Over the last two days, T&T has experienced sweltering temperatures due to abundant sunshine and little cloud cover.
On Wednesday 20th May 2020, a day where the country waited with much anticipation of our first heavy rainfall event for the year, Piarco recorded its second hottest temperature (to date).
On Wednesday, across most of the country, temperatures between ranged between 33.0°C and 35.0°C, with isolated areas between 35.0°C and 37.0°C, mainly across Trinidad. In urban areas and areas where development is prevalent, temperatures trended higher.
Because of elevated moisture moving across the islands due to Tropical Wave 01, the heat index or what outside felt like was higher than usual.
On Thursday 21st May 2020, the heat continued as mostly sunny to partly cloudy skies prevailed during the late morning through the afternoon across much of the island.
On Thursday, it was another sweltering day across most of the country. Temperatures between ranged between 33.0°C and 35.0°C, with isolated areas between 35.0°C and 38.0°C, mainly across Trinidad. In urban areas and areas where development is prevalent, temperatures trended higher.
The maximum recorded temperature occurred at the Piarco International Airport, coming in at a scorching 34.2°C on Wednesday and 34.1°C on Thursday, recorded by the Trinidad and Tobago Meteorological Service. Since this is the official temperature monitoring station for T&T’s records, this ties 13th April and 14th April at our second-highest maximum temperature on Wednesday and now our third-highest maximum temperature on Thursday, recorded to date at Piarco, for 2020. Our highest maximum temperature to date at Piarco was recorded on April 27th.
Temps in cities, such as Port of Spain, tend to be much higher than surrounding locations due to a phenomenon called the Urban Heat Island Effect. There are several causes, but the main instigator for this phenomenon tends to be increased dark surfaces such as roads and pavement in cities, which absorb solar radiation more than surrounding areas.
Where do these temps stand compared to our records? The hottest recorded in Trinidad, based on data from the Global Historical Climatology Network (pre-1980) and the Trinidad and Tobago Meteorological Service (1980-2019) stands at 37.8°C recorded on April 20th, 1946 at Wallerfield.
At Piarco International Airport, where the new official records began, the hottest temperature for the year was recorded on September 25th, 1990, at 36.5°C but the hottest May temperature occurred on May 11th, 2010 at a scorching 35.9°C.
The Heat Index
Several persons across the country took to social media to complain about the heat, or more so what outside felt like. This is called the heat index and is a combination of air temperature and relative humidity, determining what the air feels like to a person i.e., how hot it actually feels.
The heat index is important because of sweating. Your body sweats to cool the skin and maintain a constant, healthy body temperature. This cooling process means that the sweat has to evaporate off the skin to remove heat. However, if the sweat is unable to evaporate, the body isn’t able to regulate temperature.
With high volumes of moisture in the air, also known as high relative humidity, which T&T regularly experience due to its tropical climate, the rate of sweat evaporation decreased. This is because the atmosphere is unable, or has limited potential to hold additional moisture in the atmosphere.
This results in you feeling warmer in humid conditions and cooler in less humid conditions i.e. when relative humidity decreases. As temperature increases, the heat index increases. As relative humidity increases, so does the heat index.
Heat index is generally classified into four categories: caution, extreme caution, dangerous, and extremely dangerous. Generally, across Trinidad and Tobago, we experience heat indices of caution to extreme caution in times of hot days, with isolated areas experiencing dangerous heat indices such as urban areas.
High Temperatures To Continue
Even with the passage of the first tropical wave of 2020, we are still in the dry season. In the short term, a high-pressure system is forecast to continue dominating weather conditions through the next week, with another “dry” tropical wave forecast to traverse the region on Wednesday 27th May 2020.
High-pressure systems bring generally dry and stable weather, with sunny skies. This in turn results in higher daytime and afternoon temps.
In the Trinidad and Tobago Meteorological Service’s (TTMS) Rainfall and Temperature Outlook for Trinidad and Tobago, issued on Tuesday 19th May 2020.
In fact, according to the TTMS, the “above-normal temperatures are likely with warmer than average maximum day and minimum night temperatures expected. The risk for hot days and short-duration hot-spells is elevated for the August to October period.”
“There is a 75% chance for warmer than usual maximum daytime temperatures and nighttime minimum temperatures, especially during June to October 2020,” based on the TTMS’s outlook.
Through the next 5 days, maximum high temps are forecast to be near 33-34°C across Trinidad, and 32-33°C across Tobago. Heat indices are also forecast to be high, near 35-45°C across Trinidad, and 35-42°C across Tobago. Remember, heat indices will be higher in urbanized areas.
Is this a heatwave?
Currently, tomorrow’s forecast maximum high temperature is forecast to be near 34.0°C in Trinidad and 32.0°C. This means our first short-duration hot spell for 2020 is on the horizon if these temperatures materialize.
For a hot spell to be declared in Trinidad and Tobago by the Trinidad and Tobago Meteorological Service, a period of hot temperatures, characterized by maximum temperatures of at least 34.0°C in Trinidad and 32.0°C in Tobago, lasting five or more consecutive days. A short-duration hot-spell is three or more consecutive hot days.