white, puffy clouds that look like pieces of floating cotton. u!ulus clouds are often called "fair#weather clouds". $he %ase of each cloud is flat and the top of each cloud has rounded towers. &hen the top of the cu!ulus clouds rese!%le the head of a cauliflower, it is called cu!ulus congestus or o r towering cu!ulus. $hese clouds grow upward and they can develop into giant cu!uloni!%us clouds, which are thunderstor! clouds.
'n arcus cloud is a low, hori(ontal cloud for!ation. )oll clouds and shelf clouds are the two types of arcus clouds. ' shelf cloud is usually associated with the leading edge of thunderstor! outflow* roll clouds are usually for!ed %y outflows of cold air fro! sea %ree(es or cold fronts in the a%sence of thunderstor!s.
Stratus clouds are
unifor! grayish clouds that often cover the entire sky. $hey rese!%le fog that doesn+t reach the ground. ight !ist or dri((le so!eti!es falls out of these clouds.
' nimbus cloud is a cloud cloud that that produces precipitation produces precipitation.. -sually the precipitation reaches the ground as rain rain,, hail hail,, snow snow,, or sleet sleet.. alling precipitation !ay evaporate as virga virga.. )ain co!es out of ni!%us clouds and this is called precipitation. Since ni!%us clouds are dense with water, they appear darker than other clouds. /i!%us clouds are for!ed at low altitudes and are typically t ypically spread unifor!ly across the sky.