[Updated] North American Cold Front Brings Cool Temperatures To T&T

Temperatures drop below 20°C on Monday Morning

Uncalibrated thermometer recording a minimum low of 15°C at Lengua, Barrackpore at 5:00 AM Monday 4th January 2021
Uncalibrated thermometer recording a minimum low of 15°C at Lengua, Barrackpore at 5:00 AM Monday 4th January 2021

Cold temperatures were recorded across T&T on Monday morning, with a number of areas across Central and Southern Trinidad recording temperatures below 20°C. The coolest temperature recorded via a calibrated thermometer was in Penal at 17.63°C while a thermometer (uncalibrated) recorded a minimum low of 15°C in Lengua, Barrackpore.

The minimum recorded temperature across T&T on Monday 4th January 2021 as cool temperatures continue.
The minimum recorded temperature across T&T on Monday 4th January 2021 as cool temperatures continue. Asterisks indicate uncalibrated temperature recordings.

2021 is off to a chilly start across Trinidad and Tobago with overnight lows dipping below 20°C, with a few areas nearing 19°C on Sunday morning. Cool temperatures are forecast to continue through Tuesday morning before moisture returns.

The minimum recorded temperature across T&T on Sunday 3rd January 2021 as cool temperatures continue.
The minimum recorded temperature across T&T on Sunday 3rd January 2021 as cool temperatures continue.

What’s causing the cool temperatures?

Over the last several days, a cold front made its way across the entirety of the Eastern Caribbean and has since stalled over northern South America. A strong high-pressure system has also moved in behind the cold front, bringing brisk winds, dry air, and ultimately cooler temperatures to T&T and much of the Eastern Caribbean.

Surface analysis of the Tropical Atlantic from January 1st through January 3rd as a strong low-pressure system moved north of the Lesser Antilles, and a strong high pressure system followed. (NHC/TAFB)
Surface analysis of the Tropical Atlantic from January 1st through January 3rd as a strong low-pressure system moved north of the Lesser Antilles, and a strong high-pressure system followed. (NHC/TAFB)

This dry and cool airmass, originating over North America and made its way down to the Caribbean, due to the atmospheric circulations over the Atlantic.

While moisture and temperature increased on its journey to T&T, the conditions remained dry and stable enough to hinder clouds’ development. Situations like these are not frequent, but they tend to occur a couple of times during our dry season.

Back-trajectory of the air currently at low-levels of the atmosphere across Trinidad and Tobago (Weathernerds)
Back-trajectory of the air currently at low-levels of the atmosphere across Trinidad and Tobago (Weathernerds)

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).

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.

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

Forecast minimum and maximum temperatures for Trinidad through January 7th, 2021.

For tonight, 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 23°C across Tobago. Mostly clear skies are expected overnight into Monday and Tuesday.

However, models indicate an increase in moisture Tuesday morning and persist through the end of the week due to a series of low-level troughs 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 25°C across Tobago through the end of the first week of 2021.

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