The Adverse Weather Alert
As expected, the Trinidad and Tobago Meteorological Service has issued an Adverse Weather Alert as Tropical Wave 13 nears Trinidad and Tobago. Heavy showers and thunderstorms are likely to begin after 11:00 AM on Friday, with intermittent showers and thunderstorms, occur through 5:00 PM Friday night. Note that due to favorable atmospheric conditions, locally severe thunderstorms are possible, producing heavy rainfall and gusty winds. This event is likely to be our second 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 flooding, flash flooding, and even brief riverine flooding may be possible if present model guidance totals verify. Gusty winds are likely 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 issued the Adverse Weather Alert at 6:00 PM Thursday 28th June 2019, valid from 11:00 AM Friday until 5:00 PM Friday 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 28th, 2019.
“Showers and thunderstorms are expected to be accompanied at times by gusty winds in excess of 50km/hr between 11:00 a.m. and 5:00 p.m on Friday 28th June 2019. These strong winds can result in choppy seas and may negatively impact poorly secured roof structures. Street flooding may occur in heavy downpours.” 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.
The 13th tropical wave is nearing Trinidad and Tobago as of 7:00 PM Thursday 27th June 2019 of the 2019 Atlantic Hurricane Season.
What to Expect Over Next 24 Hours
Forecast For Trinidad and Tobago
Thursday, through midnight (to 12:00 AM Friday) – 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 (12:00 AM Friday to 12:00 AM Saturday) – Mostly cloudy skies with periods of showers, mainly across Trinidad. Thunderstorms are also possible throughout the day likely by the late morning through the afternoon, accompanied by gusty winds. This activity is forecast throughout Friday, leading into nightfall on Saturday.
Saturday, after midnight through 8:00 AM (12:00 AM Saturday to 8:00 AM Saturday) 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 (12:00 AM Saturday to 12:00 AM Sunday) – 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 Thursday model runs, from Thursday night (8:00 PM) through Saturday morning (8:00 AM), generally less than 15 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 60 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 24 hour period, though isolated heavier totals are possible in the vicinity of thunderstorms or heavy showers.
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 are likely. Gusts up to 75 KM/H are possible across Eastern Tobago and higher elevations across the Northern Range, Trinidad, while peak gusts across the majority of Trinidad and Tobago of up to 70 KM/H may occur. Gusty winds are most likely during the latter half of Friday. 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.
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 13 is forecast to move across T&T over the next 24 hours 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.
These favorable conditions are forecast to remain in place throughout the next 24 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 as a result of this tropical wave.