Heavy Rain Risk Area — Bangkok Samut Prakan Nonthaburi Pathum Thani Ayutthaya Lop Buri Sara Buri Chantaburi Trad Prachinburi Nakhon Nayok Sakaeo Nakhon Ratchasima Buri Rum Surin Sri Saked Nong Bua Lam

The monsoon trough lies across the North and the upper Northeast while the moderate southwest monsoon prevails over the Andaman Sea, Thailand and the Gulf. Heavy to very heavy rainfall is expected mostly in the North, the Northeast. The Central region including Bangkok and its vicinity as well as the East and South regions will be affected in the subsequent period. This is due to a high-pressure system spreading over southern China, which will move further down to cover upper Vietnam and upper Laos. As a result, the monsoon trough will shift southward to pass through the North, the Upper Central, and the Northeast, alongside a moderate southwesterly monsoon blowing across the Andaman Sea, Thailand, and the Gulf of Thailand. After that during 10-13 September 2026, the monsoon trough will move down to lie across the lower Central, the lower Northeast, and the East into an active low-pressure cell over the middle South China Sea. The heavy to veary heavy rains are over the lower North, the lower Northeast, the Central, the East and the South regions. The moderate winds and waves in the upper Andaman Sea are expected about 2 meters high and above 2 meters high in thundershowers.