
These conditions are the result of a weak high-pressure system over the upper Thailand and the South China Sea combined with southeasterly winds prevailing over the lower Northeast and the East.
Meanwhile, the monsoon trough lying across the South and the weak southwest monsoon over the Andaman Sea and the Gulf could bring heavy rains to the South, the department added.
Residents of these areas should be wary of severe conditions that could cause flash floods and overflows, especially along foothills near waterways and lowlands. All transport should exercise caution, the department warned.
For sea conditions, waves in the Andaman Sea and the Gulf could rise to 1-2 metres high and over 2 metres in thundershowers. All ships should proceed with caution and keep away from thundershowers.