If it's the WxRisk guy, he is excellent (though a bit arrogant and lacking manners sometimes). I find reading his FaceBook site a bit tedious due to all the morons following him and asking stupid questions (actually, I find all of FaceBook tedious for about the same reason). He will usually give a brief score of how his predictions panned out, but nothing in detail on the Facebook page.
I have been writing weather software since about 2006, and rarely see retrospective data analysis or validation of models against results, at least not in public. There is some of that done at the research level, in a way that is not really useful to people on the street (i.e., they will focus on vorticity or some other high-level aspect of the weather).
To be honest, I think anything more than about 15-20 days out is throwing darts. Weather is too chaotic, too sensitive to changing conditions. The equations and models are highly sensitive to initial conditions, and when you start a model run on day 1 it can be wildly out of the scope of reality by day 7, never mind day 15 or 20. I follow some of the weather model discussions on the americanwx forum, and you see that all the time. Weather predictions have to continually restart models based on the latest weather observations to get the near range 1-3 day and 3-7 day forecasts, since previous longer-range runs have diverged from reality.