@idefix37 Thank you for your input, and sorry for taking so long to reply.
Yes I understand what you're saying, and that's exactly what I do on my own account: mixing the various pieces of information and adding them together in order to come up with my own estimate of rain intensity and origin.
I wasn't aware that our Brazilian GFS, ECWMF and ICON data was less precise. This may explain the rain map information being so "spread out".
For instance, by the image below we should at this moment, have rain all around, but today no sign of rain where I stand on the Rio de Janeiro shore.
I know there are patches of storms travelling through - as I can see on the radar - and I know that where the wind is coming from there should actually be a little rain later in the day.
But if I were to judge by the rain map at this point, I should be wearing a full rain coat and umbrella just for going for a snack in the corner, instead we now see just fair weather, on a warm summer day.
Maybe someday we'll have better models for my region. Next time I am in Europe I am going to compare the efficiency of the rain maps over there!
Thanks my friend, happy sailing!