If you do not trust the weather, look at the sky, from where you can read a reliable forecast. The higher the lowest clouds are, the drier the air and the rain is unlikely. If the clouds you see swell up and down, the weather will probably get worse.
To read from the clouds, we must be able to recognize the most useful ones in forecasting. Beautiful white sheep, or black, thundering monsters – every cloud can tell us something about the weather. Clouds are not in the sky just for decoration, and their shapes do not come out of nowhere.
Learn the basic types of clouds
Cumulus – a separate, thick, white cloud, composed of drops of water. Cumulus are a type of cloud formed in the troposphere low floor. The more uplifted clouds are accompanied by slight rainfall. These clouds can transform quickly, and the typical lifetime of a small cumulus takes 10-30 minutes.
Cumulus fractus – jagged clouds have not yet developed a horizontal base or a domed top surface. They are several hundred meters thick. They occur most often as the initial stage of cloud development. They do not give rain.
Cumulus humilis – so-called beautiful weather clouds are small, relatively flat and rarely placed in the sky cumulus. Their thickness ranges from several dozen to several hundred meters.
Cumulus mediocris – moderately uplifted, intermediate stage between Cumulus humilis and Cumulus congestus. They have an average of several hundred meters to a kilometer and usually do not give rainfall.
Cumulus congestus – accumulated cumulus, very complex in the vertical direction, sometimes give a peaceful fall.
Cirrus – belongs to high clouds, made of ice crystals. Cirrus are the clouds of the high floor are found in the upper troposphere. In moderate latitudes, cirrus clouds are usually one of the first harbingers of the upcoming warm atmospheric front, and therefore worsening weather.
Cirrocumulus – clouds of the high-tuft-and-pinnate floor. Small, white petals or bundles often arranged in rows – so-called „Lambs”. Cirrocumulus clouds do not give rainfall that reaches the surface of the earth. Small, high, patched clouds, in rows.
Cirrostratus – a cloud in the form of a transparent, misty and often almost invisible curtain, does not give rain. It consists mainly of ice crystals in the shape of plaques. It often causes the halo phenomenon around the Sun and the Moon, sometimes only a halo is a clear symptom.
Cumulonimbus – a dense cloud expanded vertically to the height of several or a dozen or so kilometers. Sometimes in the shape of a tower, with an upper surface smooth, finished with a dome or cauliflower. Sometimes, in a more elaborate form, the high floor resembles a huge anvil or a mushroom. The base of this type of clouds is located at the height of 2-3 km, while their upper ceiling in the tropic zone can exceed even 20 km. Composed in the lower part with drops of water, and in the top of ice crystals, these are the most developed clouds in the vertical direction. This is why the physical phenomena that occur in them are very violent. They can be a source of rapid rain, snow or hail, which is often accompanied by electrical discharges – storms.
Predicting weather with clouds
Most travelers recognize clouds instinctively. Cumulus clouds scattered across the blue sky signal good weather and a perfect day for a hike. Cumulonimbus clouds herald a storm. And these two types of clouds can be considered as specific certainties. With other types it is not so easy. Actually, they can mean anything until we look at them very closely.
Very often we do not have the opportunity to observe the flow directions or change of clouds for a long time or we want to collect the maximum information in the shortest possible time. The exact shape of the clouds is an indication for the impatient. Each cloud is an indicator showing what is happening with the air and what the effect will be. The best example of this is Uncinus (specific type of Cirrus), which look like a horse’s tail. They can herald rather a warm front. Falling Cirrus clouds will leave a strand of bristles, and the rising ones will gather them from the sky. The declining cloud is the announcement of deterioration of conditions, while rising up indicates weather improvement.
Cloud shapes can reveal the direction of the wind around and within them. The cumulonimbus moved in the upper layer contain a clue as to the direction of the approaching storm. However, sometimes much calmer clouds will reveal this „bevel effect” when the top and bottom of the cloud are not perfectly aligned, and the wind direction varies depending on the latitude.
The friendly and harmless Cumulus have slightly less pleasant cousins: Cumulus congestus and Cumulus castellanus. A cloud similar to a soft lamb, but the growing breadth and up should be carefully studied. Its size and color will tell you how friendly it is. Look carefully at the top and bottom of the accumulating Cumulus. If their bottom is aligned and the top forms a shape resembling a cauliflower rosette, it is a friendly cloud. It is unlikely that it would herald the rain, and certainly violent. However, when one of these clouds has a thinned top layer and a ruffled or protruding bottom, it is a completely different story. The thinning top layer of the cloud indicates that the water froze there, and this is a sign of violent downpours.