Tropical wave south of Cayman expected to develop

Coming two weeks forecast to bring above-normal activity

US National Hurricane Center forecast map as of 1 Oct.

For the latest information on storm activity in the Cayman Islands, as well as information on how to prepare for hurricane season, visit Storm Centre.

A well-defined tropical wave located south of the Cayman Islands and Jamaica is likely to develop into a tropical depression.

As of Thursday afternoon, the US National Hurricane Center had placed the system at a 70% chance of formation over the following five days.

The wave is accompanied by a large area of disorganised showers and thunderstorms.

Currently, the system is expected to move west of the Cayman Islands, as it tracks into the northwestern Caribbean Sea and the Gulf of Mexico.

“Conditions are expected to be conducive for a tropical depression to form by early next week, but only if the system moves and remains over the waters of the northwestern Caribbean Sea or southern Gulf of Mexico,” the NHC wrote Friday afternoon. “Development will become less likely if the system moves over the Yucatan Peninsula or northern Central America.”

“Regardless of development, this system is expected to produce locally heavy rains – with possible flash flooding – over portions of southeastern Mexico, Central America, and western Cuba during the next several days, and interests in those areas should monitor the progress of the disturbance.”

Another tropical wave east of the Lesser Antilles was also on track to pass through the Western Caribbean, but the probability of formation over coming days remained low. The NHC forecasts a 20% chance of formation over five days on Friday.

“This wave is forecast to move westward at 15 to 20 miles per hour during the next several days, and environmental conditions could become a little more conducive for development when the system is over the central or western Caribbean Sea early next week,” NHC wrote Thursday morning.

This Colorado State University map shows historic formation of tropical cyclones during the 30 Sept.-13 Oct. period. Click to enlarge.

Forecasters with Colorado State University’s Tropical Meteorology Project expect the two-week period, from 30 Sept-13 Oct., to bring above-normal tropical cyclone activity.

The CSU forecast analyses Accumulated Cyclone Energy, a measure of the total wind energy produced by a tropical system over its lifetime. An above-normal score for the 30 Sept-13 Oct. period would surpass 9 ACE.

“While there are currently no active tropical cyclones in the Atlantic, the National Hurricane Center is currently monitoring an area of low pressure that is forecast to develop in the western Caribbean and has a [high] chance of becoming a [tropical cyclone] in the next few days,” the CSU two-week forecast read.

“While the various global models have varying solutions as to how intense this cyclone will get, this system could generate small to medium levels of ACE if it were to develop. The global models also highlight additional potential [tropical cyclone] formation in the western Caribbean and even possibly in the eastern Atlantic (although less likely) in the next two weeks.”

CSU also forecasted above-normal tropical cyclone activity for the 16-29 Sept. period and was correct in its prediction. An above normal ACE for that period would surpass 23 and the period produced 36 ACE. During that period, Teddy generated 25.8, follow by Beta with 3.3., Sally with 2.6, Paulette with 2.3, Vicky with 0.9, Wilfred with 0.8 and Alpha with 0.4.

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