Irma tightens aim on South Florida’s east coast

Irma tightened its focus on South Florida’s east coast Wednesday as one of the most powerful hurricanes ever recorded crossing the Atlantic, trampling one island after another in its path.

In their 5 p.m. update, National Hurricane Center forecasters said they are confidant Irma will continue on its north-northwest track over the next two three days. As it nears South Florida and the Keys, it’s expected to make a sharp turn to the north by the weekend, steered by a low-pressure trough moving across the U.S. But where, and how fast, that turn occurs remains unclear, leaving South Florida to scramble in the face of an uncertain threat.

Track models have generally made the turn sooner, sending the storm up South Florida’s east coast or across the northern Bahamas. But some reliable models also still track the storm slightly west, and forecasters warned the margin of error remains at 175 miles or more after four days.

“That’s why we say look at the cone. The center could be anywhere in that cone,” hurricane center spokesman Dennis Feltgen said. “South Florida and Central Florida will be impacted. We’re confident with that right now. What we’re not confident with is exactly where that center is going to go. But remember a hurricane is not a dot on the map. They’re large storms that cover a large area.”

At 5 p.m., forecasters reported that sustained winds remain at 185 mph, with higher gusts, and packing a record amount of wind energy in 24 hours surpassing 1980’s Hurricane Allen. A hurricane hunter plane recorded winds over 188 mph. The storm was located 55 miles east of San Juan.

Hurricane watches could be issued for South Florida as early as Wednesday night or Thursday.

2 pm wind speed 0906

National Hurricane Center

Over the next few hours, Irma will deliver fierce winds across Puerto Rico. Earlier in the day, sustained winds in the Virgin Islands reported at 106 mph. Nearly a thousand people in Puerto Rico had already fled to shelters, with widespread power outages already reported in advance of the storm. The island’s electric company, which has struggled with maintenance amid a deepening financial crisis, has said power could be out in some areas for four tow six months.

Irma is expected to pass the Dominican Republic first Thursday before nearing the Turks and Caicos and southeastern Bahamas later in the day.

Storm surge could reach as high as 20 feet in the Turks and Caicos. Rainfall is expected to reach between eight and 12 inches in the northern Leeward Islands and between four and 12 inches in the Virgin Islands and Puerto Rico, which is vulnerable to flash floods.

Hurricane warnings remain in effect for the Virgin Islands, Puerto Rico and parts of the Dominican Republic and Haiti and the Bahamas. Hurricane watches have been issued for parts of Cuba, from the Matanzas province to Guantanamo and the Central Bahamas. Tropical storm warnings also covered large parts of Hispaniola.

Forecasters say Irma is the strongest storm ever recorded in the Atlantic, outside the Gulf of Mexico or Caribbean. It has also set a new all-time high for the amount of wind energy ever recorded over a 24-hour period, said Colorado State meteorologist Phil Klotzbach.

Overnight, Irma rolled across the northern end of the Leeward Islands, dealing a direct hit to St. Martin and Anguilla. A NOAA weather station on Barbuda reported a 155 mph gust and sustained winds of 118 mph before failing Wednesday morning, forecasters said. Early reports from the islands, including St. Martin, Barbuda and Barthelemy, included widespread flooding, with roofs ripped off and trees downed. St. Martin’s government headquarters was destroyed, the Associated Press reported.

There were no immediate reports of casualties, but Minister Annick Girardin said officials were fearful “for a certain number of our compatriots who unfortunately didn’t want to listen to the protection measures and go to more secure sites… We’re preparing for the worst.”

In South Florida, Irma’s pending arrival triggered mandatory evacuations in the Florida Keys beginning Wednesday. Mayor Carlos Gimenez held off on evacuation orders in Miami-Dade County, but warned they could still be issued later in the week. Broward county has asked residents along the coast, in low-lying areas and in mobile homes to leave. Schools will be closed Thursday and Friday. Tolls across state highways were lifted yesterday as long lines began snaking out of gas stations and supplies including plywood and water, flew off the shelves.

If Irma hits South Florida, it could deliver the first widespread damage to the region since Hurricane Wilma in 2005. Hermine ended the state’s 10-year streak without a hurricane last year, but it landed far to the north in the state’s Big Bend. Matthew came closer, raking the coast as it rolled north, but most damage occurred north of Daytona Beach.

Wednesday morning’s track shift to the right could be bad news for South Florida’s densely developed east coast — or good news depending on how far it moves. But with hurricane force winds extending 50 miles from the storm’s center, it’s a path too close to call for most.

Since last week, meteorologists over the Great Plains and midwest have increased the number of weather balloons they send into the atmosphere to sample conditions hoping for a better read on the trough, said National Oceanic and Atmospheric Administration meteorologist Kevin Scharfenberg. As of Wednesday, every weather office capable of sending out weather balloons began releasing them every six hours, he said.

“So far it’s behaving as expected, that’s why you’re not seeing the models change a lot,” he said.

Wavering, called the wiper effect, is nothing unusual for models that often struggle to forecast turns. But it creates uncertainty, and anxiety, with the public that frustrates forecasters, particularly with so many different and often outdated and unreliable models splashed across the Internet.

“I just absolutely refuse to show what some people call the spaghetti model and throw everything in doubt,” said former hurricane center director Max Mayfield, who’s now a hurricane specialist for WPLG.

The hurricane center generally relies on models that they verify for accuracy yearly. These include the European and U.S. models, as well as an ensemble run of other models. Over the years, the official forecast tracks from the center have repeatedly fared better than single any model. Mayfield often shows the models used by the hurricane center, but only to give viewers an idea of what they’re considering.

Forecasters also look for patterns in model runs to avoid basing projections on a single run.

“I don’t like to get all excited about one run to the next run. I like to look at a lot of models over a lot of runs and look for trends and consistency,” said University of Miami hurricane researcher Brian McNoldy. “If you have a model that hops around from one run to the next to the next, it’s kind of like an eye-rolling moment. It shows it doesn’t really have a grasp on what’s happening.”

Until Irma turns, forecasters can’t say what impacts will hit Florida. Irma is not only astonishingly intense, but large, with tropical storm force winds extending 185 miles from its center. By comparison, Hurricane Andrew, which leveled parts of South Florida in 1992, had winds extending just 90 miles from its center.

“We can’t tell you if the center is going to be 100 miles to the left of the center or the right,” Mayfield said. “That’s the uncertainty we’re dealing with until it starts turning.”

Florida could begin feeling tropical storm force winds late Friday or early Saturday, with hurricane conditions moving across the state over the weekend. Until it makes landfall, it’s expected to remain a dangerous Cat 4 or 5.

“The bottom line is nobody on the planet can tell you if the corner of the hurricane is going to be over us or just off the coast. It’s just too far out,” Mayfield said. “Even if they have a perfect forecast, and if it falls in the middle of the cone, we’re close enough to have impacts.”

Staff writer Kristen Clark and the Associated Press contributed to this story.