The Republican National Convention has delayed most of its convention proceedings until Tuesday afternoon because of Tropical Storm Isaac, which is expected to reach the Florida Gulf Coast starting late Sunday.

GOP officials said late Saturday that they would open the convention Monday morning and immediately recess until Tuesday afternoon.

That meant the roll-call vote that will make Mitt Romney's nomination official, planned for Monday night, will occur Tuesday, but the balance of the four days of political pageantry and speechmaking is expected to go on, squeezed into three days.

Officials from the Republican National Committee and Romney's presidential campaign decided unanimously Saturday afternoon to postpone proceedings after consulting with Florida Gov. Rick Scott, the U.S. Secret Service and federal, state and local emergency-management officials.

"Our first priority is ensuring the safety of delegates, alternates, guests, members of the media attending the Republican National Convention, and citizens of the Tampa Bay area," Republican National Committee Chairman Reince Priebus said.

The announcement made the GOP convention the party's second in a row to be disrupted by weather. Four years ago, the delegates gathered in St. Paul, Minn., but Hurricane Gustav, slamming the Gulf Coast, led to a one-day postponement.

Russ Schriefer, a senior strategist for the Romney campaign overseeing the convention program, said officials were working to move Monday's scheduled speakers onto programs for the next three days.

"We will absolutely be able to get our message out," Schriefer said.

It didn't appear the postponement would cost the Republicans much since the broadcast television networks had already said they would not be carrying any of Monday's events live.

Tropical Storm Isaac moved into Cuba on Saturday, after causing flooding and several deaths in Haiti. Forecasters say it could strengthen into a hurricane as it heads toward Florida. A hurricane warning has been issued for southwest Florida. Tampa is under a tropical-storm watch.

Material from The Associated Press is included in this report.