The Meteorological Service (Met Office) has issued a yellow-level adverse weather alert.
A statement on Tuesday said the alert is set to begin at 5 am on Wednesday and is expected to last until 12 pm on Friday.
Periods of rain and/or showers of varying intensities are expected from early Wednesday beginning over Tobago and eastern areas of Trinidad as an active tropical wave travels westward over this area.
"There is also a 70 per cent (high) chance of heavy showers and thunderstorms that can produce intense rainfall over 25 millimetres," the statement said.
People can expect gusty winds over 55 kilometres/hour.
It said street/flash flooding and localised ponding are also likely in heavy downpours.
Seas can become agitated at times in sheltered areas. Landslides or landslips are also possible in areas prone to them.
It said people should not wade or drive through floodwaters. It also encouraged people to secure loose outdoor items and livestock.
The Met Office also asked the public to monitor weather conditions and official updates.