As of 7:30 AM Tuesday 3rd September 2019, partly cloudy to cloudy skies are ongoing across Trinidad and Tobago, with scattered moderate to heavy showers and thunderstorms south of Tobago, approaching Eastern Trinidad. Increasing showers and thunderstorms are forecast as the day progresses across both islands.
Street and flash flooding, gusty winds are possible in the vicinity of or accompanying heavy showers and thunderstorms.
There are NO alerts, watches or warnings in effect for Trinidad and Tobago from the Trinidad and Tobago Meteorological Service at this time.
As the morning progresses, showers and thunderstorms are forecast to increase across both islands, with thunderstorms and heavier showers favoring Trinidad. This activity is forecast to persist through the afternoon across both islands, interrupting cloudy intervals.
This activity is due to a shearline moving across the region, as the Intertropical Convergence Zone moves northward. An increase in deep, tropical moisture is moving across Trinidad and Tobago presently, fuelling these heavy showers and thunderstorms through Tuesday.
Note that in heavier showers or a thunderstorm, locally heavy rain and gusty winds can trigger street flooding and down trees or utility poles.
Last night’s minimum temperatures were warm at 25°C at Piarco, Trinidad, and 26°C at Crown Point, Tobago. Minimum low temperatures across Trinidad and Tobago tomorrow are forecast to range between 25°C-26°C, with temperatures at the upper end of the minimum low-temperature range favoring Tobago. Low temperatures are likely to be lower across inland and mountainous areas.
Today, maximum high temperatures across T&T are forecast to be near a mild 31°C at Piarco, Trinidad and a heat index of ranging from 33°C to 37°C. Across Tobago, maximum high temperatures are forecast to be a mild 31°C with a heat index of 32-35°C. The heat index is an index that combines air temperature and relative humidity, generating a “feel’s like” temperature.
The Heat Index
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.
The heat index is important because of sweating. Your body sweats in order 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.
With high volumes of moisture in the air, also known as high relative humidity, which T&T regularly experience due to its tropical climate, the rate of sweat evaporation decreased. This is because the atmosphere is unable, or has limited potential to hold additional moisture in the atmosphere.
This results in you feeling warmer in humid conditions and cooler in less humid conditions i.e. when relative humidity decreases. As temperature increases, the heat index increases. As relative humidity increases, so does the heat index.
The heat index is generally classified into four categories: caution, extreme caution, dangerous and extremely dangerous. Generally across Trinidad and Tobago, we experience heat indices of caution to extreme caution in times of hot days, with isolated areas experiencing dangerous heat indices such as urban areas.
Today, heat index levels are likely to remain at extreme cautious levels. Heat cramps and heat exhaustion are possible.
Seas are forecast to be moderate with waves up to 1.5 meters in open waters.
Note that King Tides are forecast to continue, which means higher than normal high tides and lower than normal low tides. Nuisance coastal flooding is possible. In the event of heavy showers, particularly along Mosquito Creek and Port of Spain during high tide, run off of any flood waters may be slow.
Over the Next 24 Hours
Winds: Sustained surface winds between 20 KM/H and 40 KM/H with gusts in excess of 50 KM/H are possible in heavy showers or thunderstorms across Trinidad and Tobago.
With wind gusts in excess of 50 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: Rainfall accumulations of at less than 15 millimeters are possible with isolated higher amounts up to 25 millimeters. With thunderstorms and downpours, totals up to 50 millimeters are possible in highly localized areas.
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.
Landslides: Heavy showers across the Northern Range may trigger landslides in landslide-prone areas. Particularly in areas that receive heavy rainfall, landslides and/or mudflows may occur. These landslides, in addition to gusty winds, may down trees, utility poles and impede traffic on roadways.
Frequent Lightning: In addition, with thunderstorms, frequent lightning is likely.
Why I May Not/Will Not See Constant 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.
Today, isolated to scattered activity is forecast.