It said the low-pressure cell over South China Sea is intensifying and is expected to develop into a tropical depression before it moves northwest to the coast of south China. This will bring heavy to very heavy rain in some places in the North, Northeast, Central, East and South of Thailand for five days from July 31 onwards.

People living in high-risk areas should be aware of severe conditions and stay tuned for weather updates, it said. 
The southwest monsoon prevailing over the Andaman Sea and Gulf of Thailand will strengthen, with Andaman and the upper Gulf getting two to three-metre high waves and thundershowers. Ships have been warned to proceed with caution, while smaller boats have been advised to remain ashore.

Heavy rain forecast across Thailand for next five days

The Thai Meteorological Department has forecast heavy rain showers in almost every part of Thailand between July 31 and August 4.