By Jane Sutton
MIAMI (Reuters) - Tropical Storm Debby formed in the central Gulf of Mexico on Saturday and storm warnings were posted for part of the Louisiana coast, the U.S. National Hurricane Center said.
Debby covered much of the eastern Gulf and was centered about 220 miles south-southeast of the mouth of the Mississippi River. The storm had top winds of 50 miles per hour (81 km per hour) and was expected to strengthen slowly, nearing hurricane force by Thursday.
Debby was moving slowly north and was expected to turn to the west on Sunday. On the hurricane center's projected path, the storm would skirt the Louisiana coast through Tuesday and hit Texas late in the week.
A tropical storm warning was issued for the Louisiana coast from the Pearl River west to Morgan City, excluding the city of New Orleans and Lake Pontchartrain. Residents were warned to expect storm conditions within 36 hours.
"Tropical storm conditions are expected to first reach the coast within the warning area by Sunday night, making outside preparations difficult or dangerous," the forecasters warned.
The combination of storm surge and high tide could cause flooding in normally dry areas near the coast, they said.
Debby could bring 3 to 6 inches of rain to the Gulf Coast from southern Louisiana to the Florida Panhandle, with up to 10 inches of rain in isolated areas.
Forecasting models still diverged on the storm's potential path, with a few swinging it east toward Florida.
Energy companies were shutting down production and evacuating workers from oil and gas platforms in the Gulf of Mexico, which is home to 20 percent of U.S. oil production and 6 percent of natural gas output.
The U.S. Bureau of Safety and Environmental Enforcement, which oversees oil and gas activity in the Gulf, said 7.8 percent of daily oil output and 8.16 percent of daily natural gas output were shut down.
(Additional reporting by Kristen Hays in Houston; Editing by Paul Simao)