* Ida weakens further as it approaches U.S. coast
* U.S. oil, gas production disrupted by Ida
* Storm soaks four states on U.S. Gulf Coast
By Kelli Dugan
MOBILE, Alabama, Nov 10 (Reuters) - Tropical Storm Ida weakened further and was losing speed on Tuesday as it drenched the U.S. Gulf Coast and oil installations, shutting down almost 30 percent of Gulf energy production.
Once a Category 2 hurricane, Ida became less threatening as its top sustained winds fell to near 60 miles an hour (95 kph), the U.S. National Hurricane Center said in a 1 a.m EST (0600 GMT) advisory.
The storm had also slowed down, with its center expected to cross the U.S. Gulf Coast near Mobile, Alabama, later on Tuesday, the hurricane center said.
Forecasters said Ida would continue weakening as it moved over cooler waters before landfall and then lose strength more quickly as it moved inland, turning east over northern Florida.
A U.S. Coast Guard helicopter plucked two workers from a storm-damaged oil rig south of New Orleans. Ida is blamed for 124 flood and mudslide deaths in El Salvador.
The Coast Guard closed the Port of Mobile, halting traffic on Mobile Bay, and authorities closed schools and government offices in coastal counties in Alabama and Florida, telling residents of flood-prone areas and mobile homes to evacuate.
An overnight curfew was issued for part of the Alabama coast.
Ida, which was downgraded from a hurricane to a tropical storm earlier on Monday, posed the first real storm threat of the 2009 Atlantic hurricane season to Gulf of Mexico oil and natural gas production, and forced some companies to shut down off-shore platforms and evacuate personnel. [ID:nN09263651]
The U.S. Minerals Management Service said Ida had shut down 29.6 percent of Gulf oil production and 27.5 percent of gas output.
Energy markets have been hypersensitive to Gulf cyclones since the devastating 2004 and 2005 seasons, when storms like Katrina disrupted U.S. output and sent pump prices soaring.
With Ida weakening, most offshore oil rigs in the Gulf would not see any damage, said Jim Rouiller, senior energy meteorologist at private forecaster Planalytics Inc.
"I think that by tomorrow it will be normal operations across the production region," Rouiller said on Monday.
OIL PRICES EASE
Oil prices eased to below $79 a barrel as Ida, which cut U.S. oil and gas supplies, was downgraded from a powerful hurricane.
The Louisiana Offshore Oil Port, the only U.S. terminal capable of handling the largest tankers, stopped unloading ships due to stormy seas. The Independence Hub, a major offshore natural gas processing facility, also was closed.
A quarter of U.S. oil and 15 percent of its natural gas are produced from fields in the Gulf, and the coast is home to 40 percent of the nation’s refining capacity.
At 1 a.m. EST (0600 GMT), the center of Ida was about 95 miles (153 km) south-southwest of Mobile and was moving north at about 10 mph (16 kph), the hurricane center said.
A tropical storm warning was in effect from Grand Isle, Louisiana, eastward to Aucilla River, Florida. Some 2.8 million residents of Louisiana, Mississippi, Alabama and Florida could feel the storm’s effects, the U.S. Census Bureau said.
The warning area included New Orleans, which is still recovering from the devastation of Hurricane Katrina in 2005.
By nightfall, the region was already being pounded by heavy rain and there were reports of flooded streets.
In Mobile, Governor Bob Riley warned residents to be on guard and declared a state of emergency for the state.
A few coastal Alabama businesses boarded up their windows but many residents and visitors seemed to dismiss the late-season storm as little more than a nuisance.
"Why do you think I waited until November to come down here?" asked Lisa Pouncey, a visitor from North Carolina.
Schools, beaches and parks closed in the Florida Panhandle, the same area hit in August by Tropical Storm Claudette, the only other cyclone to make a U.S. landfall during the 2009 Atlantic season, one of the least active in a decade.