I like this idea man. I see what you’re saying about the rain though. I kind of think this particular rain effect just doesn’t work for some reason. Maybe another would, or messing with the opacity of the effect.

If the rain doesn’t work, maybe you could just add distant sounds of thunder instead.
I think the color grading looks cool, though the horizon does seem a little bright. I think that kind of gives the effect away a little bit since you can’t really do much about the sky being clear despite how stormy the mood feels now.

Totally my opinion, but I think adding thunder sounds, and maybe trying to darken the sky somehow, might be more effective than adding rain in the background.