Typhoon Ragasa, with sustained winds of approximately 185 km/h near its centre, is moving west-northwest from east of the Philippines toward the South China Sea.

The Thai Meteorological Department (TMD) reports that Ragasa is expected to enter the South China Sea today, and as its path progresses, it will likely pass over the Gulf of Tonkin and make landfall in northern Vietnam between September 25 and 26.

Although Thailand lies outside Ragasa’s projected core path, secondary effects are expected to be significant.

The southwest monsoon will intensify across the country between September 23 and 26, especially in the northern and upper northeastern regions, the upper central plain, the east, and Bangkok and its surrounding areas.

TMD warns of heavy to very heavy rainfall in foothill and low-lying zones.

River runoff and flash flooding are possible, especially in regions with steep terrain.

Maritime conditions will worsen in the Andaman Sea, with waves reaching two to three metres, and higher in storm-affected zones.

Small boat operators are advised to remain ashore and mariners to proceed with caution.

Residents in vulnerable areas are urged to prepare for potential flooding, accumulation of rainwater, disruptions in transport, and heightened risk during the period while monsoon trough and Ragasa’s influence overlap.

Thailand’s weather outlook also notes that, even after Ragasa weakens, the established moisture and rainfall patterns may linger, contributing to continued instability in weather systems into late September.