Weather forecasters warn of flash floods, runoff, landslides and burst riverbanks in the North and the Northeast on Wednesday and Thursday as a depression arrives over upper Vietnam.
Wanchai Sakudomchai, director-general of the Meteorological Department, said on Sunday that at 4pm the depression was located over the coast of southern China and was moving slowly south.
His department expected it to arrive over upper Vietnam on Wednesday and Thursday, bringing heavy rain to the North and the Northeast.
Storms could result in flash floods, runoff, burst riverbanks and landslides in those regions, Mr Wanchai said.
He also warned that the southwestern monsoon would strengthen over the Andaman Sea and the Gulf of Thailand, raising waves 2-4 metres high in the Andaman Sea and 2-3 metres high in the gulf. Mr Wanchai advised operators of small boats to stay ashore.