While dust levels are forecast to diminish through the next 48 hours as two tropical waves move across T&T, a significant surge of Saharan Dust is forecast to arrive by late Sunday into Monday, reducing visibility and air quality into the upcoming week.
What you need to know
— Saharan Dust Surges: Little to no Saharan Dust concentrations are forecast through Saturday, July 9th, 2022. Two significant dust surges are forecast to arrive by late July 10th into the 11th, and by late July 14th into July 15th.
— Impacts: Air quality levels across Trinidad and Tobago will vary between good and moderate through the forecast period, dipping to unhealthy levels for sensitive groups next week.
— What Should You Do: Sensitive groups will have brief periods 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 to moderate 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: Through Friday, July 8th, 2022
A moderate dust surge arrived across Trinidad and Tobago on Wednesday, July 6th, 2022. Air quality levels have fluctuated between good to moderate, with the visibility near ten kilometers outside of shower or thunderstorm activity over the last several days.
On Friday, July 8th, 2022, Saharan Dust will still be present, particularly across northern Trinidad and Tobago, but higher dust levels are forecast to remain north of the country. Through the weekend, Tropical Waves 16 and 17 are forecast to traverse the region, gradually diminishing dust levels until the start of the upcoming week.
Surge #1: Monday, July 11th, 2022
Following Tropical Waves 16 and 17 over the upcoming weekend, a significant surge of Saharan Dust is forecast to begin moving across the Lesser Antilles, with higher concentrations affecting countries north of Trinidad and Tobago. Peak dust concentrations are forecast between Monday, July 11th, and Tuesday, July 12th, with gradually diminishing dust levels.
Air quality levels will vary from good to unhealthy for sensitive groups, with the visibility dropping to six kilometers outside of shower or thunderstorm activity.
Surge #2: Thursday, July 14th, 2022
While this tropical wave is yet to be analyzed or even move off the African Coast, forecast models indicate another tropical wave moving across the Lesser Antilles on Wednesday, July 13th. The wave’s passage will reduce – but not remove – Saharan Dust from our area.
Instead, another high-concentration surge of dust is set to follow on Thursday, July 14th, 2022, and linger through the middle of July. Higher dust levels are forecast to remain north of the country
Air quality levels will vary from good to moderate, with the visibility dropping to six kilometers outside of shower or thunderstorm activity.
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 in April and continue through November.
