The cold air mass is weakening and covering the upper regions of Thailand and the southern part of the South China Sea. This condition brings moisture-laden winds from the east and southeast, leading to the continuation of thunderstorms and heavy rainfall in some areas of the southern region, the department said.
Residents in these areas should beware of sudden floods and landslides, especially in low-lying areas and near waterways.
Waves around a metre high, and over 2 metres are forecast for the Andaman Sea and the Gulf of Thailand, in areas with thunderstorms.
Small vessels are advised to navigate with caution and avoid sailing in thunderstorm-affected areas, the department said.