Forecast: Chance of Thunderstorms by Mid-Week, Saharan Dust by Weekend.

Thunderstorms across Southern Trinidad, seen from Ste. Madeline on Thursday 13th September 2018. Photo: Rishe Madho

Weather Forecast (Next 24 Hours)

As of 4:00PM Monday 22nd April 2019, partly cloudy to cloudy skies are occurring across much Western and Northern Trinidad. Elsewhere, across Trinidad and Tobago, partly cloudy to mostly clear skies are occurring.

Through the evening, isolated showers are likely across Northeastern Trinidad and Tobago as a surface to low-level shearline drifts southward. These isolated showers are forecast to remain light to moderate, favoring eastern parts of the island, pushing southward as the night progresses.

On Tuesday, mostly sunny conditions across both islands are forecast to be interrupted by isolated showers and partly cloudy conditions after midday. A building low level equatorial high pressure system will be dominant across Trinidad and Tobago. However, another surface to low level shearline over the southern Windwards is forecast to interrupt settled conditions.

Showers are forecast to favor eastern areas of both islands overnight. On Tuesday, showers and cloudiness are forecast to favor eastern areas throughout the day, with western parts of Trinidad and hilly regions predominantly after midday.

Upper level dynamics are not favorable to support heavy shower development on Monday night into Tuesday. However, by late Tuesday, increased low-level moisture is forecast to travel across the Southern Windwards, including Trinidad and Tobago from South America. This may fuel overnight showers and showers into Wednesday.

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Weather Forecast (Next 4 Days)

Generally, mostly sunny skies throughout the week are forecast to be interrupted by afternoon cloudiness and showers, some becoming heavy and possibly thundery by mid to late week.

We may see our first thunderstorm(s) by mid-week, particularly Thursday. As mentioned above, by late Tuesday into Wednesday, low-level moisture is forecast to move across the Southern Windwards, including Trinidad and Tobago, from South America. On Wednesday, mid and even upper level conditions are forecast to become more moist. This is due to moisture on the south western periphery of the low level equatorial high is advected northward, from South America, over the area.

Daytime showers are forecast to favor Southern and Western Trinidad, as well as hilly areas. Day time heating, sea breeze convergence and light winds are forecast to be present due to a deep layered low pressure system in the North Atlantic, weakening the pressure gradient. With ample moisture present throughout lower, mid and upper levels of the atmosphere, an isolated heavy shower or possible thunderstorm can’t be ruled out, particularly on Wednesday, Thursday and Friday.

Note that even with possible thunderstorms in the forecast, drought-busting rainfall is not expected, with very little daily rainfall accumulation forecast, with the exception of parts of Southern and Eastern Trinidad, which may record 5-10 millimeters daily.

By late Friday, mid and upper level conditions are forecast to become noticeably drier. Combined with the surge of Saharan Dust on Friday, a mostly sunny and hazy Friday and weekend is forecast.

Note: Showers, rainy or wet days and thunderstorms are possible and do occur in the dry season, such as the severe thunderstorm on March 4th 2018, which produced flash floods across Northern and Central Trinidad. Similarly, dry spells also occur during the wet or rainy season. These seasons generally dictate the overall climate, i.e. generally drier or wetter conditions, but day-to-day weather can vary.

Across Trinidad and Tobago, winds are forecast to be up to 40 KM/H throughout the week.

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Temperatures

Minimum low temperatures across Trinidad and Tobago over the next week are forecast to range between 24°C-26°C, with temperatures at the upper end of the minimum low temperature range favoring Tobago. Low temperatures are likely to be lower across inland and mountainous areas. Last nights’ minimum temperatures were 24°C at Piarco, Trinidad and 25°C at Crown Point, Tobago.

Today, maximum high temperatures across T&T was a warm 31°C at Piarco, Trinidad and a heat index of 35°C . Across Tobago, maximum high temperatures are forecast to be near 30°C with a heat index of 32°C. The heat index is an index that combines air temperature and relative humidity, generating a “feel’s like” temperature.

Maximum high temperatures may hover between 30-33°C at Piarco, Trinidad and 29-31°C at Crown Point, Tobago throughout the reminder of the week. Isolated showers, particularly between 11:00AM and 3:00PM may reduce maximum high temperatures.

Seas

Seas are forecast to remain slight to moderate in open waters through the week. Waves in open waters are forecast to remain up to 2.0 meters particularly East of Trinidad and Tobago. In sheltered areas, seas are forecast to remain smooth, below 1.0 meters. Winds are forecast to be from the east through the next 5 days at 10-15 knots.

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Minimal Saharan Dust Forecast Through Thursday, Dust Plume Forecast to Arrive on Friday

Presently, dust concentrations remain at minimal levels across the Southern Caribbean. Across Trinidad and Tobago, air quality is at good levels. Most places across the Eastern Caribbean are presently experiencing good air quality. Areas in the immediate vicinity of bushfires may experience moderate air quality.

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

By late Thursday, into Friday, based on current information as of 4:00PM Monday 22nd April 2019, a plume of mild to moderate concentrations of Saharan Dust is forecast to arrive at Trinidad and Tobago shores. Air quality is forecast to be reduced.

More: Surge of Saharan Dust Forecast by End of Week

Air Quality Index For The Next 5 Days
Air Quality Index For The Next 5 Days.

Throughout the week, i.e. Tuesday through midday Thursday, very minimal concentrations of Saharan Dust are forecast across Trinidad and Tobago. Air quality is generally forecast to remain at good levels. The exception will be in areas experiencing smokey conditions due to bush fires and blowing dust in dry areas. In these situations, air quality may be reduced to moderate levels.

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00Z April 22nd 2019 NASA GEOS-5 Dust Model showing a mild surge of Saharan Dust arriving across T&T shores beginning on 26th April 2019. Credit: Weatherbell
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