Tropical storm Tapah intensifies, strengthening southwest monsoon over Thailand

In its weather advisory no. 9, the TMD reported that as of 4 am the storm was centred about 150 kilometres southeast of Guangdong, China, at latitude 20.6 degrees north and longitude 113.1 degrees east, with maximum sustained winds of around 90 km/h.

The storm is moving north-northwest at a speed of 20 km/h and is expected to make landfall over southern China later today, the department said.

Although the storm will not move into Thailand and will have no direct impact on the country’s weather, it will intensify the southwest monsoon prevailing over much of Thailand.

The department advised travellers to monitor weather updates for the regions they plan to visit.

TMD forecasts widespread rainfall, with heavy to very heavy showers expected in parts of Bangkok, surrounding provinces, and the eastern region.

Bangkok is forecast to face up to 80% rainfall coverage, which could cause flash flooding, waterlogging, and drainage delays in urban areas. 

Eastern provinces, including Nakhon Nayok, Prachin Buri, Rayong, Chanthaburi, and Trat, are also at risk of severe downpours. Residents in low-lying areas, foothills, and near waterways are urged to be on high alert for flash floods and run-off.

The southwest monsoon continues to prevail over the Andaman Sea, the South, and the Gulf of Thailand. Moderate winds in the upper Andaman Sea are generating waves about two metres high, rising beyond two metres during thunderstorms.

The lower Andaman and upper Gulf will see waves of 1–2 metres, also higher in stormy areas. Mariners are advised to proceed with caution and avoid sailing in thunderstorms.

Thailand weather forecast from 6am on Monday (September 8) to 6am on Tuesday (September 9):

Bangkok and vicinity

• Thunderstorms cover 80% of the area, with heavy to very heavy rain in some spots.
• Temperature: 24–25°C (low), 31–33°C (high).
• Southwesterly winds 10–15 km/h.

North

• Thunderstorms in 60% of the area, heavy rain in Tak, Kamphaeng Phet, Phitsanulok, Phichit, and Phetchabun.
• Temperature: 23–25°C (low), 32–33°C (high).
• Variable winds 5–15 km/h.

Northeast

• Thunderstorms in 70% of the area, heavy rain in Sakon Nakhon, Nakhon Phanom, Chaiyaphum, Khon Kaen, Roi Et, Maha Sarakham, Yasothon, Kalasin, Mukdahan, Amnat Charoen, Nakhon Ratchasima, Buri Ram, Surin, Si Sa Ket, and Ubon Ratchathani.

Central

• Thunderstorms in 80% of the area, heavy rain in Nakhon Sawan, Uthai Thani, Chai Nat, Suphan Buri, Sing Buri, Ang Thong, Lop Buri, Saraburi, Ayutthaya, Kanchanaburi, Ratchaburi, Nakhon Pathom, and Samut Sakhon.
• Temperature: 24–26°C (low), 31–34°C (high).
• Variable winds 10–15 km/h.

East

• Thunderstorms in 80% of the area, heavy to very heavy rain in Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Chon Buri, Rayong, Chanthaburi, and Trat.
• Temperature: 23–24°C (low), 28–33°C (high).
• Southwesterly winds 15–35 km/h.
• Waves 1–2 m; over 2 m in thundershowers.

South (east coast)

• Thunderstorms in 40% of the area, mainly in Phetchaburi, Prachuap Khiri Khan, Chumphon, and Surat Thani.
• Temperature: 23–26°C (low), 31–34°C (high).
• Southwesterly winds 15–35 km/h.
• Waves about 1 m, 1–2 m offshore; over 2 m in thundershowers.

South (west coast)

• Thunderstorms in 60% of the area, heavy rain in Ranong, Phangnga, Phuket, and Krabi.
• Temperature: 23–27°C (low), 30–32°C (high).
• From Phangnga northwards: southwesterly winds 20–35 km/h, waves about 2 m, over 2 m in thundershowers.
• From Phuket southwards: southwesterly winds 15–35 km/h, waves 1–2 m, over 2 m in thundershowers.