Area of Low Pressure (AL91) Predicted To Approach Lesser Antilles By Wednesday [5-Day Weather Outlook]

According to the Trinidad and Tobago Meteorological Service (TTMS), the axis of a Tropical Wave in the Eastern Atlantic is presently located near 36W, and is moving slowly Westward at approximately 5 kts. An associated low-pressure area (AL91) has been exhibiting high vorticity, and is flagged with a 60% chance for tropical cyclone formation through the next forty-eight (48) hours, and a 90% chance through the next seven (7) days.

A Tropical Depression is likely to form over this weekend or early next week. Present analysis of the numerical models is indicating some variation in the predictions for the strength development and the track of this system. However it is expected to be to the near-East of the Central islands (between the Northern Windward and the Leeward Islands) by Wednesday (10th September, 2025).

Meteorologist Gary Benjamin provided an update earlier this week on tropical activity in our Area of Interest:

Looking Beyond This Outlook Period 

• By Saturday (6th), preliminary analysis is indicating that an area of weak vorticity is likely to enter the Atlantic off the African West coast. Early indications are that this area is expected to track across the Cabo Verde Islands and eventually pass to the Northeast of the Lesser Antilles, likely as a Wave/Trough.
• Very early analysis suggests that by Wednesday (10th), an area of low vorticity is likely to develop to the South of the Cabo Verde Islands. At this time, the indication is that this area could show some increase in vorticity as it crosses the Tropical Atlantic and pass to the near-Northeast of the Leeward Islands, around Thursday (18th).
• These very 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, and possible developments, within our Area of Interest.

Seas

• 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 Windward Islands (2,000 ft to 5,000 ft), is expected to be generally 15 kts to 20 kts until Sunday (7th). From Sunday (7th), a general reduction in speed to between 8 kts to 12 kts is expected for the remainder of this outlook period. Direction is expected to be generally East-Southeast to Southeast until Tuesday (9th), and light and variable between Tuesday (9th) and Wednesday (10th).

Dust

• Generally mild concentrations of Saharan dust are present in the atmosphere today (5th). Moderate to high is expected by tomorrow (6th) from Northern Trinidad and Northward for this outlook period. Generally mild to moderate concentrations are expected over Southern Trinidad during this outlook period.
• Persons who are adversely affected by the elevated concentration of the dust are advised to take the necessary precautions.

Synopsis And 5-Day Outlook 

• Generally varying low-level convergence and intermittent moisture advection, especially over the Windward Islands, are expected during this outlook period. An area of low pressure (AL91) is, at this time, predicted to approach the Lesser Antilles by Wednesday (10th).

Saturday (6th September, 2025) 

• Trinidad and Tobago and the Southern Windward Islands: From pre-dawn to early morning, partly cloudy to cloudy periods are expected with light to moderate showers in varying areas, and a medium to high chance for isolated heavy showers or thunderstorms. A medium to high chance exists for an isolated afternoon thunderstorm over Trinidad and low to medium chance over Tobago during the late morning to early afternoon.
• The remainder of the Lesser Antilles: Varying areas with partly cloudy periods, interrupting otherwise fair conditions, with light to moderate showers. During the late morning to early afternoon, there will be a high chance for isolated heavy showers and thunderstorms over the Northern Leeward Islands, and during the afternoon, a low to medium chance for isolated heavy showers or a thunderstorm over the Southern Leeward and Northern Windward Islands.

Sunday (7th September, 2025)

• Trinidad and Tobago: Fair conditions with interruptions of partly cloudy patches, producing a few brief showers. A low to medium chance exists for an isolated heavy shower or thunderstorm to develop over Central and Western Trinidad during the afternoon.
• The remainder of the Lesser Antilles: Partly cloudy conditions with a few light to moderate showers over varying areas. There is a low to medium chance for an isolated heavy shower or thunderstorm to develop in some areas and favouring the Northern Leeward Islands.

Monday (8th September, 2025)

• Trinidad and Tobago: Initially partly cloudy periods, interrupting otherwise fair conditions. By early afternoon over Trinidad, a medium to high chance exists for thunderstorm activity to develop, favouring Central to Western Trinidad.
• The remainder of the Lesser Antilles: Mostly fair conditions with a few brief, light or moderate showers over varying areas. There is a low to medium chance for an isolated heavy shower or thunderstorm to develop, favouring the Northern Leeward Islands.

Tuesday (9th September, 2025)

• Trinidad and Tobago: Generally fair conditions, but there is a low to medium chance for an isolated heavy shower or isolated thunderstorm to develop, near hilly areas or Western Trinidad during the afternoon.
• The remainder of the Lesser Antilles: The Windward Islands are likely to be mostly fair. Over the Leeward Islands, partly cloudy to cloudy conditions are expected with medium to high chances for heavy showers and thunderstorm activity, from mid-morning to late afternoon.

Wednesday (10th September, 2025)

• Trinidad and Tobago and the Windward Islands: Mostly fair daytime conditions with a low chance for an isolated heavy shower or thunderstorm to develop, near hilly areas and Northern Trinidad during the afternoon. As the evening progresses, there is the possibility for increased cloudiness to approach Barbados with winds from the Northeast.
• The Leeward Islands: Partly cloudy conditions with a few light or moderate showers over varying areas. A low chance exists for a moderate or brief heavy shower, near hilly areas.

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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