I know our 3 get very 'strong' when they haven't been out walking for awhile. And sometimes it takes nearly the whole walk to get them to settle down and be the good kids I know they are. So part of it is probably because he's not getting out as much as he's use to.
With the bad weather and all, could you go to a pet store or some other business and walk around until he settles down and remembers how to behave? I try to get my 3 out to someplace with people at least once a week, just so that they remember the world does not revolve around them.
Shocking, I know, but sometimes they do need to be reminded of this.
Maybe the obedience class would help, not so much for the training, but just because it will get him out and interacting with others.