Tropical Update: Dry, Dusty Atlantic. Tropical Wave to Bring Rainfall to T&T on Friday

Tropical Weather Update:
Tropical Wave 10: The axis of this wave moved across T&T on Sunday 23rd June 2019, with a few heavy showers and thunderstorms, mainly affecting Western and Central Trinidad, even triggering some street flooding along the East-West Corridor. This wave is now entering the Pacific Ocean.
Tropical Wave 11: This wave was added onto the surface analysis by the National Hurricane Center (NHC) early Monday 24th June 2019, and passed over T&T early that morning. A line of light to moderate showers, with a few heavy pockets and a definitive wind shift, marked the passage of this wave across T&T. This wave is well west of T&T, stifled by Saharan Dust across the Caribbean Sea.
Tropical Wave 12: This wave was also added by the NHC causing a shift in numbering. No convection is occurring with this wave due to its location in the Central Atlantic, within a plume of Saharan Dust. This wave is likely to dissipate before reaching the Lesser Antilles. If it does retain its characteristics, very little change in weather is forecast.
Tropical Wave 13: This wave was previously TW11 but based on the above additions to the surface analysis, the numbering has changed. This wave is located in the Eastern Atlantic, embedded within the ITCZ. The axis of this wave is forecast to move across Trinidad and Tobago on Friday, bringing the ITCZ closer to T&T as well. Cloudy skies, scattered to widespread showers and isolated thunderstorms, mainly across Trinidad, are in the forecast. Locally heavy rainfall possible due to favorable atmospheric conditions forecast. Possible locally severe weather.
No Tropical Development forecast elsewhere across the Atlantic basin over the next 5 days as of the latest tropical update.

Tropical Wave 10 & 11

Both of these tropical waves moved across T&T on Sunday 23rd and Monday 24th June 2019 respectively, bringing some showers with isolated heavy pockets, isolated thunderstorms and on Sunday, some street flooding.

These waves also improved air quality, briefly, across Trinidad and Tobago has Saharan Dust continues to plague the Eastern Caribbean.

Both of these features are well west of Trinidad and Tobago, with no further impacts expected.

Tropical Wave 12

This wave is located from 18N44W to 09N47W, moving west at 10-15 knots. This position is supported by model guidance. Dry Saharan air surrounds the wave limiting convection at this time.

This wave is forecast to dissipate. However, even if it maintains its wave characteristics, it will likely merge with the following wave, Tropical Wave 13 behind it.

Regardless, this wave is not forecast to bring any notable change in the dry, dusty weather ahead of Tropical Wave 13.

No impacts to Trinidad and Tobago forecast.

Tropical Wave 13

This tropical wave’s axis extends from 13N35W to 02N35W, moving west at 10-15 knots. A total precipitable water maximum is noted just behind the wave’s axis. Model guidance also supports this position. Scattered showers are noted in the wave’s environment between 30W-40W.

This wave is forecast to move across T&T on Friday into the early hours of Saturday of next week, bringing increased cloudiness, scattered showers and possible thunderstorms, favoring Trinidad. The ITCZ may also pay another visit to the islands, beginning Thursday night, which may bring a heavy rainfall threat.

In addition, an upper level trough will be favorably positioned on Friday into Saturday. This is forecast to create favorable upper level divergence, aiding in the development and sustaining deep convection such as heavy showers and thunderstorms across the Southern Windwards, including Trinidad and Tobago.

As of this tropical update, this wave is not forecast to produce widespread severe weather. However, isolated to scattered severe weather is possible as isolated to scattered heavy showers and thunderstorms are in the forecast. This potential severe weather is likely to begin by 2:00 AM Friday, through 8:00 AM Saturday.

Forecast For Trinidad and Tobago

Thursday, through midnight – Initially sunny and slightly hazy conditions across Trinidad and Tobago. A few isolated showers are possible during the late morning through the late afternoon, due to an induced trough from the ITCZ, coupled with a surge in moisture ahead of Tropical Wave 13.

Friday, through midnight – Mostly cloudy skies with periods of showers, mainly across Trinidad. Thunderstorms are also possible throughout the day. This activity is forecast throughout Friday, leading into nightfall on Saturday.

Saturday, after midnight through 8:00 AM – Initially isolated to scattered showers and the isolated thunderstorm overnight through dawn will give way to a partly cloudy morning. Much of the possible inclement weather is forecast to subside by 8:00 AM.

The Remainder of Saturday, until midnight – An increase in low-level winds, as well as Saharan Dust, is forecast as the day progresses, with degrading air quality. The upper-level trough is forecast to generate some mid to upper-level clouds across the region, resulting in a partly to mostly cloudy but hazy day.

Possible Impacts to Trinidad and Tobago

Locally Heavy Rainfall & Flooding: Based on the 12Z Tuesday model runs, from Thursday night (8:00 PM) through Saturday morning (8:00 AM), generally less than 10 millimeters across Tobago, with locally heavier amounts along the Southern coast of the island or where thunderstorms/heavy showers occur.

Across Trinidad, heavy rainfall is likely across Eastern parts of the island, with rainfall totals generally between 20-40 millimeters, and isolated areas receiving up to 80 millimeters, as of the latest model guidance. Across Southern and Central Trinidad, generally, 20-40 millimeters of rainfall is also forecast. Western and Northwestern Trinidad may see the “lowest” totals, as expected with weaker tropical waves in June, with generally less than 20 millimeters of rainfall forecast over the 36 hour period.

The heaviest activity is forecast to occur on Friday. 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.

Frequent Lightning: In addition, with thunderstorms, frequent lightning is likely. Thunderstorms are forecast to occur mainly after midnight Friday, through the early hours of Saturday, across T&T.

Gusty Winds: Gusty winds, generally between 50-60 KM/H, up to 75 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 74 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.

High Wind Event Precautions
High Wind Event Precautions

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.

Tropical Cyclone Climatology

Tropical Cyclone Points of Origin during the month of June. Though attention is usually placed on the Western Caribbean, Gulf of Mexico and the Western Atlantic, a few storms have developed east of Trinidad and Tobago during the month of June, most recently and notably – Tropical Storm Bret in 2017.

In June, we turn our eyes to the Western Caribbean and the Gulf of Mexico for the formation of tropical cyclones in the Atlantic Basin, historically. However, tropical cyclones can form in the Atlantic Basin, without regard for the location once conditions support development.

There are NO tropical cyclone threats to the Eastern Caribbean, including Trinidad and Tobago at this time in the latest Tropical Update.

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