Six types of clouds you need to know - and what they say about the weather

Modern weather forecasts are based on complex computer simulations . These simulations use physical equations that describe the atmosphere, including air movement, solar heat, cloud formation and rain. The gradual improvement of forecasts over time means that today's five-day forecasts are as accurate as three-day forecasts were 20 years ago.

But you don’t need a supercomputer to predict how the weather will change above your head in the next few hours - such signs have been known in different cultures for many thousands of years . By following the sky and having some knowledge of cloud formation, you can predict whether it will rain.

Moreover, a little understanding of the physics of cloud formation emphasizes the complexity of the atmosphere and sheds light on the reasons why predicting weather for a period longer than several days is such a difficult task.

Here are six types of clouds that you can see, and how they can help you understand the weather.

1) Cumulus clouds

Small white fluffy clouds.

Clouds appear when the air cools to the dew point , the temperature at which the air can no longer cope with the water vapor contained in it. At this temperature, water vapor condenses and forms droplets of liquid water, which we see as a cloud. For this to happen, air must be forced to rise in the atmosphere, or moist air must come in contact with a cold surface.

On a sunny day, the rays warm the earth, which heats the air located directly above it. Heated air rises due to convection and forms cumulus clouds. These “good weather” clouds are like cotton wool. If you look at the sky filled with cumulus clouds, you can see that they have a flat bottom, located at the same level for all clouds. At this altitude, air rising from ground level is cooled to the dew point. From cumulus clouds, it usually doesn’t rain - which means the weather will be fine.

2) Cumulonimbus clouds

Small cumulus clouds do not rain in the rain, but if they increase and grow in height, this is a sign that there will be heavy rain soon. This often happens in the summer, when morning cumulus clouds turn into cumulonimbus in the afternoon .



Not far from the earth, cumulonimbus clouds are clearly formed, but with height they begin to become smokier at the edges. Such a transition indicates that the cloud no longer consists of water droplets, but of ice crystals. When gusts of wind blow water droplets outside the cloud, they quickly evaporate in a drier environment, which is why the edges of water clouds are very sharply defined. Ice crystals carried outside the cloud do not evaporate so quickly, making the edges of such a cloud look smokier.

Cumulonimbus clouds often have a flat top. Inside such a cloud, air convection occurs and it gradually cools until it reaches the temperature of the surrounding atmosphere. At this moment, it loses buoyancy and can no longer rise higher. Instead, it extends to the sides, forming the characteristic shape of the anvil.

3) Cirrus clouds

Cirrus clouds can mark the approach of a warm front and rain

Cirrus clouds form in very high layers of the atmosphere. They are smoky because they are entirely composed of ice crystals falling in the atmosphere. If cirrus clouds carry winds moving at different speeds, they acquire a characteristic curved shape. And only at very high altitudes or at high latitudes cirrus clouds give out rain reaching the earth.

But if you notice that cirrus clouds begin to cover a large area of ​​the sky, become lower and thicker, then this is a sure sign of the approach of a warm front. In a warm front, warm and cold air masses are found. Lighter warm air rises above the cold, which leads to the formation of clouds. The lowering of the clouds indicates the approach of the front, and that it will rain in the next 12 hours.

4) Layered clouds

Layered Clouds: Darkly

Layered clouds are a low-lying, continuous cloud sheet covering the sky. Stratus clouds are formed slowly by ascending air or light wind, covering moist earth with cold air or the surface of the sea. The layered clouds are thin, therefore, despite the gloomy picture, it is unlikely that it will rain from them, with a maximum light drizzle. Layered clouds are identical to fog, so if you ever walked through a mountainous area on a foggy day, you were inside the cloud.

5) Lenticular clouds

The last two types of clouds will not help you predict the weather, but will give a primary idea of ​​the extremely complex movements of the atmosphere. Smooth and lenticular lenticular clouds form when air is blown up and through the ridge.



Having crossed the mountain, the air descends to the previous level. At this time, it warms up and the cloud evaporates. But it can slip further, as a result of which the air rises again and forms another lenticular cloud. This can lead to a chain of clouds extending far beyond the boundaries of the mountain range. The interaction of wind with mountains and other surface features is one of many details that must be taken into account in computer simulations to obtain accurate weather forecasts.

6) Kelvin - Helmholtz

And finally, my favorites. Kelvin - Helmholtz clouds resemble a breaking ocean wave. When air masses at different heights move horizontally at different speeds, their condition becomes unstable. The boundary between the air masses begins to become rippled and forms large waves.



Such clouds are quite rare - I personally saw them only once over Jutland, western Denmark - since we can observe this process in the atmosphere only if there is a cloud in the lower air mass. Then it can outline breaking waves and detect the intricate movements that occur above our head, which are usually not visible.