Awesome! This is a lot simpler than me opening 3 tabs on Simply Noise to try to recreate a thunderstorm. The color transition is a nice touch too.

I'm not sure I would use the word chromotherapy specifically though, since it has some associations with psuedoscience (which isn't to say it's not nice to look at): http://en.wikipedia.org/wiki/Chromotherapy#Reception

One more thing: I think I'm experiencing a bug where individual sounds stop playing after a few minutes...