Actually, I think unreal weather has a bug, that might be able to be fixed. I wrote the developer. It seems that you can adjust the snow and other settings while using the mod, but only initially when the mod loads. Once the metar changes/refresshes , you won’t be able to.
The sliders will move but if you let go it returns to the normal that Unreal is using. I think this is a bug or something that might be able to be fixed because if you change out of unreal to “clearskies” and back to unreal while in the sim, the sliders will work once again, until a new metar refresh.
I am no programmer, but I can see it as something that can be fixed probably.