Irma ramps back up to Cat 4 for expected dawn strike in Keys

Its strength bounding up and down like a meterological yo-yo in the wake of a day of hovering over Cuba, Hurricane Irma reached Category 4 status again early Sunday morning as it continued to crawl toward the Florida Keys.

Now about 70 miles southeast of Key West, the hurricane is lumbering northwest at a speed of 6 mph. “Irma is expected to cross the lower Florida Keys during the next several hours, and then move near or along the west coast of Florida,” the National Hurricane Center said in its 2 a.m. advisory.

The storm’s continued westward movement has likely spared the Miami area the storm’s worst wrath. Even so, Irma’s immense size and strength — pushing hurricane-force winds outward up to 70 miles from the center and tropical-storm force winds to 205 miles — mean it can wreak considerable havoc in Miami-Dade and Broward counties, even from a distance.

And the Keys will fare much worse. The wind gauge atop the National Weather Service’s Key West Office recorded a hurricane-force gust of 79 mph in the early morning hours Sunday. With Irma’s strongest winds and eyewall not expected to arrive until daybreak, the outlook is not good.

Chip Casper, a senior forecaster for the Service, told The Weather Channel that Irma would be worst for the Keys since Donna in 1960, which crossed Marathon as a Cat 4 with 130 mph winds.

But Irma was a much larger storm, he said, and on a path closer to Key West. It could first inundate city streets with sea water, then pound it with major hurricane winds for 12 hours or more.

“We are expecting a very damaging storm storm surge just before sunrise,” he said.

Wind shear, a force that weakens hurricanes, built up while Irma loitered almost 24 hours over Cuba, the center said, dropping the storm to a Category 3. But it has already picked up strength as it moves away from land and over warm water and will continue to do so as it takes a north-by-northwest track up Florida’s Gulf Coast, the hurricane center said.

One possible target up the coast: the Tampa-St. Petersburg area, which hasn’t suffered a direct hit from a powerful hurricane in more than 90 years.

Meanwhile, powerful winds and stinging raid continue to buffet Miami-Dade and Broward Counties.

A tornado was sighted in Oakland Park Saturday night, and the National Weather Service issued a tornado for every place between Monroe and Palm Beach counties. Florida officials urged residents not to let down their guard against Irma or assume that the storm’s worst has already passed, which is surely not true.

“Don’t be the guy that gets killed by the tree, all right?” U.S. Senator Marco Rubio said at a press conference, warning people against leaving their refuges. “Every year, we have it – the guy that’s standing around, the tree falls on their head. Don’t be the guy or gal that gets killed by the tree.”

While the forecast track shows the storm’s center crossing south of Big Pine, fierce winds and storm surge will likely be widespread. Water could as high as 10 feet throughout the Keys. From Card Sound Road to Miami Beach, a four- to six-foot surge is possible, hurricane center officials said.

Ed Rappaport, the acting director of the hurricane center, said Hurricane Irma’s impending visit to the Florida Keys and the state’s west coast is “capable of causing loss of life and major damage.”

Irma’s jog to the west caught much of the Gulf Coast by surprise. At midday Saturday, the plywood sheets and metal window shutters so ubiquitous in South Florida were still comparatively rare in St. Petersburg.

As for the Keys, their relationship with hurricanes is intimate and infamous, going back in recorded history at least to the early 17th century.

Over the past 100 years, the islands have been struck by a hurricane an average of one every 4.5 years — most disastrously on Labor Day weekend of 1935, when a nameless storm with 200 mph winds killed as many as 485 people and an entire railroad, the Keys extension of the the Florida East Coast Railway, which was totally wrecked and never rebuilt.

The Keys were already taking punches from Irma on Saturday. Tropical-storm force winds pounded the islands, pushing storm surge ashore. Water levels were up throughout the day, rising nearly a foot above normal in Key West after 4:30 p.m. and more than a foot near Vaca Key.

The toll extended to many other areas of the state. Florida Gov. Rick Scott said in a news conference Saturday that 76,000 people were without power, and that the number of outages would only grow as the storm gets closer.

Irma has killed more than 20 people and left a wide swath of destruction as it smashed its way through Caribbean resort islands like Saint Martin, St. Barts, St. Thomas, Barbuda and Antigua.

And little is known of the damage Irma did to Cuba, where it lingered much of the day Saturday. It struck the island as a Category 5 storm and moved away as a Category 3. It lashed the island with such fury that the government began moving people into underground military bunkers built decades ago when the Castro regime expected war with the United States.

But not much news has emerged since Irma reached Cuba. The national electric company announced that high winds were forcing it to cut power to Havana, and the Ministry of Communications said it was shutting down all public wi-fi receivers in the capital.

Miami Herald staff writers Kyra Gurney and Curtis Morgan contributed to this report.