North, Northeast forecast is for heavy rain, flood risk

Heavy to very heavy rain is expected across parts of northern and northeastern Thailand from Tuesday into Friday, raising the risk of flash floods and forest runoff in vulnerable areas.

In its second weather warning issued on Sunday, the Meteorological Department said that a monsoon trough over the North and upper Northeast, coupled with a fairly strong south-westerly monsoon over the Andaman Sea and the Gulf of Thailand, would drive the wet conditions.

The weather system is expected to bring widespread rain and isolated heavy to very heavy downpours across the upper country during the four-day period.

Residents in affected areas were urged to remain alert for flash flooding, particularly in foothill communities, areas along waterways and low-lying districts. Accumulated rainfall could trigger sudden flooding and runoff, according to the warning.

People were also advised to avoid routes prone to recurrent flooding, especially low-lying roads where short-term inundation may occur.

At sea, conditions are forecast to worsen between Wednesday and Friday. Waves in the upper Andaman Sea are expected to reach 2-3 metres and exceed 3 metres during thunderstorms.

In the lower Andaman Sea and the upper Gulf of Thailand, waves are forecast at around 2 metres, rising above 2 metres in areas experiencing thundershowers.

The department advised all vessels in the Andaman Sea and the Gulf of Thailand to navigate with caution and avoid stormy areas. Small boats in the upper Andaman Sea are advised to remain ashore during the warning period.