MIAMI (Reuters) - The fifth tropical storm of the 2008 Atlantic hurricane season formed near a major oil and gas producing area of the northern Gulf of Mexico on Sunday, the U.S. National Hurricane Center said.

Tropical Storm Edouard, located around 95 miles southeast of the mouth of the Mississippi River by 6 p.m. EDT, was expected to come ashore at close to hurricane strength in a few days on the Texas coast, the Miami-based hurricane center said.

One of the computer models used to predict storm paths and intensities indicated Edouard could become a hurricane, with winds in excess of 74 miles per hour (119 km per hour), the hurricane center said. But its official forecast called for Edouard to top out at 60 knots, or 69 mph (111 kph).

Edouard's top sustained winds had reached 45 mph (75 kph) by 6 p.m. It was moving west at 6 mph (9 kph) on a track that would take it to the upper Texas coast by Tuesday.

Much of U.S. offshore oil production was in the likely path of the storm, which could also threaten Gulf Coast refineries.

Oil companies have been working to strengthen platforms to withstand hurricane-force winds and so storm level winds should not pose an undue threat.

A series of powerful hurricanes in 2004 and 2005, including Hurricane Katrina, toppled oil rigs and severed pipelines in the Gulf, where the U.S. produces almost a third of its crude and 15 percent of its natural gas.

A tropical storm warning, meaning tropical storm conditions could be expected within 24 hours, was posted from the Mississippi River westward to Intracoastal City in Louisiana.

A tropical storm watch, meaning storm conditions are likely to occur within 36 hours, was issued for the coastline west of Intracoastal City to Port O'Connor in Texas.

The six-month hurricane season, which began on June 1, has already seen two of its four storms strengthen into hurricanes. This July was the third most active month of July for storms since Atlantic hurricane season records began in 1851.

The early and unusually vigorous storm activity has given storm experts reason to believe that predictions for an above average season could turn out to be accurate.

Among the storms this year, Hurricane Dolly came ashore on the southern Texas coast on July 23, dousing the area with tremendous downpours but causing relatively little damage.

Hurricane Bertha grazed Bermuda and became the eighth longest-lived Atlantic storm on record before fading over the cool waters of the northern Atlantic while Tropical Storm Cristobal brought heavy rain to the Carolinas.

(Reporting by Michael Christie, additional reporting by Erwin Seba in Houston; Editing by Doina Chiacu)
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