Speculation that Palin might use the Labor Day weekend event to declare her candidacy has ramped up on cable news and the conservative blogosphere, but RCP has learned from sources close Palin that an official announcement is unlikely at that time.

Still, Palin’s speech is expected to offer more clues about whether she will jump into the race sometime in September, as some of her public comments and behind-the-scenes actions over the past several months have suggested is possible. And a core group of self-appointed volunteer organizers hope that the Indianola shindig will be one of the best-attended events of the presidential campaign season to date.

“It’ll be big,” vowed veteran Iowa GOP grass-roots organizer Susan Geddes, who helped launch the Palin event.