OK, if interpolation in AW works, then something other in AW is wrong, because only FG AW generates discontinuity and only in live METAR mode.
Well, your own sentence contradicts you, because obviously AW has no rapid changes when you run it in offline mode despite using the same set of interpolation routines.
So your logic is flawed - if the same routines handle generated data fine but fetched data not, the logical conclusion is that the difference has to do with how online data is fetched and thus differes from generated data. But again, that's been explained in a dozen of threads in detail, and just because you insist in ignoring the info given to you I won't bother to repeat it.
Yes other programs use the same data and don't exhibit the phenomenon.
How do you know they fetch METAR the same way (i.e. fetch only the nearest station whatever it is, and only if within a given distance)? I don't think that's a reasonable assumption (clearly it's not what I would do if I were interested in flying live METAR because, well, it causes all the trouble).
Well saying it's the Iinput data is just a copout.
Whether you like it or not, it's what the problem is. But you've so far been very successful in diverting attention from the real issue, and as a result nobody has tried to fix the real issue - congratulatoins (it's been known for nearly a decade, but I've also made clear repeatedly that I am supremely not interested in working on any functionality that requires FG to be online - be it MP or live weather - because I usually never let FG go online in the first place, so... somebody else has to do that kind of work).
But yeah, I know exactly how to do the algorithms for weather synchronization over MP or smooth live weather fetching (and have also sketched these in different threads) - that however doesn't make me responsible for implementing a feature you want and I do not.
Again - if you don't want things 'as they are' and don't want to get your sleeves up and code a change - use offline weather (apparently that works for you) - or do not use FG and be happy with whatever other sim you like.
But the takeaway message is - stop random finger-pointing at systems you do not understand. Assigning the blame to a system that isn't actually responsible doesn't help anyone, it just makes life worse for everyone.
Thus it should be considered if the interpolation should have a higher minimum transition time / distance so that it does not generate rapid (although smoothed) transitions that are most likely not really there.
Yawn...
Actually that time is in (and has been from the beginning, I actually know the math of interpolations really well...) - the issue is that there's also a maximum time you have that's given by the requirement that you need the weather reported by the METAR right at the station - if you set the timescale too long, you may end up landing in winds that have not adapted at all to what the weatherman said. So by easing one issue you always make the other issue worse and vice versa.