The Meteorological Department issued its 11th alert warning several provinces to prepare for heavy to very heavy rain, urging vigilance for flash floods and forest runoff.
On 20 Sep 2026 GMT+7, the Meteorological Department announced heavy to very heavy rain over Thailand and strong winds over the Andaman Sea, effective until 20 Sep 2026 GMT+7, in bulletin number 11 (215/2569).
On 20 Sep 2026 GMT+7, heavy rain is expected in some areas of Thailand due to a high-pressure cold air mass from China covering the upper northern and northeastern regions, while a monsoon trough passes through the lower central, eastern, and upper southern regions, combined with a fairly strong southwest monsoon over the Andaman Sea, the south, and the Gulf of Thailand.
The public in Thailand is advised to be cautious of heavy and accumulated rain, which may cause flash floods and forest runoff, especially in mountain foothill areas near waterways and lowlands. Avoid traveling on routes frequently affected by flooding, particularly in low-lying areas where short-term waterlogging may occur.
The upper Andaman Sea is experiencing fairly strong winds with waves 2-3 meters high; in areas with thunderstorms, waves exceed 3 meters. Mariners in the Gulf of Thailand and Andaman Sea should navigate with caution and avoid sailing where thunderstorms occur. Small boats in the upper Andaman Sea should refrain from setting out for another day.
For safety and to minimize potential impacts, the public is advised to plan their activities and travel cautiously during this period. Please follow announcements from the Meteorological Department and check updates on their website.http://www.tmd.go.thOr call 0-2399-4012-13 and 1182, available 24 hours.
20 Sep 2026 GMT+7
