As we mentioned in our last forecast, “too much rain, too soon could usher in new problems – from bushfires to floods.” This has unfortunately come to pass with significant flooding ongoing across parts of northeastern Trinidad on Tuesday, on the heels of back-to-back heavy rainfall days on Sunday and Monday.
While April 2023’s extremely dry period has come to an end, we are still entrenched in the 2023 Dry Season, and by the end of this week, while it will be less parched outside, drier conditions are set to return.
What you need to know
— Rainfall: From Tuesday through Saturday, overall rainfall accumulations are forecast to range between 25 to 75 millimeters, with isolated totals exceeding 125 millimeters in localized areas. Note that the bulk of this rainfall has already fallen and will continue accumulating on Tuesday through Wednesday.
— Saharan Dust: A mild to moderate concentration surge of Saharan Dust is forecast to arrive across T&T Wednesday evening into Thursday.
— Hazards: Through Wednesday, the main hazard will be street/flash flooding across both islands, with possible riverine flooding in northeastern Trinidad. There is also the potential for wind gusts exceeding 45 KM/H, with occasionally higher gusts which can cause localized wind damage and topple trees. Landslides are possible in elevated areas, particularly across northern Trinidad. Funnel clouds are still possible from Tuesday into Wednesday. For the remainder of the forecast period, localized street flooding, occasional wind gusts exceeding 45 KM/H, and reduced air quality are set to be the main hazards.
— Marine: Seas are forecast to be slight to moderate in open waters with waves up to 1.5 meters and smooth to near calm in sheltered areas. Seas may become locally choppy or rough in heavy showers and thunderstorms.
Latest Alerts
Adverse Weather Alert Discontinued. Heavy Rainfall Still Possible
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: Moderate Seas, Reduced Visibility
Temperatures
Generally, over the next five days, maximum highs and minimum lows are forecast to be fairly seasonal to below average.
Tuesday through Saturday
Low: 23-25°C
High: 29-32°C
Maximum high temperatures are forecast to range between 29°C to 32°C with slightly cooler temperatures on Tuesday compared to the remainder of the forecast period. From Thursday, maximum highs are set to trend slightly warmer as sunshine returns. Minimum lows are forecast to remain near 23°C to 25°C in Trinidad and Tobago, trending cooler in interior areas. The heat index will generally remain below 35°C through Thursday, with heat indices exceeding 35°C by Friday into the weekend.
Forecast Impacts
Flooding (Through Wednesday)
Flooding (Through Wednesday)Flooding (Thursday through Saturday)
Flooding (Thursday through Saturday)Forecast Rainfall Totals
- Tuesday: Minimum accumulations of 5 to 25 millimeters across the country, with most areas across Trinidad and western Tobago receiving between 25 and 75 millimeters of rainfall. Isolated higher totals exceeding 125 millimeters are likely, favoring eastern Trinidad.
- Wednesday: For southern Trinidad and northern Tobago, less than 10 millimeters of rainfall is forecast. For the remainder of the country, between 5 and 15 millimeters of rainfall is forecast, with isolated totals up to 25 millimeters. In isolated thunderstorms or heavy showers, higher totals are possible.
- Thursday: Up to 5 millimeters of rainfall across both islands, with isolated totals reaching 25 millimeters across western Tobago and the northern and western halves of Trinidad.
- Friday: Up to 5 millimeters of rainfall across both islands, with isolated totals reaching 10 millimeters along western coastal and southeastern Trinidad.
- Saturday: Little to no rainfall is forecast, with less than 5 millimeters of rainfall accumulating in areas where showers occur, favoring eastern Trinidad.
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 ThunderstormsGusty Winds
Gusty WindsPossible impacts include localized wind damage to trees, power lines, and small structures. 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
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.
Through Wednesday, scattered to widespread rainfall is forecast, with highly isolated showers thereafter.
Forecast Discussion
Over the last two days, and this pattern is forecast to continue through the next 24-36 hours, Trinidad and Tobago has remained under a highly favorable upper, mid-, and low-level environment with deep, equatorial moisture in place. Favorable upper-level divergence, and low-level convergence, combined with a weak steering flow and light to moderate wind shear, have supported periodic thunderstorms, persisting rain, and isolated to scattered moderate to heavy showers.
These conditions are a result of an induced low-level trough just west of the southern Windwards and Trinidad and Tobago being on the western periphery of a surface-to-mid-level ridge located east of the Lesser Antilles. At the mid and upper levels, winds remain light and variable.
On Wednesday, PWAT (precipitable water) levels are forecast to remain high, above 2 inches, with veering winds continuing (winds turning clockwise with height). As showers and isolated thunderstorms form, activity will generally move north to northwest, with sea breezy convergence and orographic effects enhancing rainfall along northern and western areas of Trinidad.
Low-level winds are set to increase from late Wednesday, resulting in rainfall moving slightly faster across the country, which reduces the flood threat.
By Thursday, a surface-to-low-level ridge is forecast to move into the area, with a drier air mass at 800-millibar to 300-millibar levels of the atmosphere returning in tandem with a surge of mild to moderate Saharan Dust. Conditions are forecast to gradually settle into the weekend.
Larger-scale features like the Madden Julian Oscillation (MJO) and a convectively-coupled atmospheric Kelvin Wave (CCKW), which has enhanced convection (showers and thunderstorms), are both on their way out over the coming week, with the suppressive phases of both the MJO and CCKW moving in by next week. These features, after enhancing rainfall accumulations, will be leading to overall drier conditions in the coming days and the first half of May.
