According to Trende, it's possible, but it's probably too soon to tell. For one, there have been some races in which the wave did not show major signs of developing in Senate races around late August:
Interestingly, Trende also claims that an election could be called a wave when a party gains six seats. I disagree with that, but his reasoning for the claim was useful.
He notes that while Republicans do have a chance in races like Alaska and Colorado because the Democratic incumbents are both under 50% in the polls, the undecided voters should not be expected to swing heavily against the incumbent.
While Trende drove home his arguments about how a Republican wave could happen, he did assess the claims that countered this, and found them to be plausible:
Overall, I thought this was a solid article.