ITCZ Continues to Affect T&T. Intermittent Showers, Thunderstorms Forecast.

Satellite Image Courtesy Brohav WeatherFax. Forecast from TTWC.

What happened today?

Between 8:00 AM and 9:00 AM this morning, the axis of Tropical Wave 35 moved across Trinidad and Tobago, bringing a few isolated showers across Eastern and Southern Trinidad.

As forecast, the ITCZ was dragged across T&T, bringing showers and thunderstorms across the islands beginning at 10:00 AM.

The Trinidad and Tobago Meteorological Service, at 10:00 AM, updated their Adverse Weather Alert to include Tobago and shift the start time of the alert to 12:00 PM.

Activity following Tropical Wave 35, combined with the ITCZ triggered showers and thunderstorms across T&T. The ITCZ is forecast to linger, triggering locally heavy rainfall, street/flash flooding and inclement weather T&T through Thursday. Credit:
Activity following Tropical Wave 35, combined with the ITCZ triggered showers and thunderstorms across T&T. The ITCZ is forecast to linger, triggering locally heavy rainfall, street/flash flooding and inclement weather T&T through Thursday. Credit:

Periods of showers and thunderstorms continued from 10:00 AM through 2:00 PM.

Favorable upper-level and low-level conditions were in place for showers and thunderstorms to develop. However, a dry mid-level environment persisted, which has plagued much of the Atlantic this hurricane season/wet season.

Cloudy and humid conditions with a few isolated showers maintained through the evening, as convection waned east of T&T.

Street flooding did occur across parts of Southwestern Trinidad due to locally heavy rainfall, with up to 20 millimeters falling between 11:00 AM and 1:00 PM. Wind gusts up to 45 KM/H were recorded at several weather stations across Western Trinidad. A downed utility pole and power lines also hindered traffic in Tobago.

What We Forecast

Tropical Wave 35 is now well west of Trinidad and Tobago, with no further direct impacts from this wave forecast. However, the ITCZ remains across Trinidad and Tobago today through the end of the week.

Overnight tonight, intermittent showers and isolated thunderstorms are forecast overnight, interrupting partly cloudy to mostly cloudy skies across both islands.

After midnight, an increase in showers and thunderstorms are forecast, based on model guidance. Favorable low-level convergence is forecast to be in place through Thursday, with the ITCZ in place combined with elevated concentrations of atmospheric moisture.

Periods of showers and thunderstorms are likely across Trinidad, lesser so Tobago, on Thursday, gradually becoming settled with partly cloudy skies by the late evening.

6:50 PM Wednesday 14th August 2019 Radar Imagery from the Trinidad and Tobago Meteorological Service.

Based on the latest model guidance, isolated to scattered showers and isolated thunderstorms are forecast to move across both islands, with heavier activity favoring much of Eastern and Southern Trinidad, as well as Tobago.

Locally Heavy Rainfall & Flooding: Based on the latest model runs on Wednesday evening from Wednesday afternoon (2:00 PM) through Friday morning (2:00 AM), generally, over the 36 hour period, models are in agreement of fewer than 20 millimeters across of Trinidad and Tobago and between 20-40 millimeters across isolated areas of Trinidad and up to 50 millimeters across Eastern and Southern 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, based on the above-mentioned forecast rainfall totals associated with the ITCZ as it moves across the area.

Frequent Lightning: In addition, with thunderstorms, frequent lightning is likely.

Gusty Winds: Gusty winds, generally between 40 and 65 KM/H are possible Gusty winds are most likely prior to, in the vicinity of, or occur during heavy showers or thunderstorms. With wind gusts up to 65 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.

High Wind Event Precautions
High Wind Event Precautions

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 across both islands. These landslides, in addition to gusty winds, may down trees, utility poles and impede traffic on roadways.


Last night’s minimum temperatures were warm at 25°C at Piarco, Trinidad and 27°C at Crown Point, Tobago. Minimum low temperatures across Trinidad and Tobago tomorrow are forecast to range between 25°C-27°C, with temperatures at the upper end of the minimum low-temperature range favoring Tobago.

Today, maximum high temperatures across T&T were near 31°C at Piarco, Trinidad and a heat index of ranging from 33°C to 35°C. Across Tobago, the maximum high temperatures were near 31°C with a heat index of 32-34°C. The heat index is an index that combines air temperature and relative humidity, generating a “feel’s like” temperature.

Maximum high temperatures on Thursday are forecast to be near 31°C across both islands.


Seas are forecast to remain moderate in open waters throughout the week. Waves in open waters are forecast to remain up to 2.0 meters particularly East of Trinidad and Tobago through the week, with swells up to 1.5 meters possible. In sheltered areas, seas are forecast to remain below 1.0 meters. Winds will be from the east, at times southeast, at 15-20 knots on Thursday, through the remainder of the week.

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