Tropical Depression 15 forms, could soon become Nigel and next hurricane danger in Atlantic
An area of showers and thunderstorms that moved off the western coast of Africa earlier this week is expected to become the next tropical storm in the Atlantic, and according to AccuWeather hurricane experts, it could bring impacts to Bermuda and perhaps the eastern United States later next week.
The developing storm, which was dubbed Tropical Depression Fifteen by the National Hurricane Center (NHC) at midday on Friday, will likely be named Nigel. The storm could follow a path similar to that of Lee over the past week. Lee, a large hurricane, was approaching eastern New England and Atlantic Canada and is forecast to make landfall there this weekend.
Because the expected path of the new storm and its risk for strengthening could mirror Lee, interests along the East Coast of the U.S., Bermuda and southeastern Canada should monitor it closely. Indirect impacts could begin as early as the middle of next week.
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While Lee was still churning in the Atlantic, AccuWeather meteorologists were highlighting another area in the central Atlantic for likely development. This system, which was a tropical wave over the past week, is the latest in a series that has moved off the African continent and will be moving west into the central Atlantic this weekend.
There is a high risk for additional strengthening of this system not only to a tropical storm but also a hurricane as it moves across the central Atlantic this weekend, AccuWeather Senior Meteorologist Adam Douty said.
The factors driving the potential for strengthening as the system moves to the west are very high ocean water temperatures and light winds higher up in the atmosphere fighting the storm, known as wind shear to meteorologists. The same conditions led to an explosive strengthening in Hurricane Lee last week. It became the first Category 5 hurricane with maximum sustained winds in excess of 157 mph (252 km/h) on the Saffir-Simpson Hurricane Wind Scale (SSHWS) in the basin this season.
Steering winds in the short term should take the new storm away from a direct impact with the Leeward Islands early next week, but swells generated by the storm will make for rough surf and dangerous rip currents there as early as this weekend. It is also not out of the question that some outer rain bands could eventually bring downpours and gusty winds to the far northern islands.
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Lee (circled in purple) and Margot (circled in white), and Tropical Depression Fifteen that is expected to become Nigel (circled in blue), as seen on AccuWeather RealVue™ Enhanced Satellite on Saturday, Sept. 16, 2023. |
It is just days after the climatological peak of hurricane season in the Atlantic. Given ripe conditions for development in the basin, the ceiling for strengthening with the next storm is high, according to AccuWeather experts.
"With the next storm potentially tracking over deep warm water, it's not out of the question it can become another major hurricane and perhaps even a Category 5 storm," AccuWeather Hurricane Expert Dan Kottlowski said.
A major hurricane is defined as a Category 3 or stronger storm on the SSHWS, meaning that it would pack winds of at least 111 mph (178 km/h).
Lee strengthened into a Category 5 hurricane rapidly last week, but the next storm's evolution to a major hurricane could be more gradual if it directly mirrors Lee's path. This is because Lee stirred up the warm ocean waters, creating slightly lower water temperatures in its wake due to a process called upwelling, which brings deep, cooler water to the ocean's surface.
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Despite the prospects of upwelling, the Atlantic waters are still relatively warm in the wake of Lee and may not significantly hinder the development of the new tropical feature. As of Saturday, water temperatures were around 80 to 85 degrees Fahrenheit (27 to 29 degrees Celsius), more than warm enough to promote tropical storm development and intensification.
Ever since the system emerged off the coast of Africa, AccuWeather began honing in on the potential for impacts from this storm down the road.
"This next system is one to watch as a potential threat to the East Coast of the United States given how strong the Bermuda high-pressure area will be as it builds westward across the Atlantic," said Kottlowski. "With that and the upper-level wind pattern factored in, we could see this storm coming toward the United States."
The location of that high pressure centered over the open northern Atlantic was key in determining where Lee tracked this week, and the same will be the case for the next storm. Another determining factor in the longer term will be any potential cold fronts moving off the coast of the eastern United States.
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Similar to the early days of tracking Lee, there appear to be two possible scenarios later next week: a track more out to sea or one toward the East Coast.
If the area of high pressure is stronger and builds more toward the northeastern U.S., steering winds can pull the storm closer to the East Coast. However, if the high doesn't build toward the Northeast and is weaker, the storm will tend to steer close to Bermuda or perhaps even farther to the east and out to sea.
With either scenario, the archipelago of islands that make up Bermuda could be the first to feel direct impacts from the new storm by the middle of next week.
"Even if the storm remains offshore of the eastern U.S., the impacts in Bermuda could be more significant [than with Lee]," added Kottlowski.
Hurricane Lee spread wind and rain to the islands through Friday as a Category 1 hurricane. If the next storm is a stronger system that tracks even closer, the impacts would be substantially more elevated.
Regardless of the final destination with the next storm, indirect impacts are a near lock from the Bahamas to Bermuda and along the entire U.S. East Coast into Atlantic Canada. They will come in the form of dangerous wave action and rip currents, which pose a threat to swimmers at unguarded beaches.
AccuWeather Meteorologist Elizabeth Danco contributed to this story.
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