NEW ORLEANS – With Gustav approaching hurricane strength and showing no signs of veering off a track to slam into the Gulf Coast, authorities across the region began laying the groundwork Thursday to get the sick, elderly and poor away from the shoreline.

The first batch of 700 buses that could ferry residents inland were being sent to a staging area near New Orleans, and officials in Mississippi were trying to decide when to move Katrina-battered residents along the coast who were still living in temporary homes, including trailers vulnerable to high wind.

The planning for a potential evacuation is part of a massive outline drafted after Hurricane Katrina slammed ashore three years ago, flooding 80 percent of New Orleans and stranding thousands who couldn’t get out in time. As the region prepared to mark the storm’s anniversary Friday, officials expressed confidence those blueprints made them ready for Gustav.

“There are a lot of things that are different between now and what we faced in 2005 when Katrina came ashore,” said U.S. Homeland Security Secretary Michael Chertoff, who was flying to Louisiana to meet with New Orleans Mayor Ray Nagin and Gov. Bobby Jindal. “We’ve had three years to put together a plan that never existed before.”

With Gustav still several days away, authorities cautioned that no plans were set in stone, and had not yet called for residents to leave. Projections showed the storm arriving early next week as a Category 3 storm, with winds of 111 mph or greater, anywhere from the Florida Panhandle to eastern Texas. But forecasts are extremely tentative several days out, and the storm could change course and strength.

At a news conference Thursday, Nagin said an evacuation order was likely in the coming days, but he didn’t expect officials to tell people to leave before Saturday.