Thursday 9 July, 2020

Met Office warns: Above-average rainfall coming from July-September

Photo: Marcin Kilarski/Getty

Photo: Marcin Kilarski/Getty

Concerns about Trinidad and Tobago's current water shortages may change to concerns about flooding as the Trinidad and Tobago Meteorological Service has forecast normal to above-normal rainfall conditions for July to September 2019.

In its Rainfall and Temperature Outlook Update, issued July 2, 2019, the Met Office said Trinidad's outlook for July has a greater than 40 percent chance of above average rainfall.

Tobago's rainfall is likely to be near average with forecast wet spells 

"The rainfall outlook for July to September 2019 indicates an enhanced signal for wetter than usual conditions across most of Trinidad with accumulated rainfall totals likely to be in the above normal category, when compared with the chance for near- or below-normal. At the same time, Tobago is likely to be just as wet as usual with near average rainfall totals expected (high confidence);

"This means most areas in Trinidad are likely to receive 3-month rainfall totals that are greater than 125% of their long term averages while areas in Tobago are likely to receive totals between 75% and 125% of their long term averages.

"For instance, at Piarco, this means possible accumulated JAS (July/August/September) rainfall totals greater than 877.0mm and at Crown Point possible totals between 380.0mm and 633.0mm. This suggests at least one prolonged wet spell (3 or more extremely wet days) is expected," the report said. 

The Met Office said the outlook indicates an increase in the number wet days with a 50-60% chance for accumulated rainfall totals in excess of 700 mm across most of Trinidad and a 40-50% chance for rainfall in excess of 500 mm in Tobago.

Days and nights are also likely to be warmer than average during July to September. September is likely to be the warmest month during the period.

Increased risk for flooding, landslides

The Met Office said, as a result, there is an increased risk for flash and riverine flooding and landslips and landslides on heavy rainfall days and short duration wet spells during this period and a 'much-elevated flooding risk for October and November'.

"Warmer than average temperatures can aid more intense showers on hot days. This increases the risk for flash floods on hot days in the cities and built-up areas," the Met Office said. 

This also means more reliable rains for water resource management and agriculture in areas with enhanced chances for wetter than usual conditions. 

As a result, surface wetness is likely to increase at a faster rate during the period. 

More mosquitos?

The Met Office said due to increases in surface water ponding there may be a growth in mosquito breeding, leading to a higher risk of spikes in vector-borne diseases such as malaria and dengue. 

The Met Office is therefore advising public and private groups and individuals to clean drains, canals and guttering, and to prepare, if based in flood-prone areas.

Early actions and preparedness

The Met Office is urging citizens in flood-prone areas to:

- Stock up on emergency supplies for 3-7 days;

- Pack a flood-ready go-bag with clothes and essentials;

- Develop an emergency communication plan, which includes a place to stay;

- Clear dry branches/tree-overhang near residence;

- Guard against the effects of excessive heat;

- Clean drains, canals and guttering; Conserve, store and manage water in a safe and adequate manner;

- Take measures to lessen impacts from flooding. Be sand-bag ready.


Elevated flood risk for October-December

The Met Office added that October to December  2019 (OND) is likely to be just as wet as usual with greater than 35% chance for accumulated rainfall totals to be in the near average category, across both islands.

The Met Office said November is likely to be wetter than usual and the risk of for flooding remains elevated.


Increased rainfall likely from September to October

The Met Office added that August to September forms part of the second heat season in Trinidad and Tobago, with September often being the hottest month and therefore Trinidad and Tobago is likely to receive warmer than usual conditions during JAS.

"There is a greater than 60% chance for maximum day-time and minimum night-time temperatures to be above  average with  September days and nights likely to be the warmest during the period."

"Concerns for short duration hot-spells and increase in the number of  hot days (days with maximum temperature greater than 33.9'C in Trinidad and greater than 32.0'C in Tobago) are elevated for the August to October period."

"The chance for increases in the number of hot days is higher in Port of Spain and built-up areas," the Met Office said. 

As a result the Met Office warns of an increased rish of flash and riverine flooding, landslips and landslides on heavy rainfall days and short duration wet spells for the September to November period.

There is also the chance of an increase in agricultural pests, diseases and fungal growth, while heavier rainfall can mean an increased in flies, which can spread diseases such as Gastroenteritis and Salmonella infections. 

Citizens are advised to continue monitoring weather developments via the Met Office and the Office of Disaster Preparedness and Management (ODPM), as well as retaining the Regional Corporation Disaster Management hotline numbers below.



Diego Martin Regional Corporation

800-DMRC (3672)

San Juan/Laventille Regional Corporation

800-SLRC (7572)

Arima Borough Corporation

800-2ABC (2222)

Tunapuna/Piarco Regional Corporation

800-TPRC (8272)

Port-of-Spain City Corporation

800-PSCC (7722)

Sangre Grande Regional Corporation

800-SGRC (7472)

Chaguanas Borough Corporation

800-DCBC (3222)

Couva/Tabaquite/Talparo Regional Corporation

800-CTTC (2882)

Mayaro/Rio Claro Regional Corporation

800-4MRC (4672)

Princes Town Regional Corporation

800-PTRC (7872)

Point Fortin Borough Corporation

800-PFBC (7322)

San Fernando City Corporation

800-SCDU (7238)

Penal/Debe Regional Corporation

800-PDRC (7372)

Siparia Regional Corporation

800-4SRC (4772)

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