ISSUED AT: 06:19 PM
Date: Wednesday 13th of December 2023
Key Messages:
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Likely Impact
Early Actions & Preparedness
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ISSUED AT: 06:19 PM
Date: Wednesday 13th of December 2023
Key Messages:
• The 2024 Dry Season rainfall outlook indicates strongly enhanced signals for suppression of rainfall towards drier-than-usual conditions in the first half of the season followed by wetter than usual for the second half of the season for both islands. December is likely to get near-normal rainfall;
• Below-normal rainfall totals are favoured for January to March while above-normal rainfall totals are favoured for March to May 2024;
• The majority of the country is likely to get a percentage of average dry season rainfall totals that range between 61% to 102%;
• Trinidad and Tobago normally receives 3 to 8, 7-day dry spells and 1 to 5, 10-day dry spells in the dry season. For 2024, there is a 70% probability for 4-7, 7-day dry spells and 1 to 3, 10-day dry spells;
• The outlook indicates relatively moderate to high probabilities (31%-98%) across most areas for seasonal rainfall totals to exceed the national dry season average of 412.0 mm;
• The probability for totals to be in the lowest 10% of all dry season rainfall totals is low (8%-27%);
• The Dry Season 2024 temperature outlook indicates above-normal seasonal mean, maximum and minimum temperatures are likely, but at least three to seven cool nights when temperatures can fall below 20.0 oC in Trinidad and 22.0 oC in Tobago are possible in January and February 2024;
• There is a moderate probability (55%-60%) that a moderately strong El Niño will persist throughout the first half of the dry season followed by weakening in the second half of the Dry Season 2024.
Likely Impacts:
• Recent rainfall events during November and the first week of December 2023 have already positively influenced surface water flows, river levels and groundwater recharge. The expected drier-than-usual conditions in the first half of the dry season will negatively impact surface and groundwater recharge rates and stream flow rates;
• Initial drier than usual and warmer than usual conditions at the beginning of the dry season may lead to an increase in breeding areas for insect vectors such as mosquitoes due to uncovered water storage devices;
• The expected 2024 dry season conditions will increase chances for bush, forest and landfill fire potential, especially from early January to March 2024 but less so in April and May 2024. This will likely reduce air quality and negatively affect persons with existing respiratory and other ailments.
Early Actions & Preparedness
• Review household water plan. Conserve, store, and manage water safely and adequately.
• Sensitize vulnerable communities on the negative impacts of the forecast and actions to be taken
• Raise awareness on dry season agriculture pest and disease control measures and bushfire risk.
• Ramp-up contingency plans to mitigate the possible occurrence of landfill fires.
• Review contingency plans to manage dry season spikes in vector-borne diseases such as gastroenteritis and leptospirosis; and dust/smoke-related respiratory ailments.
Figure 1: Category of rainfall likely for DJF (December to February) 2023/4 with the highest chance of occurrence expressed as probabilities represented on the map. Blue areas indicate places with an increased chance for above-normal rainfall, brown areas show an increased chance for below-normal rainfall, while green areas show an increased chance for near-normal rainfall. Normal is defined by the rainfall that was observed in the middle one-third of the DJF period rainfall totals during the historical period used to produce the outlook.
Figure 2: Category of rainfall likely for the 2024 Dry Season with highest chances of occurrence expressed as probabilities represented on the map. Blue areas indicate places with an increased chance for above-normal rainfall, brown areas show an increased chance for below-normal rainfall, while green areas show an increased chance for near-normal rainfall. Normal is defined by the rainfall that was observed in the middle one-third of the JFMAM period rainfall totals during the historical period used to produce the outlook.
Figure 3: Percentage of average rainfall totals likely for the 2024 Dry Season.
Figure 4 : The map shows the chances for extremely dry conditions over the 2024 Dry Season. Extremely dry conditions refer to the lowest 10% of dry Season total rainfall amount in historical records.
• The probability for totals to be in the lowest 10% of all dry season rainfall totals is low (8%-27%);
• Although there is a moderate (65%) chance of dry spells to occur in the first half of the season, the probability of long-term drought conditions by the end of May 2024 is low.
Figure 5: The map shows the probability of the 2024 Dry Season rainfall totals exceeding the national average of 412 mm.
• The outlook indicates moderate to high probability (31%-98%) that the national average of 412 mm will be surpassed;
• Areas in eastern Trinidad and central Tobago have the highest probability of exceeding the national average, while small areas in northwest Trinidad and southwest Tobago have lower probabilities of surpassing the national average;
Figure 6: Possible accumulated rainfall totals with the highest chance of occurrence during the 2024 Dry Season.
Figure 7: Possible rainfall totals with the highest chances of occurring during December 2023.
Figure 8: Category of rainfall likely for January to March (JFM) with the highest chances of occurrence expressed as probabilities represented on the map. Blue areas indicate places with an increased chance for above-normal rainfall, brown areas show an increased chance for below-normal rainfall, while green areas show an increased chance for near-normal rainfall. Normal is defined by the rainfall that was observed in the middle one-third of the JFM period over the 1991-2020 period used as the climate normal.
Figure 9: Category of rainfall likely for March to May (MAM) with the highest chances of occurrence expressed as probabilities represented on the map. Blue areas indicate places with an increased chance for above-normal rainfall, brown areas show an increased chance for below-normal rainfall, while green areas show an increased chance for near-normal rainfall. Normal is defined by the rainfall that was observed in the middle one-third of the MAM period over the 1991-2020 period used as the climate normal.
Figure 10: The map shows the colour-coded category (below-normal, above-normal, and near-normal) of maximum and maximum temperatures that is most likely to occur across Trinidad and Tobago for the 2024 Dry Season. The colour-coded bar-graph with the numbers to the right gives the likelihood for each forecast category to occur.
The Temperature Outlook Favours Above-Normal Temperatures over large sections of Trinidad and Tobago for the Dry Season of 2024.
Climatic Influencers and Context of the Outlook