The operations for low vis approaches are often very thoroughly defined. To keep things simple let's discuss about Cat 1 and the visibility required to see the runway.
The basic questions are:
1. Do you also use 1000m vis to relate to seeing runway at 160' agl. If not, why or any other method?
2. Do you discount the visibility reported if there is precipitation? If yes, how do you go about doing that?
Trying to make it simple. Thanks a lot for your inputs fellow aviators.
ps: Weather is probably one of the biggest enemy for pilots. The evaluation of it can be a matter of "art"