More Saharan Dust is forecast to traverse the region over the next ten days, generally following the passages of tropical waves.
What you need to know
— Saharan Dust Surges: A high-concentration dust surge remains across the region, with peak concentrations ending tonight (late Thursday). Reinforcing moderate to high concentration surges are forecast to arrive on late Saturday, June 11th, 2022, and late Wednesday, June 15th, 2022, following tropical waves.
— Impacts: Air quality levels across Trinidad and Tobago will vary between good to unhealthy for sensitive groups through the forecast period.
— What Should You Do: Sensitive groups should continue taking the necessary precautions, while the general population would be able to continue activities with minimal Saharan Dust safety measures.
Current AQI Levels Across T&T
The Environmental Management Agency (EMA) air quality monitoring stations at San Fernando, Port of Spain, and Signal Hill have all recorded moderate air quality levels over the last 24 hours, with levels dipping to unhealthy for sensitive groups at Port of Spain and San Fernando, and unhealthy levels at Signal Hill on Wednesday evening.
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 between six to 10 kilometers at the Piarco International Airport and A.N.R. Robinson International Airport at Crown Point, Tobago.
Saharan Dust Forecast
Ongoing Surge: Through Friday, June 10th, 2022
A major surge of Saharan Dust has been moving across the Lesser Antilles since late Monday, June 6th, 2022. Peak concentrations ended today, Thursday, June 9th, 2022, with moderate to high concentrations lingering through late Friday, June 10th, 2022.
Surge #2: Late Saturday, June 11th, 2022
Following Tropical Wave 07 on Friday into Saturday, another surge of dust is forecast to move across the region with high concentrations. Peak concentrations are forecast between Saturday evening and early Monday morning (June 11th through 13th), with higher dust levels north of T&T.
By mid-Monday, air quality is forecast to improve substantially due to a predominantly southeasterly wind flow, bringing deep tropical moisture.
Surge #3: Late Wednesday, June 15th, 2022
Forecast models indicate Tropical Wave 08 moving through the area on Tuesday, June 14th, 2022, which is forecast to improve air quality and reduce dust levels briefly. However, following the wave axis will be a moderate to high-concentration dust surge, with higher concentrations well north of T&T. This dust surge is forecast to linger into the following week.
Air quality levels will vary between good and moderate, with the visibility dropping as low as seven to eight kilometers outside of shower or thunderstorm activity. Dust levels will remain at moderate levels through the end of the upcoming week.
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.
Sensitive groups, such as children, the elderly, and persons who suffer from respiratory ailments and allergies, should avoid prolonged or heavy exertion and keep medication nearby.
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.