2nd Half of Dry Season 2021: Still Forecast To Be Wetter Than Usual

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

What you need to know

  • March is likely to be wetter than usual, with above-normal rainfall totals expected in large areas.
  • Similarly, the 2021 Dry Season through May 2021 is likely to wetter than usual across most of Trinidad. Near-average rainfall is forecast across Tobago and parts of Southern and Southwestern Trinidad.
  • Many sunny days with typical dry season weather are expected, including periodic Saharan Dust events.
  • 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 are increased chances for hot days and short-duration hot spells when maximum day-time temperatures are likely to reach or exceed 34.0oC in Trinidad and 32.0oC in Tobago.
  • La Niña conditions in the tropical Pacific Ocean continue to decline and are likely to reach neutral conditions by the end of the local dry season.

Likely Impacts

  • Above-normal rainfall totals during March through May 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.
  • Reduced air quality is likely during bush-, grass-, forest- and landfill-fires. This can negatively affect persons with existing respiratory and other ailments.

2nd Half of The 2021 Dry Season (March-May) Rainfall Outlook

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

From March to May, most areas of Trinidad are likely to experience slightly wetter than usual conditions.

In their outlook, the odds are tilted towards above-normal rainfall over the three months across most areas of Trinidad, with the highest likelihood for wetter than average conditions existing over northeastern areas. In Tobago and southwest Trinidad, near-normal rainfall is anticipated.

Across Trinidad, between 95% and 136% of the rainfall long term average is likely, while between 90% and 95% is likely across Tobago.

Even though slightly wetter than usual conditions are favored for most areas, impactful drying is still likely. Dryness will still occur as days with moderate to heavy rainfall will be sparse, but these heavy rainfall days will push rainfall totals to above average.

Percentage of average rainfall totals likely for March to May 2021 (Trinidad and Tobago Meteorological Service)

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

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 May 2021. (Trinidad and Tobago Meteorological Service)

The TTMS has given the period between March to May a low to medium chance, 8% to 18%, 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 60-65% chance for at least three 7-day dry spells during the 2021 Dry Season, from March through May 2021.

Possible accumulated rainfall totals with the highest chance of occurring during March to May 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 395.0mm and 515.0mm.

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 300.0 mm over the three months.

In Tobago, accumulated rainfall totals are likely to range between 270.0 mm in northeast Tobago and 190.0 mm in the southwest.

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

The TTMS is also calling for March 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  between 44.0 mm and 115.0 mm in Trinidad and between 35.0 mm and 72.0 mm in Tobago for March 2021

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 May 2021. (Trinidad and Tobago Meteorological Service)

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

March to May marks the start of the first half of Trinidad and Tobago’s heat season. 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.

April is usually one of the hottest months of the year in Trinidad and Tobago, with April 2021 forecast to be no exception. There are high chances for 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.

The Trinidad and Tobago Meteorological Service advises the public to “conserve, store and manage water safely and adequately. Take measures to lessen the impacts of dry season conditions and excessive heat. Be dry-season and heat-ready. Stock up on water.”

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