Forecast: More Afternoon Showers, Thunderstorms Interrupts Hot, Sunny Day

A mostly hot and sunny day is forecast across Trinidad and Tobago as a ridge of high pressure moves in, ahead of Tropical Wave 54. However, afternoon showers and thunderstorms are possible.

There are no alerts, watches, or warnings from the Trinidad and Tobago Meteorological Service at this time.

Forecast For Thursday

Forecast: A mostly sunny to partly cloudy morning is forecast across Trinidad and Tobago. By the late morning through the late afternoon, isolated, brief showers are possible across the western half of Trinidad and hilly areas of both islands. Isolated, brief thunderstorms are also possible along western coastal Trinidad during the afternoon. Conditions are forecast to settle by the evening into the night.

Hazards: The main hazards include isolated, heavy rainfall, which may reduce visibility and gusty winds up to and in excess of 45 KM/H. Street or flash flooding will be possible in violent showers and thunderstorms, particularly across western areas of Trinidad during the afternoon. In thunderstorm activity, frequent lightning is also possible. Gusty winds may cause power dips/outages, downed trees, and localized wind damage.


Marine: Seas are forecast to be slight to moderate, with waves between 1.0 and 1.5 meters in open waters. Swells are forecast to be from the northeast, with a swell period between seven and nine seconds. In sheltered areas, near calm. However, in areas where thunderstorms occur, seas can become choppy and locally rough.

Winds are forecast to be light to moderate offshore, between 10 and 15 knots prevailing from the east to southeast.

Sea breeze convergence mechanisms for the Gulf of Paria and the Atlantic Ocean across Trinidad which can produce thunderstorm activity. On Thursday, sea breeze convergence will be possible across all coasts of Trinidad and Tobago due to light to no winds.
Sea breeze convergence mechanisms for the Gulf of Paria and the Atlantic Ocean across Trinidad which can produce thunderstorm activity. On Thursday, sea breeze convergence will be possible across western coasts of Trinidad due to light winds.

Forecast Discussion: A deep layered but weak high-pressure system is across the Lesser Antilles. This will allow for mostly settled conditions, though some weak surface to low-level confluencing will enhance low-level convergence in some areas, resulting in brief shower activity.

Across Trinidad, by the late morning through the afternoon, with light winds, daytime heating and sea breeze convergence will act as triggers for shower and thunderstorm development across western parts of Trinidad, with orographic lift triggering/enhancing showers along hilly topography of both islands.

Moisture associated with Tropical Wave 54 and associated instability will move across T&T overnight into Friday. Conditions will become favorable for shower and thunderstorm development overnight Thursday through Saturday, with severe thunderstorms possible Friday afternoon across Trinidad.

Temperatures

Across both islands, hot and humid conditions are forecast. The maximum high for Trinidad is forecast to be near 34.0°C, up to 37.0°C in urban and built-up areas, particularly between 9:00 AM and 3:00 PM. In Tobago, the maximum high is forecast to be near 33.0°C.

Temperatures in cities, such as Port of Spain, tend to be much higher than surrounding locations due to a phenomenon called the Urban Heat Island Effect. There are several causes, but the main instigator for this phenomenon tends to be increased dark surfaces such as roads and pavement in cities, which absorb solar radiation more than surrounding areas.

The Heat Index

The heat index will be near dangerous levels on Thursday across Trinidad and Tobago. The heat index is a combination of air temperature and relative humidity, determining what the air feels like to a person, i.e., how hot it actually feels.

Across Trinidad, the maximum heat index is forecast to be between 35°C and 45°C and even higher in urbanized areas. In Tobago, the maximum heat index is forecast to be between 35°C and 42°C

The heat index is important because of sweating. Your body sweats to cool the skin and maintain a constant, healthy body temperature. This cooling process means that the sweat has to evaporate off the skin to remove heat. However, if the sweat is unable to evaporate, the body isn’t able to regulate temperature.

 Heat Index Values Explained
Heat Index Values Explained

Heat index is generally classified into four categories: caution, extreme caution, dangerous, and extremely dangerous. On Thursday, the heat index is forecast to be near dangerous levels! Remain hydrated!

Forecast Impacts

Winds

Sustained surface winds will be light but increasing throughout the day. By the afternoon, sustained winds between 25 KM/H and 35 KM/H with gusts up to and in excess of 45 KM/H are possible.

With wind gusts in excess of 45 KM/H, whole trees are expected to be in motion, and there may be some inconvenience when walking against the wind gusts. Light outdoor objects may topple or become airborne such as garbage cans, potted plants, loose galvanize or construction material, and other outdoor furniture. Tents may jump. Older/weaker trees may fall, bringing down utility poles and lines.

Rainfall

Across most areas of Trinidad and Tobago, little to no rainfall is anticipated, with maximum accumulation totals near 5 millimeters. In areas where isolated heavy showers or thunderstorms occur, accumulations up to 25 millimeters are possible, with higher totals possible along western coastal Trinidad.

Generally, with heavy showers and thunderstorm activity, street flooding, particularly in flood-prone areas or areas with poor drainage, is possible as well as flash flooding in areas where more prolonged heavy rainfall may occur.

Frequent Lightning: Frequent lightning is possible in thunderstorm activity. Lightning can cause power outages, voltage dips, damage to life and property, particularly during cloud-to-ground lightning strikes.

Why I May Not/Will Not See Rainfall?

A frequent complaint is the forecast is wrong because I didn’t experience any rainfall. Scattered showers mean that you, individually, may experience some showers intermittently throughout the day and there is a higher chance for this activity than isolated activity. Widespread showers mean that nearly all persons and areas may experience rainfall.

Highly isolated rainfall is forecast on Thursday. Most will experience very hot and sunny conditions.

Forecast - Isolated, Scattered, Widespread - What do they mean?

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