Heavy rain, flash flood warnings in northern Thailand

Heavy rain is expected in 53 provinces across northern and northeastern Thailand, with the Meteorological Department of Thailand (TMD) warning of potential flash floods and forest runoffs, particularly in mountainous regions and low-lying areas. In Bangkok, the rain is forecasted to hit from afternoon to evening.

The TMD’s 24-hour weather forecast indicates increased rainfall across Thailand, particularly heavy to very heavy rain in the northern and northeastern regions, and heavy rain in some eastern areas. This prediction is due to the strengthening of the southwest monsoon covering the Andaman Sea, Thailand, and the Gulf of Thailand, alongside a monsoon trough passing through upper northern Thailand and Laos into a low-pressure area in upper Vietnam.

Residents in affected areas are advised to be cautious of heavy to very heavy rain and accumulated rainfall, which might trigger flash floods and forest runoffs, especially on mountain slopes, near waterways, and in low-lying areas.

In the upper Andaman Sea and the upper Gulf of Thailand, moderate winds are expected, with waves reaching heights of one to two metres, and over two metres in thunderstorm areas. Mariners are advised to avoid sailing in stormy regions.

For the northern region, thunderstorms are anticipated in 60% of the area, with heavy to very heavy rain expected in Mae Hong Son, Chiang Mai, Chiang Rai, Lamphun, Lampang, Phayao, Nan, Phrae, Uttaradit, Sukhothai, Tak, Phitsanulok, and Phetchabun provinces. Temperatures will range from 24-28°C, with highs of 32-34°C. The southwest wind speed will be 5-15 kilometres per hour (km/h).

In the northeastern region, 70% of the area will experience thunderstorms, with heavy to very heavy rain expected in Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, Khon Kaen, Maha Sarakham, Roi Et, Kalasin, Mukdahan, Yasothon, and Amnat Charoen provinces. Temperatures will range from 23-26°C, with highs of 30-36°C. The southwest wind speed will be 10-20 km/h.

Other regions

The central region will see thunderstorms in 40% of the area, mainly in Kanchanaburi, Ratchaburi, Ayutthaya, Lopburi, and Saraburi provinces. Temperatures will range from 24-26°C, with highs of 35-37°C. The southwest wind speed will be 10-20 km/h.

In the eastern region, thunderstorms are expected in 60% of the area, with heavy rain in Nakhon Nayok, Prachin Buri, Chon Buri, Rayong, Chanthaburi, and Trat provinces. Temperatures will range from 23-28°C, with highs of 32-36°C. The southwest wind speed will be 15-35 km/h. Waves will be 1 to 2 metres high and over 2 metres in thunderstorm areas.

For the southern region (east coast), thunderstorms are predicted in 40% of the area, mainly in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, and Narathiwat provinces. Temperatures will range from 24-27°C, with highs of 34-37°C. From Surat Thani upwards, the southwest wind speed will be 15-35 km/h, with waves 1 to 2 metres high and over 2 metres in thunderstorm areas.

From Nakhon Si Thammarat downwards, the southwest wind speed will be 15-30 km/h, with waves reaching up to 1 metre and over 2 metres in thunderstorm areas.

On the southern region’s west coast, thunderstorms are expected in 60% of the area, primarily in Phang Nga, Phuket, Krabi, Trang, and Satun provinces. Temperatures will range from 25-26°C, with highs of 33-36°C.

From Phuket upwards, the southwest wind speed will be 15-35 km/h, with waves one to two metres high and over two metres in thunderstorm areas. From Krabi downwards, the southwest wind speed will be 15-30 km/h, with waves approximately 1 metre high, and over 2 metres in thunderstorm areas.

In Bangkok and surrounding areas, thunderstorms are expected in 60% of the area, mainly from afternoon to evening. Temperatures will range from 27-29°C, with highs of 34-36°C, reported Khaosod.