The latter appears as a uniform cloud cover where the sun or moon shine weakly through. They may produce local rain or snow showers. Nimbostratus clouds are far less friendly than any clouds so far mentioned. These clouds appear as a huge dark gray cloud that covers a large percentage of the sky. High altitude clouds are found from 20,000 to 50,000 feet.
All varieties appear as thin wispy and windblown.
Cirrus clouds are thin white swirling clouds, often curling elaborately. Cirrostratus are thin and veil like and are usually the clouds associated with lunar halos. All three types produce no noticeable precipitation, but are usually harbingers of bad weather to follow. Perhaps the most ominous cloud of all, and the one associated with the most spectacular weather, is the cumulonimbus cloud, that wicked looking thunderhead. This cloud system may range from lower altitude far into the upper atmosphere where it flattens at the top.