Fortunately, we can do better than simple noise texture. Back when I came up with noise, I also used it to build some other interesting functions. One of them was the turbulence function, which creates a kind of fractal texture.
Here you can see I’ve replaced noise with turbulence:
Now the texture looks a lot more like cloud cover. But it doesn’t yet have that delicate wind-blown wispy quality, and it doesn’t yet animate. You can see it live, together with the code that generates it, by CLICKING HERE.