SurveyUSA is no fly-by-night operation in polling. They've been around a while, they have a reputation, and a great many newspapers seem use them to poll local House races.
So we can't dismiss their continuing series of polls which look very good for Republicans, including this new Kentucky Senate poll for the Louisville Courier-Journal with Republican Randal Paul seeming to overwhelm Democrat Jack Conway.
The top line of this poll is just brutal: Paul 55, Conway 40 (MoE 4.2). With this poll we're at the range of a 96/4 split of lead probabilities. Paul wins 82% of Republicans, 32% of Democrats, and 56% of Independents, and I think it's that number for Democrats (double what I would expect) that is the difference between Paul a close race and this large margin.
I'd be curious to see that split for Democrats without the Likely Voter filter put in. I suspect among all registered Democrats it's closer to 15% for Paul and not this massive 32%. Barack Obama's "professional left" just isn't showing up this year, according to SurveyUSA's projection..
It also doesn't help Conway that the TEA party activists are so important this year. Those people who favor it (40%) back Paul 87-10. Neutrals (26%) also favor Paul 60-35. Those people with no opinion of the movement (9%) also support Paul 45-37. Conway has to find a way to win when he only leads among the 25% who oppose the TEA party, because those he wins 90-8.
This is a TEA party year, and Randal Paul is (a particular kind of) TEA party candidate, since some supporters of his father claim that they were the TEA party before anyone paid attention to the TEA party. So while some may question SurveyUSA's likely voter screening, I think this poll reading is definitely plausible.