I agree with Jessicayla about the vignette and I understand her observation that the sky looks like night but not storm particularly.
My observations: gloomy can be beautiful and you have a good start, but treat this like you would a scene of a sunset. In other words, bring some light and contrast into the muddy foreground and make it really stand out and look luscious. The rock is also getting lost. It can have some ghostly glow, maybe just a slight color shift and some brightening (which color sift can sometimes do). Finally, I would consider changing the sky altogether to something a bit more foreboding. You can paint darker areas on a layer above, use a gradient and alter the results, etc.
Those are my thoughts. Add some drama to the scene.
Here's kind of what I had in mind, not perfect but a sort of quick edit: