Some things are easy to explain. No one likes Republicans, and in CT, no one likes steroid promoter Linda! McMahon (R). No kidding.
While this internal GQR (D) poll (via Politico) has a 15 point lead, confirming PPP and others (and blowing away the Q-poll that claimed the race was tied due to a flawed LV model), the important thing is the internals. Look at Linda!'s fav/unfav in this and every other poll.
Linda!'s unpopularity is, no doubt, due to a combo of pushing steroids in an earlier life and her trying to buy the election now. Her unforced error on the minimum wage hasn't helped her any (do you know what the CT minimum wage is yet, Linda!?)
That unfav number makes it awfully hard to play attack dog with Dick Blumenthal, who people like and know. And that makes it hard to see how she wins.
Dick Blumenthal's campaign page.