“Alabama is postured for a coastal wind and water event, but the key will be preparation of our citizens,” said Brian E. Hastings, the director of the Alabama Emergency Management Agency. “If you live in the coastal counties, especially in surge- and flood-prone areas, it is imperative that you get to a safe place by early afternoon and stay there through Wednesday morning.”

Many schools closed Tuesday morning, and some districts announced that their classrooms would also be empty on Wednesday. The Mississippi Gaming Commission ordered coastal casinos to close, and the authorities imposed curfews in some places.

The city of Biloxi, Miss., ordered its harbors and marinas evacuated, affecting about 300 vessels. But local leaders were plainly trying to avoid prompting any wide panic.

“We’re asking people to do the same things that we’re doing: prepare,” Mayor Andrew Gilich said in a statement. “There’s no reason to be alarmed. We’re being told to expect rain and wind, and we’re preparing accordingly. We expected our citizens to be doing the same.”

It could have been a lot worse

Two things have kept Gordon from gaining more strength, according to Michael Brennan, chief of the National Hurricane Center’s hurricane specialist unit. There is plenty of dry air over the gulf, he said, as well as wind shear, meaning winds that are blowing one way at one altitude and a different direction or speed at another. Dry air tends to suppress the warm updrafts that are characteristic of hurricanes, and wind shear can disrupt the storm’s structure.

“It’s over very warm water,” Dr. Brennan said about Tropical Storm Gordon. “If it was in an environment where there wasn’t wind shear, it would have strengthened more than it has.

New Orleans watches warily

Although New Orleans, the economic and cultural center of the coast, is not expected to suffer a direct strike, the city’s new mayor, LaToya Cantrell, issued an emergency declaration and a voluntary evacuation order for certain neighborhoods. A handful of Louisiana parishes handed out sandbags to residents.