This weather pattern is due to the influence of a moderate high-pressure system from China, covering the northeastern, northern, and southern parts of the Gulf of Thailand, bringing in moisture from the Andaman Sea and the Gulf of Thailand. People in these areas are advised to be cautious of heavy rain and accumulated rainfall, which could result in sudden flooding and flash floods, especially in low-lying and mountainous areas.
For the Andaman Sea and the Gulf of Thailand, waves are expected to be around 1-2 metres, or higher in areas with thunderstorms. Small vessels are advised to be cautious and avoid storms.