The warning is in effect through to Friday (Oct 21).
A monsoon trough across Southern Thailand is making southwesterly winds across the Andaman Sea and the South of Thailand to become stronger with torrential rains in the South, said the warning.
“The stronger wind will force the waves in the Andaman Sea to two to three metres high and in thundershowers more than three meters high,” the warning said.
“People must beware of the severe conditions that may cause flash floods and overflows,” the warning added.
All ships must proceed with caution, and small boats in the Andaman Sea must keep ashore while the warning is in effect, the warning added.
The Southern Western Meteorological Center located near Phuket airport reported 283.8mm of rainfall across Phuket throughout the 24 hours of yesterday (Oct 17).
The total rainfall for Phuket so far this year stands at 2,152.7mm, the centre reported.