An unstable atmosphere with multiple weather features, including an active Intertropical Convergence Zone (ITCZ), a tropical wave by Tuesday into Wednesday, and a deep-layered trough, are forecast to produce additional rainfall over the next four days. Note that rainfall totals have been revised upwards.
What you need to know
— Rainfall: Through Friday, a combination of mostly cloudy to cloudy skies, periods of rain, isolated to scattered showers, and thunderstorms are forecast across the country. Over the next four days, between 50 and 100 millimeters of rainfall is forecast across both islands, with totals nearing 150 millimeters, favoring eastern and southern areas of Trinidad. In isolated areas across both islands, totals may exceed 150 millimeters.
— Hazards: Over the next four days, the main hazards will be street/flash flooding, localized gusty winds, and landslides. Wind gusts up to 45 KM/H are very likely, mainly through Wednesday, with gusts up to or over 55 KM/H possible in heavy showers or thunderstorms possible. Lightning will accompany thunderstorms. Riverine flooding is likely.
Latest Alerts
Riverine Flood Alert Discontinued For South Trinidad
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
FridayMarine: A combination of spring tides and long-period swells are forecast over the next few days. Seas in open waters are forecast to be moderate, gradually becoming slight. In sheltered areas, waves remain below 1.0 meter but will be agitated. Additional information can be found here.
Temperatures
Generally, over the next four days, with increased cloud cover, maximum highs and minimum lows are forecast to be cooler than usual.
Tuesday through Friday
Low: 23-25°C
High: 28-30°C
With mostly cloudy skies over the next five days, maximum high temperatures are forecast to struggle to reach 30°C, with minimum lows remaining near 23°C to 24°C in Trinidad and near 24°C to 25°C in Tobago. The heat index will generally remain below 35°C.
Forecast Impacts
Flooding
FloodingStreet/flash flooding is likely across both islands through the next four days. Riverine flooding is now likely.
Forecast Rainfall Totals
- Tuesday: Between 5 and 25 millimeters of rainfall across both islands. Across eastern Trinidad and Tobago, totals could reach 50 millimeters with isolated higher amounts favoring extreme coastal areas.
- Wednesday: Between 10 and 25 millimeters of rainfall across both islands. Higher totals of up to 75 millimeters are forecast, trending across the eastern and southern halves of Trinidad and along the western coastal areas of Trinidad. Isolated higher totals are possible, favoring southern and eastern halves of Trinidad.
- Thursday: Between 5 and 15 millimeters of rainfall across both islands. Higher totals of up to 25 millimeters are forecast, trending across the eastern and southern halves of Trinidad and along the western coastal areas of Trinidad. Isolated higher totals are possible.
- Friday: Between 10 and 25 millimeters across both islands, with isolated totals exceeding 50 millimeters across eastern Trinidad and Tobago in persisting heavy shower/thunderstorm activity.
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 ThunderstormsStrong thunderstorms can produce frequent lightning, gusty winds, and violent rainfall rates. Short-lived funnel cloud development is possible, particularly on Friday into the weekend when low-level winds weaken. If a funnel cloud touches down on a body of water, it becomes a waterspout; if it touches down on land, it becomes a tornado.
Gusty 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
With forecast rainfall accumulations and already saturated soils, landslides are likely across both islands over the next two to three days.
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 three days, isolated to scattered rainfall is forecast.
Forecast Discussion
Tropical Waves (and other notable weather features) near and east of T&T: Based on the Tropical Analysis and Forecast Branch’s 06Z surface analysis on November 8th, 2022, as well as the latest satellite and model guidance:
- The 51st tropical wave for 2022 (TW51) is along 53°W, south of 18°N, moving west at 10-15 knots (18-27 KM/H). Scattered moderate convection has been noted with this wave where the axis interacts with the ITCZ both east and west of the wave axis. This wave is forecast to interact with the ITCZ as it moves across T&T on Tuesday night into Wednesday, followed by a deep-layered trough system.
- Subtropical Storm Nicole: The National Hurricane Center is issuing advisories on Nicole, 665 kilometers east-northeast of the Bahamas, as of 2:00 AM (AST) Tuesday. Tropical storm and hurricane watches and warnings are in effect for several parts of the Bahamas and Florida, with storm surge watches and warnings in effect for parts of Florida. The latest can be found at the National Hurricane Center. This system poses no threat to T&T.
- Disturbance in the North Atlantic: The National Hurricane Center is also monitoring an area of low pressure in the North Atlantic Ocean, producing disorganized showers and thunderstorms. It has a low chance of development over the next 48 hours and five days, posing no threat to T&T.
Today, an active Intertropical Convergence Zone (ITCZ) ahead of TW51 is forecast to affect Trinidad and Tobago due to an increase in surface to low-level moisture under very favourable upper-level conditions. Low-level convergence is also being aided by the influence of Subtropical Storm Nicole. By the late afternoon into the evening, a marginally less favourable atmosphere is forecast to hold briefly, leading to some settling.
However, tonight, TW51 is forecast to begin moving across the islands, moving away from the region on Wednesday. In its wake, additional low-level convergence, as well as a deep-layered trough system interacting with the ITCZ, is forecast to maintain unsettled weather conditions across the Windwards, including Trinidad and Tobago, through the end of the week.
Wind shear is forecast to be light through Thursday, leading to deeper convection developing, but it increases from Friday afternoon across Trinidad and Tobago.
The Larger-Scale Cause Of Our Prolonged Rainy Spell
Over the last two weeks and through the next week or so, a series of larger-scale features supported shower and thunderstorm development. The convectively active phase of a Convectively-Coupled Kelvin Wave (CCKW) is forecast to remain across the region through the end of the month. CCKWs are huge impulses spanning thousands of miles, moving west to east through the stratosphere, typically rolling along at about 30 to 40 mph. Like a giant chimney, each CCKW has a broad zone of rising air at its heart, tilted toward the west as you move up. As low-level air converges, the resulting circulation favours the development of showers and thunderstorms ahead of the CCKW.
Another factor aiding shower and thunderstorm development will be the convectively active phase of the Madden-Julian Oscillation (MJO). Like the CCKW, the MJO is a large-scale rising air area promoting shower and thunderstorm development. This convectively active phase of the MJO is also forecast to remain across T&T and the Caribbean region through the next week, promoting rainfall activity.
