2021 Dry Season Update: Less Dry Than Usual

In Trinidad and Tobago Meteorological Service’s rainfall and temperature outlook for February through April 2021, the Service is calling for above-normal rainfall and temperatures.

What you need to know

  • February is likely to be wetter than usual, with above-normal rainfall totals expected.
  • Similarly, the 2021 Dry Season through April 2021 is likely to be less dry than usual, with the chances being highest for above-normal rainfall. Despite this, many sunny days with typical dry season weather is expected, including visitation of typical dust events, but more so during March and April.
  • The TTMS is also calling for both day and night average temperatures are very likely to be warmer than average over Trinidad and Tobago.
  • There is the chance for one or two relatively cold nights during February when minimum night temperatures are likely to be close to, or below 20.0°C.
  • La Niña conditions in the tropical Pacific Ocean may have reached its peak strength in terms of sea surface temperatures.

Likely Impacts

  • Above-normal rainfall totals during February through April may not be significantly large rainfall totals but can still reduce some of the usual drying expected during the season.
  • Dry season conditions usually lead to an increase in the need to collect and store water in containers. This can increase breeding areas for mosquitoes if collected water is not stored properly.
  • The expected drying is likely to increase bush and forest fire potential, especially during late February and March.
  • Reduced air quality is likely during bush-, grass-, forest- and landfill-fires. This can negatively affect persons with existing respiratory and other ailments.

2021 Dry Season (February – April) Rainfall Outlook

Category of rainfall likely for February to April 2021 (FMA) with the highest chance of occurrence expressed as probabilities and colour coded on the map. Blues indicate that it is more likely for above normal rainfall to occur than for below normal or near normal. Browns indicate it is more likely for below normal rainfall, while greens indicate it is more likely for near normal rainfall. Normal is defined by the rainfall that was observed in middle one-third of the FMA period rainfall totals during the historical period used to produce the outlook. (Trinidad and Tobago Meteeorological Servce)
Category of rainfall likely for February to April 2021 (Trinidad and Tobago Meteorological Service)

Trinidad and Tobago is forecast to experience a slightly wetter than usual February through April according to the TTMS.

In their outlook, the odds are tilted towards above-normal rainfall over the three months with the highest likelihood for wetter than average conditions existing over north-eastern and south-western Trinidad, and all of Tobago.

Even though there is a 46-55% chance of above-normal rainfall during the period, a lot of dryness is still likely, as a few moderate to heavy rainfall events can assist in pushing the monthly and seasonal rainfall totals above-average in just a few days of rainfall.

Above-normal rainfall totals during the 2021 Dry Season, from February to March, are not usually large rainfall totals but can still aid in reducing some drying impacts during the season. This would create favorable agricultural production conditions, but if excessive rainfall occurs, it could be harmful to some agricultural activities and beneficial to others.

The TTMS is reminding the farming community that they need to understand that their level of risk might change if intense rainfall occurs, which could have negative impacts, including flooding in some areas.

With above-average rainfall, there are increased risks of pest infestation and the likelihood of an increased prevalence of crop pests and crop and animal diseases. This above-average rainfall will likely affect pastures and livestock body conditions positively in farms depending on grass for feeding according to the TTMS.

Chance for extremely dry conditions over the three months, ending April 2021. (Trinidad and Tobago Meteorological Service)
Chance for extremely dry conditions over the three months, ending April 2021. (Trinidad and Tobago Meteorological Service)

The TTMS has given the period between February through April a low to medium chance, 8% to 12%, of the period being extremely dry. An extremely dry period would be where recorded rainfall totals are within the lowest 10% of all totals in the historical record.

Note that the Service is also calling for a 70-80% chance for at least three 7-day dry spells during the 2021 Dry Season February through April 2021.

Chance for extremely dry conditions over the three months, ending April 2021. (Trinidad and Tobago Meteorological Service)
Possible accumulated rainfall totals with the highest chance of occurring during February to April 2021. (Trinidad and Tobago Meteorological Service)

Based on their outlook, areas in the northeast and eastern half of Trinidad are likely to receive the largest accumulated rainfall totals. This is typical during the dry season.

Possible seasonal rainfall totals for Valencia, Sangre Grande, North Oropouche, and surrounding environs are expected to be between 340.0mm and 400.0mm.

Areas near Port of Spain in northwest Trinidad and other areas along the western coast are likely to receive the least rainfall totals. Accumulated totals in these areas are likely to be less than 225.0 mm over the three months.

In Tobago, accumulated rainfall totals are likely to range between 255.0 mm in the vicinity of Speyside in northeast Tobago and 180.0 mm near Canaan and environs in the northwest.

Possible rainfall totals with the highest chance of occurring during February 2021 (Trinidad and Tobago Meteorological Service)
Possible rainfall totals with the highest chance of occurring during February 2021 (Trinidad and Tobago Meteorological Service)

The TTMS is also calling for February 2021 to be likely wetter than usual with a greater than 51% chance in most areas for rainfall totals in the above-normal category.

In fact, the TTMS is forecasting possible rainfall totals from 35.0 mm to 140.0 mm in Trinidad and between 60.0 mm and 80.0 mm in Tobago for February 2021.

Category of rainfall most likely for May to July 2021 (Trinidad and Tobago Meteorological Service)
Category of rainfall most likely for May to July 2021 (Trinidad and Tobago Meteorological Service)

Looking further afield, the TTMS is expected the start of the 2021 Wet Season to have less rainfall than usual, with below normal rainfall totals likely.

2021 Dry Season (February – April) Temperature Outlook

Category of maximum and maximum temperatures that is most likely to occur across Trinidad and Tobago through April 2021. (Trinidad and Tobago Meteorological Service)
Category of maximum and maximum temperatures that is most likely to occur across Trinidad and Tobago through April 2021. (Trinidad and Tobago Meteorological Service)

Following the trend of the last several years, February to April 2021 daytime temperatures are very likely to be warmer than average for most of Trinidad and Tobago according to the TTMS’ outlook.

In fact, the chance for warmer than average maximum temperatures is 75% for both  Trinidad and Tobago with nights very likely to be warmer than average, with a similar percent chance.

Warmer than usual temperatures on hot and very hot days can lead to warmer than usual water-temperatures, which can cause heat stress such as wilting in aquaponic crops. The TTMS urges to take action ahead of time to support crop production and livestock health to prevent agriculture production losses.

Higher than usual temperatures may still be high enough to amplify existing health conditions in vulnerable persons and worsen chronic health conditions in others.

The months of March and April are part of the local heat season. April is usually one of the hottest months of the year in Trinidad and Tobago.

There are high chances for the occurrence of hot days (days with maximum temperatures reaching or exceeding 34.0oC in Trinidad and 32.0oC in Tobago) and short duration hot spells (periods of at least 5 consecutive hot days), during late March and April.

Still, on one or two cloud-free nights during February, minimum temperatures are likely to cool close to, or just below 20.0oC.

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