Is it possible to add a service like NEXRAD Weather, but with European coverage?
nexrad is a US government product, you would have to ask somebody in Europe.
In the PiAware maps, i mean. I think this integration is built by the makers of piaware, no? Not by a “US user”.
What datasource were you thinking of using?
T&Cs of that site make it a little trickier:
The following acts are expressly prohibited without prior written permission from the Originator: copying, redistribution, publishing, broadcasting (e.g. via the Internet) or making available the whole or part of the licenced data and products for any commercial use.
Also it needs to produce tiles suitable for plugging into openlayers - it’s not immediately obvious where they provide that.