Adverse Weather Alert Extended into Tuesday. Widespread Showers, Isolated Thunderstorms to Persist.

Update on the Adverse Weather Alert

As expected, the Trinidad and Tobago Meteorological Service has extended the Adverse Weather Alert as Tropical Wave 08 moves into the Caribbean Sea, the ITCZ lingering across the are and Tropical Wave 09 nears the Eastern Caribbean. While a lull in activity is forecast by late this evening, another round of showers and thunderstorms are forecast later tonight, particularly after midnight. Scattered to widespread showers and thunderstorms are possible across both islands. As we’ve forecast, this event has shaped up to be our first heavy rainfall event for 2019.

Trinidad and Tobago is NOT under any tropical storm threat, watch or warning.

Based on the latest model guidance, these scattered to widespread showers, with scattered heavy showers and thunderstorms may produce severe weather across Trinidad and Tobago. Street floodingflash flooding, and even riverine flooding may be possible if present model guidance totals verify. Gusty winds are possible in the vicinity and during heavy showers or thunderstorms. These gusty winds and heavy rainfall will be capable of triggering landslides in landslide-prone areas, as well as downing trees and utility poles. See below for more details on what impacts to expect.

Because of the impending and ongoing adverse weather, the Trinidad and Tobago Meteorological Service has extended the Adverse Weather Alert at 12:00 PM Monday 17th June 2019, valid through 2:00 AM Monday until 4:00 PM Tuesday according to the Trinidad and Tobago Meteorological Service. However, it is possible that inclement weather also extends well into the first half of Wednesday.

Information from the Trinidad and Tobago Meteorological Service concerning the Adverse Weather Alert for June 18th, 2019.

Periods of rain and/or showers and isolated thunderstorms are likely to CONTINUE to affect Trinidad and Tobago. As a result, street/ flash flooding can occur in heavy downpours and there is an increased risk of landslides or landslips in areas with prolonged rainfall. Additionally, winds can gust in excess of 55km/hr in the vicinity of showers or thunderstorms,” according to the Trinidad and Tobago Meteorological Service. This “alert” status takes into account the possibility of the event occurring. This adverse weather event is likely.

The color of the watch indicates the severity of the event and the probability of the event occurring. Currently, the alert level is at Yellow. This means that the hazard is possible to be aware of the impacts of Street/Flash Flooding and Gusty Winds in your area. Areas prone to landslides should also be aware of the hazard and impacts.

Image Credit: Trinidad and Tobago Meteorological Service

The 8th tropical wave has moved across Trinidad and Tobago, while the 9th tropical waves of the 2019 Atlantic Hurricane Season is forecast to move across Trinidad and Tobago on Tuesday.

Tropical waves typically have fair weather ahead of the wave axis, though other features in the area such as surface troughs, increased atmospheric moisture, and local climatic effects, to name a few, may trigger showers and the odd thunderstorm. Following the passage of the wave, much of the active weather typically associated with a tropical wave occurs.
Tropical waves typically have fair weather ahead of the wave axis, though other features in the area such as surface troughs, increased atmospheric moisture, and local climatic effects, to name a few, may trigger showers and the odd thunderstorm. Following the passage of the wave, much of the active weather typically associated with a tropical wave occurs.
Image Credit: Trinidad and Tobago Meteorological Service

What to Expect Over Next 24 Hours

With the axis of Tropical Wave 08 now west of Trinidad and Tobago, showers and thunderstorms are generally moving west-northwest. Hence, overcast skies are likely across parts of western Trinidad, with light to moderate showers continuing across Central and Eastern Trinidad, as well as Tobago.

By the late afternoon through the early evening, heavy showers and thunderstorms are forecast to subside, though lingering showers across both islands remain in the forecast.

Overnight, through tomorrow, another round of scattered to widespread showers are forecast across Trinidad and Tobago. Isolated to scattered thunderstorms are also in the forecast, for both islands.

Seas are generally forecast to remain moderate, with waves up to 2.0 meters in open waters and below 1.0 meters in sheltered areas. Note that in the vicinity of heavy showers or thunderstorms, seas may be locally rough and/or choppy, both in open waters and sheltered areas.

Temperatures across both islands are forecast to remain generally cool, with maximum high temperatures between 27°C and 28°C across both islands due to showers and cloud cover.

Possible Impacts to Trinidad and Tobago

Flooding: 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. As of the 00Z, 06Z and 12Z model guidance, over the next 24 hours (2:00 PM Monday through 2:00 PM Tuesday), generally, 50-75 millimeters of rainfall is forecast across Trinidad, with isolated areas receiving upwards of 75-100 millimeters.

Note that across Trinidad, over the last 12 hours, parts of the country have seen generally 20-40 millimeters with isolated areas receiving upwards of 50 millimeters, particularly Central and Eastern Trinidad.

Across Tobago, generally, 10-20 millimeters of rainfall is forecast, with higher totals possible along Tobago’s Southern coasts. Showers have generally remained light to moderate, with a few heavy pockets and the odd thunderstorm over the last 12 hours.

Across parts of Central Trinidad, namely Chaguanas and Freeport, early to mid-morning street flooding occurred.

Frequent Lightning: In addition, with thunderstorms, frequent lightning is likely. As of 12:30 PM Monday, over 7,100 lightning strikes detected since midnight, with over 3,300 of these strikes being dangerous cloud-to-ground lightning.

Gusty Winds: Gusty winds, generally between 50-60 KM/H are also possible. These wind gusts will generally occur prior to, in the vicinity of, or occur during heavy showers or thunderstorms. With wind gusts up to 60 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, loose galvanize or construction material and other outdoor furniture. Tents may jump.

As of 12:30 PM Monday, gusty winds have brought down several trees mainly across Southern and Eastern Trinidad, and a few power outages have occurred. No confirmed reports at this time of damage to homes.

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.

What’s Causing This Inclement Weather?

Tropical Wave 08 moved across Trinidad and Tobago during the first half of Monday, bringing widespread showers, scattered thunderstorms and the ITCZ across the region. A deep surge in tropical moisture associated with this wave is moving across T&T presently and is forecast to persist over the next 48 hours. In addition, an upper-level trough is favorably positioned west of the region. This is creating favorable upper-level conditions for the development of heavy showers and thunderstorms across the Southern Windwards.

Tropical waves typically have fair weather ahead of the wave axis, though other features in the area such as surface troughs, increased atmospheric moisture, and local climatic effects, to name a few, may trigger showers and the odd thunderstorm. Following the passage of the wave, much of the active weather typically associated with a tropical wave occurs.
Tropical waves typically have fair weather ahead of the wave axis, though other features in the area such as surface troughs, increased atmospheric moisture, and local climatic effects, to name a few, may trigger showers and the odd thunderstorm. Following the passage of the wave, much of the active weather typically associated with a tropical wave occurs.

These favorable conditions are forecast to remain in place throughout the next 36-48 hours, with upper level divergent and low-level convergence aiding in the development of showers and thunderstorms with the passage of the wave axis. The Intertropical Convergence Zone, or the ITCZ, is also shifting across T&T for the first time for 2019 as a result of this tropical wave. Another tropical wave, further east, Tropical Wave 09, will move across the region on Tuesday, generating another round of inclement weather. The Adverse Weather Alert issued by the Trinidad and Tobago Meteorological Service has been extended until 4:00 PM on Tuesday, though it is likely it may be further extended through 12:00 PM Wednesday based on present model guidance.

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