The Latest on a tropical weather system in the Gulf of Mexico (all times local):
Tropical Storm Barry has formed in the Gulf of Mexico and forecasters say it could become a hurricane as it threatens Louisiana's coast.
The U.S. National Hurricane Center says the storm's maximum sustained winds Thursday morning are near 40 mph with additional strengthening expected during the next day or two.
A tropical storm warning is now in effect for the Louisiana coast from the mouth of the Pearl River to Morgan City.
The mayor of a barrier island town on Louisiana's coast has ordered a mandatory evacuation as a potential tropical storm brews in the Gulf of Mexico.
Mayor David Camardelle's order takes effect at noon Thursday on Grand Isle, which is accessible only by boat or a single flood-prone state highway.
Other low-lying areas of coastal Louisiana including the towns of Lafitte, Crown Point and Barataria also came under evacuation orders Thursday.
That follows similar orders Wednesday for parts of Plaquemines Parish,. The Mississippi River runs through the parish and could overtop some levees.
The disturbance in the Gulf is expected to develop into a tropical storm late Thursday and could hit southern Louisiana as a weak hurricane this weekend.
Carnival Cruise Line says it rerouted a cruise ship headed to New Orleans because of the potential tropical storm brewing in the Gulf of Mexico.
The Miami-based company says the more than 3,700-passenger Carnival Valor was sent to Mobile, Alabama, in the interest of safety. A company statement notes that coastal Louisiana is under a hurricane watch and water levels are high on the Mississippi River.
Mobile Mayor Sandy Stimpson tweeted a welcome to Valor passengers and a photo of the ship docked in Mobile on Thursday.
Carnival says arriving passengers will be taken from Mobile to New Orleans on complimentary buses.
The ship was supposed to depart Thursday from New Orleans on its next four-day cruise to Cozumel, Mexico. Instead, passengers will be taken to Mobile by bus from New Orleans.
A potential tropical storm brewing in the Gulf of Mexico presents twin troubles for parts of southeast Louisiana.
It could contribute to the rising of an already high Mississippi River, with water reaching the tops of levees this weekend. And there is also the widespread danger of flash floods like the one that walloped New Orleans on Wednesday. Officials said that storm dumped as much as 8 inches in parts of the metro area in three hours.
The Gulf disturbance that spawned the floods was forecast to strengthen into a tropical storm by Thursday night.
Forecasters said Louisiana could see up to 12 inches of rain by Monday. Some areas could get 18 inches.
Mississippi and Texas were also at risk of torrential rains.
New Orleans Mayor LaToya Cantrell says the city's Treme neighborhood got 8.4 inches of rain in three hours, and more nasty weather is on the way.
Cantrell has declared an emergency. She and other officials spoke at a news conference Wednesday after storms swamped city streets and paralyzed traffic.
Numerous officials urged residents to stay home, check that they have supplies for at least three days and make sure neighborhood storm drains are clear.
National Weather Service meteorologist Benjamin Schott says a hurricane hunter aircraft was going to look for the center of the developing tropical cyclone in the Gulf of Mexico. He says the aircraft will provide information about its likely landfall.
Schott says storm surge could raise the Mississippi River to 20 feet, adding, "That's not what we'd consider worst-case."
Mississippi Gulf Coast residents are preparing for heavy rain as a tropical storm system causes flooding in New Orleans and other parts of south Louisiana.
Coastal Mississippi is under a flood watch until Thursday night.
Harrison County Emergency Management Director Rupert Lacy said Wednesday that free sandbags are available in several places. He said residents can pick them up to protect their property.
Lacy said that such preparations are normal during hurricane season. He says, "when you live in paradise, you have to expect some days like this."
Harrison County is the largest of Mississippi's three coastal counties. It includes Biloxi and Gulfport.
Texas Gov. Greg Abbott says officials are gearing up for a storm moving across the Gulf that could evolve into a hurricane and affect large swaths of the state's eastern region this weekend.
The storm system that has already swamped streets in New Orleans could draw more than 10 inches of rain in regions north of the Houston area and east Texas.
Abbott said at a Wednesday news conference that Texas has mobilized several departments ahead of the growing storm's expected landfall.
The governor said that includes activating the Texas Task Force 1 with four high-water rescue boat squads ready and having nearly 700 Department of Public Safety officers on standby for possible deployment.
Louisiana and Mississippi are also making preparations for heavy rain and possible flooding.
Louisiana Gov. John Bel Edwards has declared a state of emergency in anticipation of tropical weather that could dump as much as 15 inches of rain in the state over the coming days.
Edwards issued the declaration Wednesday afternoon. It came after storms from a weather system centered in the Gulf of Mexico dumped an estimated 4 to 7 inches of rain on metropolitan New Orleans in a span of three hours Wednesday morning. That caused widespread flash flooding.
Forecasters say that system could become a tropical storm in the northern Gulf by Thursday night and a weak hurricane by Friday. In addition to dumping heavy rains throughout the state, the system could push up Mississippi River levels, possibly overtopping some levees on the lower part of the river.
New Orleans officials say the system of pumps that protects the city from being overwhelmed by floodwaters is in good shape as a potential tropical storm forms in the Gulf of Mexico.
Sewerage and Water Board Executive Director Ghassan Korban said Wednesday that 118 of 120 pumps are in working order.
Several inches of rain fell during storms Wednesday, flooding many city streets. Korban said that amount of rain will overwhelm any drainage system.
Even more rain is on the way. Forecasters said parts of the region could see a total of up to 12 inches of rain.
Flash floods hit the city in August 2017, exposing major problems with equipment and personnel at the Sewerage and Water Board and led to major leadership shake-ups at the agency.
A spokesman for the U.S. Army Corps of Engineers in New Orleans says they're not expecting widespread overtopping of the levees that protect the city from the Mississippi River but there are concerns for areas south of the city.
The river has been swollen from heavy rains further north. Now a tropical system in the Gulf of Mexico is expected to push it even higher.
The spokesman, Ricky Boyett, says the river is expected to rise to 20 feet by late Friday. He says the New Orleans area is protected by levees 20 to 25 feet high.
He says the Corps is working with local officials to identify any low-lying areas and reinforce them.
Boyett says officials are out every day inspecting the levees and they're "in good shape."
The National Hurricane Center says conditions appear favorable for a weather system in the Gulf of Mexico to strengthen into a hurricane as it approaches the United States coastline by this weekend.
Forecasters said the weather disturbance is expected to become a tropical depression by Thursday morning; a tropical storm by Thursday night and a hurricane on Friday.
Forecasters said parts of the central Gulf Coast could see a total of up to 12 inches of rain, with up to 18 inches in isolated areas.
The center on Wednesday began issuing advisories about the weather system, even though it hasn't yet become a named storm. Forecasters are calling it "Potential Tropical Cyclone Two."
Louisiana Gov. John Bel Edwards says a "considerable" amount of water could over-top levees that hold back the Mississippi River in the New Orleans area as emergency officials prepared for a weekend storm.
That's because the Mississippi River is already swollen from spring rains as a tropical weather system builds in the Gulf of Mexico and could add about 3 feet (1 meter) of storm surge to the river.
Edwards said at a Wednesday morning news conference that he intends to declare a statewide disaster later in the day. He said National Guard troops were preparing to be deployed across Louisiana with high-water vehicles.
Forecasters expect a broad area of disturbed weather in the Gulf to become stronger this weekend when it threatens the region with torrential rain.
Louisiana, Mississippi and Texas are all making preparations for heavy rain and possible flooding.
Forecasters expect a tropical weather system to develop into a storm that could push the already swollen Mississippi River precariously close to the tops of levees that protect New Orleans.
The low pressure area was over water, south of the Florida Panhandle early Wednesday and was expected to strengthen into a storm as it moved west through the Gulf's warm waters.
Forecasters say parts of Louisiana could see up to 12 inches of rain by Monday, with heavier amounts possible in some spots.
Mississippi and Texas were also at risk of torrential rains.
The National Weather Service said New Orleans is protected to a river level of 20 feet, but it was forecast to rise above flood stage to 19 feet by Friday.