P3D v4 Set Weather | Raduis problem

i set the weather at small airports with set mode custom and it works great
if i select KSFO as airport the araduis become horroble
when you appraoch you have a clear sky, but once you arrive, there is rain :/

i set the mode to gloabl() but the weather won't be set correctelly as it changes the winds and QNH and many values

any help extanding the set weather by metar on cutom raduis PLZ

thnx in advance