How reliable is precipitation radar? – Weatherman Bram podcast

At first, I’d like to clear up some confusion about the name. “Buienradar” is actually the name of a website and companion app, but it is also used to name the network of precipitation radars. It’s a bit like saying “bic” for a ballpoint pen.

The Buienradar app and website, as well as many other apps and websites, are platforms where you can find rainfall images. These images are made by precipitation radars. So there are not “precipitation radars”, but “precipitation radars”.

These are radars as we know them: those rotating dishes that emit electromagnetic signals in all directions, receive the reflected signals back and extract information about the distance, shape or size of the reflector.

Precipitation radars are specific radar systems in which the frequency and wavelength of electromagnetic signals are tuned to detect precipitation in the air. Precipitation in all its forms: rain, hail and snow.

Since the range of such a radar is limited, you need an entire network to be able to “protect” an area. Belgium has four of these radars and they look like a large white and red ball on a high pole. They are located in Jabbeke, Zaventem, Helchteren and Wideumont.

Thus, precipitation radars detect where precipitation is and can also estimate the intensity and shape of that precipitation (snow, hail, rain) from the reflected signal. So the pictures from the recent past are a reality. It’s pictures of precipitation falling effectively. Therefore, Buienradar and other websites and applications provide relevant information in this regard. The source of information for all of those sites is also the same, i.e. the four precipitation radars.

From now on, these sites are less reliable. I’m not saying that they are giving false forward information, they are definitely making a good idea. But you should not take the forecast for the coming hours as a certainty. Most websites simply allow rain and downpours to continue in time, considering how fast it has moved in the past few hours. This gives an idea, but it is of course not always correct. Along the way, precipitation can become more intense, more extensive, or just stop. Most websites don’t add data from a weather computer, so sometimes it goes wrong.

In my opinion, what provides the best information is the RMI implementation. The images of future precipitation that you can find there contain additional information from the weather model, specifically the INCA model. This is a complex weather model that has been developed specifically for our country and thus adds high quality information to the precipitation forecast.

So are rain radar and all the other sites reliable? Yes for the past (the precipitation has decreased), less for the future.