TMD warns of heavy rain, flash floods and 3-metre waves from June 7-13

The Thai Meteorological Department has warned people across the country to brace for heavy rain from June 7-13, with very heavy downpours expected in parts of the North and upper Northeast as a strong monsoon system covers Thailand.

In its seven-day forecast issued at 5am on June 7, the department said a rather strong southwest monsoon would prevail over the Andaman Sea, Thailand and the Gulf throughout the period. From June 8-12, a monsoon trough is expected to lie across Myanmar, the upper North and the upper Northeast into a low-pressure cell over upper Vietnam.

Flash-flood risk in foothills and low-lying areas

The department warned that accumulated rainfall could trigger flash floods and water overflows, especially in communities near waterways, foothills and low-lying areas.

People in the North and upper Northeast have been advised to take particular caution, as these regions are expected to face heavy to very heavy rainfall during the forecast period.

Small boats told to stay ashore in upper Andaman

Marine conditions are also expected to be rough due to strong winds.

Waves in the upper Andaman Sea are forecast to reach 2-3 metres and rise above 3 metres in thundershower areas. In the lower Andaman Sea and the upper Gulf of Thailand, waves are expected to reach about 2 metres and exceed 2 metres during thundershowers.

All vessels in the Gulf and the Andaman Sea have been advised to proceed with caution and avoid thundershower areas. Small boats in the upper Andaman Sea should remain ashore throughout the period.

North and upper Northeast face heaviest rainfall

The North is forecast to see scattered to fairly widespread thundershowers and isolated heavy rain throughout the period, with isolated very heavy rain from June 10-13. Temperatures are expected to range from 23-26C at night to 30-35C during the day.

In the Northeast, thundershowers will be isolated to scattered on June 7-8 and June 13, mainly in the upper part of the region. From June 9-12, scattered to fairly widespread thundershowers are expected, with isolated heavy to very heavy rain in the upper Northeast. Temperatures are forecast at 23-27C minimum and 32-36C maximum.

Heavy rain forecast for western Central region and East

The Central region is expected to see isolated to scattered thundershowers from June 7-9 and again on June 13, with heavy rain mainly in the western part. From June 10-12, scattered thundershowers and isolated heavy rain are forecast, also mainly in the west.

The East is expected to experience scattered to fairly widespread thundershowers and isolated heavy rain throughout the week. Waves in the eastern seaboard are forecast at about 2 metres, rising above 2 metres in thundershower areas.

South to see rain on both coasts

On the southern east coast, scattered thundershowers and isolated heavy rain are expected throughout the period. Waves are forecast at 1-2 metres, around 2 metres offshore and above 2 metres in thundershower areas.

On the southern west coast, scattered to fairly widespread thundershowers and isolated heavy rain are expected in the upper part throughout the week. From Phang-nga northward, waves are forecast at 2-3 metres and above 3 metres during thundershowers. From Phuket southward, waves are expected at about 2 metres and above 2 metres in thundershower areas.

Bangkok to see thundershowers all week

Bangkok and surrounding areas are forecast to see scattered thundershowers throughout the period, with isolated heavy rain from June 10-12.

Temperatures in the capital are expected to range from 25-28C at night to 33-36C during the day, with southwesterly winds of 10-25 kilometres per hour.