Trinidad and Tobago: Periods of heavy showers and widespread continuous rain impacted Trinidad and Tobago from early morning with a low-level trough. Although this has relented last few hours, there remain areas of scattered thunderstorms to the east of the island and north of Guyana/Suriname with a well defined low to mid level trough.
A moderate steering flow at the surface to low level of about 12-15KT will help push showers into the area later this afternoon and some overnight, but especially early morning to afternoon Sunday. At mid-levels, the flow is slower 10kt or less so with heavier showers that come from tall clouds, these will move slower and be able to drop possibly high rain rates. I added some more notes on this in comments.
Renewed or new flash flooding and possible landslides on slopes will occur during such periods or with even moderate rainfall. It is possible to have a few events where flash flooding becomes more widespread given already higher river levels and flooded areas. *Riverine and adverse weather yellow alerts in effect for Trinidad and Tobago.
Occasional showers will also spread to the Windwards & southern Leewards, late tonight into Sunday but some drying takes place late Sunday from Leewards to central Windwards. Rainfall periods will continue on Trinidad and Tobago occasionally becoming heavy until Monday. Late Monday some drier air pushes further south.
Yesterday afternoon, in anticipation of the weather that we experienced and continue to experience, the Trinidad and Tobago Meteorological Service issued a Yellow Level – Adverse Weather Alert. This morning, the impacts of the weather were felt over broad areas of Trinidad and Tobago, such as heavy precipitation resulting in minor watercourses being at critical levels, street and flash flooding, flooding over low-lying areas, landslips and landslides.
As a result of this morning’s activity with major river levels across Trinidad near or above 80%, and the forecast for periods of precipitation over the next 24 to 36 hours, the TTMS issued a Riverine Flood Alert #1 – Yellow Level in effect until Monday 28th November 2022, 12:00 p.m. Note that run-off will be slow at high tide, which will be at 5:31 p.m. (Sat. 26th Nov. 2022), 6:55 a.m. and 6:24 p.m. (Sun. 27th Nov. 2022).
Monitor updates from official sources and plan safety measures, including emergency supplies of food and water. Follow the instructions of government officials. Presently, there is an Adverse Weather Alert and a Riverine Flood Alert, both at Yellow level and ongoing.
Again, in the event of heavy showers or thunderstorms, winds can become gusty in the vicinity. With bouts of heavy or prolonged precipitation and the already waterlogged ground, it is expected that there will be street or flash flooding, and the risk of landslips/landslides is greatly elevated in areas so prone.
Please be advised that we are still in the rainy season and the ongoing La Niña phase of the ENSO (El Niño Southern Oscillation). Additionally Madden-Julian Oscillation (MJO), the major fluctuation in tropical weather on weekly to monthly timescales, is still in a positive phase over our area, which can be a factor in the enhancement of convection and precipitation over the next five to six (5 – 6) days.
Please continue to pay attention to the latest forecasts, alerts, and information issued by the TTMS. The official Public Forecast is updated daily at 6AM, 10AM, and 4PM
Adverse Weather Alert extended until Monday 28th November 2022, 10:00 AM.
Description: Rainfall and/or showers of varying intensities are expected to continue from early morning tomorrow (Sunday 27th November), despite there being intermittent settled periods at times. There is still a 70% (high) chance of heavy showers and thunderstorms.