Periods of Rain, Showers, & Thunderstorms Forecast To Continue

Key Messages:
— A trough and favorable low-level convergence has triggered early morning showers and thunderstorms, favoring the Southern and Western halves of Trinidad. Additional activity to continue throughout the day, with showers and thunderstorms moving generally west-northwest.
— Through 2:00 AM Wednesday, between 1 to 2 inches (25 to 50 millimeters) are possible across Trinidad and Tobago with isolated totals up to 3 inches (75 millimeters) across Western, Southern and Northwestern Trinidad and Tobago. There is an elevated threat of street flooding and flash flooding.
— Seas will remain slight to moderate, with waves up to 1.5 meters possible in open waters and below 1.0 meter but choppy in sheltered areas.
— Gusty winds in excess of 55 KM/H possible. Winds of this strength will produce wind damage including downed trees, utility poles and roof damage. Localized power outages possible.
— Frequent Lightning is expected in thunderstorms.
— Landslides possible in elevated areas.

Trinidad and Tobago is NOT under any alerts, watches or warnings AT THIS TIME. In addition, no tropical wave is affecting the islands.

What We Know

Invest 90L north and east of the Leeward Islands and the Lesser Antilles. Credit: Weathernerds
Invest 90L north and east of the Leeward Islands and the Lesser Antilles. Credit: Weathernerds

As of 6:20 AM, an active tropical disturbance, Invest 90L is northeast of the Lesser Antilles with high chances of tropical development. This system has influenced our wind regime across the Lesser Antilles but is not forecast to directly impact our region.

A trough system, just west of Trinidad and Tobago, is allowing winds and moisture to move across both islands form the Southeast. This, in combination with favorable low-level convergence, has triggered showers and thunderstorms across parts of Trinidad since 3:00 AM Tuesday.

Thunderstorms and heavy showers developing across Trinidad, with additional thunderstorms and cloudiness forecast and developing southeast of Trinidad and Tobago. Credit: Weathernerds
Thunderstorms and heavy showers developing across Trinidad, with additional thunderstorms and cloudiness forecast and developing southeast of Trinidad and Tobago. Credit: Weathernerds

T&T is located in an area of favorable upper-level divergence and low-level convergence and deep tropical moisture across the region have allowed for strong thunderstorms and heavy showers to develop but strong wind shear has kept these heavier showers and thunderstorms brief (less than 1 hour, as it moves northwestward).

Rain is also ongoing across the Southern half of Trinidad. Rain is generally lighter and more persistent than showers and thunderstorms.

Sea breeze convergence, where trade winds from the east meet winds from the west, moving onshore from the Gulf of Paria, will also aid in the development of heavy afternoon showers and thunderstorms across Trinidad, particularly Western Trinidad later today.

Due to winds from the southeast, a feature we’ve explained prior, orographic precipitation is ongoing and will continue to occur throughout the day. Since our ranges are oriented east to west (particularly the northern range), these southerly winds are forced to rise and cool when they meet the foothills. Combined with daytime heating for extra lift, heavy showers, and thunderstorms formed and will continue to form at the foothills of the northern and central ranges.

Isolated to scattered heavy showers and thunderstorms are ongoing across Western and Northern Trinidad, as well as Tobago. Mostly cloudy to overcast skies are also ongoing across both islands.

6:30 AM Tuesday19th November 2019 Radar Update: Heavy showers and thunderstorms Northern and Western Trinidad, as well as Tobago while rain ongoing across Southern Trinidad. Conditions forecast to continue through Tuesday. Image: Trinidad and Tobago Meteorological Service
6:30 AM Tuesday19th November 2019 Radar Update: Heavy showers and thunderstorms Northern and Western Trinidad, as well as Tobago while rain ongoing across Southern Trinidad. Conditions forecast to continue through Tuesday. Image: Trinidad and Tobago Meteorological Service

Weather

On Tuesday, increasing cloudiness and showers are forecast across both islands, with heavier showers and thunderstorms favoring southern and western areas of Trinidad by the afternoon, gradually subsiding by the evening.

Wind

Peak sustained surface winds of 25 KM/H to 45 KM/H with gusts in excess of 55 KM/H are possible in heavy showers or thunderstorms across Trinidad and Tobago.

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

Through 2:00 AM Tuesday, between 1 to 2 inches (25 to 50 millimeters) are possible across Trinidad and Tobago with isolated totals up to 3 inches (75 millimeters) across Eastern Trinidad and Tobago.

There is an elevated threat of street flooding and flash flooding due to the slow-moving nature of this activity.

Thunderstorms and Lightning

With thunderstorms, locally severe wind (in excess of 55 KM/H), violent rainfall rates (in excess of 50 millimeters per hour) and lightning are all possible.

Gusty winds and lightning pose a threat to our power grid, causing localized power outages. Lightning may also strike trees, homes or utility poles causing damage to property. Lightning can also be deadly to persons outside during a thunderstorm.

Seas and Surf

Seas are forecast to be moderate in open waters with waves up to 1.5 meters. In sheltered areas, seas are near 1.0 meters, but choppy, particularly during heavier showers or thunderstorms.

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.

Generally, because of winds associated with tropical waves, showers and thunderstorms tend to follow a west-northwest track, generally missing areas across Southwestern Trinidad and even Northwestern Trinidad – though activity due to local climatic effects such as daytime heating may trigger shower and thunderstorm development across these areas. See the below graphic for a simple explanation.

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