Thailand warned of more rain through July 23 as monsoon strengthens

The Thai Meteorological Department has warned that Thailand will continue to see thunderstorms until July 23, with rainfall expected to increase in several areas from July 20-23 as the south-westerly monsoon strengthens.

The department said Thailand will remain under the influence of a low-pressure cell over upper Vietnam from July 17-19, while a moderate south-westerly monsoon continues to prevail over the Andaman Sea, Thailand and the Gulf of Thailand. 

From July 20-23, more rain is expected across the country, with heavy rain in some areas, especially in the North and the western part of the Central region. This will be caused by a low-pressure cell over Laos and upper Vietnam, combined with a stronger south-westerly monsoon. 

The department urged residents, particularly in the North and western Central region, to beware of heavy rain and accumulated rainfall, which could trigger flash floods, forest run-off and overflowing waterways, especially in foothill areas near waterways and low-lying zones. 

Waves in the Andaman Sea and the Gulf of Thailand are expected to remain moderate. In the upper Andaman Sea, waves are forecast at about 2 metres, rising above 2 metres in thunderstorm areas. The lower Andaman Sea and upper Gulf are expected to see waves of 1-2 metres, also rising above 2 metres during thunderstorms. 

Regional forecast for July 17-23

In the North, thunderstorms are expected in 30-40% of the area from July 18-19. Rain will increase from July 20-23, with thunderstorms in 60-70% of the region and heavy rain in some places. Temperatures are forecast at 23-27°C minimum and 29-35°C maximum. 

In the Northeast, thunderstorms are expected in 20-30% of the area from July 17-20, rising to 40-60% from July 21-23, with heavy rain in some areas. Temperatures will range from 24-26°C minimum to 29-35°C maximum. 

In the Central region, thunderstorms are expected in 20-40% of the area from July 17-20. From July 21-23, thunderstorms are forecast in 30-40% of the region, with heavy rain in some western areas. Temperatures are expected at 24-27°C minimum and 30-36°C maximum. 

In the East, thunderstorms are forecast in 30-40% of the area throughout the period. South-westerly winds will blow at 15-35 km/h, with sea waves of 1-2 metres, rising above 2 metres in thunderstorm areas. Temperatures will range from 24-28°C minimum to 30-35°C maximum. 

On the South’s east coast, thunderstorms are expected in 20-30% of the area from July 17-19, rising to 30-40% from July 20-23. Waves will be around 1 metre, rising to 1-2 metres offshore and above 2 metres in thunderstorm areas. 

On the South’s west coast, thunderstorms are expected in 30-40% of the area from July 17-19 and 40-60% from July 20-23. From Phuket northwards, waves are forecast at around 2 metres from July 20-23, rising above 2 metres in thunderstorm areas.

In Bangkok and surrounding provinces, thunderstorms are forecast in 30-40% of the area from July 17-20, increasing to 40-60% from July 21-23. Temperatures are expected at 26-28°C minimum and 32-36°C maximum.