Any way to "hack" weather generation to manually force fog?

[CaptainRude91]

@CoastalGamer

How could you possibly have a single “visibility” setting as part of a preset? With a volumetric atmosphere, you would create these precise conditions by modifying the individual cells of the atmosphere. That’s what we really actually need.

Still don’t get it, I want to perform a CAT-II approach, with a RVR of 300 m which corresponds with seeing the approach lights at 100 ft decision height. Without a visibility slider, how do I set 300 m RVR? I’m a dumb pilot so as simple as possible.