Cirrocumulus Clouds (“Regularly spaced cloudlets, often rippled”)
Cirrocumulus clouds, or known as mackerel cloulds, if you see these normally bad weather is on it's way.
Cirrocumulus clouds are made up of lots of small white clouds called cloudlets, which are usually grouped together at high levels. Composed almost entirely from ice crystals, the little cloudlets are regularly spaced, often arranged as ripples in the sky. Cirrocumulus cloudlets are usually made up of both ice and 'supercooled' water, this means that water remains a liquid, even at temperatures well below 0c. They form when turbulent vertical currents meet a cirrus layer, creating the puffy cumulus shape.
Precipitation from cirrocumulus clouds never reaches the surface, meaning that these clouds are usually associated with fair-weather. However their appearance can often prelude stormy weather meaning you should make the most of the sun while you still can.
Typical Altitude: 16,500-45,000 ft.
Precipitation: None that reaches ground
Composition: Ice crystals
Formation: Cloudlets formed by choppy winds and high moisture levels in upper troposphere