After a mostly wet and cloudy week, Saharan Dust has returned to Trinidad and Tobago briefly. Over the next several days, multiple tropical waves across the Tropical Atlantic are forecast to briefly improve Saharan Dust concentrations.
What you need to know
— Saharan Dust Surges: A brief, mild to moderate surge of Saharan Dust followed Potential Tropical Cyclone 2 as forecast, but it will quickly subside by early Friday. The following dust surge is forecast to arrive late Saturday, July 2nd, 2022 with fluctuating concentrations through late Tuesday, July 5th, 2022. Some improvement is forecast by Friday, July 8th, 2022 but another mild to moderate surge will arrive by Saturday, July 9th, 2022.
— Impacts: Air quality levels across Trinidad and Tobago will vary between good to moderate through the forecast period.
— What Should You Do: Sensitive groups will have several days during the upcoming forecast period where good air quality is anticipated. However, they should take the necessary precautions during dust surges. The general population will remain unaffected.
Current AQI Levels Across T&T
The Environmental Management Agency (EMA) air quality monitoring stations at San Fernando, Port of Spain, Point Lisas, and Signal Hill have all recorded good air quality levels over the last 24 hours.
These measurements are based on PM2.5 (particulates the size of 2.5 micrometers and smaller, usually associated with increases in Saharan Dust, vehicle exhaust, and smoke) and PM10 particulates.
Over the last 24 hours, visibility remained near ten kilometers at the Piarco International Airport and A.N.R. Robinson International Airport at Crown Point, Tobago.
Saharan Dust Forecast
Ongoing Surge: Late Wednesday, June 29th, 2022
A mild to a moderate concentration surge of Saharan Dust is forecast to move across the Lesser Antilles through early Friday. Air quality will briefly improve again from early Friday into late Saturday.
Surge #2: Late Saturday, July 2nd, 2022
Following Tropical Wave 13/14 (merged) on Friday into Saturday, another surge of dust is forecast to move across the region. Moderate concentrations are forecast to linger through Saturday, July 9th, 2022 with fluctuating concentrations. Minor improvement is forecast on Friday, July 8th, 2022.
What does this mean for you?
The air quality will be degraded through the forecast period. During high traffic periods, particularly between 6:00 AM and 9:00 AM, and again from 3:00 PM through 6:30 PM, air quality may be further reduced in localized areas.
According to the Trinidad and Tobago Meteorological Service, “the 2022 Saharan Dust Haze Season is likely to peak from June to August with the number of Saharan dust haze days expected to increase significantly. The duration of the plumes of Saharan dust haze visiting both islands is also likely to be more prolonged than earlier in the year, with increased odds for higher dust haze concentration during plumes visitation.”
We’re in a period where the Intertropical Convergence Zone and Tropical Waves may shield Trinidad and Tobago from the Saharan Dust events. While tropical waves play a notable role in moving dust across the Atlantic and the Eastern Caribbean, these periodic tropical waves also improve air quality.
The concentration of the dust that follows the wave depends on its strength as it moves off the West African Coast. This is because of stronger thunderstorms across Central Africa. As strong winds move downward and outward from these thunderstorms, the wind kicks up dust as it moves across parts of the Saharan Desert and transports it into the upper atmosphere. This “plume” of dust follows the axis of the wave as it progresses westward into the Atlantic.
Dust that makes it into the upper levels of the atmosphere can then get transported across the Atlantic Ocean. The plumes of dust eventually affect the Eastern Caribbean.
Larger, more concentrated plumes of Saharan dust begin to occur in April and continue through November.