Early  Actions & Preparedness

• Strengthen community coordination with disaster management personnel;

• Persons living in flood risk areas should stregnthen their flood planning and preparedness efforts;

• Take every action to maintain emergency supplies that can allow for sheltering in place for seven days;

• Purchase emergency supplies and pack a grab and go-bag with clothes and essentials and have these on standby;

• Get acquainted with your flood prone areas, shelter locations and become sand-bag ready;

• Develop an evacuation plan that outlines the safety of family members and pets;

• Update contact information for the local disaster officials and other emergency services.

Figure 1: Category of rainfall likely for October to December 2021 (OND) 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 OND period rainfall totals during the historical period used to produce the outlook.

• Rainfall for October to December is likely to be above-normal all of Trinidad and Tobago with the chance of exceed normal totals greater than 40% over large areas;

• Model outputs used for guidance maintains previous months elevated probabilities for wetter than usual conditions for OND with increased chance for  unusually wet periods and wet days;

• October rainfall totals have increased and OND accumulated rainfall totals are usually among the highest totals. Therefore, above normal rainfall for OND are likely to be substantial amounts of rainfall;

• Given grounds are reasonably soaked and water table levels relatively high, concerns increase and remain elevated  for flooding during heavy and prolonged rainfall events.

  Figure 2:  Percentage of average rainfall totals likely for October to December 2021.

• All of Trinidad and Tobago show the percent of average rainfall is likely to be greater than 100% and supports the probability of wetter than average conditions;

• Percent of average rainfall totals are likely to range from 103% to 126% of average or 3% to 26% more rainfall than average.

Figure 3: The map shows the chance for extremely dry conditions over the three months, ending December 2021. Extreme refers to the lowest 10% of  September to November accumulated rainfall totals in the historical record.

• The percent chance for October to December rainfall totals to be among the driest 10% of OND on record is low to moderate.

Figure 4: Possible accumulated rainfall totals with the highest chance of occurring during October to December 2021.

• Much of Trinidad shows a greater than 50% chance of rainfall totals above 700 mm during OND.

• Possible accumulated rainfall totals for OND range between 530 mm and 1100 mm;

• Areas long the foothills of the northern range in north-eastern Trinidad and the eastern part of the east-west corridor are likely to be the wettest areas, where accumulated rainfall totals are likely to reach and exceed 900 mm with totals as high as 1100 mm possible;

• Areas in Tobago’s southwest near Crown Point, Low Lands and Buccoo can expect rainfall totals around 530 mm, while areas in the northeast, near Mount Saint George and Kings Bay and north-side near Moriah and Castara are likely to get totals close to 900 mm.

Figure 5: Possible rainfall totals with the highest chance of occurring during  October 2021.

• October is likely to be unusually wet with a wet regime and associated unsettled conditions set to dominate and drive above-normal rainfall totals across most of the country;

• The chance for October rainfall to be above-normal is greater than 45%; 

• Expect monthly totals from near 140 mm to 450 mm in Trinidad and between 115 mm and 325 mm in Tobago;

• The Extended Range  forecast indicates that the week of  October 8^th to 14^th and 15^th to 21^st are likely to be wet, with October 8^th to 14^th likely to be the wettest.

Figure 6: Category of rainfall most likely for January to March 2022 (JFM) 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 JFM period rainfall totals during the historical period used to produce the outlook.

• It is likely that the 3-month period January to March 2022 will be drier than usual with below normal totals as the most favourable category to occur.

Temperature Outlook:

• October to December temperature outlook favours above-normal monthly mean temperatures, with warmer than average conditions expected;

• Both day maximum and night minimum are expected to be warmer than average with greater than 62% chance for this to occur;

• October temperatures are likely to be warmer than average with the greatest percent chance occurring over cities and urban areas;

• October usually brings the local heat season to a close. There is a slight chance for maximum temperatures to climb near or above 34.0^oC during the month, but this is more likely during the first week of the month;

• Cities, urban and developed areas have the highest chance for warmer than normal temperatures and experience the most intense heat on hot days;

• The risks for hot days and hot spells are highest for early October.

Figure 9: 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  October to December 2021. The colour-coded bar-graph with the numbers to the right gives the likelihood for each forecast category to occur.

Likely Implications

• Above-normal rainfall for OND usually produce a number of moderate and heavy rainfall days that are high risk enough to cause severe flooding. Flash flood risk remains elevated in occasional and well-known flood prone areas;

• Localized moderate to heavy rainfall days on already soaked soils could trigger flash-flooding in high-risk/flood-prone areas and floods and landslides within watersheds with narrow valleys and steep hill-sides;

• Expect recharge rates, surface water flows and river levels to remain high;

• Expect increased turbidity and degraded water quality on heavy rainfall days;

• More reliable rains for agriculture but the excess rainfall can lead to water logging and flooding  of agricultural fields;

• Increased rainfall, mixed with warm and humid conditions will likely promote rapid multiplication of some agricultural pests, diseases and fungal growth;

• Increased rainfall could lead to reduced traffic flows, disruptions in localized travel, and longer travelling times, which may require earlier commute start-times;

• Increased rainfall will increase surface water ponding and can promote mosquito breeding, which can lead to higher risks for spikes in vector-borne diseases;

• Higher than usual and extreme temperatures can lead to relatively excessive heat for Trinidad and Tobago which can amplify existing health conditions in vulnerable persons and worsen chronic health conditions in others during the rest of the local heat season;

• Increased heat may increase the need to access cooling, which requires energy;

• Hot days and spells can cause heat stress in livestock and wilting in newly transplanted and younger crops;

• Water-logged agricultural fields can reduce soil oxygen and increase the loss of nitrogen and other important nutrients, which can negatively affect fruit and crop quality and yields;

• Warmer than usual temperatures can lead to warmer than usual water-temperatures, which are particularly important for the health of aquaponics fishes and plants and hydroponic plants;

• Water temperatures much warmer than 30.0^oC can affect warm-water fishes such as tilapia.