NEW ORLEANS (Reuters) - New Orleans, devastated by Hurricane Katrina six years ago, faced a new threat on Saturday from Tropical Storm Lee, which was set to challenge the city's flood defenses with an onslaught of heavy rain.
The storm was expected to bring up to 20 inches of rain to southeast Louisiana over the next few days, including to low-lying New Orleans, the U.S. National Hurricane Center said.
Lee's tidal surge could spur coastal flooding in Louisiana, Mississippi and Alabama before drenching a large swath of the Southeast and Appalachian regions next week.
The slow-moving storm has bedeviled forecasters. Lee's winds weakened on Saturday night as it meandered northward toward the marshy Louisiana coast at 2 miles per hour, after stalling for several hours in the afternoon.
Late on Saturday, the center of Lee was just off the Louisiana coast 85 miles west-southwest of Morgan City, with maximum winds of 50 mph, the hurricane center said. Lee's winds were expected to stay well below the 74 miles per hour threshold of hurricane strength as the storm prepared to crawl ashore, possibly overnight, and into Sunday.
New Orleans' extensive levee system has pumped away about 8 inches of rain so far, with isolated reports of flooding in roads and homes. The system can process about 1 inch of rainfall per hour, but the storm's slow-moving nature remained a worry, officials said.
"We are not out of the woods," Mayor Mitch Landrieu told a news briefing, noting that hurricane-force gusts had been logged at City Hall. "This storm is moving painfully slow."
New Orleans is under a flash flood watch through Monday night due to heavy rain potential, the National Weather Service said on Saturday. Potential damage from wind gusts up to 50 mph will also be a concern for New Orleans on Sunday as Lee's center moves inland, it said.
The prospect of flooding in low-lying New Orleans evoked memories of Hurricane Katrina, which flooded 80 percent of the city, killed 1,500 people and caused more than $80 billion in damage in 2005. Half the city lies below sea level and is protected by a system of levees and flood gates.
Slivers of sunshine in the afternoon brought some tourists out and drew grumbles from some local businesses that advance reports on Lee may have been overdone.
But Landrieu said stormy conditions could continue for the next 36 hours, warning, "Don't go to sleep on this storm."
No injuries or deaths were reported in Louisiana, but rough waters off Galveston Island in Texas led to the drowning death of a 34-year-old man, an island official said.
The storm could also bring heavy rains and flooding to Mississippi, Alabama and the Florida Panhandle as it creeps eastward over the U.S. Labor Day holiday weekend.
Low-lying parishes around New Orleans saw rising waters, which covered some roadways in Plaquemines and St. Bernard parishes, but no homes or businesses were threatened. Some residents in Jefferson Parish were ordered to evacuate.
Periodic breaks in the rainfall allowed the city's giant pumps to catch up with the water flow and clear standing water, said Jefferson Parish President John Young.
"Everything looks good," Young told local television. "The pumps are keeping up with the water. We are getting some street flooding."
About 8,000 houses were without electrical power due to the storm, down from about 35,000 earlier on Saturday, according to utility Entergy Corp.
Over 60 percent of U.S. offshore oil production, all based in the Gulf of Mexico, and nearly 55 percent of offshore gas production were shut as of Friday, according to the government. Most of that output should quickly return once the storm passes.
Major offshore producers like Royal Dutch Shell, Exxon Mobil Corp and BP Plc shut down platforms and evacuated staff earlier this week.
Shell and Anadarko Petroleum Corp started to return workers to offshore platforms in the western Gulf of Mexico on Saturday.
Low-lying refineries in Louisiana that collectively account for 12 percent of U.S. refining capacity were watching the storm closely, but reported no disruptions.
ConocoPhillips' 247,000 barrel-per-day refinery in Alliance, Louisiana, 25 miles south of New Orleans, was operating normally as Lee moved overhead, the company said.
In the open Atlantic, Hurricane Katia weakened to a tropical storm on Saturday and was forecast to wobble back and forth between hurricane and tropical storm strength far from land, the hurricane center said.
(Additional reporting by Erwin Seba and Deborah Quinn Henselin Houston and Jane Sutton in Miami; Writing by Chris Baltimore; Editing by Peter Cooney and Paul Simao)
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