Thailand's National Water Resources Office issued a warning on 17 August for heavy rainfall and flash floods across 17 provinces from 19–21 August, driven by a monsoon trough over the North and Northeast combined with a strong southwest monsoon. At-risk areas span the North, Northeast, East, and West, with particular concern for urban flood-prone zones and areas vulnerable to landslides and riverbank overflow. National reservoir levels stand at 60% capacity (48,320 million cubic meters), varying by region from 34% (Central) to 69% (West).