To answer such questions, there is now the specialized thermal forecast XC Therm, which is based on the proven Regtherm thermal model.
The weather forecasts that we know from windy.com, meteo-shv.ch or meteoblue.com are based on numerical weather models (e.g. ICON, Cosmo, GFS, NEMS, AROME). These models divide the atmosphere into a three-dimensional grid and calculate countless parameters for each of these grid points, such as wind, temperature, humidity and air pressure.
However, the climb rates, cloud base and the resulting potential flight distance required to assess thermal quality are not calculated by numerical models. The Regtherm thermal model closes this gap.
The Regtherm forecasts are only available in text format. The new XC Therm app prepares these forecasts with attractive visualizations and allows them to be viewed on the go at any time using a smartphone. In addition, the display of the potential flight distance makes it immediately clear how much distance potential a particular day offers for paragliders. XC Therm converts the values provided by Regtherm into the speed polar of paragliders.
When you click on the regions, XC Therm then shows a graphical representation of the detailed forecasts from Regtherm, which immediately provides detailed information (see Figure 2). The most important parameters here are undoubtedly the climb rates and cumulus cloud cover.
However, other information can also be read from the display. For example, the ideal take-off point and flight altitude above inversions, the time of the first thermals or when the morning inversion will dissipate and the thermals will be continuous.
The stratification of the air mass and the available solar radiation largely determine the climbing values. The more the temperature of the ambient air decreases with increasing altitude, the faster a heated air parcel rises.
But the Regtherm model uses many other parameters such as soil moisture, expected shadowing and vegetation to get a complete picture of the climb rates, height and size of cumulus clouds. If you want to know more about it, you can read about it here: https://xctherm.com/de/regtherm
The Regtherm model integrated in XC Therm is primarily intended as a thermal forecast. However, it is by no means a substitute for consulting fine-meshed wind, cloud and precipitation forecasts, as the regions defined in XC Therm are far too large for this. For this reason, XC Therm also offers high-resolution forecasts (https://xctherm.com/icon) from the brand new ICON-D2 model, which is also able to break up foehn currents.
In a foehn current, very good thermal conditions can prevail. The XC Therm often shows large possible distances in foehn conditions. And the climb rates promise top XC conditions. Nevertheless, the day is rather unflyable for us paraglider pilots! So always take wind and pressure forecasts into account.
We at the paraworld.ch team have been using the Regtherm model to create our thermal forecasts for many years. In the past, we did this via laborious logins at SMA or via the JAVA - Toptask module. This was usually more tiring than pleasant, but the results were still impressive.
Since the XC Therm service came into existence, we have of course been using it. The site is very simply structured and mobile-friendly. It makes our lives much easier. There are three offers, one for pilots who fly regionally or nationally, and one for frequent flyers who travel internationally.
