By Sunday, at least 6 to 10 inches of rain had fallen in some spots along the Louisiana and Mississippi coasts, and the National Weather Service warned there was a threat of extensive flooding and flash floods because of the storm's slow, meandering jog inland.
The drenching rain bands were expected to head northward into the Tennessee Valley later in the week as forecasters warned that 10 to 15 inches of rain were possible along the central Gulf Coast and up to 20 inches in isolated spots.
National Hurricane Center specialist Robbie Berg said the flash flood threat could be more severe as the rains moves from the flatter Gulf region north into the rugged Appalachians.
Closer to the Gulf, the water is "just going to sit there a couple of days," he said. "Up in the Appalachians you get more threat of flash floods — so that's very similar to some of the stuff we saw in Vermont."
Vermont is still cleaning up and digging out dozens of communities that were damaged and isolated by heavy rain from Hurricane Irene last week that quickly overfilled mountain rivers.
No injuries were reported so far from Lee. But even before Lee swept ashore, there were scattered instances of water entering low-lying homes and businesses in Louisiana's bayou country — a region of fast-eroding wetlands long vulnerable to hurricanes and tropical storms. The storm prompted evacuations in bayou towns such as Jean Lafitte. Thousands were without power.
Late Saturday, lifelong Jean Lafitte resident Brad Zinet was riding out the storm in his mobile home mounted on pilings. He was hoping it wouldn't take on water.
"We got nowhere to go. We're just getting everything put up out of the way and hope for the best," said the 31-year-old plumber.
"This is a way of life around here," he added. "You just do the best you can and ride it out."
A week after Hurricane Irene caused massive flooding and claimed at least 46 lives as it barreled up the East Coast, President Barack Obama was heading to northern New Jersey later Sunday for a first-hand look at the damage while keeping an eye on Lee.
The president was to visit Paterson, N.J., where the Passaic River swept through the once-booming factory town of 150,000, flooded its downtown and forced hundreds to evacuate.
At 8 a.m. EDT, the National Hurricane Center in Miami said Lee's center had come ashore on the Louisiana coast about 50 miles (80 kilometers) west of Lafayette. Maximum sustained winds were 45 mph (75 kph) as the storm headed to the north at 3 mph (5 kph).
Tropical storm warnings stretched from near the Louisiana-Texas state line to Destin, Fla.
Although Lee's expected to weaken in coming days, the system was expected to unleash heavy rains over a wide area of the central Gulf Coast and then spread that precipitation into the Tennessee Valley, forecasters said.
To the east, coastal businesses were suffering. Alabama beaches that would normally be packed for the Labor Day holiday were largely empty, and rough seas closed the Port of Mobile. Mississippi's coastal casinos, however, were open and reporting brisk business.
In New Orleans, sporadic downpours caused some street flooding Saturday, but pumps were sucking up the water and sending it into Lake Pontchartrain. Officials said the levees were doing their job in the city that is still recovering from the deadly Hurricane Katrina a half decade ago.
New Orleans Mayor Mitch Landrieu warned residents not to let their guard down, saying: "We're not out of the woods. Don't go to sleep on this storm."