Blind River Slim does not play any musical instruments, I don't think, but he's reportedly a fan of both the blues and country music. He has taken a lot of harassment from the human denizens of Blind River over the years, many of whom have been known to shoot and eat groundhogs (some of whom were probably Slim's close relatives) so I think he may have been playing a little mindgame on them with that weather prediction just to get even. We'll have to wait and see.

By the way, although he is called "Slim", he isn't. Like any healthy groundhog, he is quite plump and nicely rounded.