Don't go to sleep on storm : Mayor MIAMI—Tropical Storm Lee made landfall in the southern US state of Louisiana Sunday, bringing with it torrential rains threatening floods in parts of the country, US government forecasters said. Louisiana Governor Bobby Jindal has declared a state of emergency, saying flooding was the state's “primary concern.” Lee came ashore just 80 km southwest of Lafayette, packing sustained winds of 75 km per hour, the Miami-based National Hurricane Center said. “A slow northeastward motion is expected later today, followed by a turn to the east northeast tonight,” the center advised. With some areas forecast to receive up to 20 inches of rain over the Labor Day holiday weekend, residents of coastal states as well as landlocked Kentucky and Tennessee should prepare themselves for extensive flooding, experts warned. Oil companies evacuated workers from offshore rigs ahead of the arrival of Lee, a disorganized but major rainmaker. “If we get the five to 10 inches (12.5-25 centimeters) that come out into a tropical storm in that kind of terrain, the flash flooding is fast and it's violent,” Bill Read, director of the National Hurricane Center in Miami, told reporters. In New Orleans, about 70 miles west of Morgan City, the storm recalled Hurricane Katrina, which flooded 80 percent of the city, killed 1,500 people and caused more than $80 billion in damage to the popular tourist destination. Half the city lies below sea level and is protected by a system of levees and flood gates. The levees can process about one inch (2.5 cm) of rainfall per hour and the storm's slow-moving nature remained a worry, officials said. There were isolated reports of flooding in roads and homes. “Don't go to sleep on this storm,” Mayor Mitch Landrieu told residents. He said stormy conditions could continue for the next 36 hours. New Orleans is under a flash flood watch through Monday night, the National Weather Service said. Potential damage from wind gusts will also be a concern, it said. Lee was battering the Gulf Coast six years after the region was devastated by Hurricane Katrina. The levee system around New Orleans failed after Katrina, putting much of the city underwater. More than 1,500 people died. On Monday, Katrina's sixth anniversary, the Times-Picayune reported that an upcoming Army Corps of Engineers report gives the levee system a “near-failing grade,” despite a $10 billion post-Katrina rebuilding job. The intense rain that Lee is already dumping on the city is expected to provide the most severe test of the levee and canal systems at Lake Pontchartrain and elsewhere since Hurricane Gustav came close to overwhelming the levees three years ago. Earlier this week New Orleans Mayor Mitch Landrieu said the water pumps that are key to the city's flood mitigation are “100 percent operational.” Mississippi Governor Haley Barbour has declared a state of emergency in several counties, urging residents to prepare well in advance. “Do not underestimate the impact of this system of tropical weather,” he said. US forecasters are also monitoring Tropical Storm Katia in the Atlantic Ocean. Forecast models vary, and Katia is still well out to sea, but some tracks show the storm nearing and perhaps clipping the US eastern seaboard sometime next week.