Are you wanting to get rid of the noise in the image?
Try a median filter or a really light blur. Blurring clouds is risky since they don't really have any highlights or much detail to begin with.
Surface blur filter is a pretty light blur.
After you blur it a bit, try bringing back some subtle detail by sharpening it using the high pass method. Play around a bit with the blending modes of the high pass layer. I like to use soft light as the blending mode with 30-50% opacity on the layer for high pass, but many people like the screen mode for this method.
If you really want to make it pop, examine the channels in the image and choose the one with the most contrast and least noise and load it as a selection. Apply the sharpening to the selection and play with the blending modes again.
As always, start out with some color correction, levels-curves.
Then end it with some sharpening.