The warning was directed at Ratchaburi, Phetchaburi, Prachuap Khiri Khan, Ranong, Phang Nga, Phuket, Surat Thani, Krabi, Nakhon Si Thammarat, Trang, Satun, Phatthalung, Songkhla, Pattani, Yala and Narathiwat, according to Surasri Kidtimonton, secretary-general of the Office of the National Water Resources (ONWR).
The monsoon trough now lying across the upper part of the South has brought heavy rain to these provinces, where people were being advised to pay extra attention to local reservoirs where storage capacity has hit 80%, Mr Surasri said yesterday.
A source confirmed that heavy rain and strong winds have been affecting parts of Phetchaburi since late Tuesday night, reports the Bangkok Post.
In Muang district, Khiriratthaya and Ratchadamnoen roads about half a metre under water early yesterday morning, the source added.
Certain sections of Phetkasem Road in Cha-am district were also covered with floodwater of the same depth, while several parts of Kaeng Krachan district experienced a blackout after strong winds caused trees to fall onto electrical cables.
As a result, Thetsaban 1 School in Cha-am had to defer exams scheduled to be held yesterday to today instead.
Meanwhile, in the Central region, the ONWR has warned communities along the Chao Phraya, Tha Chin and Mae Klong rivers in Samut Prakan, Bangkok, Nonthaburi, Pathum Thani, Samut Sakhon, Nakhon Pathom and Samut Songkhram to brace for possible high-tide flooding from Sunday until Oct 24, said Mr Surasri.
In Chai Nat, the flooding in Muang, Manorom and Wat Sing districts, which are upstream of Chao Phraya Dam, has improved, with the water level in the Chao Phraya River receding to a level well below the river bank.
However, as the dam continued discharging excess water at a rate of 2,199 cubic metres per second for the fourth consecutive day yesterday, low-lying areas in Sapphaya district of Chai Nat province, downstream of the dam, experienced about the same level of floodwater as in the previous days.
The situation in Ayutthaya, which was receiving the northern run-off from the Chao Phraya, intensified yesterday, with flood-impacted areas expanding.