The high-pressure areas and cool air mass covering the northeastern and northern regions, as well as the Gulf of Thailand, are weakening. This shift has caused the monsoon trough to move across the central, upper southern, and eastern regions, along with the southwest monsoon that covers the lower southern region and the lower Gulf of Thailand, gaining in strength.
This weather pattern is expected to lead to heavy rainfall and thunderstorms. People in these areas are advised to be cautious of flash floods, especially in hilly areas near waterways.
Additionally, waves 1-2 metres, and even higher in areas with thunderstorms in the upper Gulf of Thailand, can be expected, the department said.
Small vessels have been advised to be cautious and avoid navigating in areas affected by thunderstorms.
