By Edward Linsmier, Getty Images
Earl Harris, second from right, and Terri Harris, second from left, fill sand bags ahead of Tropical Storm Isaac on Sunday in St. Pete Beach, Fla.
By Dennis Cauchon, USA TODAY
Tropical Storm Isaac now has a chance of striking New Orleans as a hurricane on Wednesday, the seventh anniversary of Hurricane Katrina, according to one computer model at the National Hurricane Center.
The federal center put New Orleans on a hurricane watch at 2 p.m. ET Sunday and upgraded it to a more serious hurricane warning at 5 p.m. ET. The latest hurricane warning covers a large swatch of the Gulf Coast, from Louisiana to the Florida Panhandle.
The likelihood of a repeat strike on the 2005 storm's anniversary is far from certain. Other models show the storm going farther east - to the Mississippi and Alabama Gulf coasts, which were also slammed hard by Katrina. Biloxi, Miss., is near the center of where the various computer models predict Isaac will strike.
It will take another day or two to get an accurate fix on where Isaac will hit land, said National Hurricane Center meteorologist James Franklin.
Isaac, now a powerful tropical storm, is expected to gain hurricane power in the next 24 hours. The hurricane center reported that the storm had sustained winds of 60 miles per hour Sunday.
The storm was moving at 18 miles per hour and its center is expected to roll over the Florida Keys late Sunday afternoon. Storm winds were already battering the islands. Rainfall of 4 to 8 inches is expected.
Key West, Fla., was under a hurricane warning - meaning hurricane winds were expected in the area - as was Bonita Beach, Fla., on the southwest Gulf Coast.
Hurricane Gustav in 2008 was the last major hurricane to affect New Orleans. It came ashore about 60 miles south of the city. Many residents had evacuated, and flooding was minimal.
Gustav did not have the extraordinary storm surges that Katrina did in 2005 or deadly Hurricane Camille in 1969. So far, Isaac has not been forecast to have the enormous storm surges that could cause similar flooding.
The new predicted course is a sharp shift to the west and means the heart of the storm will avoid the Republican National Convention in Tampa. Republicans canceled the first day of the convention, Monday, to avoid the storm.
The Port of Miami, Port Everglades and the Port of Palm Beach all closed Sunday. Miami-Dade County locked down all its drawbridges. Palm Beach County opened three general evacuation shelters. Key West opened shelters and will close City Hall on Monday.
The center of Isaac made landfall Saturday near the far-eastern tip of Cuba, downing trees and power lines. At least seven people were reported dead in Haiti, including a 10-year-old girl who had a wall fall on her. The Haitian government also reported "considerable damage" to agriculture and homes. Nearly 8,000 people were evacuated from their houses or quake shelters and more than 4,000 were taken to temporary shelters.
In Tampa, the roll call of the states, which is the vote on the nomination of Mitt Romney, will happen Tuesday, a day later than planned. The convention is trying to accommodate all the previously announced speakers in a compressed schedule - which may mean earlier starts for the remaining three days.
"I think we will absolutely be able to get our message out," said Russ Schriefer, a strategist for the Romney campaign.
Contributing: Gregory Korte in Tampa; Doyle Rice