Simul Weather, a volumetric C++ Cloud and Weather library, has just reached v1.2. Their website has some stunning examples of what it can do.
Simul Weather is a C++ library which generates weather system data and updates it in real time. Simul Weather creates volumetric cloud data, and provides realtime access to that data via a lightweight API. The cloud system generates pure volumetric data, it is cross platform and renderer-independent. The sample applications that come with the SDK show how realtime clouds can be rendered using the generated cloud data, in various graphics API’s.
