Cloud top is a well-known weather parameter for outdoors enthusiasts who engage in a various wind sports in the air — for example, paragliders but not only them. If you haven't tried this or other air sports yet but want to do, this article is right for you.
Learn what the cloud top is, why you may need it, how else do we measure clouds, and how to use it all for your outdoor activity.
A cloud is the tiny liquid particles of water vapor, frozen water crystals, and other particles suspended in the air. Clouds form in the sky because the air becomes saturated with moisture when it cools to the dew point, or when much water evaporates from the earth's surface and water vapor forms.
The cloud top is the height at which the upper visible part of the clouds is located as opposed to the cloud base, which is the lower visible part. So it is measured with the same instrument we use to measure the base of the cloud called a “ceilometer” or a type of atmospheric lidar. Its working principle is based on the laser. We also measure cloud top with the same units as cloud base, although sometimes not meters or feet, but hectopascal (hPa) as the corresponding pressure level.
The concept of a cloud top is opposite to the concept of a cloud base, but they are related. The height of the cloud top is often more variable than the height of the cloud base. It is also at the top and not at the base that rain, snow, sleet, and other types of precipitation form.
Knowing cloud top is useful for anyone who practices various wind sports and outdoor activities in the air, such as paragliding, parachuting, air ballooning and different types of aviation. It helps you navigate and avoid loss of visibility, which is vital weather element in the air. But you don’t have to be a paraglider to see top of the clouds. Mountaineers and even many hikers often climb above the clouds because they often lie so low that they are below the tops of the mountains. In this situation you are sure to find yourself in clear and cloudless weather without precipitation. Plus, you can take stunning photos like this one:
Clouds under the top of the mountains. Photo: Samuel Ferrara / Unsplash
Clouds are measured not only by this weather parameter but by several others. Here we will mention them very briefly, and later we will talk more about each of them in the separate articles. But if you see a link, there is already one, so go to learn more about it:
How do we measure clouds. Valerya Milovanova / Windy.app
The forecast of clouds is one of the main in the Windy.app, along with the wind speed and direction, air and water temperatures, precipitation and other forecasts. Of all the above types of cloud measurements, you can find two in the app: cloud base and cloud cover (clouds).
You can find the cloud base parameter in a special weather profile for all wind sports in the air called the same — "Air". To do so:
1. Open your favorite or nearest spot from the Home Screen of the app or from the Weather Map. Let's take the Monte Avena paragliding spot located in the Dolomites mountains in Veneto region in Italy, as an example. It is a fairly flat mountain that is easy to jump from. The height of this mountain is 1,450 m (4,770 ft) above sea level.
Monte Avena paragliding spot in the Dolomites, Italy, in the Windy.app for iOS
2. Select the Air Weather Profile using the icon to the right of the weather models:
Air Weather Profile in the Windy.app for iOS
3. Get a cloud base forecast for today as well as for the next 10 days. You can also change the forecast step from 1 to 3 hours.
On the date of the writing of this particular text, in the forecast we see that the maximum cloud base on Monte Avena in the next three days will be 3,200 m (10,498 ft) on Friday, November 12 at 7 am, and the minimum cloud base will be 1,100 m (3,608 ft) on Saturday, November 12 at 08 am.
Maximum cloud base for Monte Avena in the Dolomites, Italy, in the Windy.app for iOS
Minimum cloud base for Monte Avena in the Dolomites, Italy, in the Windy.app for iOS
This means that at the minimum cloud base the clouds will cover the highest point of the mountain, so jumping on that day and at that time may be problematic.
Looking at the forecast for many days, you can also calculate the average base of clouds for the spot by yourself. This is somewhere around 1500–2000 m (4,921–6,561 ft).
The cloud cover is available in the same Air Weather Profile, as well as in all other 10 weather profiles according to all 10 weather models in the application under the general name “Clouds”.
Cloud cover in the Windy.app for iOS
In contrast to the common expression of the parameter in percentages or oktas on weather maps, in the Windy.app you see a graph with layers of clouds. It can be one layer, two layers, or three layers — but no more, or no layers at all.
The number of layers also literally shows how many layers of clouds are in the sky in a system of three main layers, which refers to the clouds layers parameter.
Pay attention also to the color and thickness of each layer itself, I mean, the line. The darker it is and the thicker it is, the more clouds are in the sky and the denser the layer. And vice versa: the lighter and thicker the line, the thinner the layer, and the fewer clouds in the sky.
In any case, before you get in the air to do your favorite wind sport, check the forecast by different models, as well as just visually on the day of your trip.
Last but not least, you can select the Clouds forecast as a separate item and add it to your Custom Weather Profile using the Cusmotization feature. To do this, go to the Weather Profiles Screen and select it in one of the models. Then check the forecast.
Adding cloud cover on the Weather Profile Screen in the Windy.app for iOS
Learn more about clouds in the Windy.app Meteorological Textbook.
Cover photo: Raman Balakrishnan / Pexels
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