A weather system identified as Invest 93L by the National Hurricane Centre in Miami on Monday is forecast by some computer models to become a tropical cyclone in the western Caribbean later this week.

The large westward-moving weather system was centred around 65W in the eastern Caribbean Sea on Monday afternoon.

“This system is showing some signs of organisation and environmental conditions appear conducive for gradual development during the next couple of days,” the Hurricane Centre stated in an advisory, noting that there was a 30 per cent chance of the system becoming a tropical cyclone by Wednesday afternoon.

In his blog on the Weather Underground website, meteorologist Jeff Masters called the system “a major concern”.

“This disturbance... has the best chance to become Tropical Storm Alex of any system we’ve seen so far this year,” he wrote.

Masters noted that weather conditions in front of the storm were favourable for development.

“With wind shear expected to drop to low values less than 10 knots over the central and western Caribbean this week, I don’t see any major impediments to the storm becoming a tropical depression by Friday,” he wrote. 

“Expect 93L to bring flooding rains of 3 - 6 inches to Jamaica, eastern Cuba, and extreme south western Haiti on Wednesday,” he added. “These rains will spread to the Cayman Islands and central Cuba by Thursday.”

The Cayman Islands National Weather Service forecast periods of rain and thunderstorms Wednesday through Friday.  Chief Meteorologist John Tibbetts said the forecast didn’t take into account any specific impact from Invest 93L.

“Not at this point,” he said, adding that the Weather Service would constantly monitor the system.

Mr. Tibbetts said the upcoming rains were “almost typical” for the season.

“We’ve got a number of tropical waves coming across [the Caribbean Sea] and the moisture pattern is one that supports a long period of cloudiness and showers,” he said.

The weather system is of particular concern to the oil-spill-stricken Gulf of Mexico. The leading European weather model, which has been the most accurate at forecasting tropical cyclones in the Atlantic Basin over the past three years, shows the system becoming a major hurricane in the Gulf next week.

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