Due to several weather features, more heavy showers and thunderstorms are forecast this week, particularly over the next 36 hours, through Wednesday morning and again on Friday.
What you need to know
— Rainfall: Over the next five days, overall rainfall accumulations across the eastern and southern halves of Trinidad are forecast to range from 50 to 125 millimeters. Across the west-central, northwestern, and north-central regions of Trinidad and Tobago, between 25 and 50 millimeters of rainfall is forecast, with isolated higher totals.
— Saharan Dust: Mild to moderate concentrations of Saharan Dust are forecast over the next five days, with higher dust levels on Wednesday and Thursday.
— Hazards: Over the next five days, the main hazards will be sporadic street/flash flooding in heavy showers/thunderstorms, which may be accompanied by gusty winds between 45 KM/H and 65 KM/H, as well as lightning in thunderstorm activity. Landslides may be possible starting on Tuesday, particularly in elevated areas of eastern and southern Trinidad and eastern Tobago.
— Marine: Seas are forecast to be moderate over the next five days, with waves in open waters generally up to 1.5 and 2.0 meters, and occasionally up to 2.5 meters through Wednesday. In sheltered areas, waves are forecast to be up to 1.0 meters and choppy in showers/rain and thunderstorms.
Latest Alert
Adverse Weather Alert Discontinued For T&T
Trinidad and Tobago is NOT under any tropical storm or hurricane threat, watch, or warning at this time.
The Forecast
Monday Night
Monday NightTuesday
TuesdayWednesday
WednesdayThursday
ThursdayFriday
FridaySaturday
SaturdayMarine Forecast
Sea Forecast: Increasing Winds To Agitate Seas Into Weekend
Temperatures
Tuesday
Low: 23-24°C
High: 28-31°C
Wednesday
Low: 24-26°C
High: 31-33°C
Thursday
Low: 25-27°C
High: 32-34°C
Friday
Low: 24-26°C
High: 29-31°C
Saturday
Low: 24-26°C
High: 32-34°C
Forecast Impacts
Flooding
FloodingForecast Rainfall Totals
- Tuesday: Between 10 and 35 millimeters across both islands, with higher rainfall totals up to 60 millimeters across eastern Trinidad and Tobago. In isolated heavy shower/thunderstorm activity, locally high totals exceeding 25 millimeters are likely.
- Wednesday: Between 5 and 15 millimeters of rainfall across Trinidad’s eastern and southern halves, with isolated higher totals of up to 25 millimeters favoring southeastern areas. Elsewhere, less than 5 millimeters.
- Thursday: Most areas, little to no rainfall. Across the southern half of Trinidad, isolated totals between 5 and 15 millimeters.
- Friday: Across both islands, between 5 and 15 millimeters of rainfall, with eastern and southern halves of Trinidad accumulating between 15 and 35 millimeters.
- Saturday: Across Tobago, little to no rainfall. Across the northern half of Trinidad, less than 5 millimeters, while across the southern half of Trinidad, between 5 and 15 millimeters.
Understanding Rainfall Accumulations
Putting the rainfall forecast into context, rainfall rates in excess of 50 millimeters per hour or areas that receive in excess of 25 millimeters within an hour tend to trigger street flooding across the country or flash flooding in northern Trinidad. For riverine flooding to occur, a large area of the country (not just in highly localized areas of western coastal Trinidad) would have to record upwards of 75 millimeters within 24 hours, and rainfall would have to fall across major rivers’ catchment areas.
Strong Thunderstorms
Strong ThunderstormsWhat is a strong or severe thunderstorm?
Given how rare these types of thunderstorms are in our region – we classify a severe or strong thunderstorm as one that produces any of the following:
- Damaging wind gusts exceeding 55 KM/H;
- Frequent lightning (more than 30 cloud-to-ground strikes within a 10-minute period);
- Hail (of any size);
- Rainfall of more than 50 millimeters or more within an hour or exceeding 75 millimeters or more within three hours;
- The sighting of a funnel cloud or touchdown of a waterspout/tornado associated with the thunderstorm.
Gusty Winds
Gusty WindsWith winds gusting to 55 KM/H and occasionally above, whole trees can be in motion, with larger trees and weaker branches falling. Light outdoor objects can topple or become airborne, such as garbage cans, loose galvanize, construction material, and outdoor furniture. Tents may also jump.
Other Hazards
Saharan Dust Forecast
Short-Lived Saharan Dust Surge From Thursday into Weekend
Why I May Not/Will Not See 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. Widespread showers mean that nearly all persons and areas may experience rainfall.
Isolated to scattered rainfall is forecast on Tuesday and Friday, with highly isolated rainfall on all other days of the forecast period.
Forecast Discussion
Tropical Update
Tropical Update: Tracking Two Tropical Waves, Area of Interest East of Lesser Antilles
Trinidad and Tobago has been affected by two tropical waves interacting with the Intertropical Convergence Zone over the last three days. These waves have produced scattered showers and thunderstorms, with three-day rainfall totals as high as 125 millimeters, mainly across eastern areas of Trinidad. Wind gusts as high as 63 KM/H were recorded on Sunday, June 9th, at Aripero, in heavy rainfall activity. A funnel cloud was also seen west of the Piarco International Airport on Monday, June 10th.
The seventh tropical wave analyzed by the National Hurricane Center is located approximately 420 kilometers east of Trinidad and Tobago, along 57W, and moving west at 10 knots (18 KM/H). The tropical wave is producing scattered showers and thunderstorms, mainly associated with the Intertropical Convergence Zone.
Across the wave axis, total precipitable water (TPW) values, which measure atmospheric moisture, are high, between 2.5 and 3 inches. Wind shear generally south of 11N ranges between 15 and 25 knots, with light shear, less than 15 knots, across Trinidad and Tobago.
Forecast models indicate favorable low-level and upper-level conditions as this tropical wave nears Trinidad and Tobago, particularly overnight tonight (Monday into Tuesday). This will lead to cloudiness, scattered showers, and isolated to scattered thunderstorms through Wednesday morning. Heavy rainfall is likely on Tuesday due to a saturated environment and favorable mid-level conditions, with high relative humidities and total precipitable water.
On Wednesday, a high-pressure ridge is forecast to briefly move in and remain present through Thursday. By Wednesday morning, a surge of Saharan Dust is forecast to move in, leading to the low-level and mid-level environment becoming increasingly dry and increasing wind shear. This will reduce rainfall and cloudiness, with conditions becoming increasingly hazy as the day progresses.
However, a low-level trough embedded within the ITCZ is forecast to move across the region, bringing rainfall across the country once more from Thursday evening through Friday night. There is some difference in model guidance for Friday. The ECMWF is showing an atmosphere unsupportive of any scattered or widespread rainfall due to strong wind shear and dry low- and mid-levels, while the GFS shows scattered to widespread rainfall. At this time, based on our analysis, the GFS may trend closer to reality but may have overproduced precipitation. This may change in the coming days.
Even with heavy rainfall over the last three days, flooding has been sparse due to very dry soils. As a result, riverine flood chances remain low at this time. However, the threat of short-lived street/flash flooding remains high through Tuesday and it is possible again on Friday.
Note that as an extended forecast goes further into the future, it is normal for the certainty to be reduced relative to the extended period.
