Short-Lived Surge Of Saharan Dust Forecast By Mid-Week

Fluctuating concentrations of Saharan Dust continue to move across the region with higher amounts of dust remaining north of Trinidad and Tobago.

Through the next 10 days, fluctuating mild to moderate concentrations of Saharan Dust are forecast to move across Trinidad and Tobago with higher concentrations remaining north of the country.

Over the last 24 hours, air quality has been good to moderate across Trinidad and Tobago. The Environmental Management Agency (EMA) air quality monitoring stations are recording AQI values at levels that are good across the country. 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.

The Saharan Dust Forecast

Over the next 10 days, tropical cyclone activity east of the Lesser Antilles is forecast to be minimal with tropical waves, troughs, and the Intertropical Convergence Zone providing Saharan Dust relief across the region.

Across Trinidad and Tobago, the Intertropical Convergence Zone (ITCZ) will linger near the country, shielding the islands from higher dust concentrations.

Model guidance suggests a mild to moderate ongoing surge is forecast to lessen across T&T on Monday 11th October 2021. A period of relatively good air quality and minimal Saharan Dust is forecast until mid-Wednesday 13th October 2021, where a brief surge of dust will linger through Friday 15th October 2021. Higher dust concentrations are forecast to remain north of the country.

Air quality is forecast to remain at good levels until next Tuesday 19th October 2021, where another brief and mild surge of dust arrives.

Generally, air quality levels are forecast to remain good levels, only becoming moderate during high-traffic periods as well as during late Wednesday through Friday. Outside of rainfall and peak dust days, visibility is forecast to remain at or above 10 kilometers.

12Z October 10th, 2021, NASA GEOS-5 Dust Extinction Model Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust.
12Z October 10th, 2021, NASA GEOS-5 Dust Extinction Model Monitoring Tropical Atlantic Dust Aerosol Optical Depth showing Saharan Dust.

What does this mean for you?

Over the next 10 days, air quality is forecast to remain at mostly good levels. However, during high traffic periods, particularly between 6:00 AM and 9:00 AM, and again during 3:00 PM through 6:30 PM, air quality may dip to moderate levels in localized areas. Also, across Tobago and at times Northern Trinidad, air quality may dip to moderate levels, particularly between Wednesday and Friday.

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 during these high traffic periods.

We’re in a period where the ITCZ, tropical cyclones, and tropical waves may shield Trinidad and Tobago from significant 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 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.

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 dust begin to occur in April and continue through November.

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