Organizers for the party's three-day national convention here this week announced Wednesday they were moving President Barack Obama's big Thursday night speech from a giant outdoor stadium to a much smaller indoor arena because of a chance of thunderstorms.

Mother Nature also hammered the Republican convention last week in Florida with peripheral rain and wind from Hurricane Isaac.

"We have been monitoring weather forecasts closely and several reports predict thunderstorms in the area, therefore we have decided to move Thursday's proceedings to Time Warner Cable Arena to ensure the safety and security of our delegates and convention guests," the fete's organizing committee CEO Steve Kerrigan wrote in a statement.

But Obama's critics say the move isn't weather related and smells like a political ploy to avoid the embarrassment of potentially speaking to a less-than-packed Bank of America stadium, which seats 74,000.

The Time Warner Cable Arena seats 21,000.

Earlier reports suggested students and supporters were going to be bused in from around the state, but campaign officials said they were not worried about filling the venue and reportedly had a 19,000-strong waiting list.

Republicans, though, aren't buying it.

"After promising to speak at Bank of America stadium rain or shine, Team Obama is moving inside," GOP party chairman Reince Priebus tweeted Wednesday after the announcement.

"Troubles filling the seats?"

Campaign officials say they had 65,000 people -- organizers, volunteers and supporters -- expected to attend, in addition to convention delegates and media, but now they'll have to turn many away.

Speaking with a reporter in Virginia Tuesday before the change was made, Obama said his job was to focus on the message, not the medium.

"My main goal is not to worry about the logistics of the convention," he reportedly said. "My main goal, I think, is to communicate to the American people how we can move forward."

The Democratic National Convention wraps up Thursday after Obama formally accepts the party's nomination for the November presidential election.