
Residents of the province have been urged to be ready to evacuate in case of emergency.
Meanwhile, heavy rains have affected about 300 households in Kanchanaburi.
Heavy rains since Saturday have left some areas in the province's Chombung and Muang districts inundated under 50 centimetres of floodwater.
Other provinces that will probably also face heavy downpours and are at risk of flash flood include Phetchaburi, Prachuap Khiri Khan, Chumphon and Nakhon Si Thammarat, Uthai Thani, Suphan Buri, Ratchaburi, Samut Songkhram, Samut Sakhon, Chon Buri, Rayong, Chanthaburi and Trat.
State Railway of Thailand southern region centre is preparing to deal with the possible landslide and flash flood.
The centre's director Thanongsak Pongprasert said he had ordered officials to survey railroad tracks in 14 southern provinces under its responsibility.
Tracks in the areas of Chong Khao cave in Nakhon Si Thammarat's Tungsong district and some in Songkla's Namom district are reportedly at risk of being flooded and covered up by landslide.
Officials are installing drainage pipes and building dams to protect the tracks from landslide.
Hundreds of small fishing boats in Trang province yesterday stopped fishing in the Andaman Sea and returned to ports after the department issued the warning.
At 4pm yesterday, an active low pressure cell covered the Burmese coast. It is expected to move further to the upper Bay of Bengal. The low pressure trough lies across from the low pressure cell in the Burmese coast, passes the lower central, upper southern to eastern Thailand towards the low pressure cell in the lower South China Sea.
Torrential rain is likely with heavy falls in many places in the western north, the central, the east and the upper south.