Stormy forecast: Extreme rain and thunderstorms in 42 provinces

The Meteorological Department of Thailand (TMD) issued another severe weather warning for 42 provinces nationwide, forecasting heavy rainfall and thunderstorms. Bangkok is expected to experience significant rain coverage at 70%, with authorities urging caution for flash floods and forest runoff.

The TMD released a 24-hour weather forecast today, highlighting the strengthening southwest monsoon covering the Andaman Sea, Thailand, and the Gulf of Thailand. A low-pressure area over northern Vietnam and the central South China Sea is also influencing the weather.

The forecast predicts increased rainfall across Thailand, particularly in the northeastern and central regions, including Bangkok and its vicinity. Eastern and western southern regions face heavy rainfall in some areas.

Residents in these regions are advised to be vigilant against potential hazards from heavy to extreme rain and accumulated rainfall, which could cause sudden flooding and forest runoff, especially in foothill areas near waterways and low-lying regions.

Mariners in the Andaman Sea and the Gulf of Thailand are warned of strong winds and high waves. The upper Andaman Sea is expected to see waves around 2 metres high, with higher waves in areas experiencing thunderstorms.

The lower Andaman Sea and the Gulf of Thailand will have waves ranging from one to two metres, with higher waves in thunderstorm areas. Sailors are advised to navigate with caution and avoid areas with thunderstorms.

Regional forecasts

The northern region will experience thunderstorms in 40% of the area, mainly in Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Nan, Tak, Kamphaeng Phet, Phitsanulok, and Phetchabun provinces. Temperatures will range from 24 to 27 degrees Celcius for the lowest and 34 to 37°C for the highest, with southwesterly winds at 10 to 20 km/h.

The northeastern region is expected to see thunderstorms in 60% of the area, with heavy rain in some places, including Nong Khai, Bueng Kan, Sakon Nakhon, Nakhon Phanom, Mukdahan, Amnat Charoen, Buriram, Surin, Sisaket, and Ubon Ratchathani provinces. Temperatures will range from 25 to 28°C at the lowest and 35 to 38°C at the highest, with southwesterly winds at 10 to 20 kilometres per hour.

The central region will have thunderstorms in 60% of the area, with heavy rain in some areas, particularly in Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram, and Samut Sakhon provinces. Temperatures will range from 24 to 27°C for the lowest and 35 to 37°C for the highest, with southwesterly winds at 10 to 25 km/h.

The eastern region is forecasted to experience thunderstorms in 70% of the area, with very heavy rain in some places, including Nakhon Nayok, Chachoengsao, Rayong, Chanthaburi, and Trat provinces. Temperatures will range from 25 to 29°C for the lowest and 30 to 36°C for the highest, with southwesterly winds at 15 to 35 km/h. The sea will have waves between 1 to 2 metres with higher waves in thunderstorm areas.

The southern region (eastern coast) will see thunderstorms in 40% of the area, mainly in Phetchaburi, Prachuap Khiri Khan, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, and Yala provinces. Temperatures will range from 24 to 27°C for the lowest and 32 to 35°C for the highest, with southwesterly winds at 15 to 35 km/h. The sea will have waves between 1 to 2 metres, with higher waves in thunderstorm areas.

The southern region (western coast) will experience thunderstorms in 70% of the area, with very heavy rain in some areas, particularly in Ranong, Phang Nga, Phuket, Krabi, Trang, and Satun provinces. Temperatures will range from 24 to 25°C for the lowest and 28 to 31°C for the highest.

Extreme winds

From Phuket upwards, winds will be southwesterly at 20 to 35 km/h, with waves around two metres high and higher in thunderstorm areas. From Krabi downwards, with westerly winds at 15 to 35 km/h, with waves between 1 to 2 metres and higher in thunderstorm areas.

Bangkok and its vicinity will have thunderstorms in 70% of the area, with heavy rain in some areas. Temperatures will range from 26 to 28°C for the lowest and 34 to 37°C for the highest, with southwesterly winds at 10 to 25 km/h.