Now I remember why I stopped looking at my ATPL books
You must be regretting that decision now. Just look at how ATPL met theory would have improved your flight planning. You would have been so brilliant at weather data interpretation - so much better than the professionals who do it all day long - that with a tephigram or two you would have never needed to look at another TAF ever...
I have yet to find an example of weather theory which is actually useful to flying. The really useful stuff is knowing which websites to hit and how good or crap the data is likely to be, knowing about practical structural icing stuff, and practical stuff like that. All the stuff about Hadley cells is just a load of crap. About as useful as a radar altimeter when at FL150 over Dover.
Internet? That is an unapproved data source. Can't use that!!