Cloud Poster

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Cloud Description
Cumulus (Cu) clouds have noticeable vertical development. Looks like white fluffy balls of cotton. The elevation of the flat cloud base depends on the humidity. The more humid the air, the lower the cloud base. Stratocumulus (Sc) is generally seen as a low gray or whitish layer showing little vertical development. Individual elements are often arranged in bands or rolls. Stratus (St) is a flat, featureless cloud that is low to the ground. It varies in color from gray to white and usually covers the entire sky. The cloud also appears fragmented during and after periods of rain. Stratus on the ground is called fog. Cumulonimbus (Cb) is a thunderstorm cloud that can reach heights of ten miles or more. Mature clouds are identified by the flat anvil-shaped top. This flattening indicates the height of the tropopause which is the boundary between the troposphere and stratosphere. Altocumulus (Ac) clouds are composed of water and they appear as white or gray colored roll-like elements, bands or individual puffs. They tend to occur in sheets or patches with wavy rolls and are the most common 'middle' cloud. Altostratus (As) clouds are always translucent enough to reveal the sun or moon, but prevents objects on the ground from casting shadows. These clouds also appear to have gray or bluish hues and never produce halos. Nimbostratus (Ns) is a dark gray cloud that produce steady rain. Resulting from thickening Altostratus, the cloud base decreases into the 'low' cloud region as rain increases. It often becomes difficult to distinguish from Stratus clouds. Cirrus (Ci) appears as detached clouds in the form of white, delicate filaments, patches or narrow bands. Composed of ice crystals, these clouds have a hair-like or silky sheen appearance. Cirrostratus (Cs) are transparent or semitransparent, whitish clouds with a hair-like or smooth appearance that totally or partially covers the sky. Composed of ice crystals, they frequently produce a partial or complete halo around the sun or moon. Cirrocumulus (Cc) clouds are thin, white patches or layers without shading. Comprised of super-cooled water, they consists of very small elements in the form of grains or ripples. The size of cloud elements appear less than the width of one finger held at arm's length.

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