Forecast: Partly Cloudy Skies, Isolated Showers & Thunderstorms

While no significant, widespread rainfall is forecast across the country over the next five days, a nearby tropical disturbance is forecast to influence the atmosphere across T&T, leading to increased cloudiness, isolated showers, and thunderstorms.

What weather T&T ultimately experiences is highly dependent on the proximity of Invest 94L to the Windwards, whose eventual track remains highly uncertain.

What you need to know

Rainfall: Over the next five days, between 15 and 25 millimeters are forecast across T&T. In isolated areas across western and northern Trinidad, as well as Tobago, up to 50 millimeters is forecast. In highly isolated heavy showers and thunderstorms, 24-hour rainfall totals could exceed 25 millimeters.
Saharan Dust: Mild Saharan Dust is forecast across T&T over the next five days.
Hazards: The main hazard over the next five days will originate from isolated thunderstorms, which may produce cloud-to-ground lightning, brief gusty winds, and highly isolated, heavy/violent rainfall, which can trigger short-lived, localized street/flash flooding.
Marine: Seas are forecast to be slight to moderate, with waves in open waters generally reaching as high as 2.0 meters, mainly on Friday and Saturday. In sheltered areas, waves are forecast to be near calm to calm initially but develop up to 1.0 meter by the end of the week.

Latest Alert

Adverse Weather Alert Discontinued For T&T

The Trinidad and Tobago Meteorological Service (TTMS) has discontinued the Adverse Weather Alert for Trinidad and Tobago. — What has happened: Fast-moving showers and thunderstorms affected…

Trinidad and Tobago is NOT under any tropical storm or hurricane threat, watch, or warning at this time.

The Forecast

Tuesday

Tuesday
5 10 0 1
Partly to mostly cloudy with isolated showers and thunderstorms from the morning. favoring eastern Trinidad and Tobago, through the afternoon, favoring western Trinidad, with a mostly settled night, barring the odd shower.
Partly to mostly cloudy with isolated showers and thunderstorms from the morning. favoring eastern Trinidad and Tobago, through the afternoon, favoring western Trinidad, with a mostly settled night, barring the odd shower.
5/10
Thunderstorm Chances
Medium

Wednesday

Wednesday
7 10 0 1
Mostly sunny start to the day, becoming increasingly cloudy by late morning with periods of light to moderate showers, becoming heavy at times, with isolated thunderstorms from the mid/late morning through the afternoon, settling by the late afternoon into the evening. Heavier rainfall to favor western coastal areas.
Mostly sunny start to the day, becoming increasingly cloudy by late morning with periods of light to moderate showers, becoming heavy at times, with isolated thunderstorms from the mid/late morning through the afternoon, settling by the late afternoon into the evening. Heavier rainfall to favor western coastal areas.
7/10
Thunderstorm Chances
High

Thursday

Thursday
6 10 0 1
Mostly hot and sunny, with partly cloudy periods developing by the late morning through the afternoon. A medium to high chance of isolated showers or thunderstorms across interior and hilly areas of both islands. Similar conditions are forecast overnight, interrupting long, settled periods.
Mostly hot and sunny, with partly cloudy periods developing by the late morning through the afternoon. A medium to high chance of isolated showers or thunderstorms across interior and hilly areas of both islands. Similar conditions are forecast overnight, interrupting long, settled periods.
6/10
Thunderstorm Chances
Medium – High

Friday

Friday
5 10 0 1
Mostly hot, sunny, and hazy with partly cloudy conditions developing from the late morning through the afternoon, with the isolated showers and thunderstorms, favoring western and hilly areas of both Trinidad and Tobago, with activity moving from south to north.
Mostly hot, sunny, and hazy with partly cloudy conditions developing from the late morning through the afternoon, with the isolated showers and thunderstorms, favoring western and hilly areas of both Trinidad and Tobago, with activity moving from south to north.
5/10
Thunderstorm Chances
Medium

Saturday

Saturday
5 10 0 1
Partly to mostly cloudy conditions developing from the late morning through the afternoon, with the isolated showers and thunderstorms, favoring western and hilly areas of both Trinidad and Tobago, with activity moving from south to north.
Partly to mostly cloudy conditions developing from the late morning through the afternoon, with the isolated showers and thunderstorms, favoring western and hilly areas of both Trinidad and Tobago, with activity moving from south to north.
5/10
Thunderstorm Chances
Medium

Marine Forecast

Temperatures

Tueday

Low: 24-26°C

High: 32-34°C

Wednesday

Low: 24-26°C

High: 31-33°C

Thursday

Low: 24-26°C

High: 32-34°C

Friday

Low: 24-26°C

High: 31-34°C

Saturday

Low: 24-26°C

High: 31-34°C

Maximum high temperatures are forecast to return to average levels for October across Trinidad and Tobago over the next five days, with actual temperatures reaching as high as 32°C in Tobago and 33°C in Trinidad. Across the country, over the next five days, the heat index, or feels like temperature, is forecast to range between 34°C and 44°C, reaching as high as 50°C across western and urbanized areas of both islands. Heat indices above 42°C are dangerous. Note that while warm temperatures are still forecast, pop-up showers/thunderstorms could keep the actual temperature lower than forecast while the heat index remains high.

Forecast Impacts

Flooding

Flooding
3 10 0 1
Over the next five days, between 15 and 25 millimeters are forecast across T&T. In isolated areas across western and northern Trinidad, as well as Tobago, up to 50 millimeters is forecast. In highly isolated heavy showers and thunderstorms, 24-hour rainfall totals could exceed 25 millimeters. As a result, the overall risk for street/flash flooding is low, given these isolated downpours can cause potentially impactful but short-lived floods.
Over the next five days, between 15 and 25 millimeters are forecast across T&T. In isolated areas across western and northern Trinidad, as well as Tobago, up to 50 millimeters is forecast. In highly isolated heavy showers and thunderstorms, 24-hour rainfall totals could exceed 25 millimeters. As a result, the overall risk for street/flash flooding is low, given these isolated downpours can cause potentially impactful but short-lived floods.
3/10
Likelihood
Low

Forecast Rainfall Totals

  • Tuesday: Less than 5 millimeters of rainfall across the country, except for the odd heavy shower or thunderstorm, favoring western areas of Trinidad, where totals could exceed 15 millimeters.
  • Wednesday: Less than 5 millimeters of rainfall across the country, except for the western and northern halves of Trinidad and across Tobago, where totals could exceed 15 millimeters. In isolated thunderstorm activity, rainfall totals could reach as high as 75 millimeters.
  • Thursday: Less than 5 millimeters of rainfall across the country, except for the odd heavy shower or thunderstorm, favoring western areas of Trinidad, where totals could exceed 15 millimeters.
  • Friday: Less than 5 millimeters of rainfall across the country, except for the western and northern halves of Trinidad and across Tobago, where totals could exceed 15 millimeters.
  • Saturday: Less than 5 millimeters of rainfall across the country, except for the eastern half of Trinidad and across Tobago, where totals could exceed 15 millimeters.

Understanding Rainfall Accumulations

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
4 10 0 1
With veering (clockwise) winds forecast by Wednesday, and again on Friday, with some upper-level support, isolated strong thunderstorms are possible on both days. However, these thunderstorms will remain short-lived as strong to very strong southwesterly wind shear is forecast.
With veering (clockwise) winds forecast by Wednesday, and again on Friday, with some upper-level support, isolated strong thunderstorms are possible on both days. However, these thunderstorms will remain short-lived as strong to very strong southwesterly wind shear is forecast.
4/10
Likelihood
Low – Medium
What is a strong or severe thunderstorm?

Given how rare these types of thunderstorms are in our region – we classify a severe or strong thunderstorm as one that produces any of the following:

  • Damaging wind gusts exceeding 55 KM/H;
  • Frequent lightning (more than 30 cloud-to-ground strikes within a 10-minute period);
  • Hail (of any size);
  • Rainfall of more than 50 millimeters or more within an hour or exceeding 75 millimeters or more within three hours;
  • The sighting of a funnel cloud or touchdown of a waterspout/tornado associated with the thunderstorm.

Gusty Winds

Gusty Winds
4 10 0 1
Through the forecast period, sustained winds are forecast to reach as high as 30 KM/H, with gusts exceeding 45KM/H in showers or thunderstorms, particularly on Friday into Saturday.
Through the forecast period, sustained winds are forecast to reach as high as 30 KM/H, with gusts exceeding 45KM/H in showers or thunderstorms, particularly on Friday into Saturday.
4/10
Likelihood
Low – Medium

Little to no wind impacts are forecast through the next five days. With possible (marginally) stronger gusts Friday into Saturday, some weaker trees may lose some branches, and unsecured outdoor furniture and structures may sustain some damage or move.

Other Hazards

Saharan Dust Forecast

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.

Over the next five days, isolated rainfall is forecast.

Forecast Discussion

Tropical Update

Trinidad and Tobago’s forecast is highly dependent on the eventual track of Invest 94L, which is forecast to move well north and northeast of T&T, potentially passing near the Leewards, based on forecast models on Monday night.

On this trajectory, firstly, convergence ahead of the low-pressure area will lead to enhanced chances for cloudiness, showers, and thunderstorms, coupled with an increase in moisture (humidity). Then, by Wednesday, continuing low-level convergence and a stronger northeasterly flow will lead to northeast-to-southwest moving rainfall, with activity being enhanced along western Trinidad, particularly as a favorable upper-level environment will be in place. However, strong southwesterly wind shear will limit persisting rainfall, spreading cloudiness northeastward.

From Thursday through Saturday, a low-level to surface trough will extend southwestward from Invest 94L and its eventual low-pressure area, leading to light southerly to southeasterly winds, bringing copious levels of moisture across T&T, supporting cloudiness, showers, and thunderstorms and the Intertropical Convergence Zone across T&T. However, in the sunny periods during the morning, strong daytime heating, combined with sea breeze and orographic convergence, could act as triggers for isolated thunderstorms.

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