I think his Rasmussen numbers will bounce back. I don't think they'll hit the 60's any time soon, but I don't think people are completely fed up with him just yet. It's very possible that yesterday was an outlier.
Lookng at the trends, it does seem to be more partisan than the previous days.
Agreed. Plus look at what's listed: "Strongly Approve" and "Strongly Disapprove". It looks like it only has the polls of people who have strong convictions about their opinion about Obama and not fencesitters. The cumulative "Agree" or "Disagree" percentages could be higher or lower.