Meteorological Department Warns 40 Provinces of Heavy Rainfall and Flash Floods
The Meteorological Department warns 40 provinces of heavy rainfall and flash floods over the next 24 hours, with the southern region facing the most severe conditions as a powerful low-pressure system intensifies toward a tropical cyclone.
On September 11, 2025, the Meteorological Department forecasts heavy to very heavy rainfall in parts of the southern region over the next 24 hours, with heavy rain in some areas of the central region, Bangkok, its suburbs, and the eastern region. The northern and northeastern regions will experience declining rainfall. Residents are warned to watch for dangers from heavy rain accumulation, which may cause sudden flash floods, flash flooding, and landslides, particularly in hilly and low-lying areas near water channels. Avoid traveling through flood-prone routes, especially low-lying areas prone to water pooling. A high-pressure system and cool air mass have moved over the upper northern and upper northeastern regions, pushing a monsoon trough southward through the lower central, upper southern, upper Gulf of Thailand, and eastern regions toward a powerful low-pressure system over the central South China Sea. The moderate southwest monsoon covers the Andaman Sea, southern, central, eastern regions, and the Gulf of Thailand. Wave conditions in the Andaman Sea and Gulf of Thailand are moderate, with the upper Andaman Sea having waves around 2 meters, exceeding 2 meters in thunderstorm areas. Fishermen are advised to exercise caution and avoid areas with thunderstorms. Between September 11-13, the strong low-pressure system over the central South China Sea is expected to intensify into a tropical cyclone, moving toward the upper Vietnamese coast on September 13-14. The public should monitor weather forecasts closely. For the next 24 hours: Northern region—60 percent thunderstorms, mainly in Tak, Phichit, Kamphaeng Phet, and Phetchabun provinces; low 22-26 C, high 31-37 C; easterly winds 10-20 kph. Northeastern region—40 percent thunderstorms, mainly in Chaiyaphum, Nakhon Ratchasima, Buriram, Surin, Si Sa Ket, and Ubon Ratchathani; low 21-23 C, high 30-34 C; northeast winds 10-20 kph. Central region—70 percent thunderstorms with heavy rain in places, in Ayutthaya, Suphan Buri, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Sakhon, and Samut Songkhram; low 23-24 C, high 32-34 C; northerly winds 10-20 kph. Eastern region—70 percent thunderstorms with heavy rain in places, in Nakhon Nayok, Prachuap Khiri Khan, Chachoengsao, Chon Buri, Rayong, Chanthaburi, and Trat; low 22-25 C, high 30-34 C; variable winds 15-35 kph; sea waves 1-2 meters, exceeding 3 meters in thunderstorm areas. Southern region (east coast)—70 percent thunderstorms with heavy rain in places, in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, and Narathiwat, with very heavy rain in some areas of Phetchaburi and Prachuap Khiri Khan; low 23-25 C, high 30-36 C.
