1 Altocumulus have distinct cloud elements and can appear in linear bands.

12 Fog can be considered as a low stratus cloud in contact with the ground.

2 Altostratus have a more uniform and diffuse coverage.

13 Instability waves in the atmosphere cause the spiral shape.

3 Cumulonimbus are the clouds that can produce severe weather.

14 Lenticular are lens-shaped clouds.

4 Cirrocumulus are high clouds with a distinct patchy and/or wavelike appearance.

15 Lenticular cloud as the sun moved lower on the horizon.

5 Wavy cirrocumulus have a banded linear structure.

16 Same cloud formation from about 20-25 miles further away.

6 Cirrus are wispy and usually quite thin and often have a hairlike appearance.

17 Another version from about 20-25 miles further away.

7 "contrails" (short for "condensation trails") and look like lines in the sky.

18 Mammatus are cumulonimbus clouds with appendages protruding from the base of the cloud

8 Cirrostratus are high clouds that usually blanket the sky in ill-defined sheets.

19 Nimbostratus are considered multi-layer clouds because their vertical extent.

9 Cumulus cloud viewed from the ground and is directly overhead.

20 Stratocumulus are usually concentrated closer together in clusters.

10 Cumulus are usually puffy with usually a noticeable vertical development.

21 Stratus are usually the lowest of the low clouds.

11 Cumulus cells can be grouped together in clusters.

22 Stratus cloud deck.