My 2 bob worth:
- If it happens, and you can divert to a suitable alternate (not necessarily one you planned for) with the fuel you have left, then do it. If you have to divert now, then divert now, but if you have the fuel to continue to the destination then on to the alternate then do that. I would consider using some of the variable reserve if I had to, but as a last resort.
- If there's no straightforward way to divert, and even though wx is below Alt min, if there is still a reasonable chance of landing then carry on, but you better have a bloody good reason for continuing!
The way I read it is that you now need an alternate, and you must be able to make it to the alternate if the Wx at dest is ****e. Since you will only know if the dest is below mins when you get there, if you don't have the fuel to go to dest then to the alt, then you must divert straight away.
