One of the most obvious weather phenomena, clouds, is not a single entity, but more than a dozen different kinds of clouds. You yourself have noticed one or the other, but most likely you do not know how they differ from each other and what kind of weather they bring with them. Yes, you can predict the weather by the kind of clouds you see.
In this new lesson, we're going to break down the main types of clouds. Follow the links to read the lesson about this or that type.
Sometimes a mass of warm air can rise to such a height that it encompasses the entire lower layer of the earth's atmosphere (that is, the troposphere). Such monsters grow to 15–18 km up. But when it reaches the tropopause, the cloud stops growing and, due to strong winds at this height, begins to blur, forming the shape of an anvil cloud.
Is it a UFO? No, it’s a lenticular cloud, also known as a lens cloud. Such clouds don’t move, even in strong winds. How does that happen? The higher air is, the colder it is. When it cools, the moisture it contains transforms into water drops. It’s these drops that form clouds. Thus, a warm air current cools moving up a mountain, creating a cloud.
The cirrus uncinus clouds are the precursors of weather changes. They are a form of cirrus clouds. They stretch across the sky in the form of parallel thin threads, which end with a ‘curl’. The name is derived from Latin, meaning ‘curly hooks’.
Those are noctilucent clouds. They are often called night-glowing clouds. Noctilucent clouds appear in the sky only at night and only in warm seasons. In the Northern Hemisphere they appear from May to September, and in the Southern Hemisphere - from November to March.
Polar stratospheric clouds also called nacreous clouds because of their unusual color are form at Polar latitudes. This is an extremely rare phenomenon! Because of this, there has always been a lot of interest in these clouds. And also because of the painting by the world famous Norwegian artist Edvard Munch.
Surely, you have observed how sometimes streaks “hang” from under the clouds — this is a so-called virga, which can appear under cumulonimbus clouds, so it is also called virga clouds. This is the same rain, but it evaporates before reaching the surface of the earth. The reason for this is low ambient humidity. That is, dry air in the way of drops tends to saturate with moisture and "absorbs" them.
Cumulus cloud is one of the most common and distinctive types of cloud. Cumulus clouds are mostly spotted in fair weather conditions, but they can also be a precursor of stormy weather. On a sunny day we tend to see cumulus clouds looking like floating cotton wool balls. These puffs of cotton strewn around the sky are actually low-level clouds with a flat base. That's why cumulus clouds are often called "Cotton wool in the sky". They look as if they are rather large, thick clouds which could be quite high.
These clouds are usually associated with heavy thunderstorms and are capable of producing severe weather. The process starts with the formation of a cumulus cloud, which requires a dramatic change in temperature with altitude: warm air close to the surface gets significantly colder the higher up you go.
Nimbostratus clouds are dense, grey, featureless clouds which produce persistent and often heavy rain, snow or ice pellets. Nimbostratus are low level clouds and their base generally lies between 100 m and 1 km.
Text: Windy.app team
Cover photo: NOAA / Unsplash