Update on the Adverse Weather Alert
As expected, the Trinidad and Tobago Meteorological Service has extended the Adverse Weather Alert as Tropical Wave 09 and the ITCZ affects T&T. While a lull in activity is forecast over the next few hours, 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 flooding, flash 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 yet again the Adverse Weather Alert at 3:30 PM Tuesday 18th June 2019, valid through 12:00 PM Wednesday according to the Trinidad and Tobago Meteorological Service.
Information from the Trinidad and Tobago Meteorological Service concerning the Adverse Weather Alert for June 19th, 2019.
“Periods of rain and/or showers and isolated thunderstorms are likely to continue to affect Trinidad and Tobago, however, most of the activity is expected during the early morning period. As a result of recent rainfall activity, areas susceptible to landslips/landslides are at greater risk and the presence of strong low-level winds can result in gusts in excess of 55km/hr at times. Also note that the possibility for street or flash flooding still exists during periods of 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 8th tropical wave has moved across Trinidad and Tobago, while the 9th tropical wave of the 2019 Atlantic Hurricane Season is forecast to move across Trinidad and Tobago overnight.
What to Expect Over Next 24 Hours
Intermittent showers, generally light to moderate across Western Trinidad but with heavy pockets across Eastern and Central Trinidad, continue to affect the island overnight, after a lull in activity this afternoon through the evening. Across Tobago, isolated showers have been occurring, but as of present, mostly overcast conditions are persisting.
Showers and possible thunderstorms are likely by the late night through the evening, with intermittent cloudy periods across both islands. Heavier showers are likely to favor Eastern parts of both islands.
By 3:00 AM Wednesday, through the late morning, showers and thunderstorms are likely to return to Trinidad and Tobago, with scattered to widespread activity likely. Conditions are forecast to become mostly settled by nightfall, with breezy conditions and a dense plume of Saharan dust returning across Trinidad and Tobago.
On Wednesday (8:00 PM Tuesday – 8:00 PM Wednesday), 24-hour rainfall accumulation is forecast to be less than 20 millimeters across Tobago. Across Trinidad, 15-25 millimeters are forecast, with isolated areas receiving between 30-50 millimeters, particularly Eastern Trinidad and Tobago and Southern areas of Trinidad.
On Thursday (8:00 PM Wednesday – 8:00 PM Thursday), 24-hour rainfall accumulation is forecast to be less than 15 millimeters across Eastern parts of Trinidad and Tobago, with less than 10 millimeters elsewhere.
In addition, this tropical wave is forecast to bring a trade wind surge, with wind gusts beginning on Wednesday much of the Eastern Caribbean of 60-70 KM/H, and at times, higher.
Seas are generally forecast to remain moderate, with waves up to 2.5 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. Rainfall accumulations between 20-50 millimeters, with isolated areas between 50-100 millimeters were recorded across both Trinidad and Tobago over the last 48 hours. While most of this rainfall is generally welcome, some rivers across Northeastern Trinidad are at elevated levels.
Frequent Lightning: In addition, with thunderstorms, frequent lightning is likely. Most of the thunderstorm activity on Tuesday has generally remained offshore.
Gusty Winds: Gusty winds, generally between 50-60 KM/H are also possible on Tuesday. On Wednesday, these maximum wind gusts may increase to 60-70 KM/H, particularly across Northern Trinidad and Tobago. 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, with weaker trees coming down 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. As a result of recent rainfall activity, areas susceptible to landslips/landslides are at greater risk.
What’s Causing This Inclement Weather?
A tropical wave (09), with its axis a several hundred kilometers east of Trinidad and Tobago, is approaching the Windwards. A deep surge in tropical moisture associated with this wave is moving across T&T presently and is forecast to persist over the next 24-36 hours. In addition, the ITCZ is present across T&T, generating favorable low-level convergence and aided by favorable upper-level divergence.
These favorable conditions are forecast to remain in place throughout the day, 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 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 later tonight through Wednesday. This will bring another round of adverse weather across T&T, though the present Adverse Weather Alert is only through 4:00 PM on Tuesday. It is likely that this may be extended through the first half of Wednesday at a minimum.