Eight provinces were warned of possible flash flooding due to the effects of the tropical storm Kompasu, Thai authorities said on Friday.
Twenty reservoirs are also at risk of overflowing, the National Water Command Centre said.
Heavy rains are expected throughout the country between October 15 and 17 with possible rain in 41 provinces on Friday, according to the Thai Meteorological Department.
The Department of Disaster Prevention and Mitigation (DDPM) warned on Friday of possible flash floods in the central and southern regions including Nakhon Nayok, Prachinburi, Sa Kaeo, Chantaburi, Trat, Surat Thani, Ranong and Phang Nga.
Chantaburi and Trat were also warned of possible landslides and high waves.
Currently, 13 provinces including Khon Kaen, Maha Sarakham, Nakhon Ratchasima, Nakhon Sawan, Lopburi, Suphanburi, Singburi, Ang Thong, Ayutthaya, Pathum Thani, Phetchabun, Chantaburi and Trat are inundated from previous storms, Tien Mou and Lion Rock.
Some 8,214 villages and 333,257 Households have been affected by the flooding with 14 dead.