Heavy rain is expected nationwide, continuing until Saturday, with flooding already in 12 provinces.

The Meteorological Department said the monsoon trough in the upper North and over upper Laos,  and the southwestern monsoon over the Andaman Sea and the Gulf of Thailand would bring heavy rain to the North, the East and the western coast of the South on Monday.

The rain would move into the northern provinces of Mae Hong Son, Chiang Mai, Chiang Rai, Kamphaeng Phet and Tak; the eastern provinces of Chanthaburi, Rayong and Trat; and the southern provinces of Krabi, Phangnga, Phuket, Ranong and Trang.

From Tuesday to Saturday a low pressure area in upper Vietnam would enter the monsoon trough over the North, the Northeast and the upper Central Plain. This would cause heavy rain nationwide.

Flooding was already reported in 339 villages in parts of 12 provinces - Phetchabun, Uttaradit, Phrae, Phitsanulok, Phayao, Nan, Ubon Ratchathani, Khon Kaen, Udon Thani, Prachin Buri, Ayutthaya and Ang Thong.