A monsoon trough lies across the lower Central region, including Bangkok and its vicinity, the East and the lower Northeast, while the intensifying southwest monsoon across the Andaman Sea and the Gulf of Thailand will bring thundershowers and isolated heavy rains in the East and South.
Flash floods and overflowing waterways remain a danger in much of the country, while ships should avoid thundershowers in both the Gulf of Thailand and the Andaman Sea.
A low pressure system over the middle of the South China Sea is forecast to move into the monsoon trough later this week, bringing more rainfall to the entire country and scattered heavy rains to isolated very heavy rains in the Northeast, the Central region, including Bangkok and its vicinity, the East and the South.
North
Isolated thundershowers are forecast for Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Tak, Nan, Phrae, Sukhothai, Uttaradit, Phitsanulok and Phetchabun provinces. The minimum temperature will range from 24-26 degrees celcius and the maximum temperature from 34-36°C. Winds will range from five to 15 kilometres per hour.
Northeast
Isolated thundershowers are forecast for Chaiyaphum, Nakhon Ratchasima, Yasothon, Amnat Charoen, Surin, Sisaket and Ubon Ratchathani. The minimum temperature will range from 23-25°C and the maximum temperature from 33-36°C. Easterly winds will range from 10-20 km/hr.
Central
Scattered thundershowers are forecast for Phra Nakhon Si Ayutthaya, Kanchanaburi, Ratchaburi, Lopburi, Saraburi, Nakhon Pathom, Samut Sakhon and Samut Songkhram. The minimum temperature will range from 24-25°C and the maximum temperature from 34-36°C. Winds will vary from 10-20 km/hr.
East
Scattered thundershowers and isolated heavy rains are forecast for Nakhon Nayok, Prachinburi, Sa Kaeo, Chachoengsao, Chonburi, Rayong, Chanthaburi and Trat. The minimum temperature will range from 23-27°C and the maximum temperature from 33-35°C. Southwesterly winds will range from 15-30 km/hr. Waves will be about one metre in height and more than 2 metres in thundershowers.
South (East Coast)
Scattered thundershowers are forecast for Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat and Phatthalung. The minimum temperature will range from 23-25°C and the maximum temperature from 31-34°C. Easterly winds will range from 15 to 30 km/hr. Waves will be about one metre in height and more than 2 metres in thundershowers.
South (West Coast)
Widespread thundershowers and isolated heavy rains are forecast for Ranong, Phangnga, Phuket, Krabi, Trang, and Satun. The minimum temperature will be 24-25°C and the maximum 30-34°C. Southwesterly winds will range from 15-35 km/hr. Waves will range in height from one to two metres and surpass two meters in thundershowers.
Bangkok
Scattered thundershowers are forecast for the metropolitan area. Temperatures will range from a minimum of 25-26°C to 33-35°C. Winds will range from 10-20 km/hr.