Republicans are set to descend on Florida as Mitt Romney's team works to cram four days of events into three after the threat of Tropical Storm Isaac forced the soon-to-be nominee to cut short his national convention.

The convention will convene only briefly on Monday, then immediately recess until Tuesday afternoon.

As aides in Tampa scramble, Romney is taking a rare day off the campaign trail at his lakeside vacation home in New Hampshire, receiving updates on the storm and making final preparations for the Thursday speech with which he will accept his party's presidential nomination.

"The safety of those in Isaac's path is of the utmost importance."—Former Massachusetts Gov. Mitt Romney

"The safety of those in Isaac's path is of the utmost importance," Romney tweeted after Republican officials announced they had called off Monday's convention proceedings. "I applaud those in Tampa making appropriate schedule changes."

As many as 70,000 visitors are expected in Tampa for the confirmation of Romney as the party's choice for U.S. president in the November election.

Tampa remains calm

"People are going about their normal business. It's not a case of batten down the hatches, but they are stocking up on water," said the CBC's Andrew Davidson, reporting from Tampa on Sunday morning. "The wind speeds are not that high and there is no rain."

Forecasters say Isaac could grow into a hurricane by the time it reaches the Florida Keys late Sunday. Around mid-morning, a hurricane watch was extended along the Louisiana coast to include the New Orleans area ahead of Isaac.

The outer bands of the storm were lashing southern Florida on Sunday morning and forecasters said there was a high risk of tornadoes and sinkholes. Isaac is expected to spare Tampa a direct hit, but heavy rains and high winds were still expected Monday.

Because of possible storm surges and flooding Isaac could bring, convention organizers said they were making contingency plans to move delegates who have been booked into beachfront hotels to other locations if necessary.

People in Tampa were stocking up on bottled water ahead of the storm.People in Tampa were stocking up on bottled water ahead of the storm. (Andrew Davidson/CBC)

They indicated the schedule shift also was meant to prevent overburdening emergency response personnel at the height of the storm.

The GOP made the announcement late Saturday, saying that while the convention would officially be gaveled into session on Monday as scheduled, events would be postponed until Tuesday.

With Isaac boring down on the coast, President Barack Obama, who was spending the weekend at the Camp David presidential retreat in Maryland, dispatched the Federal Emergency Management Agency to establish a command center and move more resources into the state.

PHOTOS Preparing for the 2012 U.S. Republican National Convention

Republicans hope to use this week's convention to cast Romney as a determined leader with the know-how to fix the country's economy. They also want to introduce him as a family oriented figure to counter the image of him as a ruthless businessman as Democrats have sought to brand him.

Romney and his wife, Ann, looked to show off the more personal side with a joint interview airing Sunday.

"I wish everyone could see him how I see him, because as a mother, I've seen him, how compassionate he's been with me, as a wife and my raising these small children and how he always valued my work as being more important than his," Ann Romney said in the "Fox News Sunday" interview taped at the family's summer home in New Hampshire.

Obama charting course before Democratic convention

While the Romneys revelled in their convention, Obama was due to travel next week to college towns in Iowa, Colorado and Virginia to court young voters and college students.

The president's nomination for a desired second term is to come a week later in Charlotte, N.C., during a Democratic convention beginning Sept. 4, right on the heels of the Republican convention.

Vice President Joe Biden scrapped a planned campaign trip into Florida that was to counter the start of the GOP convention.

The candidate described his wife as his "best friend, obviously, and my counsellor throughout my life," according to an advance transcript.

After a near-constant travel schedule since he was announced as the GOP vice presidential candidate, Ryan was also taking a rare break. Following a Saturday evening fundraiser in Manchester, N.H., he returned home to Janesville, Wis. Aides said Ryan planned a quiet Sunday. Then, before flying to Florida, he was to appear at a Monday rally in his hometown that was likely to offer him a hero's sendoff.

A few of Romney's former presidential rivals were holding events of their own in Tampa. Herman Cain and Minnesota Rep. Michele Bachmann — both have endorsed Romney — were appearing at a joint event. Texas Rep. Ron Paul, who hasn't conferred his blessing on the presumptive nominee, was anticipating thousands at a University of South Florida rally.