Thailand braces for severe monsoon rains and potential flash floods

The Meteorological Department of Thailand (TMD) issued a weather warning for today, September 2, predicting severe monsoon rains across 51 provinces, with 80% of Bangkok set to experience heavy rainfall. Citizens are advised to brace for potential flash floods.

The TMD forecasts that a monsoon trough will traverse the northern and northeastern regions of Thailand, extending to a low-pressure area in the central South China Sea. Coupled with a moderate southwestern monsoon over the Andaman Sea, Thailand, and the Gulf of Thailand, this weather pattern will lead to increased rainfall and isolated heavy showers.

In the Andaman Sea, moderate winds are expected in the upper part, with waves reaching about 2 metres. The lower Andaman Sea and the upper Gulf of Thailand will see waves between 1 to 2 metres. Areas experiencing thunderstorms may encounter waves exceeding 2 metres. Mariners in these regions are advised to navigate cautiously and avoid sailing in stormy conditions.

From tomorrow to the next five days, the monsoon trough is predicted to shift over the lower northern, central, and northeastern regions of Thailand, moving towards the central South China Sea. The southwestern monsoon over the Andaman Sea, Thailand, and the Gulf of Thailand is also expected to intensify.

This will result in increased rainfall across Thailand, with some areas in the eastern and southern regions experiencing very heavy rain. The Andaman Sea and the Gulf of Thailand will see stronger winds and higher waves, with the Andaman Sea expecting waves between two to three metres and areas with thunderstorms seeing waves exceeding 3 metres.

The upper Gulf of Thailand will have waves around 2 metres, with thunderstorm regions experiencing waves over two metres. Mariners are advised to exercise caution and avoid sailing in stormy conditions, and small boats in the Andaman Sea should remain ashore from the fourth to the seventh of September.

Tropical storm

The tropical storm “Yagi” near the Philippines is anticipated to move towards the southern part of Taiwan and China, entering the upper South China Sea between the third and fourth of September.

In the northern region, 70% of the area will experience thunderstorms, with heavy rain in some places, including Mae Hong Son, Chiang Mai, Chiang Rai, Lampang, Phayao, Nan, Uttaradit, Phitsanulok, Tak, and Phetchabun. Temperatures will range from 24 to 25 degrees Celsius (°C) at the lowest and 31 to 35°C at the highest, with southwestern winds at 10 to 15 kilometres per hour (km/h).

The northeastern region will see 70% of the area affected by thunderstorms, with some heavy rain in Loei, Nong Khai, Bueng Kan, Nong Bua Lamphu, Udon Thani, Sakon Nakhon, Nakhon Phanom, Mukdahan, Yasothon, Amnat Charoen, Ubon Ratchathani, Chaiyaphum, and Nakhon Ratchasima. Temperatures will range from 23 to 25 °C at the lowest and 32 to 34 °C at the highest, with southwestern winds at 10 to 20 km/h.

The central region will have 70% of the area experiencing thunderstorms and some heavy rain, particularly in Lopburi, Saraburi, Phra Nakhon Si Ayutthaya, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram, and Samut Sakhon. Temperatures will range from 24 to 25°C at the lowest and 33 to 35°C at the highest, with southwestern winds at 10 to 20 km/h.

In the eastern region, 80% of the area will see thunderstorms, with very heavy rain in Nakhon Nayok, Chachoengsao, Prachinburi, Sa Kaeo, Chon Buri, Rayong, Chanthaburi, and Trat. Temperatures will range from 24 to 25°C at the lowest and 29 to 33°C at the highest, with southwestern winds at 15 to 35 km/h. The sea will have waves between 1 to 2 metres, with areas experiencing thunderstorms seeing waves over 2 metres.

The southern region (eastern coast) will have 60% of the area with thunderstorms and some heavy rain, particularly in Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Songkhla, Yala, and Narathiwat. Temperatures will range from 23 to 26°C at the lowest and 33 to 35°C at the highest.

Bangkok and its surrounding areas are expected to experience 80% thunderstorms, with some areas seeing very heavy rain. Temperatures will range from 24 to 25°C at the lowest and 33 to 35°C at the highest, with southwestern winds at 10 to 20 km/h.