Fig. 5. — Cumulus Clouds 



Cumulus clouds, as in the above, illustrating the formation of a central core 

 of ascending warm air, generally precede local rains or thunderstorms by a few 

 hours. 



Photos by Henry 



Fig. 6. — Near View of Large Cumulus Clouds 



The small detached clouds on the lower left-hand margin of the cloud are 

 almost invariably seen in advance of thunderstorms. Cumulus clouds, like those 

 shown, rarely give rain at the point of observation, since their prevailing drift in 

 these latitudes is eastward. 



