A combination of the Intertropical Convergence Zone (ITCZ) and the influence of Tropical Storm Laura is affecting Trinidad and Tobago presently. Tropical Storm Laura has influenced our low-level winds, now from the south, bringing strong thunderstorms from across Venezuela towards and across Trinidad, as well as offshore eastern Trinidad, nearing Tobago.
There are no adverse weather alerts in effect from the Trinidad and Tobago Meteorological Service. However, a Riverine Flood Alert (Yellow Level) is in effect, beginning at 11:00 PM Friday through 3:00 PM Saturday.
Abundant low-level moisture associated with the ITCZ and Tropical Storm Laura will be moving across T&T. Favorable low-level convergence, and upper-level divergence and low wind shear will allow for isolated strong thunderstorms and heavy showers, in addition to an overall favorable atmosphere.
Through the afternoon on Saturday, strong to severe thunderstorms are possible across Trinidad and Tobago. These thunderstorms may produce damaging wind gusts, flooding rainfall, and dangerous lightning.
Through tonight and after midnight, isolated to scattered showers and thunderstorms are forecast continue affecting Trinidad, as well as Tobago, with heavy rainfall forecast through daybreak. Conditions will gradually subside through the morning, with lingering light to moderate rain, but isolated thunderstorms and showers may return during the late morning through the afternoon across both islands, generally favoring Trinidad
A mostly settled evening into the night is forecast across both islands with the odd lingering shower.
Seas forecast to be moderate, with waves up to 2.5 meters in open waters. In sheltered areas, below 1 meter but choppy in areas of heavy showers or thunderstorms. Note that high tides are forecast at 6:09 AM and 6:45 PM with low tides near 12:00 AM and 12:21 PM.
The main hazards include heavy rainfall, which may reduce visibility and gusty winds up to and in excess of 55 KM/H. Street or flash flooding will be possible in slow-moving showers and thunderstorms. Riverine flooding is possible across central and southern Trinidad. In thunderstorm activity, frequent lightning is also possible. Gusty winds may cause power dips/outages, downed trees, and localized wind damage. Landslides are likely in heavy rainfall.
Note that with weak winds, with sea breeze convergence, heat, and orographic effects may act as triggers for additional shower and thunderstorm development across western and hilly areas of Trinidad, particularly on Saturday.
Possible Impacts From ITCZ & Tropical Storm Laura
Sustained surface winds will be weak, generally below 25 KM/H, increasing to 45 KM/H on Saturday during the afternoon at its peak. However, Gusts up to and in excess of 55 KM/H are possible in heavy showers or thunderstorms across Trinidad and Tobago.
With wind gusts in excess of 55 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, potted plants, loose galvanize or construction material, and other outdoor furniture. Tents may jump. Older/weaker trees may fall, bringing down utility poles and lines.
Overall, less than 25 millimeters are forecast, with areas across southern and eastern Trinidad recording up to 50 millimeters, particularly in slow-moving downpours or thunderstorms due to the ITCZ.
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. Riverine flooding is possible across southern and central Trinidad.
Frequent Lightning: In addition, with forecast thunderstorms, frequent lightning is likely. Lightning can cause power outages, voltage dips, damage to life and property, particularly during cloud-to-ground lightning strikes.
Why I May Not/Will Not See Constant 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.
Scattered activity is forecast through midnight, gradually becoming isolated as the day progresses on Saturday.