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Capital Weather Gang

Strengthening Hurricane Dorian is a growing threat to Florida Labor Day weekend

Dorian could be a major Category 3 hurricane as it approaches the mainland United States.

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August 29, 2019 at 5:40 a.m. EDT
Hurricane Dorian is drifting west-northwest at just 1 mph towards the southeast U.S. on Sept. 2 as its path remains uncertain. (Video: The Washington Post)

This story was last updated very early Thursday morning and will no longer be updated.

For the latest on Dorian throughout the day Thursday, see our latest article: Hurricane Dorian: Florida on guard for potential major hurricane strike

As it barreled through the U.S. Virgin Islands and scraped eastern Puerto Rico, Dorian intensified from a tropical storm to a hurricane on Wednesday.

Pulling away from Puerto Rico, the storm continued strengthening, with maximum sustained winds near 85 mph and higher gusts as of 5 a.m. Thursday.

And even more strengthening is predicted.

Late in the weekend and into early next week, Dorian is forecast to approach the Florida coast as a major Category 3 hurricane with 125 mph winds and dump 4 to 8 inches of rain, with isolated areas receiving up to 12 inches.

“All indications are that by this Labor Day weekend, a powerful hurricane will be near or over the Florida peninsula,” the National Hurricane Center said Wednesday.

Florida Gov. Ron DeSantis (R) declared a state of emergency Wednesday afternoon “to ensure local governments and emergency management agencies have ample time, resources and flexibility to get prepared,” he posted to Twitter.

Increasing risk of direct impacts in Florida and Southeast U.S.

Based on the latest model forecasts, landfall along Florida’s east coast seems most likely, timed between Sunday evening and Monday morning. That said, shifts in Dorian’s projected track are inevitable considering the storm is still over four days away from land.

While the east coast of Florida is the most likely landfall target, additional possible scenarios include tracks farther north toward southern Georgia or even south over the Florida Keys. There is a small chance the storm will recurve out to sea and miss the Lower 48.

Louisiana, Mississippi, Alabama and the Florida Gulf Coast should also monitor the storm, as there is a scenario in which it crosses the Florida peninsula, enters the Gulf and then makes a second landfall.

Because Dorian did not interact with the high terrain of the Dominican Republic or Puerto Rico, it is now forecast to steadily strengthen. There is little holding Dorian back, and computer models show it has the potential to rapidly intensify to a major hurricane — Category 3 or greater.

“Dorian’s unanticipated northward jog changes a few things, all for the worse,” wrote Brian McNoldy, the Capital Weather Gang’s tropical weather expert. “It significantly increases the odds of a hurricane landfall in the southeast U.S. later this weekend.”

Models also show an expanding storm with an increasingly large wind field as it approaches the mainland United States over the weekend. Some modeling indicates a significantly elevated likelihood of rapid intensification, in which the storm’s peak winds could increase substantially in a short time interval (at least 35 mph in 24 hours).

The potential for rapid strengthening is particularly concerning, considering that high tides along the East Coast will be running unusually high as “King Tides” could cause coastal flooding in the absence of any storm, and could exacerbate storm surge effects from Dorian.

Effects on Puerto Rico and the U.S. Virgin Islands

Hurricane Dorian appeared to spare Puerto Rico on Aug. 28, weaving an erratic path in an area still recovering from Hurricane Maria’s destruction from 2017. (Video: Juan C. Dávila/The Washington Post)

Much of Puerto Rico escaped the brunt of Dorian as the storm passed slightly to the east, directly over St. Croix and St. Thomas.

Bob Henson at Weather Underground summarized some of the observed effects on Puerto Rico and the U.S. Virgin Islands:

Winds on the south shore of Saint Thomas peaked at a sustained 72 mph between 1:17 and 1:27 pm EDT Wednesday, with gusts as high as 97 mph. Saint Thomas was in the developing northern eyewall of Dorian at the time.
On the weaker south side of Dorian’s circulation, Christiansted on Saint Croix in the U.S. Virgin Islands had peak sustained winds of 34 mph, gusting to 44 mph, at 11 am EDT Wednesday. Puerto Rico escaped seeing tropical storm-force winds from Dorian; Puerto Rico’s highest winds were 27 mph, gusting to 45 mph, on Culebra Island, off the northeast coast of mainland Puerto Rico. ...
The greatest rainfall from Dorian recorded on a WU Personal Weather Station was at ISTTHOMA12 on St. Thomas, which had 5.66” as of 6:30 pm EDT. The highest rainfall amount in Puerto Rico was 1.36” at Fajardo.

Florida should prepare now

Residents in Florida, especially in coastal areas along its east coast, should begin preparing for this storm. Have a plan of action and a hurricane kit ready, and stay tuned for updates as this forecast comes further into focus.

The Capital Weather Gang will post its latest in-depth briefing on Dorian by around 10 a.m. Thursday.