Here is the HDR version done with TrueHDR app. You can faintly see some diffusion from the wet window, which actually makes it look more painterly.
Next I tried a faux infrared with Tiffen IR filter in PhotoFX. Believe it or not, we have rainbows like this on Moloka`i - it is called the land of the night rainbows. They happen during the full moon when it shines on the veils of upland rain. Sometimes they are pastel colors; more often I've seen the in varying shades of white. It is always awe inspiring to see the night rainbow.
Fnally, I combined the faux IR with the color shot and blended them in DXP, the double exposure app for this watercolor effect.