Forecasters say the tropical storm could have winds of about 120 km per hour when it comes ashore, making it a Category 1 storm.
Thousands of Louisianans broke out sandbags or fled to higher ground on Thursday as Tropical Storm Barry threatened to turn into the first hurricane of the season and blow ashore with torrential rains that could pose a severe test of New Orleans' improved post-Katrina flood defences.
National Guard troops and rescue crews in high-water vehicles took up positions around the state as Louisiana braced for the arrival of the storm along its swampy southern tip Friday night or early Saturday.
Barry could have winds of about 75 mph (120 kph), just barely over the 74 mph threshold for a hurricane, when it comes ashore, making it a Category 1 storm, forecasters said.
But it is expected to bring more than 0.5 meters (a foot and a half) of rain in potentially ruinous downpours that could go on for hours as the storm passes through the metropolitan area of nearly 1.3 million people and pushes slowly inland.
President Donald Trump declared a federal declaration of emergency for Louisiana.
The declaration late Thursday authorises the Department of Homeland Security and Federal Emergency Management Agency, to coordinate all disaster relief efforts.
States long the Gulf Coast are preparing for Tropical Storm Barry, which could make landfall as early as Friday. https://t.co/S8VhR83Jfi— Twitter Moments (@TwitterMoments) July 11, 2019
New Orleans Mayor Latoya Cantrell warned her city's residents to review their emergency plans and supply kits, and to stay updated with the latest forecasts.
The city was under a tropical storm warning, and "we could see impacts as early as Friday morning," Cantrell said.
"The center of Barry will be near the central or southeastern coast of Louisiana Friday night or Saturday," the National Hurricane Center predicted in its 1800 GMT bulletin, forecasting additional strengthening "during the next day or two."
Between two major bodies of water
For 65 years, Clarence Brocks has lived in Plaquemines Parish.
And for nearly the same amount of time, he has memories of loading up the car to evacuate.
Brocks' family was one of the few left, Thursday afternoon, as evacuation orders pushed residents to higher ground.
He serves as the Volunteer Fire Chief in the town and insists on being one of the last people out.
"We are in between two major bodies of water and the only thing protecting us is two 18 foot levees and one of them failed already for Katrina," Brocks said.
While Brocks can't count how many times he's evacuated, he can recall the most memorable; Hurricane Katrina.
His home sits in the same place as the one he lost during that storm.
He spent years rebuilding himself.
"We lost everything. We started from scratch. But we didn't lose everything because we still had our lives and our health," he said.
Brocks, an Air Force veteran, knows the risk he lives with when Hurricane season rolls around.
But it's one he's willing to take year after year.
"I was born and raised here. This is all I know. I've been all over the world and guess where I want to be at? Right here," he said.
While they didn't have flood insurance for Katrina, they do now.
And if he returns to nothing after the storm passes, Brocks plans to rebuild yet again.
Most recent rainfall forecast for Tropical Storm Barry from @NWSWPC covers a lot of real-estate with 5", 10" up to 20".— Ryan (@RyanMaue) July 11, 2019
6.3 Trillion over Louisiana
4.4 Trillion over Mississippi
3.3 Trillion over Arkansas
The Mississippi River has a lot of work to do. pic.twitter.com/sUcmlBtwMJ
'A tornado or two' possible
Meanwhile, mandatory evacuations were ordered for parts of Jefferson and Plaquemines parishes, and voluntary evacuation was in effect in Grand Isle, according to news website NOLA.com.
The NHC noted that sustained winds had increased to near 40 mph (65 kph) and "a tornado or two" were possible Thursday or Friday night.
The governor has authorised the mobilisation of up to 3,000 members of the National Guard.