A storm swamped New Orleans streets and paralyzed traffic Wednesday as concerns grew that even worse weather was on the way: a possible hurricane that could strike the Gulf Coast and raise the Mississippi River to the brim of the city's protective levees. The storm was associated with a broad area of disturbed weather in the Gulf that forecasters said was on track to strengthen into a hurricane by the weekend.

The system was expected to become a tropical depression by Thursday morning, a tropical storm by Thursday night and a hurricane late Friday, according to the National Hurricane Center.

The system was likely to be named Barry, and it would be the second named Atlantic storm this year. As of 11 p.m. ET Wednesday, it had maximum sustained winds of 30 mph, according to the hurricane center. Tropical storms have maximum sustained winds of at least 39 mph.

Get Breaking News Delivered to Your Inbox

The system's center was located about 120 miles southeast of the mouth of the Mississippi River, the hurricane center said. It was moving west-southwest at 9 mph.

Lines of thunderstorms associated with the system ranged far out in into the Gulf and battered New Orleans, where as much as 7 inches of rain fell over a three-hour period Wednesday morning, forecasters said. Mississippi and Texas were also at risk of torrential rains.

Terrian Jones reacts as she feels something moving in the water in New Orleans on Wednesday, July 10, 2019. AP

In New Orleans, streets turned into small, swift rivers that overturned garbage cans and picked up pieces of floating wood. Water was up to the doors of many cars. Other vehicles were abandoned. Kayakers paddled their way down some streets.

Alexandra Cranford, a meteorologist with CBS affiliate WWL-TV, said the worst of the rain was over for Wednesday. She said some scattered rain is expected across the city.

Chandris Rethmeyer lost her car to the flood and had to wade through water about 4 feet deep to get to safety. She was on her way home after working an overnight shift when she got stuck behind an accident in an underpass and the water started rising.

"I was going to sit in my car and let the storm pass," she said. "But I reached back to get my son's iPad and put my hand into a puddle of water."

Valerie R. Burton woke up Wednesday to what looked like a lake outside her door. "There was about 3 to 4 feet of water in the street, pouring onto the sidewalks and at my door. So I went to my neighbors to alert them and tell them to move their cars," she said.

It was all a grim reminder of sudden flooding that surprised the city during an August 2017 rain. That flood exposed major problems at the agency overseeing street drainage. It led to personnel shake-ups at the New Orleans Sewerage and Water Board and required major repair efforts.

On Wednesday, the board said 118 of 120 drainage pumps were operational and the agency was fully staffed. But the agency's director says that much rain in such a short time would have overwhelmed any drainage system.

Gov. John Bel Edwards declared a state of emergency and said National Guard troops and high-water vehicles would be positioned all over the state.

"The entire coast of Louisiana is at play in this storm," Edwards said.

Forecasters said Louisiana could see up to 12 inches of rain by Monday, with isolated areas receiving as much as 18 inches. The heavy additional rain could push the already swollen Mississippi River precariously close to the tops of levees that protect New Orleans, officials said.

Frank Conforto Jr. drives a University Medical Center (UMC) truck with the Mercedes-Benz Superdome in the background on Glavez Street in New Orleans after flooding from a storm Wednesday, July 10, 2019. Matthew Hinton / AP

A spokesman for the Army Corps of Engineers in New Orleans said the agency was not expecting widespread overtopping of the levees, but there are concerns for areas south of the city. The river was expected to rise to 20 feet by late Friday at a key gauge in New Orleans. The area is protected by levees 20 to 25 feet, he said.

The Corps was working with local officials to identify any low-lying areas and reinforce them, he said. He cautioned that the situation may change as more information about the storm arrives.

"We're confident the levees themselves are in good shape. The big focus is height," spokesman Ricky Boyett said.