What is the winds aloft forecast and how to read it

In the wind forecast that you see in your weather app, there is one small and important detail that not everyone knows about: it is the wind at 10 meters (33 feet) high.

But it is clear that the wind blows not only at this level, but also below and, which is more importantly, above. The good news is that this kind of wind forecast can also be obtained. It is not important for pedestrians but critical for all those who are engaged in wind sports in the air: paragliding, ultra-light aviation, and others.

In this short article, we will understand what the winds aloft forecast is and how to read it.

What is the winds aloft forecast?

Usually, the wind is measured at about 10 meters (33 feet), which is counted from the Mean Sea Level (MSL). Why do meteorologists place anemometers at this height? Simple: at ground level, there are many obstacles to the wind, including trees, buildings, and other things that prevent making the most accurate measurement. Therefore, wind instruments are usually placed on the roofs of low buildings or weather stations located there.

I think you are wondering how much is 10 meters (33 feet)? It is about 10 walking steps. Or, here is a list of some objects equal to this high, if we put them one on top of the other:

5 sofas
11 baseball bats
5 garage doors
3 alligators

The second reason by which the wind is measured at the height of 5 couches is so that wind data from similar stations around the world can be collected at the same altitude and can be compared to each other. After all, it is known that winds blow stronger at a higher altitude. There are three main reasons for this:

The atmospheric pressure gradient increases with altitude, especially at mid-latitudes, and we already said in the article on how to read an isobar map that pressure change is the only thing speeding wind up.
Again: objects near the ground interfere with the wind, which collides with them as obstacles. Hence, at higher altitudes, the wind will be faster — there is nothing in its way.
The farther away from the ground, the less dense and thinner air becomes. It is easier for such air to move than the denser air near the ground. In this case, the air moves faster.

So the winds aloft forecast is a special forecast that differs from the standard one and can only be obtained from specialized meteorological services.

A forecast at altitude is necessary for all those who are engaged in air sports because data on the wind on the ground is of little use to them. Such forecasts are made and used all over the world for aviation purposes.

Before we go to the next part, it is also important to note that the other two basic weather elements in the general weather forecast, air temperature and atmospheric pressure, are also measured at about sea level. But they could be measured at different altitudes, too. Anyone who has ever climbed a mountain knows themselves that air temperature drops as the altitude increases, and so does pressure.

Winds aloft forecast for Monte Gordo in Portugal in the Windy.app for iOS

How to read winds aloft forecast?

The wind forecast at altitudes is generally not different from the standard forecast at 10 meters (33 feet) in terms of what it contains and what it looks like. It is the same wind direction and speed.

The actual difference is that the forecast indicates the altitude. It can be different depending on the source of information. For example, in the Windy.app you can see the wind forecast at altitudes for the following values:

1,949 m (6,394 ft)
1,457 m (4,780 ft)
988 m (3,241 ft)
762 m (2,500 ft)
540 m (1,771 ft)
111 m (364 ft)

How high is it? Well, it’s easy to do the math: 111 m (364 ft) is 55 sofas and 1,949 m (6,394 ft) is 974 couches. Or another example: this altitude is also a good altitude for any real rocky mountain. At about 2,000 meters, trees and other vegetation stop growing and only rocks remain.

It is good to know also that in the standard altitude weather forecasts that used to be on paper in tables, you might also see the following designation — for example, 3127+04. The first two digits are the wind direction: 310 degrees true north. The second two digits are wind speed: 27 knots (aviation and sailing traditionally use knots to measure speed, as they are more convenient). The last two figures are the air temperature in degrees Celsius, i.e. +4 degrees (39.2 F). Above 7,315 m (24,000 ft) the +/- signs for temperature are not used because the temperature at higher altitudes is below zero Celsius (32 F). So the wind and temperature were listed together.

Wind speed at different altitudes can also be calculated independently by knowing, in fact, the speed at 10 meters (33 feet) and the desired altitude. There are several formulas for this. However, there is no consensus about which one is better.

Where to get winds aloft forecast?

In the Windy.app you can find the wind forecast for different heights in a special Air weather profile. To activate the profile and get the forecast, do the following:

1. Open your favorite spot or closest one to your location from the Home screen or on the Weather Map. For example, Monte Gordo in Portugal. In the case of the map, you can also select absolutely any point and get the forecast for it.

2. Switch the profile to Air through the icon on the right side of the list of weather models. Here you can also create your own weather profile in the Pro version of the app by adding additional elements to it.

3. Read the forecast in the table below the models. The wind forecast is always at the very top at the beginning of the table, so you don’t even need to scroll down. The profile also has the altitude pressure forecast we mentioned above. It is also useful for predicting wind speed.

Read Mini guide to paragliding with Windy.app.

Text: Ivan Kuznetsov, an outdoor journalist, editor and writer from the Dolomites, Italy, and Karelia, Finland, with 10 years of professional experience. His favorite sports are hiking, cycling and sauna. Read his other articles

Cover photo: Jared Watney / Unsplash