4 p.m.: The National Weather Service said Thursday it’s likely that a tropical wave in the central Gulf of Mexico will develop into a tropical depression and stall just off the coast of southeast Louisiana.

The chance of the wave turning into at least a tropical depression and possibly a tropical storm is 70 percent, said meteorologist Christopher Bannan.

The wave could transform into a depression or storm in the next 24 to 48 hours, Bannan said.

Although there is a lot of uncertainty about where the system ends up, Bannan said the system is going to mean a lot of rainfall for south Louisiana starting as early as Thursday night and through the weekend and Monday.

There are tracks that have the system going “all over the place,” but many of the tracks have it heading to Louisiana, Bannan said

Even if the system does not turn into a depression or storm, it will still produce significant rain for southeast Louisiana, Bannan said.

“It’s disorganized now but it could develop real quick,” Bannan said.

Farther east, Hurricane Katia is making its trek across the Atlantic with little change in strength.

Katia had maximum sustained winds early Thursday near 75 mph (120 kph). The U.S. National Hurricane Center in Miami says some strengthening is expected and Katia could become a major hurricane by the weekend.

It’s centered about 1,065 miles (1,710 kilometers) east of the Leeward Islands and moving west near 20 mph (32 kph).

Jack Beven, a senior hurricane specialist at the hurricane center, says it’s too early to tell if Katia will hit the U.S., where parts of the East Coast are still recovering from Hurricane Irene.

The Associated Press contributed to this report.