It is quite odd actually and it doesn't bode well for him that he's losing the most liberal counties like Cuyahoga by massive margins. He's also losing consistently 55-45 to 65-35 in many of the rural counties. He'll likely get no help in Hamilton or Butler which are considerably more conservative. His best bet is to take college voters but what stood out early in Michigan was that he was winning the rural counties really consistently... Michigan is more liberal than Ohio at the margins, despite possessing what was a perceived advantage in the minority vote for Clinton (specifically in Wayne Cty).
I think what you're seeing in Ohio, Florida and NC is that Hillary is the FAR more palatable candidate for the more moderate/conservative and generally less liberal elements of Democrat voters - they probably also don't know Bernie that well. The rural county votes in those states are NOT indicative of her getting strong black vote but instead, indicative of strong white voting.
You'll look back at this night as the moment when Bernie's campaign effectively came to an end.