Cirrus clouds

All high clouds are a type of cirrus, a common cloud that can be seen at any time of the year.

The height of the base varies from 20,000 feet up to 40,000 feet.

Cirrus clouds are short, detached, hair-like clouds found at high altitudes. These delicate clouds are wispy, with a silky sheen, or look like tufts of hair. In the daytime, they are whiter than any other cloud in the sky. While the Sun is setting or rising, they may take on the colours of the sunset.

Cirrus clouds form from the ascent of dry air, making the small quantity of water vapour in the air undergo deposition into ice (to change from a gas directly into a solid). Cirrus is made up completely of ice crystals, which provides their white colour and form in a wide range of shapes and sizes.

Cirrus clouds can also form through contrails, the vapour trails left by planes as they fly through a dry upper troposphere. These streaks can spread out and become cirrus, cirrostratus and cirrocumulus.

What weather is associated with cirrus clouds?

They often form in advance of a warm front, where the air masses meet at high levels, indicating a change in the weather is on the way.

Technically these clouds produce precipitation but it never reaches the ground. Instead, it re-evaporates, creating virga clouds.

detached: جدا

wispy: پر مانند 

silky sheen: درخشندگی مثل ابریشم

tufts: دسته ای از مو

ascent: بالای چیزی ، فوق 

streaks: رگه ها و خطوط 

contrails: پس دمه، ابر تشکیل شده  پشت موتور جت در ارتفاعات بالا 

associated: همراهی می شود

re-evaporates: دوباره بخار شدن