Tropical Storm Ernesto barrels through Caribbean; It's to become the Atlantic's next major hurricane

The next named storm of the 2024 Atlantic Hurricane Season has taken shape and is forecast to strengthen this week.

On the heels of Hurricane Debby, AccuWeather hurricane experts are tracking the latest tropical system, Tropical Storm Ernesto, across the central Atlantic Ocean, as it sweeps through the Caribbean bringing heavy rain, strong winds and rough surf into midweek.

Late Saturday, Aug. 10, AccuWeather initiated a forecast track map for a tropical rainstorm, highlighting the risk for impactful weather across the Caribbean and Bermuda. At Monday, 5 p.m. EDT, the tropical rainstorm strengthened and became a tropical storm (sustained winds of 39-73 mph on the Saffir-Simpson Hurricane Wind Scale), claiming Ernesto as the next name on the 2024 Atlantic Hurricane Season storm lineup.

At 8 a.m. EDT, Wednesday Ernesto was just under hurricane strength with 70-mph winds and moving northwest at 16 mph. The tropical storm was located about 125 miles to the northwest of San Juan, Puerto Rico.

Tracking into anomalously warm waters

Forecasters continue to warn that this feature could ramp up to at least a Category 1 hurricane as it travels across the warm waters just north of Puerto Rico and Hispaniola on Wednesday. Sea-surface temperatures across this zone in the Atlantic are well above the minimum threshold required for tropical development (>26º C, or 78.8º F), currently reading between 28-30º C (82.4-86º F).

"Ocean temperatures across the Atlantic basin as a whole remain near record levels, only trailing 2023 values," explained AccuWeather Meteorologist and Lead Hurricane Expert Alex DaSilva.

Ocean Heat Content, a measure of how much energy and warmth is absorbed by the sun and takes into account the depth of how far that warm water extends vertically, is also at near-record levels in the Main Development Region. Not only are water levels anomalously warm at the surface, the elevated ocean temperatures extend hundreds of feet down below the ocean's surface.

"Factors such as near-record ocean heat content levels can help to significantly contribute to the rapid intensification of hurricanes. Both Hurricane Beryl this year and Hurricane Ian in 2022 took advantage of very high sea-surface temperatures and ocean heat content, which allowed these storms to rapidly intensify as a result," added DaSilva.

AccuWeather hurricane experts warn that areas of the northwestern Leeward Islands, Puerto Rico and eastern Hispaniola will continue to be impacted by Ernesto on Wednesday as the storm takes a general west-northwesterly track. Wind shear is forecast to be pretty light as the storm moves through the northeastern Caribbean Islands, which will allow Ernesto to maintain tropical storm strength.

After moving through the islands, the storm will likely be drawn to the north by an amplified southward dip in the jet stream, pulling it away from the Bahamas and the United States. Even though these areas are likely to avoid direct impacts from Ernesto, a strengthening storm will allow strong waves to reach the beaches, leading to dangerous seas and rip currents for the Southeast.

At this time, Ernesto is expected to veer northward around midweek and then slightly northeast by late week. AccuWeather meteorologists believe that Ernesto will become the Atlantic's next major (Category 3 or stronger) hurricane and could pass close to Bermuda by the upcoming weekend.

Meteorologist Emma Belscher noted that while the storm is expected to journey near Bermuda, if it takes a longer westward track through the Caribbean initially, it could be pushed closer to the East Coast.

Beyond Bermuda, Nova Scotia and Newfoundland could feel impacts from Ernesto in the form of strong winds, heavy rain and rough seas early next week.

Intense rainfall and boisterous winds to impact the islands

As Ernesto advances across the northeastern islands of the Caribbean during midweek, including the U.S. and British Virgin Islands, and Puerto Rico, it will deliver rounds of squally rain, gusty winds and rough seas and surf.

Heavy rain from this feature will pose the risk for flash flooding, mudslides and washouts across the islands, especially across the mountainous terrain. In general, tropical rainfall totals will range up to 4-8 inches for the British and U.S. Virgin Islands and Puerto Rico.

Gusty winds can be expected through midweek as Ernesto barrels across the northeastern Caribbean Islands. Gusts can exceed 80 mph in Puerto Rico as the center of the storm passes through the region. Winds can even surpass 100 mph, primarily over water, as the storm strengthens and begins a more northwest to northerly course on Wednesday.

Due to impacts of flooding rain, gusty winds and storm surge from Ernesto, the AccuWeather RealImpact™Scale for Hurricanes is a 1 across the Northeast Caribbean and a 3 in Bermuda.

2024 Atlantic Hurricane Season

AccuWeather meteorologists insist that a super-charged Atlantic hurricane season will unfold this year, with a large number of tropical storms and hurricanes. Some storms are likely to undergo rapid intensification due largely to the ongoing higher-than-historical average water temperatures.

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