Mild Surge of Saharan Dust Forecast on Sunday, Again Late Next Week.

As of 3:00 PM Saturday 25th May 2019, Saharan Dust concentrations are minimal across Trinidad and Tobago. A slight increase in concentrations of Saharan Dust is forecast across T&T on Sunday, reducing air quality to moderate levels at times and producing hazy skies across the islands. A tropical wave on Tuesday into Wednesday is forecast to briefly reduce dust concentrations. Parts of the Southern Windwards, mainly islands north of T&T, are experiencing moderate air quality. An additional surge in dust is forecast late Wednesday next week, with a more significant surge of dust forecast in early June.

Presently, minimal concentrations of Saharan Dust is present across Trinidad and Tobago, with air quality generally at good levels. As of 3:00 PM Saturday 25th May 2019, most islands across the Eastern Caribbean are at good air quality levels. However, islands across the Southern Windwards, with the exception of Trinidad and Tobago are already seeing the mild surge of dust, which is forecast to move across T&T tonight into tomorrow. Air quality across Grenada, St. Vincent and the Grenadines, St. Lucia and Barbados are at moderate levels presently, forecast to remain near those levels through Sunday (tomorrow).

At moderate air quality levels, unusually sensitive groups should consider reducing prolonged or heavy exertion.

Now that tropical waves are beginning to move across the Atlantic, Saharan Dust follows a more predictable pattern. Hot, mostly sunny and slightly hazy conditions with mild concentrations of Saharan Dust are typical ahead of a tropical wave, as it will be Sunday into Monday. Dust concentrations will decrease as the wave axis nears and passes over T&T, with showers and possible thunderstorms following the wave axis, as will be the case Tuesday into Wednesday. Then, a surge of dust is forecast to follow the showers and possible thunderstorms as the tropical wave progresses westward, as will be the cast late Wednesday into Thursday.

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 transport 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.

5-Day Air Quality Index, Saharan Dust Forecast For Trinidad and Tobago.
5-Day Air Quality Index, Saharan Dust Forecast For Trinidad and Tobago.

Dust models continue to show, following the passage of tropical waves, mild to moderate concentrations of Saharan Dust moving across Trinidad and Tobago. Over the longer term, at the beginning of June, following the passage of the second tropical wave of the 2019 Hurricane Season, a moderate plume of dust is forecast to move across T&T, and the Eastern Caribbean. This dust event is more than a week away. Updates will be posted accordingly.

 00Z May 25th 2019 NASA GEOS-5 Dust Model showing increased concentrations of Saharan Dust aimed at the Lesser Antilles at the start of June 2019. Credit: Weatherbell
00Z May 25th 2019 NASA GEOS-5 Dust Model showing increased concentrations of Saharan Dust aimed at the Lesser Antilles at the start of June 2019. Credit: Weatherbell

Sensitive groups such as persons with respiratory ailments, children, the elderly and cardiopulmonary disease should take the necessary precautions on days where dust concentrations degrade air quality to moderate to unhealthy for sensitive groups.

Saharan Dust Precautions
Saharan Dust Precautions
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