Understanding the Weather 



rain; yet the cloud stays aloft if conditions favor condensation, 

 and if the particles it has lost are replaced. 



Most clouds are formed by rising, warm, moist air that becomes 

 visible as billowy masses of moisture when it comes in contact 

 with the cold upper atmosphere; and generally this same process 

 which produces clouds counteracts their natural tendency to fall 

 earthward. 



We get fog when warm, humid air meets a cool surface such 

 as that of a lake or sea, or ground which has rapidly lost the heat 

 it absorbed during the day. As in the case of clouds, the vapor 

 in the warm air then condenses and becomes visible. 



How TO READ THE CLOUDS 



Anyone, young or old, enjoys playing the role of weather 

 prophet. While many factors enter into the predictions made by 

 the weatherman, you can nevertheless have the fun of making rea- 

 sonably accurate forecasts just from clouds. And because you are 

 concerned only with your immediate vicinity, your prediction may 

 be more successful than that of the professional forecaster! 



As far as a youngster is concerned, the simplest indications for 

 clear weather are high, white clouds, while dark, heavy, low 

 clouds point to bad weather. Long before people knew much about 

 clouds, this much was about all that anyone looked for in them. 

 Today, however, we have the benefit of years of study of the clouds, 

 and we know that scientists have divided them into three general 

 classes. Each class has its own story to tell about conditions high 

 above the earth. 



SPECTACULAR CUMULUS CLOUDS 



The spectacular cumulus is the kind of cloud that children 

 are likely to notice first. Its name, taken from the Latin word for 

 "heap," is a good description; these clouds are heaps upon heaps 

 of billowy mounds that may reach a height of several miles! The 

 name becomes easy to remember when you associate it with 

 "accumulated." 



