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Hurricane Irma on a collision course with Florida

  • In this geocolor image captured by GOES-16 and released by the National Oceanic and Atmospheric Administration, Hurricane Irma, a potentially catastrophic category 5 hurricane, moves westward Tuesday morning in the Atlantic Ocean. NOAA via AP



Washington Post
Tuesday, September 05, 2017

Hurricane Irma is an “extremely dangerous” Category 5, barreling toward the northern Lesser Antilles and Southern Florida. It’s already the strongest hurricane ever recorded outside the Caribbean and the Gulf of Mexico, and it’s likely to make landfall somewhere in Florida over the weekend.

If it does, the impact could be catastrophic.

The storm is life-threatening for the United States, including Puerto Rico, the U.S. and British Virgin Islands, the Dominican Republic, Haiti, Cuba and the southeastern Bahamas. Hurricane warnings have been issued for the northern Leeward Islands, Virgin Islands, and Puerto Rico. A hurricane watch is in effect for Hispaniola and southeastern Bahamas.

With maximum winds of 185 mph, Irma is tied for the second strongest storm ever observed in the Atlantic. And in its Tuesday morning discussion, the National Hurricane Center said the storm is in an environment “ideal for some additional intensification.”

The hurricane is expected to remain at least a Category 4 for the next few days with minor fluctuations in intensity. It could even become slightly stronger, but it is already nearing historical precedent and a theoretical limit for how strong it can get.

It cannot be overstated that Hurricane Irma is extremely dangerous and will produce the full gamut of hurricane hazards across the Caribbean and potentially in South Florida, including a devastating storm surge, destructive winds and dangerous flash flooding.

All of Florida – especially South Florida and the Keys – should be preparing for a major hurricane landfall on Sunday. Tropical-storm-force winds are expected to arrive as soon as Friday.

Mainland U.S. landfall threat

Computer models are in strong agreement that by Saturday, Irma will be approaching the Florida Keys - where dangerous storm conditions are likely. Then, they show a sharp northward turn by Sunday morning. The precise timing and location of the turn has huge implications for Florida.

It is impossible to say with certainty whether Irma will track up along the eastern side of the Florida peninsula, the western side, or straight up the peninsula. Since the weekend, models have generally shifted westward with the storm’s forecast track, which means interests along the coast of the Gulf of Mexico should also closely monitor this storm.

For a major hurricane, the exact track of the storm’s eyewall – the zone surrounding its calm center – is critical as it will determine where the most severe effects tend to concentrate. The most violent winds coincide with the eyewall, and the biggest storm surge occurs just to its right (or north).

But as Irma is such a large and powerful hurricane, very dangerous weather will also occur up to 200 miles away from the eyewall – including coastal surge, flooding rains and potentially damaging winds.

“The hurricane force winds in Irma are wider than Florida,” tweeted Bryan Norcross, hurricane specialist at the Weather Channel. “You won’t need a direct hit to get Wilma-type winds & storm surge on both coasts.”

Beyond the weekend, the scenarios really depend on which side of Florida the hurricane tracks. But for now, it’s safe to say that the southeast United States, including the Florida panhandle, Georgia and the Carolinas, should also brace for potential impacts, such as flash flooding, storm surge and hurricane-force winds.