Thursday 23 January, 2020

End of year will be ‘wetter than usual’, says Met Office

The Trinidad and Tobago Meteorological Service warned of higher than average rainfall from November to January 2020, with an accompanying higher risk of riverine and flash flooding.

In its Rainfall and Temperature Outlook for the period, the Met Office said the risk of flooding remains elevated, a 60 percent chance for at least one seven-day wet spell (seven consecutive days with measurable rainfall).

The Met Office said total rainfall amounts for the period are likely to be above-normal over most of the country and that historically, the month of November has produced high-impact flooding events.

“Flash flooding is expected to be of general concern for the country during November and December. There is increased risk for riverine flooding, landslips and landslides during prolonged rainfall periods.”

The Met Office said the percent chance for above-normal amounts ranges between 35% and 52%. In the few areas where near-normal seasonal amounts are expected, the percent chance ranges between 38% and 44%.

The Met Office said however that there would be more reliable rains for water management and agriculture.

Heavy showers likely in North-east Trinidad

The Met Office said the largest seasonal total rainfall amounts are likely to be as much as 1010 mm in Valencia, Sangre Grande, North Oropuche and surrounding environs in east Trinidad while the smallest totals are likely to be as low as 393.0 mm, near Port of Spain in north-west Trinidad and Icacos, Cedros  and other areas in south-western areas of the island.

Across in Tobago the largest totals are likely to be near 770.0 mm in the vicinity of Hillsborough and other north-eastern areas, while smallest totals are likely in the south-western areas near Crown Point, Mount Irvine and environs.

November is likely to be the wettest of the three months.

 

Temperature Outlook

Both daytime and night temperatures are likely to be above-normal across all of Trinidad and Tobago during November 2019 to January 2020 and during February to April 2020, the Met Office said, with a greater than 60 % chance for maximum daytime and minimum night temperatures to be warmer than normal.

Even though days and nights are likely to be warmer than average during NDJ, temperatures are not likely to be excessively uncomfortable.

 

Likely Implications

The Met Office said as a result, there is an increased risk of flash and riverine flooding, landslips and landslides, on heavy rainfall days and short duration wet spells. Flooding risk is elevated for the months of November and December;

The Met Office said there may also be an increase in recharge rates at water reservoirs associated with wetter than usual conditions.

Increases in surface water ponding can promote mosquito breeding, leading to a higher risk for spikes in vector-borne diseases.

There may also be an increase for agricultural pests, diseases and fungal growth.

“Increased rainfall is often associated with more flies and flies are known to carry and spread diseases such as gastroenteritis and salmonella infection.”

“Increased rainfall could lead to reduced traffic flows, disruptions in localized travel, longer travelling times, which may require earlier start time for commute,” the report said.

 

Sea temperature rising

The Met Office said sea temperatures surrounding Trinidad and Tobago are currently+0.4oC to +1.2oC warmer than average. A number of models surveyed by the MSD indicate the ongoing warming is likely to continue and maintain above-average temperatures during the period November-January 2020.

“Warmer than average SSTs in waters east of Trinidad and Tobago are likely to be the primary driver of Trinidad and Tobago’s climate over the next 3 months.”

The precipitation and temperature outlook is based on statistical and dynamical seasonal climate models output and known seasonal climate influencers.

"The outlook is in reasonable agreement with several of the global climate models. Multiple climate influencers appear to be at play and can cancel out each other," the Met Office said. 

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