On the eve of Hurricane Katrina's third anniversary, a nervous New Orleans watched Wednesday as another storm threatened to test everything the city has rebuilt, and officials made preliminary plans to evacuate people, pets and hospitals in an attempt to avoid Katrina-style chaos. Forecasters warned that Gustav could grow into a dangerous Category 3 hurricane in the next several days and hit somewhere along a swath of the Gulf Coast from Florida to Texas - with New Orleans directly in the middle. Taking no chances, city officials began preliminary planning to evacuate and lock down the city in hopes of avoiding the catastrophe that followed the 2005 storm. Bobby Jindal declared a state of emergency to lay the groundwork for federal assistance, and put 3,000 National Guard troops on standby. If a Category 3 or stronger hurricane comes within 60 hours of the city, New Orleans plans to institute a mandatory evacuation order. Unlike Katrina, there will be no massive shelter at the Superdome, a plan designed to encourage residents to leave. Instead, the state has arranged for buses and trains to take people to safety.