TAMPA, Fla. — Mitt Romney's Republican National Convention sputters to life Monday with the lonely banging of a gavel in a mostly empty hall, then hits full speed on Tuesday, just as forecasters say Tropical Storm Isaac could reach hurricane strength and make landfall somewhere between Mississippi and New Orleans.

"Our sons are already in Tampa and they say it's terrific there, a lot of great friends. And we're looking forward to a great convention," Romney said as he prepared to rehearse his convention speech at a New Hampshire high school auditorium. He suggested there were no thoughts of canceling the gathering.

Romney said he hopes those in the storm's path are "spared any major destruction." Looking ahead, the former Massachusetts governor signaled that he and his wife Ann are close to finalizing their speeches.

Tom Del Beccaro, a California delegate and chair of the state GOP, predicted the one-day delay would supercharge the rest of the convention.

"I think there's going to be a lot of bottled up energy, and I think that's going to show," he said.

But Sally Bradshaw, a Florida Republican and longtime senior aide to former Florida Gov. Jeb Bush, was not so sanguine. "It's a mess all around and it's fraught with risk," she said. "It's not good for anybody — particularly the people impacted by the storm."

It was hardly the opening splash that convention planners had hoped for, and risked the juxtaposition of Republicans partying as the storm batters toward the gulf — almost exactly seven years after Hurricane Katrina devastated New Orleans.

"Obviously we want to pray for anyone that's in the pathway of this storm," Party Chairman Reince Priebus said Monday on NBC's "Today" show, "but the message is still the same: that all Americans deserve a better future and that this president ... didn't keep the promises he made in 2008."

The party hastily rewrote the convention script to present the extravaganza's prime rituals and headline speakers later in the week, and further changes were possible. Convention planners said Monday's speakers would be worked into the schedule later in the week.

"We're going to continue with our Tuesday, Wednesday, Thursday schedule," said Russ Schriefer, the chief convention planner.

As the threat of the storm to Tampa diminished, delegates focused on party message and the near-term task of making Romney the nominee and working to defeat Obama in November.

"There's a mission here," said Gary Harkins, a delegate from Brandon, Miss. "We have to nominate a candidate for president. Our mission is to save America from becoming a socialistic state."

Sen. Rob Portman delivered a message to the Ohio delegation that was echoed at meetings and news conferences all across Tampa — the Obama presidency has been a failure.

"It's time to stop blaming others and take responsibility," Portman said at a breakfast session. "There are families all over Ohio that are suffering as a result. He hasn't measured up to his own standards. "

The weather was a constant concern for some. Jeanne Luckey of Ocean Springs, Miss., whose family lost a beachside home to Hurricane Katrina, said friends were helping secure their inland home for Isaac.

"It's a very busy time, certainly, but we've got to take care of the business of the party and make sure we get Governor Romney nominated," Luckey said. "We have a lot of work to do between now and November."

Vice presidential candidate Paul Ryan decided to head to Florida on Tuesday, a day later than expected. He was in his hometown of Janesville, Wis., on Monday putting final touches on his convention speech and addressing students at his former high school. Signs at the school proclaimed him "The pride of Janesville."

The storm was a complication, at best, for a party determined to cast the close election as a referendum on Obama's economic stewardship and Romney as the best hope for jobs and prosperity.

The concern was two-fold: that Tampa, hosting thousands of GOP delegates, would get sideswiped by the storm; and that it would be unseemly to engage in days of political celebration if Isaac made a destructive landfall anywhere on U.S. soil.

"You can tone down the happy-days-are-here-again a bit," said Rich Galen, a veteran Republican consultant in Washington. "Maybe you don't have the biggest balloon drop in history."

In Washington, aides said Obama was being updated at the White House on the storm. He was still planning his two-day campaign trip to Iowa, Colorado and Virginia, beginning Tuesday morning.

In a boost to Obama's convention next week, Florida's former Republican Gov. Charlie Crist was added as a speaker. Crist had announced on Sunday that he was endorsing Obama, saying he was the correct choice and criticizing his former party for its move to the right.

For all the weather concerns, a mix of partly sunny skies, fast-moving clouds and occasional rain covered Tampa at midmorning Monday as the outer bands of the tropical storm delivered unsettled conditions.

Traffic was light as streets around the arena were blocked off and security patrolled the area.

Under the reworked convention schedule, organizers planned a pro forma opening Monday afternoon to last just 10 minutes. Priebus was to gavel the convention to order, then immediately recess. Few delegates were expected to attend. In the only bit of convention-hall theater, a debt clock was to be set in motion, to tally the nation's red ink during the convention.

Speakers who had been scheduled for Monday were to start making the case against Obama, under the day's theme, "we can do better." That theme now will be threaded through the following three days, Schriefer said. "Even though the days will be abbreviated, I absolutely believe we'll be able to get our message out."

The roll call of state delegations affirming Romney as the party's nominee now is to unfold Tuesday, an evening capped by speeches from Ann Romney and an assortment of GOP governors. Ryan gets the prime-time spotlight Wednesday, and Romney closes out the spectacle Thursday night, his springboard into the final leg of the contest. That's all if the storm brings no further complications.

So far, many taking the shakeup in stride. "People are pretty resilient, and people knew going in that there were some weather issues," said Pat Shortridge, the Minnesota state GOP chairman, from Lino Lakes, Minn. "I don't think it's dampened enthusiasm."

Louisiana Gov. Bobby Jindal, scheduled to speak on Wednesday, said he wouldn't leave Louisiana "as long as we're in harm's way."

Weather was recognized as potential trouble when Republicans chose to hold their convention in politically vital Florida during hurricane season, a decision made well before Romney locked up the nomination. And it's clear that memories of Hurricane Katrina, and the failure of a Republican administration to respond effectively to its Gulf Coast devastation in 2005, are hanging over Tampa now. Republicans have been so sensitive to the political risks from natural disasters that they delayed the start of their national convention by a day in 2008, when Hurricane Gustav bore down on the Gulf, far from their meeting in Minnesota.

Polls find a tight race, and it's one that is likely to be settled in a small number of battleground states.

An estimated $500 million has been spent on television commercials so far by the two candidates, their parties and supporting outside groups, nearly all of it in Florida, North Carolina, Virginia, New Hampshire, Ohio, Iowa, Colorado and Nevada. Those states account for 100 electoral votes out of the 270 needed to win the White House. Republicans hope to expand the electoral map to include Pennsylvania, Michigan, perhaps Ryan's Wisconsin and even Minnesota, states with 68 electoral votes combined.

All four are usually reliably Democratic in presidential campaigns. Yet Romney has a financial advantage over the president, according to the most recent fundraising reports, and a move by the Republicans into any of them could force Obama to dip into his own campaign treasury in regions he has considered relatively safe.

Republican office-holders past and present said the economy is the key if Romney is to expand his appeal to women and Hispanic voters.

"We have to point out that the unemployment rate among young women is now 16 percent, that the unemployment rate among Hispanics is very high, that jobs and the economy are more important, perhaps, than maybe other issues," said Arizona Sen. John McCain, who lost to Obama in 2008.

The Romney campaign released a Spanish-language radio ad with son Craig's testimonial to his father.