if the pilot believes, on reasonable grounds
How are you going to assess the met conditions from 2-300nm away and honestly believe that you know mroe than the Met man who has written the forecast?? talking to your ops room or a company aircarft in the circuit and getting an accurate weather assessment t is about the only way you could believe "on reasonable grounds".
Agree with ftrplt that the reg only relates to landing minima not alt min.