Over the next 24 hours (through Wednesday afternoon), increased cloudiness, showers, and isolated thunderstorms are forecast across Trinidad, Tobago, and the southern Windward Islands associated with the passage of Tropical Wave 25 interacting with the Intertropical Convergence Zone (ITCZ).
Following the passage of this wave, a significant surge of Saharan Dust is forecast to move across T&T and the southern Windwards, decreasing air quality and visibility. As a relatively strong high-pressure ridge establishes itself across the region through the end of the week and trade winds remain relatively light, temperatures are forecast to get uncomfortably warm into the weekend.
What you need to know
— Rainfall: Over the next five days, between 15 and 25 millimeters are forecast across Trinidad and Tobago, with five-day totals nearing 50 millimeters across the eastern halves of both islands, as well as localized areas of western coastal and northern Trinidad. Most of the rains are forecast to occur through Wednesday afternoon.
— Saharan Dust: Elevated Saharan Dust concentrations are forecast across T&T through the next five days, with a significant surge likely by Wednesday into Thursday, July 19th into 20th.
— Hazards: Over the next five days, the main hazards will be localized street/flash flooding and brief gusty winds in isolated heavy showers and thunderstorms, particularly on Tuesday evening into Wednesday afternoon. In and ahead of heavy showers or thunderstorms, sustained winds can reach 35 KM/H with gusts to 45 KM/H. Air quality through the forecast period will be reduced, particularly from late Wednesday. Heat indices will also reach levels that require extreme caution from Thursday into the weekend.
— Marine: Seas are forecast to be slight to moderate, with waves in open waters ranging between 1.0 and 1.5 meters, while in sheltered areas, waves are forecast to remain below 0.5 meters.
Latest Alerts
Hazardous Seas Alert Discontinued For T&T
Trinidad and Tobago is NOT under any tropical storm or hurricane threat, watch, or warning at this time.
The Forecast
Tuesday
TuesdayWednesday
WednesdayThursday
ThursdayFriday
FridaySaturday
SaturdaySunday
SundayMarine Forecast
Seas Forecast: Moderate Seas, Reduced Visibility
Temperatures
Wednesday
Low: 24-26°C
High: 29-31°C
Thursday
Low: 24-26°C
High: 30-32°C
Friday
Low: 24-26°C
High: 31-33°C
Saturday – Caution due to high temperatures!
Low: 24-26°C
High: 32-34°C
Sunday – Caution due to high temperatures!
Low: 24-26°C
High: 32-34°C
Maximum high temperatures are forecast to range between 31°C to 33°C, with higher temperatures across urbanized areas of Trinidad, where in built-up areas, maximum high temperatures could exceed 34°C. Minimum lows are forecast to remain mild, ranging between 24°C and 26°C in Trinidad and Tobago, trending cooler in interior areas. The heat index will generally be above 35°C through the forecast period after Wednesday.
Forecast Impacts
Flooding
FloodingForecast Rainfall Totals
- Wednesday: Across both islands, up to 10 millimeters in most areas, with totals between 15 and 25 millimeters favoring eastern and southern areas, as well as along western coastal areas, where locally high totals are possible.
- Thursday: Across Tobago, less than 5 millimeters of rainfall accumulates as little to no rainfall is forecast across the island. For Trinidad, most areas are forecast to receive less than 10 millimeters of rainfall accumulations where showers occur. Along western coastal Trinidad, isolated totals exceeding 25 millimeters are possible.
- Friday Little to no rainfall across T&T, with isolated totals less than 5 millimeters.
- Saturday: Little to no rainfall across T&T, with isolated totals less than 5 millimeters.
- Sunday: Between 0 and 5 millimeters of rain across Trinidad and Tobago, with isolated totals nearing 10 millimeters across eastern areas of both islands.
Understanding Rainfall Rates
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 ThunderstormsWhat 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 WindsPossible impacts include localized wind damage to trees, power lines, and small structures. Small potted plants may blow over with light outdoor objects becoming airborne in stronger gusts. Tents may jump.
Other Hazards
Saharan Dust Forecast
Major Saharan Dust Surge Now Moving Across T&T
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.
On Tuesday night through Thursday, isolated to scattered rainfall is forecast, with highly isolated rainfall to no rainfall through the weekend until Sunday.
Forecast Discussion
The Intertropical Convergence Zone (ITCZ) approached Trinidad and Tobago on Tuesday as Tropical Wave 25 nears the region, supporting cloudiness with isolated to scattered showers and isolated thunderstorm activity, mainly east of the country.
Tropical Wave 25 is forecast to move across T&T and the Lesser Antilles during the early hours of Wednesday, interacting with the ITCZ with generally favorable atmospheric conditions. Highly favorable upper-level divergence, with low wind shear and high atmospheric moisture, will support cloudiness, showers, and isolated thunderstorm activity.
By Wednesday afternoon into the evening, a high-pressure ridge is forecast to rebuild across the Windwards, pushing the ITCZ southward and bringing in an influx of Saharan Dust. The ITCZ is still forecast to be near Trinidad on Thursday, which will support early morning and early afternoon showers, but Saharan Dust will limit any widespread or even scattered convection from developing.
The atmosphere is forecast to be fairly dry from late Thursday through Saturday, with occasional pockets of moisture moving in by Sunday. Additionally, forecast models indicate the high-pressure system that is forecast to be in place will be anomalously strong, about two standard deviations above what is expected for mid to late July. This sinking air, combined with light winds and relatively high humidity, although dry air will be in place just above the surface levels, will result in warmer-than-usual temperatures.
By late Sunday into early next week, Tropical Wave 26 is forecast to move across the region, with forecast models keeping the highest total precipitable moisture and stronger winds well north of T&T, tracking across the central and northern Windwards, French Antilles, and Leewards.
