Monsoon trough brings heavy rain to northern provinces
The Thai Meteorological Department (TMD) has issued a weather advisory for Tuesday, August 19, warning of heavy rainfall across several northern provinces as the monsoon trough moves over the upper North. Bangkok and the surrounding areas can expect thunderstorms covering about 40% of the area.
In its 24-hour forecast, the TMD said overall rainfall nationwide is expected to ease, but heavy showers will persist in parts of the North and Northeast. Residents in at-risk areas are urged to be cautious of flash floods and runoff, particularly in foothills, near waterways, and in low-lying areas.
The monsoon trough has shifted northwards across upper Thailand and into Laos, linking to a strong low-pressure system over the northern coast of Vietnam. Meanwhile, the southwest monsoon, which covers the Andaman Sea, Thailand, and the Gulf of Thailand, has weakened.
Sea conditions have also improved slightly, with waves of 1–2 metres reported in the upper Andaman Sea and the upper Gulf of Thailand, and around 1 metre in the lower Andaman Sea and the lower Gulf. However, in areas with thunderstorms, waves may exceed 2 metres. Mariners are advised to exercise caution and avoid sailing in storm-affected zones.
The TMD issued its forecast at 6am on Tuesday (August 19) for the 24 hours until 6am on Wednesday (August 19).
Bangkok and vicinity
- Thunderstorms are expected in 40% of the area.
- Temperature: 25–26°C minimum, 33–35°C maximum.
- Southwesterly winds 10–20 km/h.
North
- Thunderstorms cover 40% of the region with heavy rain in Phayao, Nan, Uttaradit and Tak.
- Temperature: 23–25°C minimum, 32–35°C maximum.
- Southwesterly winds 10–15 km/h.
Northeast
- Thunderstorms in 40% of the area with heavy showers in Loei, Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon and Nakhon Phanom.
- Temperature: 23–24°C minimum, 29–33°C maximum.
- Southwesterly winds 10–20 km/h.
Central region
- Thunderstorms in 40% of the area, mainly in Lopburi, Saraburi, Kanchanaburi and Ratchaburi.
- Temperature: 23–26°C minimum, 33–35°C maximum.
- Southwesterly winds 10–20 km/h.
East
- Thunderstorms in 40% of the area, especially in Nakhon Nayok, Prachin Buri, Chanthaburi and Trat.
- Temperature: 23–25°C minimum, 32–34°C maximum.
- Southwesterly winds 15–35 km/h.
- Sea waves 1–2 metres, over 2 metres in stormy areas.
South (east coast)
- Thunderstorms in 20% of the area, particularly in Phetchaburi, Prachuap Khiri Khan, Yala and Narathiwat.
- Temperature: 24–26°C minimum, 33–36°C maximum.
- Southwesterly winds 15–35 km/h.
- Waves around 1 metre, offshore 1–2 metres, over 2 metres in thunderstorms.
South (west coast)
- Thunderstorms in 20% of the area, mainly in Ranong and Phang Nga.
- Temperature: 24–25°C minimum, 33–35°C maximum.
- From Phuket northwards: Southwesterly winds 15–35 km/h, waves 1–2 metres, over 2 metres in thunderstorms.
- From Krabi southwards: Southwesterly winds 15–30 km/h, waves about 1 metre, 1–2 metres in thunderstorms.
