Hurricane Irma began a dreaded march north late Saturday, erasing any hope the Tampa Bay region and Florida's Gulf Coast would be spared its devastation.
At shelters where thousands waited for the storm to arrive, and in living rooms where families gathered around their TVs, a community wondered just how bad it would be.
"I'm terrified," said Nicole Manuel, 37, who huddled with family at her mother's house in Clearwater. "I keep on hearing different things, different changes. How fast is it coming? When is it even coming? It's different every time I see the TV."
For days, the storm's track had wobbled west and east and west again, leaving Floridians to speculate which cities were most at risk. But some clarity emerged as Irma edged nearer to the Florida Keys late Saturday, regathering strength.
In every scenario, forecasters warned of deadly storm surge, menacing winds and sporadic tornadoes for Florida's Gulf Coast.
"I wish I could give you better news, but it's bad," said Phil Klotzbach, a Colorado State University research scientist and hurricane forecaster. "At this point, I don't think there's a whole lot that can happen to not make it bad."
Irma will likely slam into the Keys at daybreak, then make another landfall south of Sarasota before colliding with the Tampa Bay region late Sunday.
Residents should brace for sustained winds in the 80 mph range and gusts up to 115 mph, forecasters said. Irma's top winds measured 125 mph on Saturday, making it a strong Category 3 storm.
Even more devastating would be a shift further west, holding Irma just offshore and putting Tampa Bay on the east side of the storm.
In that case, the region would stand directly in the path of the strongest winds, and the potential storm surge would rise.
"There's no ideal here, unfortunately," said meteorologist Bryan Mroczka of the National Weather Service in Ruskin. "But we don't want this storm moving any further west."
The expansive storm pivoted off of Cuba's northern coast Saturday, leaving in its wake a string of island nations still counting their dead.
Cuba knocked down Irma's strength, but with more warm water ahead, experts predicted the storm would only intensify on its path to Tampa. Already, two U.S. deaths have been reported.
For decades, disaster officials and meteorologists have put the Tampa region as one of their worst-case scenarios, along with Miami, New Orleans, Houston and New York. The other four cities have been hit in the last 25 years but a major hurricane hasn't hit Tampa since 1921, when its population was about 10,000, said National Hurricane Center spokesman and meteorologist Dennis Feltgen.
Now it has around 3 million people.
"It's certainly one of those metropolitan areas where we have one of the greatest concerns, particularly with storm surge, particularly with inexperience," Feltgen said.
Tropical storm-force winds (at least 39 mph) should set in Sunday afternoon, and ramp up throughout the evening, meteorologists said. By late evening, the region could start seeing hurricane-force gusts (at least 74 mph) — and possibly sustained hurricane-force winds.
"Sometimes the message can be overhyped," Mroczka said. "But as Irma proved in the Caribbean, this is a killer hurricane."
Deadly storm surge
For most meteorologists, the chief concern is storm surge.
Experts expect 5 to 9 feet along the entire shoreline of Tampa Bay starting Sunday night and peaking early Monday morning. The highest levels are expected in northeast Hillsborough Bay and in the Feather Sound area of Pinellas County.
Storm surge, or the water pushed ashore by a hurricane, often poses the greatest threat to life and property. It was responsible for many of the 1,500 deaths associated with Hurricane Katrina in 2005, according to the National Oceanic and Atmospheric Administration.
"The storm surge is what really scares me," Florida Gov. Rick Scott said Saturday.
Even if the storm makes landfall south of Tampa Bay, weakening its winds, Irma will have already done significant damage in storm surge, said Jeff Masters, co-founder of Weather Underground.
Surge tends to creep up as a storm approaches, and when the eyewall hits, the water rises rapidly.
"It's not a wall of water," he said. "You're looking down at your feet and you say, 'There go my ankles, there go my shins, there go my knees,' and before you know it, it's up to your neck."
The situation could be worse if it coincides with high tide, which will come Monday morning.
"Say there is a surge at 4 feet. (High tide) makes it worse. Now you're at 6 or more feet," said Paul Close, a meteorologist at the National Weather Service's Tampa Bay office.
In Pinellas County, low-lying areas like Snell Isle and Shore Acres are particularly vulnerable, as are the beach communities along the Gulf Coast.
In Hillsborough, officials said parts of Palmetto Beach near the Port of Tampa and the Palm River area could get 6 or more feet of flooding.
Harbour Island, Bayshore Boulevard, the Westshore area, MacDill Air Force Base, Apollo Beach, Ruskin and coastal areas along Tampa Bay north of the Courtney Campbell Causeway could see surge flooding of 3 feet or more.
Dangerous winds pose another threat. Tropical storm-force winds will blow for a full 24 hours, Masters said, with the storm peaking around 11 p.m. Sunday. For two hours before and after the peak, he said, the winds will reach hurricane strength.
Irma will bring heavy rain and tornadoes, too.
Meteorologists are expecting between 6 and 9 inches of rain throughout the region, causing urban and rural flooding starting Sunday. Areas further inland, east of Interstate 75, could see up to 16 inches, said 10Weather WTSP meteorologist Bobby Deskins.
In Pasco, Assistant County Administrator Kevin Guthrie said some parts of the county could see up to 20 inches of rain, much of it expected in the central region.
Major river flooding is also possible Monday into mid week.
The Alafia River has more than a 30 percent chance of major river flooding, according to the National Weather Service.
Tornadoes, which are most likely to form in a hurricane's right-front quadrant, could appear as the hurricane's eye approaches, from Sunday afternoon to night.
Weather experts point out that tornadoes formed by tropical cyclones are usually weak and short lived. But they say residents should be on high alert anyway.
As Irma stalls out over Georgia and Tennessee, experts say, the storm's effects will linger in Florida. Heavy rains will intensify flooding. As the region tries to drain, winds will blow in from the Gulf, keeping the bay's water levels high for days. Roads will be blocked. Huge swaths of homes and businesses will wait to regain power.
"It's going to be a mess," Masters said.
The threat is real
Even late Saturday, meteorologists hesitated to make definitive claims about Irma's path. The storm was moving just parallel to the coast. Any shift in its trajectory would set off a series of new predictions.
More important, they said, was the message to take Irma's threats to heart, even though Tampa hasn't sustained a direct hit in nearly a century.
After watching Hurricane Harvey devastate Houston, many did.
Almost 7 million people — more than a third of the state's population — have been ordered to evacuate. Roads clogged with outbound traffic.
Some 50,000 people who remained turned to government-operated shelters. Publix employees handed out cases of water as fast as shoppers could fill their carts. Plywood sheets darkened the windows of bungalows. Pinellas Sheriff Bob Gualtieri ordered a complete closure of all access points to the county's barrier islands. No one may return to the islands after 6 a.m.
The governor, making the rounds on morning television shows, urged Floridians not to gamble with their lives.
"You cannot survive this," Gov. Scott cautioned.
Times staff writers Richard Danielson, Divya Kumar, Tracey McManus and Megan Reeves contributed to this report, and information from the Associated Press was used. Contact Kathleen McGrory at firstname.lastname@example.org and Claire McNeill email@example.com.