Heavy rain and flash floods expected in Thailand, with rough seas in Andaman and Gulf

Thailand faces isolated heavy rains, flash flood risks, and rough seas as the southwest monsoon prevails. Caution urged for areas near waterways and lowlands.

The low-pressure cell currently covering upper Vietnam and the moderate southwest monsoon over the Andaman Sea, Thailand, and the Gulf of Thailand are bringing isolated heavy rain across the country, the Thai Meteorological Department said on Thursday. 

Very heavy rain is likely in the East, with the potential for flash floods and overflows. People in affected areas, especially those near waterways, foothills, and lowlands, are advised to stay alert for sudden heavy rainfall and possible flooding.

Moderate winds and waves in the upper Andaman Sea are expected to reach around 2 metres in height, with waves rising above 2 metres during thunderstorms. In the lower Andaman Sea and the upper Gulf, waves are forecast to be around 1-2 metres, with waves above 2 metres in thundershowers. All vessels in these areas should exercise caution and avoid areas with storms, the department warned.

Looking ahead to July 11-13, the monsoon trough will stretch across upper Myanmar, the upper North, upper Northeast, and upper Vietnam, while the low-pressure cell will move through this trough. The moderate southwest monsoon will continue, with isolated very heavy rains expected in the North, Northeast, East, and South, the department added.The weather forecast for the next 24 hours is as follows:

North: Scattered thundershowers and isolated heavy rain in Mae Hong Son, Chiang Mai, Chiang Rai, Nan, Uttaradit, Phitsanulok and Phetchabun; minimum temperature 23-26 degrees Celsius, maximum 32-36°C. 

Northeast: Scattered thundershowers and isolated heavy rain in Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, Mukdahan, Amnat Charoen, Nakhon Ratchasima, and Ubon Ratchathani; minimum 23-26°C, maximum 28-33°C.

Central: Scattered thundershowers and isolated heavy rain in Nakhon Sawan, Chainat, Lopburi, Saraburi and Kanchanaburi; minimum 25-27°C, maximum 30-32°C. East: Fairly widespread thundershowers and isolated heavy to very heavy rain in Nakhon Nayok, Prachin Buri, Chachoengsao, Chonburi, Rayong, Sa Kaeo, Chanthaburi and Trat; minimum 24-28°C, maximum 27-33°C; waves 1-2 metres high and above 2 metres high in thundershowers.

South (east coast): Scattered thundershowers mostly in Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Songkhla, Yala and Narathiwat; minimum 24-26°C, maximum 30-34°C; waves about a metre high and above 2 metres high in thundershowers.

South (west coast): Scattered thundershowers and isolated heavy rain in Ranong, Phang Nga, and Phuket; minimum 24-27°C, maximum 31-33°C; waves about 1-2 metres high and above 2 metres high in thundershowers.

Bangkok metropolitan area: Fairly widespread thundershowers; minimum 26-27°C, maximum 32-34°C.

(2025/07/10-00:00)