Yeah radar extrapolation only works when storms are matured and moisture plumes are fairly predictable. Even then it's an unwieldy tool.
Edit: and I'm talking about eyeballed extraps, not the shit tools that they provide on weather.com and whatnot. Speaking of which, it's infinitely annoying that weather.com and Accuweather don't even let you loop anymore--like, as far as I'm concerned, you have to watch the radar morph into their totally useless future extrapolation.