ST. PETERSBURG, Fla. (AP) -- Irma's leading edge brought hurricane-force winds to the Florida Keys late Saturday, bending palm trees and spitting rain as the storm swirled north with 120 mph (190 kph) winds on a projected new track that could expose St. Petersburg - not Miami or even Tampa - to a direct hit.

St. Petersburg, like Tampa, has not taken a head-on blow from a major hurricane in nearly a century.

The National Hurricane Center's latest tweak to Irma's forecasted track has the storm hugging the Florida's west coast off Fort Myers, but possibly not making landfall there before moving back to the Gulf of Mexico. By moving the likely track a few crucial miles west, the storm would be able to regain strength over water before its deadliest winds hit St. Petersburg and Clearwater, rather than the more populated Tampa.

After that, the storm is now expected to skirt the coast again a bit north of Horseshoe Beach, then finally go inland around Fish Creek, northwest of Ocala, with a hurricane-force wind field well over 100 miles wide.

Irma's forward motion slowed to 6 mph (10 kph) as the storm stuttered off the coast of Cuba. Forecasters say it could still increase in strength, but their forecast didn't show it.

An estimated 70,000 Floridians huddled in shelters as Irma closed in on the Keys, where the storm's center was expected to swirl over land Sunday morning.

"This is your last chance to make a good decision," 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.

Earlier in the day, Irma executed a westward swing toward Florida's Gulf coast that appeared to spare the Miami metropolitan area of the catastrophic direct hit that forecasters had been warning of for days.

Still, Miami was not out of danger. Because the storm's damaging winds stretch 350 to 400 miles wide, forecasters said the metro area of 6 million people could still get life-threatening gusts and a storm surge of 4 to 6 feet.

Irma - at one time the most powerful hurricane ever recorded in the open Atlantic - left more than 20 people dead across the Caribbean as it steamed toward the U.S.

It was chugging toward Florida as a Category 3, with winds down considerably from their peak of 185 mph (300 kph) earlier in the week.

Meteorologists predicted Irma would plow into the Tampa Bay area by Monday morning, delivering the area its first major hurricane since 1921, when its population was about 10,000, National Hurricane Center spokesman Dennis Feltgen said. Now the area has around 3 million people.

The new course threatens everything from Tampa Bay's bustling twin cities to Naples' mansion- and yacht-lined canals, Sun City Center's retirement homes, and Sanibel Island's shell-filled beaches.

The course change from Florida's east coast caught many off guard and triggered a major round of evacuations. Many west coast businesses had yet to put plywood or hurricane shutters on their windows, and some locals grumbled about the forecast.

"For five days, we were told it was going to be on the east coast, and then 24 hours before it hits, we're now told it's coming up the west coast," said Jeff Beerbohm, a 52-year-old entrepreneur in St. Petersburg. "As usual, the weatherman, I don't know why they're paid."

Nearly the entire Florida coastline remained under hurricane watches and warnings, and leery residents watched a projected track that could still shift to spare, or savage, parts of the state.

Forecasters warned of storm surge as high as 15 feet.

"This is going to sneak up on people," said Jamie Rhome, head of the hurricane center's storm surge unit.

With the new forecast, Pinellas County, home to St. Petersburg, ordered 260,000 people to leave, while Georgia scaled back evacuation orders for some resident's of the state's Atlantic shore. Motorists heading inland from the Tampa area were allowed to drive on the shoulder.

On Saturday morning, the state was already beginning to feel Irma's effects. More than 75,000 people had lost power, mostly in and around Miami and Fort Lauderdale, as the wind began gusting. By Saturday night, winds near hurricane force were recorded in the Keys.

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 started to blow.

"Tonight, I'm sweating," she said. "Tonight, I'm scared to death."

At Germain Arena not far from Fort Myers, on Florida's southwestern corner, thousands waited in a snaking line for hours to gain a spot in the hockey venue-turned-shelter.

"We'll never get in," Jamilla Bartley lamented as she stood in the parking lot.

The governor activated all 7,000 members of the Florida National Guard, and 30,000 guardsmen from elsewhere were on standby.

In the Orlando area, Walt Disney World, Universal Studios and Sea World all prepared to close Saturday. The Miami, Fort Lauderdale, Tampa and Orlando airports shut down. The Sunshine Skyway Bridge spanning Tampa Bay was closed.

Given its mammoth size and strength and its projected course, it could prove one of the most devastating hurricanes ever to hit Florida and inflict damage on a scale not seen here in 25 years.

Hurricane Andrew smashed into suburban Miami in 1992 with winds topping 165 mph (265 kph), damaging or blowing apart over 125,000 homes. The damage in Florida totaled $26 billion, and at least 40 people died.

Boat captain Ray Scarborough was 12 when Andrew hit and remembers lying on the floor in a hall as the storm nearly ripped the roof off his house. This time, he and his girlfriend left their home in Big Pine Key and fled north for Orlando.

"They said this one is going to be bigger than Andrew. When they told me that," he said, "that's all I needed to hear."

More From KROC-AM