Tropical Storm Nate kills 22 in Central America, heads for US

At about 8 p.m. EDT (0100 GMT) Nate was some 45 miles (72 km) west of the Honduran town of Puerto Lempira, moving north-northwest at 10 mph (16 kph), the NHC said.

Blowing maximum sustained winds of 40 mph (64 kph), Nate was expected to move across eastern Honduras on Thursday and enter the northwestern Caribbean Sea through the night.

The storm will be near hurricane intensity when it approaches Mexico's Yucatan Peninsula late on Friday, where up to 8 inches (20 cm) of rain were possible, the NHC said.

Nate is expected to produce 6 to 10 inches (15 to 25 cm)of rain in southern Honduras, with up to 20 inches (50 cm) in some areas, the NHC said. The storm was forecast to dump 3-6 inches(7.5-15 cm) of rain in northern Costa Rica, with up to 10 inches (25 cm) in some areas, it added.

US officials from Florida to Texas told residents on Thursday to prepare for the storm. A state of emergency was declared for 29 Florida counties and the city of New Orleans.

"The threat of the impact is increasing, so folks along the northern Gulf Coast should be paying attention to this thing," the NHC's Feltgen said. 

In Mississippi, the U.S. Environmental Protection Agency plans to release as a precautionary measure 40 million gallons (151 million liters) of acidic water from storage ponds at a Pascagoula waste site.

The release to a drainage bayou is intended to prevent a greater spill during the storm, the EPA said, adding there are no anticipated impacts to the environment.

Major Gulf of Mexico offshore oil producers including Chevron  BP plc, Exxon Mobil Corp, Royal Dutch Shell Plc and Statoil were shutting in production or withdrawing personnel from their offshore Gulf platforms, they said.

About 14.6 percent of U.S. Gulf of Mexico oil production and 6.4 percent of natural gas production was offline on Thursday, the U.S. Department of the Interior's Bureau of Safety and Environmental Enforcement said.