VIDEO: Tropical Storm Looms Off U.S. Coast

The fifth tropical storm of the 2008 Atlantic hurricane season has formed on Sunday.

Tropical Storm Edouard moved across the northern Gulf of Mexico on Monday and has a 20 percent chance of hitting the Texas-Louisiana coast as a hurricane, U.S. forecasters said.

Edouard, the fifth tropical storm of the 2008 Atlantic hurricane season, had maximum sustained winds of 45 mph (75 kph), the U.S. National Hurricane Center said in its 2 p.m. (1800 GMT) report.

The storm has a 20 percent chance of reaching hurricane speeds of 74-mph (119-kph) before it makes landfall on Tuesday morning near Galveston, Texas, the Miami-based center said.

The storm, which formed near a major oil- and gas-producing area of the northern Gulf of Mexico on Sunday, was about 145 miles (230 km) south-southeast of Lafayette, Louisiana, and 240 miles (390 km) east-southeast of Galveston. It was moving west at about 8 mph (13 kmh).

A tropical storm warning was in effect from the mouth of the Mississippi River in Louisiana to Port O'Connor, Texas, south of Galveston.

The storm could cause rain accumulation up to five inches in coastal regions of Louisiana and up to 10 inches in some parts of southeast Texas, U.S. forecasters said.

Though Galveston's west side could see some flooding, officials on the barrier island are not ordering any evacuations, said Lyda Ann Thomas, the town's mayor.

"If it remains a tropical storm we are prepared," Thomas told reporters.

Edouard, the second named storm to threaten oil operations in the Gulf of Mexico so far this year, shut down a huge offshore oil port, closed the Houston Ship Channel and prompted several offshore operators including Chevron Corp and Shell Oil to evacuate staff from their platforms.

But so far, energy companies reported little production slowdown as a result of the foul weather. The Gulf of Mexico supplies about a quarter of the nation's crude oil and 15 percent of its natural gas, while refiners along the coast produce about a quarter of domestic gasoline.

U.S. crude oil futures fell more than $5 to below $120 a barrel earlier on Monday as signs of a slowing U.S. economy and rising supply from OPEC outweighed storm fears.

The Louisiana Offshore Oil Port, the only deep-water U.S. oil port and a major conduit for the country's crude oil imports, said it temporarily suspended offloading oil tankers in the Gulf of Mexico due to high waves and winds.

A series of powerful hurricanes in 2004 and 2005, including Hurricane Katrina, toppled oil rigs and severed pipelines in the Gulf.

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

The early and unusually vigorous 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.