TAMPA, Fla. — The prospect of a major storm blowing through the Gulf of Mexico toward New Orleans upset the tight choreography of the Republican convention on Sunday, straining the party’s highly scripted plans for showcasing Mitt Romney and raising the possibility that news media attention could shift elsewhere.


With the Tropical Storm Isaac now forecast to roar northwest past Tampa on Monday and Tuesday, officials scrambled to reconfigure what had been a four-night schedule into three and to make contingency plans for further changes, and news organizations.


But even if the storm largely bypasses this region, it holds the risk of creating an uncomfortable split-screen image, especially if it continues barreling toward New Orleans. “We’re watching very closely,” Gail Gitcho, communications director for the Romney campaign, said Monday morning. 


Major news organizations, including NBC and ABC, began sending some of their top correspondents to New Orleans. The governors of Louisiana, Mississippi and Alabama declared states of emergency in anticipation of the storm.


Republicans were wary of the optics of television coverage split between the revelry and partisanship surrounding Mr. Romney’s nomination and the threat of the storm making landfall in Louisiana or Mississippi seven years to the week after Hurricane Katrina left an American city in ruins.


At the very least, Mr. Romney’s image makers were coming to terms with sharing the news spotlight with the storm just as they were hoping their gathering would give their candidate the exposure he needs to surge ahead of President Obama.


Instead of focusing on the convention and on Republicans descending on the swing state of Florida, local news outlets were giving constant and increasingly urgent updates on the storm’s path. Network correspondents here were girding to be reassigned from convention coverage to hurricane coverage, heavy rain gear and all.


En route from his vacation home in Wolfeboro, N.H., on Sunday for a speech rehearsal, Mr. Romney stayed optimistic, telling reporters who asked him if he was concerned, “It’ll be a great convention.” But, he said: “I hope everybody’s fine there. I’m concerned about the people that are going to be affected by it.”


Fearing high winds and pelting rains, Republicans had already canceled most of Monday’s formal events and they could not rule out a delay on Tuesday. Still, a sense of celebratory relief pervaded at the welcoming table at Tampa International Airport as conventiongoers welcomed the news that the worst of the storm would largely bypass Tampa.


A steel-drummer played sunny melodies as a greeter, Debbie Marvin, happily shared images of the storm’s track on her iPad with streams of arriving delegates. Ms. Marvin said that Floridians knew when a real hit was coming and that she never thought it was this time.


“They should ask the locals about the weather,” she said,


That was before it became clear that the storm was threatening to hit near New Orleans as a Category 2 hurricane packing winds of 100 miles an hour, and before some residents of Plaquemines Parish, which includes portions of New Orleans, were ordered to evacuate their homes on Monday.


It is the second consecutive time Republicans have had their conventions disrupted by the August storms. Faced with a similar prospect of a Gulf Coast hurricane four years ago during his convention in Minneapolis, Senator John McCain canceled the first night of ceremonies.


“Images of revelry by Republicans at a time of suffering by other Americans — no party wants those optics,” said Steve Schmidt, who helped lead Mr. McCain’s 2008 presidential campaign. “You have terrible awareness of all that stuff.”


The suffering from Hurricane Katrina was still fresh then, with the storm representing to Democrats a failure of compassion and competence by the Bush administration.


But Tropical Storm Isaac threatens to fit just as neatly into that kind of narrative, with Mr. Obama seeking to paint Mr. Romney and Mr. Ryan as opposed to a government that takes care of its most vulnerable and intent on cutting just the sort of federal services that can be critical in emergencies.


On Sunday afternoon, the White House sent out a statement detailing Mr. Obama’s call to the Republican governor here, Rick Scott.