Residents of 26 provinces in the North, Northeast and East have been advised to brace for heavy rain and possible flash floods from Thursday to Saturday, caused by Tropical Storm Mulan.
The Meteorological Department said on Wednesday that Tropical Storm Mulan was over the upper South China Sea and moving north-northwest at about 20 kph through Hainan island, and was expected to make landfall in upper Vietnam on Thursday.
Heavy to heavy rain is expected in some areas of the North, Northeast and East from Thursday until Saturday. This could trigger runoff and flash floods.
On Thursday, areas to be affected are five provinces in the North (Chiang Rai, Phayao, Nan, Phrae and Uttaradit), eight in the Northeast (Loei, Nong Bua Lamphu, Nong Khai, Udon Thani, Bueng Kan, Sakon Nakhon, Nakhon Phanom and Mukdahan) and five in the East (Nakhon Nayok, Prachin Buri, Rayong, Chanthaburi and Trat).
On Friday, areas to be affected are 13 provinces in the North (Mae Hong Son, Chiang Mai, Chiang Rai, Lamphu, Lampang, Phayao, Nan, Phrae, Uttaradit, Phitsanulok, Tak, Sukhothai and Phetchabun), 8 in the Northeast (Loei, Nong Bua Lamphu, Nong Khai, Udon Thani, Bueng Kan, Sakon Nakhon, Nakhon Phanom and Mukdahan) and five in the East (Nakhon Nayok, Prachin Buri, Rayong, Chanthaburi and Trat).
On Saturday, areas to be affected area are 13 provinces in the North (Mae Hong Son, Chiang Mai, Chiang Rai, Lamphun, Lampang, Phayao, Nan, Phrae, Uttaradit, Phitsanulok, Tak, Sukhothai and Phetchabun) and five in the Northeast (Loei, Nong Bua Lamphu, Nong Khai, Udon Thani and Bueng Kan).
The moderate southwest monsoon prevails over the Andaman Sea, the South and the Gulf of Thailand. Wind waves about 2 metres high are likely in the upper Andaman Sea and more than 2 metres high during thundershowers, said the department.
Wind waves about 1-2 metres high are expected in the lower Andaman Sea and the upper Gulf and about 2 metres high during thundershowers.
All boats should proceed with caution, the weather office said.