This week, isolated heavy showers and thunderstorms are possible from late morning through the afternoon, generally favoring western coastal areas of Trinidad.
Locally heavy rainfall is likely to produce street/flash flooding, particularly today (Tuesday) and Friday into Saturday.
What you need to know
— Rainfall: Over the next five days, through Saturday, overall rainfall accumulations across the country are forecast to remain less than 35 millimeters, with five-day totals up to 100 millimeters possible, mainly along western coastal Trinidad. In highly isolated areas, again favoring western coastal Trinidad, daily rainfall totals exceeding 25 millimeters are likely, particularly on Tuesday and Friday into Saturday.
— Saharan Dust: Throughout the forecast period, mild to moderate Saharan Dust concentrations are likely, particularly across Tobago from Wednesday and again from Saturday evening.
— Hazards: Daily, but particularly Tuesday and Friday into Saturday, locally heavy rainfall is likely in heavy showers/thunderstorms, producing localized street/flash flooding. Gusty winds up to 50 KM/H, as well as frequent cloud-to-ground lightning, are also possible. Seas in the Gulf of Paria may also become locally choppy due to heavy downpours. During the afternoon on Tuesday, and again during the afternoons of Friday and Saturday, funnel clouds are possible along western coastal areas of Trinidad and in the Gulf of Paria.
— Marine: Generally, slight to moderate seas are forecast through Saturday.
Latest Alert
Trinidad and Tobago Placed Under Hot Spell Watch
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
SaturdayMarine Forecast
Seas Forecast: Anomalously Light Winds Lead To Mostly Tranquil Seas
Temperatures
Tuesday
Low: 25-27°C
High: 32-34°C
Wednesday
Low: 25-27°C
High: 32-34°C
Thursday
Low: 25-27°C
High: 32-34°C
Friday
Low: 25-27°C
High: 31-33°C
Saturday
Low: 23-25°C
High: 29-31°C
Forecast Impacts
Flooding
Over the next five days, through Saturday, overall rainfall accumulations across the country are forecast to remain less than 35 millimeters, with five-day totals up to 100 millimeters possible mainly along western coastal Trinidad. In highly isolated areas, again favoring western coastal Trinidad, daily rainfall totals exceeding 25 millimeters are likely, particularly on Tuesday and Friday into Saturday.
Street & Flash Flooding
Street & Flash FloodingRiverine Flooding
Riverine FloodingForecast Rainfall Totals
- Tuesday: Across the eastern half of Trinidad and across Tobago, less than 5 millimeters of rainfall, with isolated totals of up to 10 millimeters. Across the western half of Trinidad, between 10 and 25 millimeters of rainfall, with isolated higher totals of up to 50 millimeters in heavy showers and thunderstorms.
- Wednesday: Less than 5 millimeters of rainfall across the country, with isolated higher totals of up to 25 millimeters favoring western coastal areas.
- Thursday: Less than 5 millimeters of rainfall across the country, with isolated higher totals of up to 25 millimeters favoring western coastal areas.
- Friday: Between 5 and 15 millimeters across the country, with localized totals up to 25 millimeters in heavy showers or thunderstorms.
- Saturday: Across Tobago, up to 15 millimeters of rainfall. Across Trinidad, between 10 and 25 millimeters of rainfall, with isolated totals between 25 and 50 millimeters, particularly in heavy thunderstorm/shower activity favoring the western half of Trinidad. Locally higher totals are possible in isolated heavy showers and thunderstorms.
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 WindsWith winds gusting above 50 KM/H, whole trees can be in motion, with larger trees and weaker branches falling. Light outdoor objects can topple or become airborne, such as garbage cans, loose galvanize, construction material, and outdoor furniture. Tents may also jump.
Other Hazards
Saharan Dust Forecast
Fluctuating Concentrations of Saharan Dust Forecast For 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.
Over the next five days, generally isolated rainfall is forecast, with isolated to scattered rainfall possible on Tuesday into the night, and on Friday night into Saturday afternoon.
Forecast Discussion
Heavy rainfall on Monday beneficially affected parts of the country, with overall heavier rainfall favoring southern and eastern areas of Trinidad. Peak rainfall accumulations ranged between 25 and 50 millimeters (1-2 inches), favoring southern and eastern Trinidad, with less than half an inch (12.5 millimeters) in central and northwestern areas. The Trinidad and Tobago Meteorological Service issued an Adverse Weather Alert for the country on Monday.
On Tuesday, moisture trailing Tropical Wave 27 is forecast to remain across Trinidad and Tobago. Strong daytime heating coupled with sea breeze convergence is forecast to trigger isolated afternoon showers and thunderstorms favoring western coastal areas of Trinidad and, to a lesser extent, hilly areas of both islands. By nightfall, a trailing band of convergence is forecast to bring widely scattered showers and isolated thunderstorms to Tobago and mainly eastern and northern Trinidad.
On Wednesday, a ridge of high-pressure rebuilds across the country, with a very dry, dust-laden air mass moving in. However, Trinidad and Tobago, remaining on the periphery of the ridge, as well as the influence of the ITCZ, which remains to the country’s south, will lead to a fairly light wind regime. As a result, daytime heating and sea breeze convergence will lead to isolated late morning through afternoon showers and a couple of thunderstorms, mainly favoring western coastal Trinidad and, to a lesser extent, hilly areas of the country. With drier low to mid-level conditions, rainfall chances generally remain low on Wednesday and even lower on Thursday. Deep-layer wind shear through Thursday will also remain at moderate levels.
By Friday, the slow-moving Tropical Wave 28 is forecast to near the Lesser Antilles, bringing a surge of moisture from the southeast. Isolated thunderstorms are possible across southern and eastern areas of Trinidad and Tobago. As moisture and instability increase through the morning, so too will cloudiness, and by the afternoon, isolated to scattered showers and thunderstorms are forecast to mainly affect Trinidad.
This tropical wave is forecast to interact with the ITCZ on Friday night into Saturday, but there are differences in the overall severity of rainfall/thunderstorms among top model guidance. The ECMWF shows both less overall rainfall and more isolated shower/thunderstorm activity Friday night through Saturday afternoon, accounting for the surge of Saharan Dust moving in earlier on Saturday. The GFS, on the other hand, shows heavy shower/thunderstorm activity mainly between midnight and midday on Saturday, and much higher overall rainfall totals, drying out by the afternoon.
Given that the ITCZ will be across T&T and activity associated with the ITCZ peaks during the early morning hours, as well as top models showing a relatively saturated low-level environment and a divergent upper-level environment, the current forecast is more in line with the GFS outcome. It should be noted that this can change, leading to drier conditions than forecast.
Dust models also show a moderate concentration surge of Saharan Dust moving in on Saturday.
