Fade Clouds Along Horizon

I have a cloud dome and I’d like to fade the clouds, but only long the horizon when they get low enough.

Here’s a picture of Oblivion, this is kind of what I’m trying to accomplish.

How would I go about doing this? Would it be shader related? If so, how can you detect real world angles? I was thinking it could be done when the dome reaches a certain angle the shader would just fade the texture, but I’m not really sure how I would do this.

Any suggestions or help would be greatly appreciated.

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send my that script if you can please…i need this