Narra bypasses Thailand as heavy rain hits three regions

Heavy rain is expected in parts of northern, central and eastern Thailand over the next 24 hours, raising the risk of flash floods, forest run-off and overflowing waterways, the Thai Meteorological Department (TMD) said on Monday (August 24, 2026).

The department’s forecast, covering 6am on Monday to 6am on Tuesday, also indicates thunderstorms across 60% of Greater Bangkok.

A monsoon trough extends across the upper North and upper Laos into Tropical Storm Narra over the Gulf of Tonkin, while a rather strong southwest monsoon prevails over the Andaman Sea, Thailand and the Gulf of Thailand, according to the TMD’s daily forecast.

People in areas affected by heavy or accumulated rainfall were advised to remain alert to flash floods, forest run-off and rivers overflowing their banks, particularly on foothill slopes near waterways and in low-lying areas.

Narra heading towards southern China

Tropical Storm Narra is expected to make landfall in southern Guangxi, China, between August 24 and 25.

The storm will not enter Thailand and is not expected to have a direct effect on the country’s weather.

Travellers planning to visit the affected part of China were advised to check weather conditions before setting out.

Small boats told to remain ashore

Waves in the upper Andaman Sea are forecast to reach 2–3 metres and exceed 3 metres during thunderstorms.

In the upper Gulf of Thailand, waves will be about 2 metres high and exceed 2 metres in stormy areas.

Mariners in the Andaman Sea and Gulf of Thailand should proceed with caution and avoid areas experiencing thunderstorms. Small boats in the upper Andaman Sea should remain ashore.

Regional forecast
 

North: Thunderstorms across 60% of the region, with isolated heavy rain in Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Nan, Uttaradit and Tak. Temperatures will range from 22–27°C to 31–34°C, with southwesterly winds of 10–20 kilometres per hour.

Northeast: Thunderstorms across 40% of the region, mainly in Nong Khai, Bueng Kan, Nakhon Phanom, Chaiyaphum, Nakhon Ratchasima and Buriram. Temperatures will range from 23–25°C to 31–33°C, with southwesterly winds of 10–20km/h.

Central region: Thunderstorms across 60% of the region, with isolated heavy rain in Nakhon Sawan, Uthai Thani, Kanchanaburi and Ratchaburi. Temperatures will range from 23–26°C to 31–34°C, with southwesterly winds of 10–25km/h.

East: Thunderstorms across 60% of the region, with isolated heavy rain in Nakhon Nayok, Prachin Buri, Sa Kaeo, Rayong, Chanthaburi and Trat. Temperatures will range from 24–28°C to 30–33°C, with southwesterly winds of 20–35km/h. Waves will be about 2 metres high and exceed 2 metres during thunderstorms.

South, east coast: Thunderstorms across 40% of the region, mainly in Phetchaburi, Prachuap Khiri Khan, Chumphon and Surat Thani. Temperatures will range from 23–26°C to 32–37°C. From Surat Thani northwards, southwesterly winds will reach 20–35km/h, with waves of 1–2 metres, about 2 metres offshore and above 2 metres during thunderstorms. From Nakhon Si Thammarat southwards, winds will reach 15–35km/h, with waves of about 1 metre, rising to 1–2 metres offshore and above 2 metres during thunderstorms.

South, west coast: Thunderstorms across 30% of the region, mainly in Ranong and Phang Nga. Temperatures will range from 23–26°C to 31–35°C. From Phang Nga northwards, southwesterly winds will reach 20–40km/h, with waves of 2–3 metres and above 3 metres during thunderstorms. From Phuket southwards, winds will reach 15–35km/h, with waves of 1–2 metres and above 2 metres during thunderstorms.

Bangkok and surrounding provinces: Thunderstorms across 60% of the area. Temperatures will range from 25–27°C to 32–33°C, with southwesterly winds of 10–25km/h.