Tropical Wave Arrives Monday Afternoon Into Tuesday, Another On Wednesday [5-Day Weather Outlook]

According to the Trinidad and Tobago Meteorological Service (TTMS), this morning (Friday 19th September, 2025), Tropical Storm Gabrielle was centred near 520 nm (963 km) East-Northeast of the Northern Leeward Islands and is moving towards the West-Northwest at approximately 10 kts. Gabrielle is not expected to affect the islands of the Lesser Antilles, as it passes to the Northeast of the Leeward Islands by today (Friday 19th September, 2025).

The axis of a Tropical Wave is now near 34W/35W and is presently moving Westward at approximately 15 kts to 20 kts. The vorticity associated with this Wave has become somewhat reduced, but the axis is expected to arrive at the Lesser Antilles from Monday afternoon (22nd September, 2025) into Tuesday (23rd September, 2025), bringing medium to high probabilities for thunderstorm activity, extending between Trinidad and Tobago and the Southern Leeward Islands.

A Tropical Wave with its axis presently located near 18W has been flagged with a 20% probability for cyclonic formation over the next seven (7) days. This Wave is now moving towards the West-Northwest at approximately 15 kts. Early indications are showing that this Wave is likely to pass the Leeward Islands on Wednesday (24th September, 2025), with medium probabilities for thunderstorm activity over varying areas.

Looking Beyond This Outlook Period 

• Early analysis is indicating increased surface convergence and equatorial moisture build-up across Trinidad and Tobago and the Windward Islands on Saturday (27th September, 2025), with a medium chance for isolated thunderstorm activity.
• A Trough/Wave across the Lesser Antilles is likely on Wednesday 1st October, 2025, with medium probabilities for isolated thunderstorm activity.
• These early analyses so far into the future are subjected to much variation as time progresses. The Met Office said it will continue to analyze and monitor all developments, or possible developments, within our Area of Interest.

Seas

• For this outlook period, the wind waves in the open waters to the near-East and Northeast of Trinidad and Tobago are expected to be mostly near 1.5m for this outlook period.

Wind

• The wind in the near-surface to the lower mid-level over Trinidad and Tobago and the Southern Windward Islands (2,000 ft to 5,000 ft), is expected to be generally between 15 kts to 20 kts for most of this outlook period. The wind is expected to come generally from the Southeast on Saturday (20th), then gradually back to come from the East to Northeast for the remainder of the outlook period.

Dust

• Presently, moderate concentrations of Saharan dust are in the atmosphere, and rising to high on Monday (21st) and Tuesday (22nd).
• Persons are advised to take the necessary precautions.

Synopsis And 5-Day Outlook 

• The axis of a Tropical Wave is likely to arrive at the Lesser Antilles from Monday afternoon (22nd) into Tuesday (23rd). This increases the probability for thunderstorm activity over varying areas across Trinidad and Tobago and the Lesser Antilles.
• A Wave/Trough across the Leeward Islands is likely to give medium probabilities for thunderstorm activity over the Leeward Islands on Wednesday (24th).

Saturday (20th September, 2025) 

• Trinidad and Tobago and the Southern Windward Islands: Mostly fair and hot conditions are expected, but with light winds generally from the Southeast interacting with the local topographies, there is likely a low to medium chance for an isolated heavy shower or thunderstorm to develop, favouring hilly areas and also Central to North Trinidad, during the late morning to early afternoon.
• The Northern Windward and Leeward Islands: A mostly fair morning is expected with partly cloudy patches during the afternoon. A few light to moderate showers are likely to favour hilly areas. There is a low chance for an isolated heavy shower.

Sunday (21st September, 2025) 

• Trinidad and Tobago and the Windward Islands: Partly cloudy to cloudy at times, with light to moderate showers mainly during the morning to early afternoon, with a medium chance for an isolated heavy shower or thunderstorm to be expected. During the afternoon and evening, brief showers in varying areas are likely.
• The Leeward Islands: Generally fair conditions are likely, although it is likely that a few light to moderate showers may interrupt these conditions, especially near hilly areas.

Monday (22nd September, 2025) 

• Trinidad and Tobago and the Windward Islands: During the morning, it is expected to be partly cloudy to cloudy, mainly over the Eastern offshore and Eastern coastal areas, with a medium chance of isolated thunderstorm activity in those areas. During the afternoon, there is a medium chance of an isolated thunderstorm developing over Western Trinidad. Conditions are expected to remain partly cloudy during the evening and night, with a medium chance of an isolated heavy shower or thunderstorm, favouring Northeast Trinidad, Tobago, and the Southern Windward Islands.
• The Leeward Islands: Generally fair with brief, moderate showers, favouring hilly areas.

Tuesday (23rd September, 2025) 

• Trinidad and Tobago and the Windward Islands: Initially fair, but from mid to late morning until mid-afternoon, it is likely to become cloudy with showers and a medium to high chance for thunderstorm activity over varying areas.
• The Leeward Islands: Varying cloudiness is expected, with showers and a medium to high chance of thunderstorm activity.

Wednesday (24th September, 2025) 

• Trinidad and Tobago and the Windward Islands: Mostly fair conditions are expected, with a low to medium chance of an isolated heavy afternoon shower, favouring hilly areas.
• The Leeward Islands: Partly cloudy to cloudy conditions are expected with showers over varying areas and a medium to high chance for thunderstorm activity.

The TTMS said it continues to analyze and monitor all developments within the Area of Interest. 

Please continue to pay attention to the latest forecasts, alerts, and information issued by the TTMS. 

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