Tropical Wave 05 is moving across Trinidad and Tobago, interacting with a supportive atmosphere for numerous showers and thunderstorms. Based on model guidance, significant rainfall is forecast across the country over the next 48 hours.
Overall heavier rainfall is forecast to favor southern and eastern Trinidad, though significant rainfall accumulations are forecast across much of Trinidad.
The Trinidad and Tobago Meteorological Service has updated the Adverse Weather Alert (#1) Yellow Level on Friday morning at 9:22 AM. The new alert went into effect at 9:25 AM Friday 4th June 2021 and will remain in effect through 12:00 PM Saturday 5th June 2021.
Friday: Periods of rain, numerous showers, and isolated to scattered thunderstorms are forecast to affect T&T from midnight throughout the day. Rainfall will interrupt mostly cloudy to overcast skies. Heavier showers and thunderstorm activity are forecast to favor Trinidad throughout the day though thunderstorm activity is possible across Tobago. Lingering showers and isolated thunderstorms are forecast through the overnight hours.
Saturday: Similar conditions to Friday are forecast, with periods of rain, numerous showers, and isolated to scattered thunderstorms across Trinidad and Tobago throughout the day, interrupting mostly cloudy to overcast skies. Again, heavier rainfall is forecast to favor Trinidad. Conditions are forecast to settle briefly into the late evening, with a resurgence of rainfall overnight.
Marine: Seas are forecast to be moderate over the next 48 hours, with waves between 1.5 to 2.0 meters in Trinidad and Tobago’s open waters. Across sheltered coastlines, waves below 1.0 meter are likely. In heavy showers or thunderstorms, sheltered seas may become choppy.
As of 1:00 AM, a tropical wave has been analyzed at 61W, south of 12N, moving westward at 10 to 15 knots (18 to 27 KM/H). There is abundant atmospheric moisture and instability associated with the tropical wave. There is also a highly favorable atmospheric setup, with favorable low-level convergence and upper-level divergence as well as weak to moderate wind shear.
These factors will persist through the next 12-24 hours, allowing for abundant cloudiness, showers, and thunderstorms across Trinidad, Tobago, and the Windward Islands. However, much of the adverse weather will favor Trinidad.
On Saturday, lingering moisture and instability from Tropical Wave 05 will persist across Trinidad and Tobago with a favorable atmospheric setup allowing for more showers and thunderstorms to affect the country.
Across both islands, overnight lows are forecast to be mild, with daytime highs cool due to increased cloud cover.
Over the next 48 hours, the minimum low for Trinidad and Tobago is forecast to be between 22.0°C and 25.0°C. The maximum high for Trinidad and Tobago is forecast to be between 26.0°C and 28.0°C.
The main hazards include heavy rainfall and gusty winds, particularly in moderate to heavy showers or thunderstorms, bringing the high to very high risk of street flooding and medium to high risk of flash flooding. In thunderstorm activity, frequent lightning is possible. Gusty winds up to and in excess of 55 KM/H may cause power dips/outages, downed trees, and localized wind damage. By Saturday, there is a low to medium risk of riverine flooding, particularly with additional rainfall expected through Tuesday. Landslides may be possible by the start of the upcoming week due to saturated soils and additional forecast rainfall.
Sustained surface winds up to 35 KM/H. In shower activity, 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.
Over the next 48 hours, overall higher rainfall is forecast to favor eastern and southern Trinidad with accumulations between 75 to 125 millimeters. However, localized totals up to 150 millimeters are possible in prolonged heavy showers or isolated thunderstorm activity. Note that highly isolated areas across Western areas of Trinidad may exceed daily forecast totals.
- Friday: Between 25 to 50 millimeters across the country, with higher rainfall totals favoring southern and eastern halves of Trinidad, up to 75 millimeters. In isolated areas, rainfall accumulations may exceed 75 millimeters. Across Tobago, between 15 to 40 millimeters are possible.
- Saturday: Between 10-25 millimeters across the country, with higher rainfall totals favoring eastern and southern halves of Trinidad, in excess of 25 millimeters. Note that the GFS is trending higher, up to 45 millimeters across the country.
With moderate to heavy showers or thunderstorms due to Tropical Wave 05, there is the high to very high risk of street flooding and medium to high risk of flash flooding. By Saturday, there is a low to medium risk of riverine flooding, particularly with additional rainfall expected through Tuesday.
Other Adverse Weather Impacts
Lightning: 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.
Landslides: With saturated soils by Saturday and the threat of additional rainfall, landslides are possible in elevated areas, particularly hilly areas in southern and northeastern Trinidad.
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.
On Friday into Saturday, scattered to widespread rainfall is forecast.