5. Cumulonimbus With Anvil Top Beginning to Form, Lg. 



The main cloud mass is in process of transformation from X2 to 

 ig. The "caiihfiower" summits remain but they are softening and 

 the summit shows some horizontal spreading. There is a light 

 shower below the central mass. Cumulus clouds, io, also show to 

 the right in tlie picture but the cumulonimbus would be given prefer- 

 ence in coding. (Photo on Mount Wilson, Calif., by F. Ellerman.) 



6. Cumulonimbus, L3. 



The anvil is partially formed and the "cauliflower" swellings have 

 dissolved in the upper portion of the cloud mass. There is a small 

 veil cloud at the left of the summit. Heavy cumuliform masses 

 appear in the lower part of the picture with some altocumulus and 

 patches of dark fractocumulus. A heavy shower is visible. (Photo 

 at Cheyenne, Wyo., by H. T. Floreen.) 



42 



