A yellow-level adverse weather alert will be in place from 11:30am to 5pm today.
The Met Service says unstable atmospheric conditions are likely to result in scattered showers and thunderstorms with lightning over T&T.
It adds that gusty winds in excess of 55km/h and rainfall accumulations of between 25mm and 50mm are expected near the heavier showers.
Impacts can include isolated flash floods, localized street flooding, ponding, landslips and agitated sea conditions.