Barry has turned north, northwest and its remnants will eventually be pulled due north on Sunday and absorbed into an easterly trajectory of the jet stream by Monday.
Almost all businesses in Morgan City, about 137km west of New Orleans, were shuttered with the exception of Meche's Donuts Shop.
"Life-threatening, significant flash flooding and river flooding will become increasingly likely later today and tonight as Barry moves inland, especially across portions of south-central and southeast Louisiana into MS", the NHC said.
A man walks past a closed business in the French Quarter as Tropical Storm Barry approaches land in New Orleans, Louisiana, Saturday, July 13.
The center of Barry is forecast to move through southern Louisiana in the afternoon, and into central Louisiana on Saturday night, and into northern Louisiana on Sunday, according to the NWS. Since record-keeping began in 1851, according to Colorado State University meteorologist Philip Klotzbach, only Hurricanes Bob in 1979, Danny in 1997 and Cindy in 2005, have made landfall on the Louisiana coast in July.
"A voluntary evacuation is in place for residents of low lying areas, those with special needs, those who require uninterrupted electrical power or who live in manufactured housing or mobile homes", said Lafayette Parish Mayor President Joel Robideaux. "No one should take this storm lightly".
In New Orleans, a group of neighbours cleaned out the storm drains on their street.
Storms become hurricanes when their winds reach 74 miles per hour (120 kph) or higher.
"The lack of rainfall across Louisiana early Saturday morning should not fool residents into thinking that it's safe to venture out".
The New Orleans area is protected from the mighty Mississippi River by levees that started going up right around the time of the city's first settlers three centuries ago. Residents were told to shelter in place by 8 p.m. CDT Friday.
The image was captured by a National Oceanic Atmospheric Administration satellite.
Impacts from Barry were felt along the Florida panhandle as well.
"If we anticipate that this could happen with more frequency going forward, then it has to inform a lot of things we do in the state of Louisiana to prepare for disasters in the future", the governor continued.
"Our greatest concern is for torrential rain that would result in life-threatening flooding", AccuWeather Hurricane Expert Dan Kottlowski said.
The National Weather Service (NWS) earlier warned the Mississippi River could crest at 19ft or 20ft during the storm, but on Friday revised their estimate down to 17ft.
Barry was reportedly heading west-northwest across the northern Gulf of Mexico at 5 miles per hour on Friday.
Weakening is forecast after Barry hits landfall.
At least one levee, in Plaquemines Parish in the state's tip, was already overtopped by water by midday on Saturday.
Highway 23 is now open, but the highway may take on water which will likely impact travel between Phillips 66 Refinery to Venice.
Residents are encouraged to come north of the floodwall, if they can do so safely.
Authorities urged citizens to secure property, stock up provisions and shelter in place.
As natives and tourists in the Big Easy, Baton Rouge and other heavily populated areas in the storm's path hunkered down or wandered through quiet, emptied streets waiting for the worst, the Coast rescued more than a dozen people from the flooded remote island of Isle de Jean Charles.
The U.S. Coast Guard expects the New Orleans port to close Friday morning. Some airlines, including British Airways, have cancelled outbound flights from the city through Saturday.
Wave heights could reach 5 to 10 feet with a significant run-up on shore expected.