Cloud Booster

This scripts tries to emphasize the clouds by increasing contrast in the image highlights.

After applying the script you can strengthen or fade the effect by changing the opacity of the "Cloud Booster" layer.

If you need to hide the unnecessary parts of the "Cloud Booster" layer paint on the mask with black color (screenshot).

And vice versa, by painting on the mask with white color you can spread the effect to the yet untouched areas.