By The Nation
It urged people to beware of the severe conditions that may cause flash flood and water runoff.
An active monsoon trough lies across the North and the upper Northeast while the southwest monsoon prevails across the Andaman Sea and Thailand, the department said.
The affected areas are:
North: Mae Hong Son, Chiang Mai, Chiang Rai, Lamphun, Lampang, Phayao, Phrae, Nan, Uttaradit, Phitsanulok, Sukhothai, Tak, Kamphaeng Phet, Phichit and Phetchabun.
Northeast: Loei, Nong Bua Lam Phu, Udon Thani, Nong Khai, Bueng Kan, Chaiyaphum
and Khon Kaen.
Central: Nakhon Sawan, Uthai Thani, Chai Nat, Kanchanaburi and Ratchaburi.
East: Sa Kaeo, Chonburi, Rayong, Chanthaburi and Trat.