The Meteorological Department has issued the first storm warning of the year in the southern region, including provinces popular with tourists, while other parts of the country will see cooler temperatures in the days to come.
Downpours and waves up to four metres are expected in the Gulf of Thailand from Thursday, beginning with Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Yala, Pattani, Narathiwat, Krabi, Trang and Satun. Other provinces in the southern region are set for heavy rain from Friday.
Heavy rain will continue in the South every day through the weekend and the weather bureau advised small boats on the Gulf of Thailand to stay ashore.
The turbulent weather is due to a storm moving towards the Gulf from southern Vietnam, it added. While it is only a depression, storm Pabuk carries heavy rain, according to the Thailand Meteorology Department.
"The storm is moving southwest slowly through the tip of the Indochina peninsula and is expected to reach the lower Gulf of Thailand by Wednesday or Thursday," said the latest TMD bulletin issued late on Tuesday.
"By Thursday and Friday, it will affect the South with more rain and some torrential downpours," the bulletin said.
"All ships should proceed with caution, and small boats should keep ashore through [Saturday] Jan 5."
It said "torrential rainfall" will reach as far north as Petchaburi province in the lower central region.
"Strong winds are forecast for both the Gulf and the Andaman Sea with waves up to four metres high in the Gulf and about two metres in the Andaman Sea."
As the storm approaches the Gulf, PTT Exploration and Production said it is constantly monitoring weather conditions and has removed some staff from its offshore operations to the mainland in Songkhla for safety. But it confirmed normal gas supplies throughout the country.
Other parts of the country, including Bangkok, will see temperatures drop by three Celsius degrees through Thursday, the department said.