I have El Capitan, soon to be Sierra.
The unit is an all in one unit, that is the 8GB of Ram can’t be improved on. The chips are soldered to the board and there is no way to actually get into the board without destroying the computer.
Running dual platforms are possible, but not with 8 GB of Ram.
The weather software that is available is very limited for the OSX system. Sure the media always show Mac computers, but unless it is for a few games, media and net… it ain’t built for the scientific community per se.
Take WD, it works, but not to the same level of performance as the PC version, Apple has its moments,
It isn’t a PC. So what can’t it do. It can’t do a lot.