PANAMA CITY, Fla. — A frighteningly powerful Hurricane Michael made landfall on the Florida Panhandle on Wednesday, with the Category 4 storm unleashing a blitz of rain, wind and storm surge that forecasters feared would ravage parts of the South.
The storm had maximum sustained winds of 155 miles per hour, and its center reached Mexico Beach, Fla., just before 1 p.m. local time, the National Hurricane Center said.
The hurricane center said the storm was “potentially catastrophic,” and officials in Florida said they were prepared for widespread devastation.
“This is the worst storm that our Florida Panhandle has seen in a century,” Gov. Rick Scott warned. “Hurricane Michael is upon us, and now is the time to seek refuge.”
Here’s the latest:
• The eye of Michael is expected to track northeast across Georgia and the Carolinas on Thursday before moving off the Mid-Atlantic coast on Friday. Click on the map below to see the storm’s projected path.
• Weather forecasters and government officials are particularly worried about a storm surge, which they said could reach 13 feet in some areas, in a relatively flat region that is particularly vulnerable to it.
• Flash flooding is also a concern. The Florida Panhandle and Big Bend region, southeast Alabama and parts of Georgia could receive four to eight inches of rain, with some spots getting as much as a foot.
• The governors of Alabama, Florida, Georgia, North Carolina and South Carolina have all declared emergencies for at least parts of their states, encompassing tens of millions of residents.
In Panama City, the rain was already coming with that ominous hurricane rhythm, the outer bands of the storm bringing drizzle, followed by unhinged gushing, followed by drizzle again.
In the pre-dawn darkness, a few cars crawled down wide boulevards lined with closed-up retail shops and gas stations. About six blocks from the water, Pastor Carlos Thomas was standing on the front porch of Neal’s Temple First Born Church of the Living God, flagging down a passer-by in a driving band of rain.
He had driven the church’s big, shiny new tour bus from a tree-shrouded area to an open field across from the church where he thought it might be safer.
Pastor Thomas, 48, has spent his whole life in Panama City, and he said he remembered Hurricane Eloise, which passed near here in 1975 and caused millions of dollars in damage. But he said that Panama City had mostly been safe in his lifetime.
So he, like so many thousands on the Panhandle, had decided to ride it out.
“I believe from what I’ve seen in the past, we’re going to be O.K.,” he said. “I’m thinking God’s going to take us through it.”
Pastor Thomas said some of his flock had evacuated, particularly the old and infirm. But it was unclear how many people had decided to stay along the Gulf Coast.
A brother and sister, John and Laurie Hamm, had moved their mother, who has Alzheimer’s disease, to the Hilton Garden Inn, a few miles inland. Her house was near downtown Panama City, right along Watson Bayou. Ms. Hamm herself said that she lives in a townhouse one block from the beach.
“When they started a couple of days ago and said it was going to be a Category 1, it was, like, ‘Cat 1, no big deal,’” Ms. Hamm said. “When they said Cat 2, it was like, ‘Oh maybe we’d better pay attention.’ And when they said Cat 3 it was like, ‘Oh, Lord.’”
Mr. Hamm had come from Tampa to help move their mother and they had thought about moving west along the coast and out of the storm’s path. But they worried about getting stuck on Interstate 10.
And so here was Ms. Hamm, an evacuee, but just a few miles from home.
President Trump received a briefing on the hurricane and said that he expected to visit the storm-damaged area on Sunday or Monday.
Mr. Trump marveled at the size of the storm as Brock Long, the administrator of the Federal Emergency Management Agency, described its impact on the Florida Panhandle. He briefed the president along with Kirstjen Nielsen, the secretary of homeland security.
“This started out very innocently a week ago,” and then “grew into a monster,” Mr. Trump said, adding that “I’ll be totally focused on this.”
Still, he said that would probably move ahead with a rally in Erie, Pa., on Wednesday night. “I don’t know what to do because you have so many people already there,” he said.
He also expressed concern for areas in North and South Carolina that are still grappling with flooding from the last storm and remain in danger of receiving more rain.
Inside the state emergency operations center in Tallahassee, Governor Scott stood before a line of stone-faced uniformed military personnel and law enforcement to offer a somber briefing on the coming storm.
“This is the worst storm the Florida Panhandle has seen in 100 years,” he said. “Again: This is the worst storm our Florida Panhandle has seen in a century.”
Amid concerns that local officials had failed to sufficiently prepare for a storm of Hurricane Michael’s magnitude, Mr. Scott said the state would fill any gaps in the response.
“This thing happened fast,” he said. “It wasn’t like Irma. This one happened very quickly.”
After the cameras turned off, the governor went to the work floor to speak to dozens of state workers sitting behind screens and phones, managing the state’s response.
“This is going to be bad,” Mr. Scott said.
In an earlier appearance on CNN, Governor Scott said the storm surge from Hurricane Michael would be far-reaching, stretching along the Florida coast from Pensacola to Tampa. With 13-foot surges predicted in some places, he said residents should be prepared for seawater to rush inland, potentially for miles, because of the state’s flat lands near the coast.
“We have never seen anything like this,” Mr. Scott told CNN. “People just don’t realize the impact of storm surge.”
Besides rushing water, the governor said that the winds would wallop cities on the coast and even those far from the beach.
With Michael poised to be the most severe tropical cyclone to strike the United States mainland so far this year, Mr. Scott said he had activated 3,500 members of the National Guard and that 1,000 emergency responders were ready for search-and-rescue efforts. There were also 19,000 workers prepared to move in after the storm to try to restore power.
They lined up inside the cafeteria at Lincoln High School in Tallahassee late Wednesday morning, carrying grocery bags filled with snacks, bedding and the occasional pet, to seek shelter from Hurricane Michael.
Evelyn Rainey, 69, said she had seen what Florence had done in the Carolinas, and didn’t want to take any chances. “My husband stayed home because he always wants to protect the house, I guess from looters and stuff,” she said. “I’m like, we can get more stuff. This is a Category 4.”
Betty Clark and Betty Tyler, friends who live in the same neighborhood of trailer homes, shared a table in front of a television as Ms. Tyler’s grandchildren flitted around the room.
“I’d rather be safe than foolish,” said Ms. Tyler, 73, who moved into the shelter on Tuesday night. By Wednesday morning, she was “ready to go home.”
Ms. Clark, 60, waited until Wednesday morning to travel to the shelter, bringing only her medication for the breast cancer she has been battling.
“I wanted to come here so that if I got sick, somebody would be able to help,” she said.
Near the center of the room, Marco Sanchez and Lesley Padilla rested on three inflatable mattresses they bought Tuesday night at Walmart, after concluding that their trailer home might be unsafe for four young children.
“We left all our possessions but brought the most important ones: our papers and our children’s papers,” Mr. Sanchez said.
Their two-month-old daughter, Meghan Sanchez, dozed in a baby carrier as her siblings — Alberto Padilla, 11; Eli Jimenez, 7; and Isabella Jimenez, 3 — played games on tablets.
“The important thing is we’re all safe here,” Mr. Sanchez said. “Until the storm has passed.”
Hurricane Michael’s dramatic increase in strength as it approached Florida was due in part to its low barometric pressure, said Phil Klotzbach, a research scientist in the atmospheric science department at Colorado State University.
Low barometric pressure increases a storm’s intensity, and the barometric pressure within Hurricane Michael early Wednesday was just 925 millibars. There have only been a half dozen storms that struck the United States with lower barometric pressure, the most recent being Katrina, Andrew and Camille — and all six “were devastating storms,” Mr. Klotzbach said.
The rapid intensification of the storm, which means growing in wind speed by 35 miles per hour over a 24-hour period, came as a surprise, he noted — which means “There’s still stuff we don’t know about hurricanes.”
While prediction of storm track has grown increasingly accurate, the ability to predict rapid intensification has lagged somewhat, said Haiyan Jiang, an associate professor in the Department of Earth and Environment at Florida International University. “This storm is very special,” she said. “It has gone through three rapid intensifications” in its brief lifetime, despite pronounced wind shear in the region that might have been expected to weaken the storm.
“The shear was high, so nobody expected it was going to intensify this rapidly,” Dr. Jiang said.
Part of the explanation is warmer-than-average waters in the Gulf of Mexico, in some places by some 3.6 degrees Fahrenheit, or two degrees Celsius. “One to two degrees is a big deal,” she said.
Warmer sea surface temperatures, while subject to natural variation, are consistent with the effects of climate change.
Some 306 counties in the South — about 10 percent of all counties nationwide — were in states of emergency on Wednesday as Hurricane Michael threatened to ravage parts of the region and strain resources.
Gov. Nathan Deal of Georgia has declared an emergency for 92 of the state’s 159 counties, and Michael is expected to pass over at least some areas as a hurricane, not a diminished tropical storm.
The authorities have not ordered evacuations, the state said, but a handful of shelters are open.
“The time to prepare is ending, and those in the storm’s path should be prepared to shelter-in-place,” the Georgia Emergency Management and Homeland Security Agency said on Twitter on Wednesday.
Michael is also expected to race over the Carolinas — including communities still recovering from Hurricane Florence — as a tropical storm before moving offshore on Friday.
“Make no mistake: Hurricane Michael is a dreadful storm, and it poses serious risks to North Carolina,” said the state’s governor, Roy Cooper.
Richard Fausset reported from Panama City; Patricia Mazzei from Tallahassee, Fla.; and Alan Blinder from Atlanta. Reporting was contributed by John Schwartz, Matthew Haag and Sandra Garcia from New York, Emily Cochrane from Washington, and Daniel Victor from Hong Kong.