chipmeisterc
On the source of wind and met data, I use the US Gov NOAA source since (i) it is provided free of charge for non-commercial purposes; (ii) they provide a straightforward programming API for anyone to consume the data service. In terms of how "official" the data is, it's hard to say. The METARs and TAFs are numerically identical to what you find anywhere else, though the data say for UK might be delayed for some minutes (or worst case, an hour or so depending on a given day) compared with the UK met Office sources, but that's the only difference I've found. For winds aloft, I again use NOAA (specifically their global GFS forecasts). Again, it's hard to comment on how "official" this source is. However, given that these are forecasts, a margin of error is expected and acceptable. Interestingly, if you happen to check out the SkyDemon forum today, you will find an active thread relating to this very point. Someone is reporting that SkyDemon and Jeppesen give quite different values for winds for same position at same day/time. It's not clear what sources they use.
On disclaimers, yes I have the usual banner. Interestingly, even commercial software seems to carry the same sort of banner. The only one I've found that doesn't is JeppView: they warn about using out-of-date plates, but not about the overall use of their tool as long as you apply latest updates. All others I've seen, however, warn about the use of their tool fundamentally.
By the way, my main point wasn't about remembering how to use the met data per se, it was rather about the temperature/pressure corrections etc on the slide-rule side of the wizzy wheel. I'd frankly forgotten how to use that. Haven't used it since my PPL training over 30 years ago. I don't know any pilots who've used a wizzy wheel to calculate TAS since they last passed a test that needed it...