Sarah Rotman Epps – the Forrester analyst mocked for wildly underestimating how successful the iPad would be – has agreed to reset her projections for tablet sales, thanks in part to Apple’s recent quarterly financial report.

Epps’ comments have been posted to a blog on the Forrester Web site. Epps says Forrester will publish new numbers later this year, one they “have more supply-side and consumer data.”

In June Epps predicted that US consumers would buy 3.5 million tablet computers in 2010. As it turns out, Apple alone sold nearly that many itself (3.2 million), just in a single fiscal quarter.

Epps notes that Forrester’s numbers are calculated different from Apple’s – her projections were specifically for consumer sales in the U.S., while Apple reported worldwide sales numbers; she also quibbles over shipments versus final sales. Regardless, she admits that her initial estimates were off. Way off.

“A core tenet of Forrester is that our research is objective, transparent, and rigorous. We’re continually monitoring new industry and consumer data to inform our analysis. In this case, we missed the mark regarding our short-term forecast, so we’re revisiting our initial work,” she wrote.

Epps says the iPad has “a steamroller of momentum” thanks to strong consumer demand, which she attributes to Apple’s strong advertising campaign, high consumer awareness, and “the social influence” of other iPad buyers, who Forrester say are more likely to use Facebook and Twitter than average consumers.