Minimum Temperatures Recorded Across Trinidad on Saturday 2nd February 2019
Morning lows across Trinidad on Friday and Saturday hovered near 19°C to 20°C, with a few areas dipping below 18°C on Saturday morning.
Parts of interior Trinidad, such as Penal and Caroni saw morning low temperatures of 17.81°C and 17.96°C respectively on Saturday.
Temperatures across Tobago, albeit still cool, remained near 23°C on both days.
Low temperatures during this time of year is normal, as the Northern Hemisphere experiences winter.
Cool temperatures across Trinidad result of several factors occurring:
- Calm/near calm winds
- Almost no cloud coverage
- Winds originating from the North in 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, more infrared radiation (i.e. long-wave radiation) can escape from the surface of the earth and cause rapid cooling.
Calm winds and no cloud coverage are due to a persistent sub-tropical high pressure system which has dominated 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 32°C.
Particularly during El Niño years, winter storms move further southward across the United States, increasing the likelihood of cold frontal systems moving across the Caribbean and further dipping temperatures. On the rare occasion a cold front does manage to make it as far south as Trinidad and Tobago, cold conditions would be due to a process called advection, where there is a horizontal mass movement of air.
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.
According to data from the Trinidad and Tobago Meteorological Service, the coldest temperature ever recorded at Piarco International Airport was 16.1°C, recorded in January 1964.
Temperatures were slightly more mild on Friday, due to the present of minimal low-level moisture and some pre-dawn clouds, inhibiting longwave radiational cooling. Most areas had lows near 20°C with interior parts of the country recording slightly lower temperatures.
Forecast for This Weekend
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 Sunday, with sunny to partly cloudy periods throughout Sunday.
On Monday, models continue to indicate a weak low-level trough affecting the Southern Windwards, including Trinidad and Tobago. However analysis shows little moisture and instability along the axis itself as the feature drifts northwards across the island chain. Thus fair skies are expected across Trinidad and Tobago initially. Some partly cloudy skies and brisk light moderate showers are expected to interrupt generally sunny day and mostly clear and cool night.
This mild increase in moisture, as well as the increase in cloud coverage will limit cooling at the surface. Hence, lows are forecast to be in the low twenties (20°C to 22°C) across Trinidad, with lows near or at 23°C across Tobago.
Seas will remain slight to moderate in open waters, with waves between 1.0 meters and 1.5 meters and near calm in sheltered areas. Winds will be mainly from the east to northeast at times, at 10-15 knots.