker cloudlets. The 

 sheet (M3) does not increase in amount; if it increases materially it 

 should be coded M5. (Photo on IMount Weather, Va., bv A. J. 

 Weed.) 



30. Altocumulus in Small Isolated Patches, More or Less Lenticular 

 in Shape, M4. 



These clouds appear on the lateral edge of a disturbance or in 

 mountainous districts. This picture was taken in the lee of Mount 

 Washington during a gale from the northwest. Clouds of this type 

 are sometimes called "standing" clouds because they appear sta- 

 tionary, although they are actually in constant process of formation 

 on the side toward the wind and evaporation on the other side. 

 (Photo by C. F. Brooks.) 



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