CORPUS CHRISTI, Tex. — Hurricane Harvey intensified Friday morning and is on track to be the strongest hurricane to strike the United States in 12 years. The storm is expected to make landfall late Friday night or Saturday morning near this South Texas city and then stall, delivering forecasters say could be “catastrophic flooding.”

City officials insisted they’re ready for the worst.

“Game on,” said Mayor Joe McComb at a news conference. “We’re looking forward to having a very good positive result from this storm. We’ll get through this, we’ll be better for it because the community has been pulling together.”

The first outer bands of Harvey reached the South Texas coast on Friday morning. At 2 p.m. EDT, Harvey was 85 miles east-southeast of this city, with winds of 110 miles per hour.

The National Hurricane Center reported that the storm could intensity further, and if it did, would be poised to be the first Category 3 hurricane to hit the United States since Wilma in 2005.

People rush to buy plywood at Lowes in Corpus Christi, Tex., as Hurricane Harvey approaches on Friday. (Courtney Sacco/Corpus Christi Caller-Times/AP)

William B. “Brock” Long, administrator of the Federal Emergency Management Agency, was blunt in his warning: “Let’s set the expectations: Texas is about to have a very significant disaster. And we have to let people know that.”

[Complete coverage: Hurricane Harvey]

Already, several hundred miles of the Texas Gulf Coast are under hurricane and storm surge warnings. After battering the coast, Harvey is expected to stall for days and potentially drift back offshore, which would enable it to feed continuously off the hot Gulf waters and remain a tropical storm.

Forecasters warn that Harvey will likely deliver historic amounts of rain — some models show mind-boggling accumulations in feet rather than inches. Flooding is likely in and around Houston, the nation’s fourth-largest city and the headquarters of the U.S. oil and gas industry.

“Rivers and tributaries may overwhelmingly overflow their banks in many places with deep moving water. Small streams, creeks, canals, and ditches may become raging rivers. Flood control systems and barriers may become stressed,” the National Weather Service said in an advisory Friday.

[How to prepare for Hurricane Harvey — whether you evacuate or not]

A steady and orderly stream of traffic flowed out of Corpus Christi on Thursday, headed toward higher ground inland. But with Harvey just hours away now, many thousands of people apparently are going to ride out a storm.

The Texas Military Department deployed about 700 members of the State Guard and National Guard around the coastal region on Friday as the storm moved in. Black Hawk and Lakota helicopter crews were put on standby for search and rescue, while ground teams with high-clearance vehicles prepared to make incursions into flooded communities after the storm.

Other military members prepared to set up shelters in cities likely to absorb evacuees or refugees from the storm.

The American Red Cross is mobilizing staff from across the country and sending them to Texas, where it is helping to man dozens of shelters along the Gulf Coast. Paul I. Carden Jr., regional disaster officer for the National Capital Region in Washington, arrived last night in Corpus Christi as part of the leadership team. Friday morning he said that it is foolish for residents not to evacuate.

“When the Weather Service uses the language that it has been using, I know this is going to be a severe event,” said Carden, former director of emergency and international services for the Red Cross. “A hurricane in its own right is bad, but a hurricane with five to seven days worth of rain over the same area, I know it’s going to be a significant disaster.”

He added, “This is your life. This is your family’s life. This is not a time to gamble with both.”

Carden said the Red Cross is already working with the Federal Emergency Management Agency to plan for the aftermath of the hurricane, but he warned residents to be prepared for extended hardship. After the storm, the Red Cross will be dispatching feeding stations cleanup kits, health and mental health professionals and even spiritual care workers to Texas to help residents cope.

“This is going to try a person’s faith,” Carden said.

Friday morning, residents Phyllis Sweeney and Gary Balding told their story of fleeing the wrath of tropical storms. They live on a 41-foot sailboat, having moved to Corpus Christi from Key West. Two weeks ago they tried to sail to the Yucatán Peninsula in Mexico but were battered by Hurricane Franklin.

“We got within 20 miles, and couldn’t get there because the winds and currents were blowing in the wrong direction,” said Balding, 68. “We thought, “Okay, we’ll go to Corpus Christi and everything will be cool.”

Now they’re in the path of Harvey. They fled the boat early Friday and checked into the Holiday Inn downtown. The hotel has become a refuge for stranded tourists, boaters, storm chasers and journalists. But Sweeney, 70, is worried that the hotel, which is surrounded by several other skyscrapers, will also suffer significant damage.

“I’m worried about the roof of this building and if we get chased off the boat, and chased out of this hotel, it’s not going to be fun,” she said.

Many small towns and low-lying areas in South Texas are under mandatory evacuation orders, but officials in Corpus Christi and Nueces County chose to stick with voluntary evacuations. Mayor McComb said Thursday that he didn’t want to force police and firefighters to try to pull people from their homes against their wishes.

McComb defended that decision at Friday’s news conference: “When it’s all said and done we made the right decision and I think time will prove us right.”

Nueces County Judge Samuel L. Neal, who oversees the county’s emergency response, implored residents to be patient as the storm blows in and the city copes with what is likely to be days of rain and ongoing power outages.

“This storm is not going to play out overnight,” Neal said, adding that electricity is likely to be out for up to a week. “Forty-eight hours is going to seem like an eternity without power. Please be patient.”

Harvey is the first major natural disaster faced by the Trump administration. President Trump on Friday said that he had spoken with the governors of Texas and Louisiana and was “here to assist as needed.”

In a pair of statements posted to Twitter, Trump said he was “closely monitoring” the storm and had been briefed by Elaine Duke, the acting Homeland Security secretary; John F. Kelly, the White House chief of staff, who held Duke’s job until late last month; Long, administrator of FEMA; and Thomas P. Bossert, Trump’s homeland security and counterterrorism adviser.

Sen. Charles Grassley of Iowa (R) gave the president a warning via Twitter: “keep on top of hurricane Harvey dont mke same mistake Pres Bush made w Katrina.”

The storm’s forecast track could eventually take it to New Orleans, which has struggled this month already with major flooding after thunderstorms on Aug. 5 dropped about nine inches of rain in just a few hours. The city relies on pumps to remove water from low-lying areas, but 15 of the pumps have been out of commission and are in the process of being repaired, the mayor’s office said this week.

Texas has seen many hurricanes over the years, most recently in 2008, when Hurricane Ike slammed into Galveston as a a high Category 2 storm, with a massive storm surge that helped cause tens of billions of dollars in property damage.

The Gulf of Mexico is crucial to the nation’s oil industry, with offshore platforms producing 1.7 million barrels of oil every day — close to a fifth of the country’s overall crude oil production. Refineries line the coast. The storm and subsequent flooding is certain to have a massive economic impact here that will ripple across the nation.

Samenow and Achenbach reported from Washington. Dylan Baddour in Houston, Ashley Cusick in New Orleans, and Mark Berman and Steven Mufson in Washington contributed to this report.