Weaker Ida drenches US Gulf Coast, hits oil supply

* 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.