The highest resolution model Arome could help but at that level your intuition and experience is essential. BTW The most notable kitesurfer would be the founder and CEO of windy.
Convective ("heat") thunderstorms are pretty much impossible to forecast precisely. On the day of, I'd recommend to use the radar, satellite and wind measurement, to get a picture what's happening, not the forecast anymore.
The forecast that worked best for me (at least in summer in Europe) was local sailplane text forecast from the respective national service. It was an interpretation of the model by a very experienced human with a big picture introduction ("this front" or that "high pressure area") and also expressed uncertainties. They are sometimes behind soft paywalls, though (need to register, but its free. There are some weird rules of the EU about some weather data - cannot be freely available. I don't get it)
Windy has multiple models which is great to check how reliable the forecast is - if they diverge then its a clue. In general, the forecasts are great where there is a lot of good input data, like in western Europe and around the Alps. In eastern europe and on the ocean the forecasts can be way off. This is a risk because the pretty graphics and high time resolution somehow associate with precise forecasts.
About them getting the social security money in a lamborghini, lets not forget the other side of the coin: many of the original clan members never got a legal status in germany after immigrating. They were just "tolerated" and never could legally work (except when in prison). This is what created the clan economy in the 80s.
There is probably a deeper connection between the clans and the german law enforcement and (counter) intelligence agencies. That would explain the sometimes absurd leniency.
I can recommend the "Simple heuristics that make us smart" book by Gigerenzer, it's an insightful and entertainig read: for this book he and his co-authors put their money where their mouth is and invested on the stock market based on the most simple heuristics imaginable.
The Threema app was not breached. The "messages" themselves were not "extracted", it was a zip backup and password was most probably known. BTW the accomplice who handed it over had it in his custody for months, so it's weird it was even admitted as evidence.