Forecast: Mostly Hot & Sunny, Isolated Afternoon Showers

Tropical Wave 44, a weak and very slow-moving tropical wave, moved across T&T on Sunday, bringing a shallow surge in moisture. Light southeasterly winds are forecast and combined with strong daytime heating, isolated showers and the odd thunderstorm are possible, mainly across Trinidad and after midday.

The risk of scattered to widespread heavy rainfall is very low to none. However, heat-driven showers and thunderstorms can be intense, producing localized and brief street flooding and gusty winds. This activity will mainly be possible across the western half of Trinidad. With light winds, funnel clouds are also possible.

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

The Forecast


Overview: Abundant low-level moisture is present, but a dry mid to upper-level environment is in place. This means cloud and shower development will be limited unless strong daytime heating, orographic lift (along the Northern Range), and sea breeze convergence can act as triggers for afternoon shower and thunderstorm development.


Forecast: A mostly hot and sunny day is forecast across both islands. By the late morning, partly cloudy skies are forecast to develop across the Western half of Trinidad. After midday, isolated showers are possible, mainly across West-Central and Northwestern areas of Trinidad, as well as along the south-facing slopes of the Northern Range. The odd thunderstorm is possible, favoring Western Coastal Trinidad during the afternoon.

Conditions are forecast to settle by the evening, but models show and increase in shower and thunderstorm activity overnight, affecting eastern areas of both islands predominantly, mainly after midnight.


Seas forecast to be slight, with waves up to just over 1 meter in open waters. In sheltered areas, near calm.

The main hazards include brief and highly localized heavy rainfall, which may reduce visibility and gusty winds up to and in excess of 55 KM/H. Street or flash flooding will be possible in slow-moving showers and thunderstorms. In thunderstorm activity, frequent lightning is also possible. Gusty winds may cause power dips/outages, downed trees, and localized wind damage.

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 36.0°C in urban and built-up areas. 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 relatively high on Monday across Trinidad and Tobago. The heat index and 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 40°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 Monday, the heat index is forecast to be near levels where extreme caution is needed and in some areas, at dangerous levels! Remain hydrated!

Forecast Impacts

Winds

Sustained surface winds will be light to nonexistent. However, during heavy showers and thunderstorms, sustained winds between 25 KM/H and 35 KM/H with gusts up to and in excess of 55 KM/H are possible.

With wind gusts in excess of 55 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.

High Wind Event Precautions
High Wind Event Precautions

Rainfall

Across most areas of Trinidad and Tobago, little to no rainfall is anticipated, with maximum accumulation totals near 5 millimeters. However, across parts of Western and Northern Trinidad, particularly along the south-facing slopes of the Northern Range and the Western half of Trinidad, rainfall totals of up to 10 millimeters are possible, with isolated totals in excess 15 millimeters, particularly in slow-moving downpours or thunderstorms.

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: Though thunderstorm chances are low on Monday, 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 Monday. Most will experieice hot and sunny conditions.

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