As of Tuesday night, tropical storm conditions had reached Florida’s Space Coast. Although Dorian is no longer the Category 5 powerhouse it was on Labor Day, it has grown in size, and it’s capable of moving more water toward the shore than a smaller storm of similar intensity. As it moves parallel to the Florida coast, its expanding swath of tropical storm and hurricane force winds will push north, into coastal Georgia, while driving dangerously high surf toward the shoreline, resulting in coastal flooding and beach erosion.
Now a strong Category 2 storm, Dorian slammed into the northwestern Bahamas over the weekend with the historic full fury of its 185-mile-per-hour winds and 23-foot storm surge. Video and images emerging from the Bahamas show a toll of absolute devastation on Great Abaco and Grand Bahama Islands, two locations where the eye of the storm made landfall.
The storm’s growing wind field is capable of producing a damaging storm surge along the coasts of Florida, Georgia and the Carolinas, and hurricane warnings and watches have been hoisted from the Florida coastline northward to the North Carolina Outer Banks. A storm surge watch is in effect all the way north to Hampton Roads, Virginia.
Tropical-storm conditions, with sustained winds of greater than 39 mph, have been observed along Florida’s Treasure and Space Coasts, and and are expected to move farther north toward Jacksonville into Wednesday morning. Hurricane conditions, with sustained winds of at least 74 mph, are possible if the storm wobbles westward.
However, the strongest winds are more likely to occur further north of Florida, as the storm hugs the coastline while being directed to the north-northeast by a dip in the jet stream to its west.
The Hurricane Center projects a life-threatening storm surge and dangerous winds from coastal Georgia to the North Carolina Outer Banks, “regardless of the track of Dorian’s center."
The latest on Hurricane Dorian
As of 11 p.m. on Tuesday, the storm was 95 miles east of Cape Canaveral, Florida and moving northwest at 6 mph. The storm’s peak sustained winds were 110 mph, making it a high-end Category 2 storm. Dorian is expected to maintain its current intensity through Thursday, while growing in size.
Hurricane-force winds extend outward up to 60 miles from the center and tropical-storm-force winds extend outward up to 175 miles. The Hurricane Center wrote the area of hurricane-force winds is likely to expand some in the next 24 to 36 hours.
Radar from Central Florida showed Dorian’s outer rain bands pivoting inland producing heavy rain and strong winds. Wind gusts have reached up to around 60 to 70 mph along the Space Coast.
As the storm drove the ocean inland Tuesday, social media photographs showed the sea reaching the dunes at Satellite Beach, which is just north of Melbourne:
“We have received reports of significant coastal flooding and major beach erosion from Sebastian Inlet south to Saint Lucie Inlet, along the barrier islands and Intracoastal Waterway,” the Weather Service office in Melbourne tweeted on Tuesday.
The office stated that it is “expecting worse conditions” for the midnight high tide along the Space Coast.
Forecast for northeastern Florida
The forecast track keeps the storm’s most dangerous winds and highest levels of storm-surge flooding from coming ashore in the Sunshine State, but brings the storm close enough to bring heavy rains, damaging winds and storm surge flooding to the east coast of Florida.
However, hurricanes do not always behave as forecast. Despite being Earth’s most massive and powerful storms, they’re remarkably sensitive to internal and external hiccups. These storms can wobble east or west as they move generally north, for example, like a spinning top on a table.
However, if the storm stays on its present course, the coast is likely to only experience tropical storm conditions.
Hurricane warnings are in effect for much of the Florida east coast from Sebastien Inlet north.
The National Hurricane Center is warning that “life-threatening storm surge and dangerous hurricane-force winds are expected along portions of the Florida east coast.” In addition, water levels along the coast northward to the Carolinas are forecast to rise “well in advance of the arrival of strong winds.” For example, the Weather Service forecast office in Charleston, South Carolina is forecasting that storm surge flooding may begin to occur on Wednesday morning, well ahead of the storm’s center of circulation.
Areas that are especially vulnerable to storm-surge flooding, such as Jacksonville, Fla., could once again see significant flooding depending on the exact track and timing of the storm.
In Florida, the latest storm-surge forecast shows that if the peak surge occurs at the time of high tide, the area north of Volusia County could see three to five feet of water above ground. The surge is forecast to reach 2 to 4 feet in the zone farther south from Jupiter Inlet through Volusia County.
Rainfall along the Florida coast could reach 3 to 6 inches.
Forecast for coastal Georgia, Carolinas and Virginia
Conditions are expected to deteriorate early Wednesday in coastal Georgia and mid-morning to afternoon in South Carolina. Where and whether Dorian makes landfall will depend on the exact trajectory of its turn relative to the coast as it heads north and then starts to bend northeastward, but computer model projections on Tuesday evening showed an increasing likelihood of either a near miss or that the eye of the storm would make landfall.
The impacts between a near miss and landfall are insignificant in this case, since the storm no longer has a tightly wound core, but rather is a far broader system than it was when it tore across the Bahamas.
“Even if Dorian does not make landfall, hurricane-force winds are expected to reach portions of the coast from central Florida to North Carolina,” the Hurricane Center stated.
A tropical storm warning is in effect for coastal Georgia, while a hurricane warning covers the entire South Carolina coast north to Surf City, North Carolina. A hurricane watch spans from Duck to the North Carolina/Virginia border.
The Georgia and South Carolina coastlines are particularly vulnerable to storm surge flooding, even from a storm that does not make landfall, due to the shape of the land on and just offshore, as well as the effects of sea level rise and land subsidence over time. The surge could reach 3 to 5 feet in Georgia and 4 to 7 feet from the South Carolina coast north to Cape Lookout, North Carolina. Further north, the possibility of a 2-to-4-foot surge exists north to Hampton Roads, Virginia.
The Weather Service forecast office in Charleston, South Carolina is forecasting that storm surge flooding may begin to occur there on Wednesday morning, well ahead of the storm’s center of circulation. Heavy rains of 6 to 10 inches or more could worsen the surge-related flooding by impeding drainage back out to sea.
In fact, depending on the timing of the maximum storm surge, Charleston could see this storm bring one of its top 5 water levels on record.
According to the Weather Service office in Charleston, based on the present forecast track, the result could be particularly severe. Among the possible effects, it listed: “Large areas of deep inundation with storm surge flooding accentuated by battering waves. Structural damage to buildings, with several washing away. Damage compounded by floating debris. Locations may be uninhabitable for an extended period.”
Locations farther north from Virginia Beach to the Delmarva and even up to Cape Cod could get clipped by the storm Friday and Saturday, with heavy rains, tropical storm force winds and coastal flooding.
A tropical storm watch is in effect from the North Carolina/Virginia border to Chincoteague, including the Virginia Beach area, as well as the Chesapeake Bay from Smith Point southward.
“The risk of wind and rain impacts along portions of the Virginia coast and the southern Chesapeake Bay are increasing,” the Hurricane Center wrote. “Residents in these areas should continue to monitor the progress of Dorian.”
Model forecasts and uncertainties
While computer model projections all show that Hurricane Dorian will remain just offshore Florida’s coast, there is some uncertainty in the forecast farther north.
Whereas on Monday many computer models suggested Dorian may not make landfall anywhere on the East Coast, more forecasts on Tuesday and Tuesday evening suggest the storm center could come ashore in the Carolinas.
“The track envelope has edged closer to the coasts of South Carolina and North Carolina and the NHC track has been adjusted in that direction,” the Hurricane Center wrote on Tuesday afternoon. “A track that close to the coast, even if landfall does not occur, is likely to bring dangerous winds, life-threatening storm surge, and flooding rains across the eastern portions of the Carolinas.”
For example, the Weather Service increased its rainfall forecast for North Carolina, including the Outer Banks, to 5 to 10 inches, with isolated 15-inch amounts.
Northwest Bahamas took a nightmarish, 40 hour direct hit
Grand Bahama Island has suffered an onslaught from this storm that few places on Earth have experienced, remaining in the eyewall of a major Category 4 or 5 storm for 40 hours. The eyewall is the region of the storm surrounding its center that contains its strongest winds and generates the most destructive storm-surge flooding.
This is a storm that may have reshaped the northwestern Bahamas, particularly Abaco and Grand Bahama Island, for decades.
As Dorian approached over the weekend, the Hurricane Center used dire language to describe the threat, including the word “catastrophic.” Unfortunately, it appears that was the result, particularly in the Abaco Islands and on Grand Bahama Island.
Typically hurricanes move fast enough to expose one spot to their full fury for a few hours or less. But in this case, the storm reached Grand Bahama and stopped moving, with Hurricane Hunter aircraft finding essentially no movement each time they got to the storm’s center. In addition to wind gusts up to 220 mph and a 23-foot storm surge, up to 40 inches of rain may have fallen in some areas.
According to one analysis, Dorian has been the slowest-moving major hurricane ever observed in the Atlantic. Between 3 a.m. on Labor Day and 5 a.m. on Tuesday, the storm moved just 30 miles in 28 hours.
While grim news is emerging from Abaco, it may take longer to get a detailed picture of how Grand Bahama Island, where Freeport, a city of about 27,000, is located, fared in the storm. On Monday evening, the Hurricane Center released a statement saying it expected additional “extreme destruction” on the island overnight due to a combination of extreme winds and storm surge flooding.
Although the worst of the storm had lifted north of the northwestern Bahamas Tuesday afternoon, the Hurricane Center warned dangerous winds and a life-threatening storm surge could persist into the evening.
Dorian’s place in history
Dorian is tied for the second-strongest storm (as judged by its maximum sustained winds) ever recorded in the Atlantic Ocean, behind Hurricane Allen of 1980, and, after striking the northern Bahamas, tied with the 1935 Labor Day Hurricane for the title of the strongest Atlantic hurricane at landfall.
It is only 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).
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 for four straight years, according to Capital Weather Gang tropical weather expert Brian McNoldy.
The unusual strength of Dorian and the rate at which it developed is consistent with the expectation of more intense hurricanes in a warming world. Some studies have shown increases in hurricane rapid intensification, and modeling studies project an uptick in the frequency of Category 4 and 5 storms.
Dorian may have also set a record for the longest period of Category 4 and 5 conditions to strike one location in the North Atlantic Basin since the dawn of the satellite era, but historical data is relatively sparse.