PATTAYA, Thailand – Thailand is bracing for four days of heavy to very heavy rain from September 17–20, with the Meteorological Department warning of possible flash floods, forest runoff and temporary flooding in low-lying areas. The department issued its fourth warning on September 16, covering heavy rain across Thailand and strong winds and waves in the Andaman Sea. The weather system is expected to affect different parts of the country in stages. The North and Northeast will begin seeing impacts on September 17, followed by the Central, Eastern and Southern regions from September 18.
The department said a high-pressure system or cool air mass from China will move over the upper North and upper Northeast. This will push the monsoon trough southward across the lower Central region, the East and the upper South, while the southwest monsoon over the Andaman Sea, Thailand and the Gulf of Thailand will strengthen.
For September 17, Chonburi is listed among the Eastern provinces expected to experience heavy rain, along with Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Rayong, Chanthaburi and Trat.
On September 18, the same Eastern provinces, including Chonburi, remain on the heavy-rain list.
On September 19, Chonburi is again expected to receive heavy rain, while Rayong and Chanthaburi are among the Eastern provinces forecast to experience very heavy rain.
For September 20, Chonburi is again listed among the Eastern provinces facing very heavy rain, together with Chachoengsao, Rayong, Chanthaburi and Trat.
The department advised residents to take precautions against heavy and accumulated rainfall, particularly in foothill areas, near waterways and in low-lying locations where flash floods and forest runoff could occur. People were also advised to avoid routes that regularly experience flooding, as low-lying areas could see short-term water accumulation.
The Andaman Sea is expected to experience relatively strong winds and waves, with waves reaching 2–3 metres and exceeding 3 metres in thunderstorms. Boats operating in the Gulf of Thailand and Andaman Sea should proceed with caution and avoid areas experiencing thunderstorms. Small boats in the Andaman Sea should remain ashore from September 17–20.
The Meteorological Department advised the public to plan travel and daily activities carefully during the four-day period and continue monitoring official weather updates. Weather information is available from the Meteorological Department around the clock through its website or its 1182 hotline.
