With peak winds of 295km/h, Hurricane Dorian is the strongest storm on record to strike the Bahamas, and it threatens to bring hurricane-force winds, coastal flooding and other impacts to the east coast of Florida and Southeastern US.
Dorian ranks as tied for the second-strongest storm (as judged by its maximum sustained winds) recorded in the Atlantic Ocean, behind Hurricane Allen of 1980, and it tied with the 1935 Labour Day Hurricane for the title of the strongest Atlantic hurricane at landfall.
As the storm closes in on Florida's east coast, the National Hurricane Center has posted hurricane and storm surge warnings for some areas. The hurricane warning stretches from Jupiter Inlet (just north of West Palm Beach) to the Volusia/Brevard county line (just north of Titusville). The storm surge warning spans from near West Palm Beach to Titusville. These warnings are focused on the period from Monday night through early Wednesday.
Although the center of Dorian, containing its extreme Category 5 winds, may remain offshore, its forecast track so close to the coast necessitated the warnings. "A small deviation to the left of the track could bring the intense core of the hurricane its dangerous winds closer to or onto the Florida coast," the Hurricane Center wrote in its 5pm discussion Sunday.
A "catastrophic" scenario is unfolding in the northwestern Bahamas, where the storm's eyewall, the ring of destructive winds around the center, struck Sunday. The storm made landfall at 12:40pm EDT in Elbow Cay, Abacos. The Hurricane Center reported that the storm is "heading with all its fury toward Grand Bahama."
"This is a life-threatening situation. Residents there should take immediate shelter. Do not venture into the eye if it passes over your location," the Hurricane Center warned. Specifically, the storm is unleashing wind gusts over 354km/h, along with storm surge flooding of 5m to 7m above normal tide levels.
"These hazards will cause extreme destruction in the affected areas and will continue for several hours," the NHC stated.
The storm is moving slowly toward Florida and the Southeastern United States, but its exact track remains somewhat uncertain, with computer models forecasting a move slightly closer to the coast early Sunday.
Florida may miss the full fury of this severe hurricane, but hazards are still possible. Coastal Georgia and the Carolinas also are at risk.
"Life-threatening storm surge and dangerous hurricane-force winds are still possible along portions of the Florida east coast by the middle part of this week," the Hurricane Center wrote.
Even while the majority of computer models predict that Dorian will remain just off the Florida coast, the National Hurricane Center is urging residents not to let their guard down and to continue preparing for an "extremely dangerous" hurricane and that landfall can still not be ruled out.
As of 5pm UST, the storm was 152km east of Freeport on Grand Bahama Island and was crawling west at 8km/h. The storm's peak winds are 285km/h, and Dorian has maintained Category 4 and Category 5 intensity for an unusually long period.
Storms this powerful typically tend to undergo cycles that weaken their high-end winds for a time, but Dorian has avoided this dynamic.
Over the northern Bahamas, the storm's core of devastating wind and torrential rain may sit for at least 24 hours as steering currents in the atmosphere collapse, causing Dorian to meander slowly, if not stall outright, for a time.
This forecast scenario could bring catastrophic wind damage, dump more than two feet of rain, and cause a storm surge, which is the storm-driven rise in water above normally dry land at the coast of at least 5.5m to 7m above normal tide levels.
In short, this is a storm that, depending on its exact track over the northern Bahamas, particularly Grand Bahama and the Abaco Islands, could reshape these locations for decades.
It's also extremely likely to be the second Category 5 hurricane to make landfall in the Bahamas since 1983, according to Phil Klotzbach of Colorado State University. The only other is Hurricane Andrew in 1992. The international hurricane database goes back continuously only to 1983.
The storm's peak sustained-winds rank as the strongest so far north in the Atlantic Ocean east of Florida on record. Its pressure, which bottomed out at 910 millibars, is significantly lower than Hurricane Andrew's when it made landfall in south Florida in 1992 (the lower the pressure, the stronger the storm), and data taken by Hurricane Hunter aircraft flying inside the storm show that Dorian may still be intensifying.
Florida preparing for the worst
Dorian has grown, which may have implications for the Florida forecast. Hurricane-force winds now extend outward up to 72km from the center and tropical-storm-force winds extend outward up to 220 km. The latest forecast from the Hurricane Center calls for Dorian to remain a Category 5 storm for 24 hours before slowly weakening, but remaining a formidable hurricane as it moves close to Florida and northward to the Carolinas.
Because it would take just a small shift in Dorian's track for hazardous winds to reach Florida's east coast, a tropical storm warning was issued for the zone from Deerfield Beach, just north of Fort Lauderdale, to Sebastian Inlet, just south of Melbourne. These warnings were expanded at 11am on Sunday, along with tropical-storm watches, in case high-speed winds move over a larger portion along the Florida coast.
"It is emphasised that although the official track forecast does not show landfall, users should not focus on the exact track. A small deviation to the left of the track could bring the intense core of the hurricane its dangerous winds closer to or onto the coast," the Hurricane Center stated.
While most models keep Dorian offshore Florida, the Hurricane Center wrote in its 11am Sunday advisory that a track near the coast or even landfall in Florida remain possibilities.
If the storm makes a close pass to Florida, tropical-storm-force winds could arrive as soon as Sunday night or early Monday morning. Because the storm is predicted to be a slow mover, effects from wind, rain and storm surge could be prolonged, lingering through the middle of next week.
Irrespective of the storm's ultimate course near Florida's east coast to the North Carolina Outer Banks - or even inland - significant coastal flooding is likely because of the force of Dorian's winds and high tides referred to as king tides.
The risk of a direct strike on Florida is less than it was a few days ago but has not been eliminated. Much depends on the strength of the high-pressure area that has been pushing Dorian west, toward the northern Bahamas and Florida.
Most models show steering currents collapsing as Dorian nears Florida before it gets scooped up by a dip in the jet stream approaching the East Coast and starts turning north.
However, this collapse in steering currents is so close to Florida that some models continue to track the storm close enough for damage in parts of the state. One trend in the models overnight on Saturday and Sunday morning has been to show the hurricane closer to the Florida coast and the Southeast coast, before making the northward turn.
In a statement, the National Weather Service forecast office in Melbourne, Florida, said "The situation has become more serious, especially for the east central Florida coastal counties," based on recent forecast guidance.
The latest storm surge forecast for Florida shows that if the peak surge occurs at the time of high tide, the area from the Volusia and Brevard County Line to Jupiter Inlet could see four to seven feet of water above ground, while the region from Deerfield Beach to Jupiter Inlet experiences two to four feet.
Scenarios involving a direct hit, a graze and a near miss appear equally likely based on available forecasts. As the Hurricane Center writes: "Residents in these areas should continue to monitor the progress of Dorian."
The shape of the coastline from northern Florida through the Carolinas means there is a risk of significant storm-surge flooding there even if the storm's center remains just offshore.
Unlike with notorious recent storms such as Matthew and Florence, it's unlikely that the Carolinas will experience devastating rainfall amounts from Hurricane Dorian, as the storm will pick up forward speed on nearing the Carolinas.
With Dorian attaining Category 5 strength, this is the first time since the start of the satellite era (in the 1960s) that Category 5 storms have developed in the tropical Atlantic in four straight years, according to Capital Weather Gang's tropical weather expert Brian McNoldy.