NEW ORLEANS (AP) — Tropical Storm Edouard formed in the Gulf of Mexico on Sunday, and forecasters expected it to bring high winds and several inches of rain to the coasts of western Louisiana and eastern Texas.

Forecasters made Edouard, packing 50-mph sustained winds, the fifth tropical storm of the 2008 hurricane season. They expected the storm to strengthen and said it could reach near-hurricane strength by the time it made landfall in Texas sometime Tuesday morning.

A tropical storm warning was in effect from the mouth of the Mississippi River to Intracoastal City, La. That meant tropical storm conditions were expected in the next 24 hours. The warning area did not include New Orleans. A tropical storm watch extended west to Port O’Connor, Texas.

The Gulf’s warm waters offer very favorable conditions for Edouard to strengthen in coming days, said Rebecca Waddington, a meteorologist at the National Hurricane Center in Miami.

She urged residents in the path of the storm to continue watching it and warned that tropical storms can still be very powerful.

At 7 p.m. Edouard’s center was located about 90 miles southeast of the mouth of the Mississippi River and about 415 miles east-southeast of Galveston, Texas, moving west about 4 mph.

While southwestern Texas still recovers from the damage of last month’s Hurricane Dolly, the other end of the state’s coast braced for several inches of rain and a potential storm surge.

Krista Piferrer, a spokeswoman for Texas Gov. Rick Perry, said Sunday that state emergency management officials were getting updates through conference calls with the National Weather Service.

‘‘Because it might make an impact to the Texas shore, we’re looking at activating resources, including search and rescue and maybe military forces,’’ including the Texas National Guard, Piferrer said.

State emergency management officials were also conducting conference calls with officials from communities along the Texas coast, from Port O’Connor to Port Arthur, that could be affected by Edouard.

Rainfall of 1 to 2 inches was expected in coastal Louisiana. About 2 to 4 inches was possible in southeast Texas, with isolated amounts up to 6 inches. Tides of 2 to 4 feet above normal levels were expected in parts of the warning area.

In Louisiana’s Terrebonne Parish, emergency director Jerry Richard said he had called in staff members to determine if the parish’s low-lying areas could be affected by flooding.

They planned to monitor the storm through Sunday night. State emergency officials did not immediately return calls seeking details on emergency plans.

Many of the Gulf’s offshore oil and natural gas drilling platforms sit in the storm’s path.

Shell Oil Co. had not made any operational changes Sunday afternoon, but company officials were watching the storm closely, spokesman Shawn Wiggins said.

ExxonMobil Corp. had not evacuated any workers or cut production by Sunday evening, but the company was preparing its platforms for heavy wind and rain and considering whether to evacuate some workers, spokeswoman Margaret Ross said in an e-mail statement.