Forecast: More Tropical Waves & Saharan Dust To Affect T&T

The battle between Saharan Dust and tropical waves continues. High concentrations of Saharan Dust will remain present over the next five days as two tropical waves traverse Trinidad and Tobago. While strong wind shear and Saharan Dust may limit rainfall, gusty winds will still pose a threat.

What you need to know

Saharan Dust: High to significant levels of Saharan Dust is forecast to remain present across T&T over the next five days, with gradual improvement into the weekend.
Rainfall: Over the next five days, mostly hazy and variably cloudy skies are forecast to be interrupted by periods of light to moderate rain, isolated heavy/violent showers, and isolated thunderstorms. The heaviest rainfall is forecast on Friday into Saturday.
Hazards: The chances for street/flash flooding are high, particularly on Friday into Saturday, while the chances for riverine flooding remain low at this time. Gusty winds, up to and in excess of 50 KM/H accompanying heavy showers or thunderstorms are forecast, mainly on Wednesday and then again on Friday into Saturday. Lightning will accompany thunderstorms.
Alerts/Watches/Warnings: There are no alerts, watches, or warnings in effect for T&T from the Trinidad and Tobago Meteorological Service at this time.

The Forecast

Wednesday – Tropical Wave 06

Wednesday – Tropical Wave 06
5 10 0 1
Variably cloudy and hazy skies, interrupted by isolated showers favoring Trinidad, with isolated thunderstorms favoring initially northern Trinidad and Tobago, then, southern and western Trinidad from the morning through the early afternoon. Mostly cloudy and hazy conditions across Tobago, with brief showers. Conditions to remain unchanged into the evening, with brisk showers. Gusty winds likely. Street/flash flooding possible.
Variably cloudy and hazy skies, interrupted by isolated showers favoring Trinidad, with isolated thunderstorms favoring initially northern Trinidad and Tobago, then, southern and western Trinidad from the morning through the early afternoon. Mostly cloudy and hazy conditions across Tobago, with brief showers. Conditions to remain unchanged into the evening, with brisk showers. Gusty winds likely. Street/flash flooding possible.
5/10
Thunderstorm Chances
Medium

Thursday

Thursday
3 10 0 1
Variably cloudy and hazy skies interrupted by isolated showers throughout the day. Heavier activity to favor eastern areas of Trinidad. By the night, isolated thunderstorms are possible in eastern offshore areas, moving west. Gusty winds, street/flash flooding possible.
Variably cloudy and hazy skies interrupted by isolated showers throughout the day. Heavier activity to favor eastern areas of Trinidad. By the night, isolated thunderstorms are possible in eastern offshore areas, moving west. Gusty winds, street/flash flooding possible.
3/10
Thunderstorm Chances
Low

Friday – Tropical Wave 07

Friday – Tropical Wave 07
7 10 0 1
Periods of light/moderate rain, heavy/violent showers and isolated thunderstorms are forecast throughout the day, moving in from the east. By the afternoon, isolated thunderstorms may develop along western coastal Trinidad. Rainfall will interrupt cloudy and hazy skies. Conditions to briefly settle into the evening, with a resurgence of showers and thunderstorms after nightfall. Gusty winds, street/flash flooding possible.
Periods of light/moderate rain, heavy/violent showers and isolated thunderstorms are forecast throughout the day, moving in from the east. By the afternoon, isolated thunderstorms may develop along western coastal Trinidad. Rainfall will interrupt cloudy and hazy skies. Conditions to briefly settle into the evening, with a resurgence of showers and thunderstorms after nightfall. Gusty winds, street/flash flooding possible.
7/10
Thunderstorm Chances
High

Saturday – Tropical Wave 07

Saturday – Tropical Wave 07
7 10 0 1
From midnight, periods of light/moderate rain, heavy/violent showers and isolated thunderstorms are forecast throughout the day, moving in from the east. By the late morning through afternoon, isolated thunderstorms may develop along western coastal Trinidad. Rainfall will interrupt cloudy and hazy skies. Conditions to gradually settle into the evening with brief showers and light rain possible. Gusty winds likely, street/flash flooding possible.
From midnight, periods of light/moderate rain, heavy/violent showers and isolated thunderstorms are forecast throughout the day, moving in from the east. By the late morning through afternoon, isolated thunderstorms may develop along western coastal Trinidad. Rainfall will interrupt cloudy and hazy skies. Conditions to gradually settle into the evening with brief showers and light rain possible. Gusty winds likely, street/flash flooding possible.
7/10
Thunderstorm Chances
High

Sunday

Sunday
3 10 0 1
Variably cloudy, hazy and breezy conditions interrupted by brisk, isolated to scattered showers. An isolated thunderstorm may be possible during the afternoon, favoring southern and/or western Trinidad. Gusty winds possible.
Variably cloudy, hazy and breezy conditions interrupted by brisk, isolated to scattered showers. An isolated thunderstorm may be possible during the afternoon, favoring southern and/or western Trinidad. Gusty winds possible.
3/10
Thunderstorm Chances
Low

Marine: Seas are forecast to be moderate, with waves generally up to 2.0 meters, during the forecast period in open waters. In sheltered areas, waves are forecast to be near 1 meter but occasionally choppy during heavy showers or thunderstorms. King tides are also forecast to begin over the weekend.

Temperatures

Through the forecast period, the minimum low in Trinidad and Tobago is forecast to be between 23.0°C and 26.0°C.

Maximum highs across the country are forecast to be generally up to 31.0°C in Trinidad and Tobago. In urbanized areas like Port of Spain, Scarborough, San Fernando, and Chaguanas, the maximum high temperatures could exceed 32.0°C.

Over the next five days, temperatures are forecast to be cooler overall due to increased cloud cover and anticipated rainfall.

Forecast Impacts

Flooding

Flooding
7 10 0 1
Over the next five days, between 25 and 75 millimeters of rainfall is forecast across most of the country. Lower rainfall totals are forecast across northwestern areas of Trinidad while higher totals are forecast across eastern and southern halves of Trinidad. In highly isolated areas, overall five-day rainfall totals could exceed 100 millimeters.
Over the next five days, between 25 and 75 millimeters of rainfall is forecast across most of the country. Lower rainfall totals are forecast across northwestern areas of Trinidad while higher totals are forecast across eastern and southern halves of Trinidad. In highly isolated areas, overall five-day rainfall totals could exceed 100 millimeters.
7/10
Likelihood
High

There is a high chance of street and flash flooding, mainly Friday into Saturday, when the heaviest rainfall is expected over the five-day forecast period. Chances of riverine flooding remain low.

Forecast Rainfall Totals

  • Wednesday: Less than 10 millimeters across most of Trinidad and Tobago. Across the eastern and southern halves of Trinidad, as well as along isolated areas along western coastal Trinidad, rainfall totals are forecast to range between 10 to 20 millimeters, with isolated totals up to and in excess of 25 millimeters.
  • Thursday: Less than 10 millimeters of rainfall across the country. Higher totals to favor eastern coastal Trinidad.
  • Friday: Less than 10 millimeters across most of Trinidad and Tobago. Across the eastern and southern halves of Trinidad, as well as along isolated areas along western coastal Trinidad, rainfall totals are forecast to range between 10 to 20 millimeters, with isolated totals up to and in excess of 30 millimeters.
  • Saturday: Between 15 and 25 millimeters across the country, trending higher across eastern and southern areas of Trinidad and Tobago with isolated totals up to and in excess of 30 millimeters.
  • Sunday: Between 5 and 15 millimeters across the country, trending higher across eastern and southern areas of Trinidad and Tobago with isolated totals up to 25 millimeters.

Putting the rainfall forecast into context, rainfall rates in excess of 50 millimeters per hour or areas that receive in excess of 25 millimeters within an hour tend to trigger street flooding across the country or flash flooding in northern Trinidad. For riverine flooding to occur, a large area of the country (not just in highly localized areas of western coastal Trinidad) would have to record upwards of 75 millimeters within 24 hours, and rainfall would have to fall across major rivers’ catchment areas.

Strong Thunderstorms

Strong Thunderstorms
2 10 0 1
With Saharan Dust remaining present, as well as strong low-level winds, strong thunderstorms are unlikely to develop across Trinidad and Tobago.
With Saharan Dust remaining present, as well as strong low-level winds, strong thunderstorms are unlikely to develop across Trinidad and Tobago.
2/10
Likelihood
Very Low – Low

While thunderstorms are forecast over the next five days, strong wind shear, Saharan Dust, and a generally unfavorable environment (outside of Friday night/Saturday morning) will limit strong thunderstorms from forming.

Still, frequent cloud-to-ground lightning will be likely, with heavy to violent rainfall rates in thunderstorms. Funnel cloud development is unlikely. If a funnel cloud touches down on a body of water, it becomes a waterspout, and if it touches down on land, it becomes a tornado.

Gusty Winds

Gusty Winds
7 10 0 1
Low-level winds are forecast to remain elevated over the next five days. Sustained winds up to 35 KM/H are forecast, with gusts up to and in excess of 50 KM/H are likely, mainly accompanying heavy shower or thunderstorm activity on Friday into Saturday
Low-level winds are forecast to remain elevated over the next five days. Sustained winds up to 35 KM/H are forecast, with gusts up to and in excess of 50 KM/H are likely, mainly accompanying heavy shower or thunderstorm activity on Friday into Saturday
7/10
Likelihood
High

With wind gusts up to and in excess of 50 KM/H, whole trees are expected to be in motion, and there may be some inconvenience when walking against the wind gusts. Light outdoor objects may topple or become airborne such as garbage cans, potted plants, loose galvanize or construction material, and other outdoor furniture. Tents may jump. Older/weaker trees may fall, bringing down utility poles and lines.

Other Hazards

As rainfall continues through the weekend and into next week and soils become increasingly saturated, landslides are possible across elevated areas of Tobago, southern and northern Trinidad.

Saharan Dust will remain present across the region with a reinforcing surge on Sunday, reducing air quality and affecting visibility.

Why I May Not/Will Not See Rainfall?

A frequent complaint is the forecast is wrong because I didn’t experience any rainfall. Scattered showers mean that you, individually, may experience some showers intermittently throughout the day, and there is a higher chance for this activity than isolated activity. Widespread showers mean that nearly all persons and areas may experience rainfall.

Isolated to scattered rainfall is forecast into the weekend.

Forecast Discussion

Tropical Waves: Based on the Tropical Analysis and Forecast Branch’s 06Z surface analysis on June 8th, 2022:

  • The sixth tropical wave for 2022 is along 55°W, south of 14°N, moving west at 20 knots (37 KM/H). This wave is forecast to move across Trinidad and Tobago by Wednesday evening. Scattered showers and isolated thunderstorms have been observed with this wave, mainly across inland South America.
  • The seventh tropical wave for 2022 is along 43°W, south of 13°N, and moving west at 15 to 20 knots (27.8-37 KM/H). Scattered moderate convection has been observed with this wave, both ahead and following the wave axis. This wave is forecast to move across T&T overnight, June 10th, 2022, into Saturday, June 11th, 2022.

Surface to mid-level confluencing in conjunction with marginally favorable upper-level conditions continue to produce brisk rainfall, but the strongest showers and thunderstorms persist across inland South America. On Wednesday, Tropical Wave 06 will approach T&T and move across the islands by Wednesday night. This wave will bring a marginal increase in moisture and instability to T&T on Wednesday, fuelling isolated showers and even the odd thunderstorm, favoring Trinidad.

By Thursday, Saharan Dust will dry the low to mid-levels of the atmosphere out. However, an upper-level low remains anchored just northeast of the Lesser Antilles, with a trough extending southwestward from this low. This low/trough has enhanced showers and thunderstorms mainly east of T&T and allowed persistent upper-level clouds to move across the region from the southwest.

This upper-level system will gradually drift northwestward by Thursday, allowing for an increase in mid to upper-level moisture and generally more favorable upper-level conditions by Friday.

Tropical Wave 07 will be approaching and moving across the region during this period. With abundant moisture and instability and a favorable atmosphere, heavier showers and thunderstorms are possible on Friday into Saturday.

Strong westerly to southwesterly wind shear (up to 40 knots) will persist, keeping most of the heavy rainfall, showers, and thunderstorms south and east of the country.

Following the passage of this tropical wave on Saturday, a deep-layered high-pressure system is forecast to rebuild, with a gradual drying of the mid to low levels of the atmosphere. Still, we may continue to see a flow of upper-level clouds across the country from the southwest leading to a variably cloudy and hazy Sunday.

While rainfall is not forecast to be particularly severe, strong winds continue to prevail at low levels of the atmosphere, which can make their way down to the surface in heavy showers and thunderstorms. These winds remain a hazard through the weekend, with wind gusts in excess of 45 KM/H forecast, gusts in excess of 50 KM/H likely, and gusts in excess of 55 KM/H possible, mainly on Wednesday and then again Friday into Saturday.

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