After Trinidad and Tobago experienced the hottest few days since October 2020, welcome rainfall and cloudiness ushered in marginally cooler temperatures on Thursday, dropping below the threshold for a Hot Spell Warning. While the warning was discontinued by the Trinidad and Tobago Meteorological Service, hot conditions are forecast to return by the end of the weekend through the first week of October.
What you need to know
— What has happened: Over the last 13 days, Trinidad and Tobago has experienced elevated levels of heat, occasionally surpassing the definition for a hot day at both Piarco (maximum temperatures at or above 34°C) and Crown Point (maximum temperatures at or above 33°C). A tropical wave, interacting with the Intertropical Convergence Zone, brought showers, isolated thunderstorms, and cloudiness from today (Thursday) into the weekend, keeping maximum highs below the hot spell threshold.
— What is expected: Maximum high temperatures near or above 32°C in Trinidad and at or above 28°C in Tobago are forecast through the next three days. However, by Sunday, hotter temperatures are forecast to return, near the level needed to declare a hot spell once again.
— Hazards: Over the next few days, dangerous heat is not forecast. However, by Sunday, there is a real threat of heat exhaustion and heat stroke amongst the population, with heat stress likely for crops and animals into next week and even through the first week of October.
Latest Alerts
Adverse Weather Alert Discontinued For T&T
Trinidad and Tobago is NOT under any tropical storm or hurricane threat, watch, or warning at this time.
The Hot Spell Warning
Officially, according to the TTMS, a hot spell is declared when Trinidad and Tobago experiences maximum high temperatures reach or exceed 34°C at Piarco AND maximum high temperatures reach or exceed 33°C at Crown Point, Tobago. Historically, the maximum high-temperature threshold for Tobago was at or above 32°C, but this was changed in August 2023, as the definition of a hot day is meant to capture maximum high temperatures in the top 95th percentile of temperatures and, according to the TTMS climatologist office, 32°C was too low. Hot spells are the same as heat waves.
On Thursday through Saturday, the maximum high temperatures across Trinidad and Tobago are forecast to be below the hot spell threshold, leading to the discontinuation. The Trinidad and Tobago Meteorological Service discontinued the Hot Spell Warning (Yellow Level) on Thursday at 11:15 AM, for both Trinidad and Tobago.
Trinidad and Tobago is not under any tropical storm watch or warning at this time.
In their discontinuation message, they advise, “Partly cloudy to cloudy conditions and rainfall events have led to lower maximum temperatures, and these conditions are forecast for at least the next three days. As a result, the hot spell warning is discontinued. The TTMS advises, however, that Trinidad and Tobago is still in its heat season, and warm to hot temperatures are still expected.”
The color of the alert indicates the severity of the event and the probability of the event occurring. Currently, the alert level is at Green, as the discontinuation was issued, but the certainty is lower than usual, at possible, and the possible impacts are still moderate.
Generally, at Green Level, according to the TTMS, there is a low risk to public safety, livelihoods, and property. For a moderate alert, even in a discontinuation alert, there is the potential for possible injuries, where behavioral changes are required to ensure safety. Generally, there may be minor damage to property, with income-earning temporarily disrupted and a couple of communities affected more than others.
The Met Office is advising the public to wear appropriate clothing, stay hydrated at all times, and keep out of direct sunlight to avoid sunburn, open appropriate windows, vents, and doors in your homes to ventilate at times, as well as monitor weather conditions and updates from official sources.
What’s causing the excessive heat?
Since mid-August, multiple tropical cyclones have safely moved north of Trinidad and Tobago. The result of these stronger low-pressure systems traversing north of the region is weaker surface winds, coming from the southeast and south, to near calm and calm at times.
Though the mid to upper-level environment remains fairly dry, the low-level environment has marginal amounts of moisture, which leads to elevated humidity. As a result, high amounts of warm air remaining near the surface, while at night, occasional mid/upper-level clouds prevent the escape of heat into the atmosphere.
The result is warm, humid nights and hot, humid days across not only Trinidad and Tobago but the remainder of the Lesser Antilles.
On a larger scale, the solar altitude, or the angle of the sun relative to the Earth’s horizon, is at 90° across T&T (occurred on August 25th). When this occurs, solar radiation is concentrated over a smaller surface area, causing warmer temperatures.
Trinidad and Tobago is also entrenched in its heat season, which runs from March to October, with the first peak in April and May and the second peak in late August through early October. During these months, the islands experience mostly hot sunny periods and warm nights. Winds are generally weak but occasionally moderate strength from the east to southeast with speeds of 20-30 KM/H.
According to the Met Office, there are many climatic features working together to promote warmer to hotter days this month. “The winds are calm to light, with fewer cloudy periods, which enables greater incoming solar radiation, particularly during the mid-morning to afternoon periods:
- A moderately strong El Nino which generally restricts cloud development.
- A negative phase of the North Atlantic Oscillation (NAO) encourages weak winds across the Caribbean.
- A warmer than usual Atlantic Ocean Sea Surface Temperatures (SSTs) east of the Trinidad and Tobago.
- The apparent local position of the sun at our latitude.
- The southeasterly flow of wind from the equatorial region.
