Temperatures are forecast to dip below 20°C on Tuesday night into Wednesday, and possibly again on Wednesday night into Thursday across Trinidad, with slightly warmer temperatures across Tobago.
What’s causing the cool temperatures?
Cool and dry air from the northeastern Atlantic has gradually moved towards the Southern Windward Islands, embedded within the large sub-tropical Atlantic high-pressure system.
This high-pressure system has brought brisk winds across the region and is forecast to intensify this weekend, potentially causing rough seas.
While moisture and temperature increased on its journey to T&T, the conditions remained dry and stable enough to hinder clouds’ development, leading to our mostly sunny days and clear nights.
As we head into the weekend, moisture from South America may return to T&T, increasing cloudiness and even a few showers across the country.
The dew point, which is the atmospheric temperature below which water droplets begin to condense and dew can form, meteorologists can determine both the moisture content of the atmosphere near the surface, as well as an estimate for the minimum temperature.
A lower dew point means that there is less water vapor in the air. Water vapor can absorb and radiate heat back to the surface. Hence, the lower the water vapor content, the more infrared radiation (i.e., long-wave radiation) can escape from the earth’s surface and cause rapid cooling.
Calm winds and no cloud coverage are due to a persistent sub-tropical high-pressure system that will begin to dominate the weather for much of January, causing dry air at mid and upper levels of the atmosphere, inhibiting cloud formation.
Low temperatures during this time of year are normal, as the Northern Hemisphere experiences winter.
Cool temperatures across Trinidad result of several factors occurring:
- Calm/near calm winds (though over the last 3 days, it has been quite windy across T&T);
- Little to no cloud coverage;
- Winds originating from the northeast to the north at the lower levels of the atmosphere (over Trinidad);
- Low amounts of low-level moisture (water vapor).
Lack of cloud coverage also leads to fairly warm days, where temperatures can reach 30-32°C.
For vulnerable persons, who might be especially susceptible to cooler temperatures, such as babies or people suffering from arthritis, it may be best to layer up as a way to keep warm at night.
Forecast Into This Week
For tonight and tomorrow, generally dry conditions are expected to persist, with minimal cloud cover expected. This would result in temperatures in the upper teens (18°C to 20°C) across Trinidad and lows near or at 21°C across Tobago. Mostly clear skies are expected overnight into Wednesday and Thursday.
However, models indicate an increase in moisture Friday morning and persist through the weekend due to a series of low-level perturbations affecting the Windward Islands. With this increase in moisture, lows are forecast to be in the low twenties (22°C to 24°C) across Trinidad, with lows near or at 24°C across Tobago into mid-February.
The coldest February temperature ever recorded at Piarco is 16.3°C on February 24th, 1979 while the coldest ever temperature was 16.1°C occurred in January 1964. The record hottest was 36.3°C in 2010.