I've been running AWIPS II for several weeks now, and it's actually surprisingly functional. Lots to go, but better than I expected. As far as data, I discovered by accident that if you configure and install the EDEX server, it will actually pull in some GRIB data over either FTP or HTTP. I had previously not installed the EDEX server portion, but played around with it. I left it running, and the next day, I had filled my entire disk (~2TB) because EDEX was ingesting GRIB and not cleaning out the old data. You might be able to play around with some things and maybe run a stripped down EDEX to pull in data? Just a though.
Personally, I've been using the edex-azure unidata server, but it is limited to .edu domains.
EDIT:
I should also note that this is on a rather beefy linux desktop I use for work, so results may not be the same for VM or smaller machines.