Tropical Wave 27 moved across T&T without much fanfare, but in its wake, isolated to scattered showers and isolated thunderstorms have been moving across the country from Friday into Saturday. Tropical Wave 28 is forecast to move across the islands early next week.
What you need to know
— Rainfall: Over the next five days, between 25 and 50 millimeters are forecast across Trinidad and Tobago. In isolated areas across western and eastern coastal Trinidad, locally higher amounts are possible daily.
— Saharan Dust: Elevated Saharan Dust concentrations are forecast across T&T from August 1st, 2023
— Hazards: Over the next five days, the main hazards will be localized street/flash flooding and gusty winds up to 45 KM/H in heavy showers and isolated thunderstorms. From Tuesday, high temperatures and elevated heat indices will also reach levels that require extreme caution.
— 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
Friday Night
Friday NightSaturday
SaturdaySunday
SundayMonday
MondayTuesday
TuesdayWednesday
WednesdayMarine Forecast
Seas Forecast: Moderate Seas, Reduced Visibility
Temperatures
Saturday
Low: 24-26°C
High: 30-32°C
Sunday
Low: 24-26°C
High: 30-33°C
Monday
Low: 24-26°C
High: 31-34°C
Tuesday
Low: 24-26°C
High: 32-34°C
Wednesday
Low: 24-26°C
High: 32-34°C
Over the next five days, maximum high temperatures are forecast to be hot, ranging from 30°C to 35°C, with higher temperatures across urbanized areas of Trinidad, particularly from Monday, where in built-up areas, maximum high temperatures are likely to exceed 34°C. Minimum lows are forecast to remain mild, ranging between 24°C and 26°C in Trinidad and Tobago, trending marginally cooler in interior areas. The heat index will generally be above 35°C through the forecast period.
Forecast Impacts
Flooding
FloodingForecast Rainfall Totals
- Saturday: Between 5 and 15 millimeters across Trinidad and Tobago, with isolated totals up to 25 millimeters favoring northern and western areas of Trinidad.
- Sunday: Between 5 and 15 millimeters across Trinidad and Tobago, with isolated totals up to 25 millimeters favoring the western half of Trinidad.
- Monday: Less than 5 millimeters of rainfall across T&T, with little to no rain forecast. Note that the GFS is the sole outlier, showing between 5-15 millimeters across the country, with isolated amounts up to 25 millimetres.
- Tuesday: Between 0 and 5 millimeters of rain across Trinidad and Tobago, with isolated totals nearing 15 millimeters across northern and western areas of both islands. In thunderstorm activity, locally higher totals are possible.
- Wednesday: Between 0 and 5 millimeters of rain across Trinidad and Tobago, with isolated totals nearing 15 millimeters across northern and western areas of both islands. In thunderstorm activity, locally higher totals are possible.
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 WindsOther 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.
During the forecast period, isolated to scattered rainfall is forecast, with isolated activity favoring after Monday through the upcoming week.
Forecast Discussion
The Intertropical Convergence Zone (ITCZ) interacted with Tropical Wave 27 (TW27) on Friday, isolated to scattered showers and thunderstorms across Trinidad and Tobago with high atmospheric moisture, favorable low-level convergence, and favorable upper-level convergence.
On Saturday, trailing moisture and instability associated with TW27, as well as the ITCZ, will continue to affect T&T throughout the day, with the elongated axis of Tropical Wave 28 (TW28) approaching the region overnight. Increased cloudiness, showers, and isolated thunderstorms are possible overnight into early Sunday.
The axis of TW28 is forecast to move across the Lesser Antilles, specifically T&T, by Monday morning, interacting with the ITCZ. However, most models suggest fairly dry weather overall, with isolated late morning through afternoon heavy showers and thunderstorms.
However, across Trinidad and Tobago on Sunday through the upcoming week, a weak high-pressure ridge is forecast to be in place, with light southeasterly to southerly winds across the country due to a trough extending southwestward from an area of low-pressure moving well north and east of the Lesser Antilles.
Upper-level conditions are forecast to become favorable across T&T on Tuesday into Wednesday with the potential for strong convection (showers, thunderstorms) and model guidance even suggesting the potential for hail in strong, isolated thunderstorms. This is still several days away, but it is worth mentioning, given the unusual setup. Throughout the forecast period, however, with light winds, at times becoming westerly along western coastal Trinidad, there is the potential for funnel clouds throughout the forecast period.
