When Democratic National Convention organizers announced they were moving President Obama's acceptance speech indoors tomorrow, Republicans were quick to accuse Democrats of using doomsday weather claims to cover up lackluster support for the president's re-election bid.

But today on the ABC News/Yahoo Democratic National Convention live stream,Yahoo News' Olivier Knox said the move doesn't necessarily mean a rainy day for Obama supporters.

"If you ask [the Obama campaign] about your ground game, you can't shut them up," he told ABC's Amy Walter and Rick Klein. "They brag about it, they talk about it at the drop of a hat. It's gonna make the difference in the election."

Obama's acceptance speech was originally pegged for the Bank of America Stadium in Charlotte, N.C., which holds about 74,000 people. Convention organizers said they had given out about 65,000 tickets as of this morning - but the speech switch to the Time Warner Cable Arena shut out thousands of would-be convention-goers.

"It seems unlikely, especially in North Carolina, that [the Obama campaign] would risk alienating volunteers for a 20 percent chance of rain," Knox said. "Do we really think that that was their big clever move?"

Even in a much smaller venue, the campaign's message should still play out for those tuning in at home, Knox added.

"The television pics are still gonna show a cheering crowd, a packed house," he said. "They're gonna get roughly the same television pictures that they would have had in the stadium."