Heavy rain is expected across northern Thailand, with very heavy downpours forecast for western parts of the central plains, the southeastern and the southwestern coasts, prompting warnings of flash floods and forest runoff.
The Thai Meteorological Department issued a 24-hour weather warning on Thursday, attributing the surge in wet weather to a relatively strong southwesterly monsoon currently prevailing over the Andaman Sea, Thailand and the Gulf of Thailand.
Residents in areas at risk, particularly those living near hillsides, waterways and low-lying plains, are being urged to brace for severe conditions and accumulated rainfall that could trigger sudden flooding.
Meanwhile, rough seas are anticipated in the Andaman Sea and northern parts of the Gulf of Thailand, with waves reaching 2–3 metres, exceeding 3 metres in areas experiencing thunderstorms.
Mariners in these regions have been advised to navigate with caution and avoid stormy areas entirely, while operators of small boats in the Andaman Sea and northern Gulf are being strongly urged to remain ashore.
In Bangkok and its surrounding provinces, thunderstorms are expected to blanket 60% of the area, with heavy rain forecast in some locations. Minimum temperatures will hover between 26 and 27°C, with highs reaching 33°C.
Similar conditions are forecast for the north and the central region, which are both facing thunderstorms across 60% of their areas, with isolated heavy downpours. Temperatures in the north could peak at 38°C, while the central plains will see highs of 35°C.
The northeast will experience slightly less rainfall, with thunderstorms expected across 40% of the region, though heavy rain remains a threat in provinces such as Loei, Nong Khai, Bueng Kan and Nakhon Ratchasima.
The southeastern and southwestern coasts will bear the brunt of the monsoon, with stormy weather projected to cover 70% of these regions. Both areas face the prospect of very heavy downpours and strong winds, alongside treacherous coastal waves up to 3 metres high.
The southeastern coast will also see rain covering 60% of the area, with heavy falls expected from Surat Thani northward, where offshore waves could exceed 2 metres during thundershowers.
