Saharan Dust Forecast To Increase Across T&T

Following the passage of Tropical Wave 53, Saharan Dust concentrations are on the increase across T&T and the Southern Windwards, though we are in a time of the year where dust levels are at a climatological low. Across the country, air quality is at good to moderate levels with visibility above 10 kilometers as of 3:00 PM Friday 2nd October 2020.

The Environmental Management Agency (EMA) air quality monitoring stations are recording AQI values at levels that are good to moderate in Trinidad and Tobago 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.

Air Quality Index at Environmental Management Agency‘s (EMA) Air Quality Monitoring Stations Across Trinidad. Note these AQI values are to Trinidad and Tobago air quality standards.

The Saharan Dust Forecast

Based on the latest dust modeling, air quality across Trinidad and Tobago is forecast to remain at good to moderate levels through the forecast period.

The peak of this initial dust episode will occur on Saturday 3rd October 2020, though lower concentrations of dust will linger through October 8th. Concentrations will be tempered by shower and thunderstorm activity through the weekend into next week.

Another mild surge is forecast to arrive on the evening of October 9th, following the passage of Tropical Wave 54. This will be shortlived due to improvement by October 10th. Higher concentrations forecast to remain north of T&T.

02Z October 2nd, 2020, NASA GEOS-5 Dust Extinction Model Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust. (Weathermodels)
02Z October 2nd, 2020, NASA GEOS-5 Dust Extinction Model Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust. (Weathermodels)

What does this mean for you?

For the general population, little to no impacts are forecast beyond reduced visibility. For sensitive groups, such as children, the elderly, and persons who suffer from respiratory ailments and allergies, you may need to avoid prolonged exertion outdoors.

We’re in a period where the ITCZ, tropical waves and occasional tropical cyclones 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 frequent tropical waves also aid in improving air quality.

The concentration of the dust that follows the wave depends on the strength of the wave 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.

Larger, more concentrated plumes of Saharan dust begin to occur in April and continue through November.

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