The severe weather will be coupled with a sudden temperature drop, it added.
The department advised people to look after their health amid the sudden weather changes.
"People should beware of severe weather conditions that may cause flash floods and overflows, especially along foothills, near waterways and in low-lying areas," it said.
The temperature will also drop by 3-5C in the Northeast and 2-3C in the North, East and Central regions including Bangkok, it said.
The department said seven provinces in the South are also likely to see heavy rain from Friday (December 2). These are Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala and Narathiwat.
On Saturday and Sunday, heavy downpours will spread to Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, Narathiwat, Ranong, Phang Nga, Phuket, Krabi, Trang and Satun, it added.
Waves will be 3 metres in the lower Gulf, rising higher in thundershowers, and 2 metres in the upper Gulf. The department warned that small boats in the lower Gulf should keep ashore on Saturday and Sunday (December 3-4).
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