An ultra-rare tropical storm could form in the Atlantic this week
Forecasters are watching a system deep in the tropics that could defy the odds to become a named storm this week
We’re in an incredibly strange period of weather across the western parts of the Northern Hemisphere of late. The recent patterns have brought deadly heat to central Mexico, hail the size of DVDs to the southern United States, snow to as low as 1800 m in British Columbia, and almost a week of 30-degree heat on the way in far northern Ontario.
Now, we can add a likely tropical storm to that list. Tropical storms on their own aren’t uncommon in the middle of June, but a system rolling off Africa and developing deep in the Atlantic is an extremely rare feat this early in the year.
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High odds of a tropical depression or named storm this week
Meteorologists with the U.S. National Hurricane Center (NHC) are closely monitoring a tropical disturbance about halfway between Africa and the Lesser Antilles for the potential that it could develop into a tropical depression by early this week.
The latest forecast gives the system a high (80 per cent) chance of developing by Tuesday morning and 90 per cent chance in the next seven days.
This system, which the NHC has dubbed 92L for tracking purposes, is a healthy tropical wave that rolled off the western coast of Africa late last week.
Thunderstorms embedded within this disturbance have grown more robust and organized over the weekend, giving forecasters increased confidence in the potential development of a tropical depression soon.
Unusually low wind shear, decent moisture throughout the atmosphere, and very warm sea surface temperatures are all factors that will likely help this system defy the odds and grow more organized this week.
A strong ridge of high pressure nestled over the central Atlantic Ocean will steer this system west-northwest through the middle of the coming workweek, potentially strengthening into the second named storm of the 2023 Atlantic hurricane season.
If this system strengthens into a tropical storm, it would be called Bret.
It’s far too soon to say what, if any, impacts this system could have on land. Current guidance shows this system could stick around a while. As with any storm, coastal residents from Aruba to the Avalon Peninsula should watch the progress of this system as it moves through the Atlantic Ocean.
While this would be the season’s second named storm, it’s actually the season’s third storm. Our first system was an unnamed subtropical storm that formed south of Nova Scotia in January. Forecasters didn’t issue advisories on it at the time, opting instead to add it to their records upon reviewing the data in the middle of May.
Temperatures across the entire Atlantic Ocean are much warmer than normal, to an extent that’s surprised many experts who track global ocean temperatures. While a growing El Niño would act to subdue Atlantic hurricane activity under normal conditions, the Atlantic’s unseasonable warmth could counteract that effect and give this season a boost.
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Tropical activity ramps up through the summer months before reaching its peak between mid-August and mid-September, though storms are possible from now through at least the end of November.
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This storm’s location is an extreme outlier in recorded history
It’s quite unusual to have a developing tropical system in this part of the Atlantic Ocean during the month of June. Tropical systems in the Atlantic tend to follow a predictable pattern as the season wears on.
Early-season tropical storms usually develop in the Caribbean, Gulf of Mexico, or far western Atlantic. Cold fronts or thunderstorm complexes rolling off land can stall once they reach these relatively balmy ocean waters, providing the seed needed to develop a weak and short-lived tropical system.
As we get deeper into the summer months, tropical activity reaches farther east into the tropical Atlantic Ocean. The stretch of the Atlantic between the Lesser Antilles and the Cabo Verde Islands is often called the main development region.
The annual monsoon in sub-Saharan Africa allows vivid clusters of thunderstorms to roll off the continent’s west coast on a regular basis.
These tropical waves stream into the Atlantic’s main development region, where the hot summer sun has settled the atmosphere and warmed the surface of the sea, providing the necessary ingredients for storms to develop and flourish.
Only three other June storms recorded this far east
While that’s how things typically go, some storms take advantage of optimal conditions to break the rules and grow into outliers.
Since reliable hurricane records began in the late 1800s, there have only been three other tropical storms that formed this far east in the Atlantic in the month of June.
A hurricane that spun up in the far eastern Atlantic back in June 1933 hit Trinidad, Cuba, and Mexico as a hurricane during its long lifespan. 1979’s Tropical Storm Ana and 2017’s Tropical Storm Bret also formed just east of the Lesser Antilles.
Stay with The Weather Network this hurricane season for the latest information and forecasts.
