|The slow-moving Lee, which holds a substantial rain-making potential, has confounded predictions [REUTERS]
Tropical Storm Lee has made landfall in Louisiana, prompting New Orleans officials to issue flash-flood warnings as heavy rains drenched the city devastated by Hurricane Katrina in 2005.
Moer than 30cms of rain fell in some parts of the New Orleans metropolitan area on Sunday, putting the city's flood defences to a major test.
Forecasters say the storm could dump up to 51cm of rain on southeast Louisiana over the next few days.
Early on Sunday, the storm centre was about 137km west-southwest of Morgan City, with maximum winds of 80kph. Winds were expected to stay below the 74-mph (119-kph) threshold of hurricane strength as the storm crawls ashore.
In New Orleans the storm has evoked memories of Katrina, which flooded 80 percent of the city, killed 1,500 people and caused more than $80bn in damage.
Half the city lies below sea level and is protected by a system of levees and flood gates. The system can process about 1 inch (2.5 cm) of rainfall per hour, but the storm's slow-moving nature remained a worry, officials said.
"Don't go to sleep on this storm," Mitch Landrieu, the New Orleans mayor, told residents, warning stormy conditions could continue for the next 36 hours.
New Orleans is under a flash flood watch through Monday night due to heavy rain potential, the National Weather Service said.
Potential damage from wind gusts up to 50 mph (80kph) will also be a concern for New Orleans on Sunday as Lee's centre moves inland, it said.
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.
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.
Storm winds were already pushing Gulf waters inland, slamming barriers in low-lying areas and prompting mandatory evacuations in the coastal communities of Lafitte, Crown Point and Barataria.
In Mississippi, local governments were taking precautions as forecasters predicted tides could be up to 1.2 metres higher than normal.
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.
State of emergency
Bobby Jindal, Louisiana's governor, warned that heavy rains, substantial winds and tidal surges from the Gulf of Mexico could produce flash flooding throughout the Labour Day holiday weekend.
"Get ready for the wind, get ready for the rain, it's coming and it's going to be here for a while," Jindal said at a briefing in Baton Rouge, the capital.
Jindal has declared a state of emergency for Louisiana, and Mississippi governor Haley Barbour made a similar ruling for seven coastal counties.
Major offshore producers like Royal Dutch Shell, Exxon Mobil Corp and BP Plc shut down platforms and evacuated staff earlier this week.
Last week Hurricane Irene lashed the east coast and New York, killing dozens of people and knocking out power lines for millions of people.