Hurricane Irma is starting to spin up funnel clouds and at least one tornado, leading to warnings for parts of South Florida.
The National Weather Service posted on Twitter Saturday evening that a tornado had touched the ground in the Fort Lauderdale suburb of Oakland Park. Tornado warnings have been issued for Fort Lauderdale, Coral Springs, Pompano Beach and Sunrise in Broward County, as well as parts of nearby Palm Beach and Hendry Counties.
Earlier, the center of Hurricane Irma cleared the Cuban coast and entered the Florida Straits, where it will likely grow stronger as it passes over bathtub-warm water of nearly 90 degrees.
Irma had fallen to a Category 3 storm with 125 mph winds but National Hurricane Center spokesman and meteorologist Dennis Feltgen says it's already showing signs at high altitudes of regaining its previous strength.
At least 76,000 people are without power as the storm unleashes winds and rain on Florida. It continues spinning toward Florida on a projected track toward Tampa — not Miami as was originally predicted.
Tampa has not been struck by a major hurricane since 1921, when its population was about 10,000. Now the area has around 3 million people.
The westward swing in the overnight forecast caught many people off guard along Florida's Gulf coast and triggered an abrupt shift in the storm preparations. A major round of evacuations was ordered in the Tampa area, and shelters there soon began filling up.
Power outages expected to grow as Irma moves closer to the state.
The window was closing fast for anyone wanting to escape before the arrival of the fearsome storm Sunday morning. Irma — at one time the most powerful hurricane ever recorded in the open Atlantic — left more than 20 people dead in its wake across the Caribbean.
"You need to leave — not tonight, not in an hour, right now," Gov. Rick Scott warned residents in Florida's evacuation zones, which encompassed a staggering 6.4 million people, or more than 1 in 4 people in the state.
More than 75,000 people in Florida are seeking shelter in schools, community centers and churches as Hurricane Irma nears the state.
Government-sponsored shelters were open Saturday as officials warned 6.3 million Floridians to evacuate. The storm hurtled toward Florida with 125 mph winds Saturday on a shifting course that took it away from Miami and toward Tampa instead.
That represented a significant turn in the forecast, which for days had made it look as if the Miami metropolitan area of 6 million people was going to get slammed head-on by the Big One.
Hurricane Irma is expected to make landfall in Florida at daybreak on Sunday. Red Cross shelter coordinator Steve Bayer said most people at shelters are grateful and happy.
"You don't want to play with this thing," Sen. Marco Rubio warned during a visit to the Miami-Dade Emergency Operations Center. "People will die from this."
With the new forecast, Pinellas County, home to St. Petersburg, ordered 260,000 people to leave.
The overnight change in course was frustrating and frightening to Tampa Bay residents who awoke to the news, including Jeff Beerbohm, a 52-year-old entrepreneur who planned on riding out the storm in his high-rise condo in downtown St. Petersburg.
He groused about days of predictions that Irma would run up the state's east coast, only to undone by a last-minute change.
"As usual, the weatherman, I don't know why they're paid," he said.
As the storm closed in on the Sunshine State, it raked Cuba and left more than 20 people dead in its wake across the Caribbean after ravaging such resort islands as St. Martin, St. Barts, St. Thomas, Barbuda and Antigua.
Irma weakened slightly in the morning but was expected to pick up strength again before slamming Florida.
On Saturday morning, the hurricane's outer bands blew into South Florida as residents scrambled to leave. Damaging winds were moving into areas including Key Biscayne and Coral Gables, and gusts up to 56 mph (90 kph) were reported off Miami.
Already, Miami-Dade Mayor Carlos Gimenez said 19,000 homes in the county were without power before midday, including his own.
In Key West, 60-year-old Carol Walterson Stroud sought refuge in a senior center with her husband, granddaughter and dog. The streets were nearly empty, shops were boarded up and the wind began to gust.
"Tonight, I'm sweating," she said. "Tonight, I'm scared to death."
In one of the biggest evacuations ever ordered in the U.S., about 6.3 million people in Florida — more than one-quarter of the state's population — were warned to leave, and 540,000 were directed to clear out from the Georgia coast. Authorities opened hundreds of shelters for people who did not leave. Hotels as far away as Atlanta filled up with evacuees.
Gas shortages and gridlock plagued the evacuations, turning normally simple trips into tests of will. Parts of interstates 75 and 95 north were bumper-to-bumper, while very few cars drove in the southbound lanes.
"If you are planning to leave and do not leave tonight, you will have to ride out this extremely dangerous storm at your own risk," Florida Gov. Rick Scott said Friday. He urged everybody in the Keys to get out.
Major tourist attractions, including the Disney World parks, Universal Studios and Sea World, all prepared to close Saturday. The Miami and Fort Lauderdale airports shut down, and those in Orlando and Tampa planned to do the same later in the day.
With winds that peaked at 185 mph (300 kph), Irma was once the most powerful hurricane ever recorded in the open Atlantic. But given its mammoth size and strength and its projected course, it could still prove one of the most devastating hurricanes ever to hit Florida and could inflict damage on a scale not seen here in 25 years.
It could also test the Federal Emergency Management Agency's ability to handle two crises at the same time. FEMA is still dealing with aftermath of catastrophic Hurricane Harvey in the Houston area.
Ray Scarborough and girlfriend Leah Etmanczyk left their home in Big Pine Key and fled north with her parents and three big dogs to stay with relatives in Orlando. Scarborough was 12 when Hurricane Andrew hit in 1992 and remembers lying on the floor in a hallway as the storm nearly ripped the roof off his house.
"They said this one is going to be bigger than Andrew. When they told me that, that's all I needed to hear," said Scarborough, now a 37-year-old boat captain. "That one tore everything apart."
Andrew razed Miami's suburbs with winds topping 165 mph (265 kph), damaging or blowing apart over 125,000 homes. Almost all mobile homes in its path were obliterated. The damage in Florida totaled $26 billion, and at least 40 people died.
Galofaro reported from Orlando. Associated Press writers Seth Borenstein in Washington; Terry Spencer in Palm Beach County; Gary Fineout in Tallahassee, Terrance Harris in Orlando; and Jason Dearen and David Fischer in Miami contributed to this report.