1. Cirrus - thin, wispy clouds blown by high winds into long streamers called mare's tails. Usually move from west to east across the sky, indicating prevailing winds at their elevation and generally point to fair, pleasant weather.
2. Cirrocumulus - small, rounded, white puffs that may occur individually or in long rows. When in rows have a rippling appearance. Seldom cover more than a small portion of the sky.
3. Cirrostratus - thin clouds, sun and moon can be seen clearly through them. Produce a halo effect around the sun/moon. Thick cirrostratus clouds usually form in front of an advancing storm.
4. Altocumulus - composed mostly of water droplets, rarely more than 1 kilometer thick. Gray puffy masses, sometimes rolled out in parallel waves or bands. Usually, 1 part of the cloud is darker than another.
5. Altostratus - gray or blue-gray cloud composed of ice crystals and water droplets. Often cover the entire sky. The sun/moon may be dimly visible in thin sections of the cloud; but they usually block enough sun so that shadows are not visible of the ground.
6. Nimbostratus - dark gray, wet looking cloud associated with near continuous rainfall/snow. Darker gray than previous clouds, cannot usually see the sun/moon through it.
7. Stratocumulus - low lumpy clouds that appear in rows, patches, or as rounded masses with blue sky visible between the cloud elements.
8. Stratus - uniform grayish cloud that often covers the entire sky; resembles a fog that does not reach the ground. Sometimes a light drizzle. Very low.
9. Cumulus - vertically developing cloud formation. Base appears light white to light gray and on a humid day may only be 1 kilometer above the ground. Detached, lots of blue sky between each cloud. Dome or tower shaped top.
10. Cumulonimbus - thunderstorm cloud, dark base, very low (600 meters), top can extend upward to the tropopause, over 12 kilometer high. Can occur as an isolated cloud or part of a line or 'wall' of clouds.