The Meteorological Department has issued a weather warning for May 25–27, urging people nationwide to prepare for heavy to very heavy rainfall, flash floods, and runoff, especially in low-lying areas and foothills near waterways.
The warning, issued on Sunday, comes as a result of a strengthened southwest monsoon sweeping across the Andaman Sea and the Gulf of Thailand, compounded by a strong monsoon trough forecast to cross upper Thailand and the upper southern region during this period.
Authorities advise residents to avoid traveling through areas experiencing thunderstorms or known flood zones, exercise extreme caution when driving, and stay clear of landslide-prone zones, especially near hills and riverbanks.
Rough seas are expected in both the Andaman Sea and the Gulf of Thailand:
Upper Andaman Sea: Waves up to 2 metres; higher in stormy areas.
Lower Andaman Sea: Waves 1–2 metres.
Gulf of Thailand: Waves around 1 metre; higher where thunderstorms occur.
Small boats in the upper Andaman Sea are advised to stay ashore through May 27.
Although conditions are expected to improve from May 28 to 31, the threat of flash floods remains in areas that continue to receive heavy rainfall, particularly in the north and northeast.
Rainfall outlook by Region:
North: Thunderstorms covering 70–80% of the area (May 25–29), with isolated heavy to very heavy rain.
Northeast: 60–80% coverage of thunderstorms and heavy rain (May 25–27).
Central: 70–80% of the area affected by storms (May 25–27), with potential for intense rainfall.
East: Similar conditions with thunderstorms and heavy rain affecting 70–80% of the region (May 25–27).
South (East Coast): Thunderstorms covering 60–70% of the area, with some heavy rain (May 25–27).
South (West Coast): 70–80% thunderstorm coverage, with heavy to very heavy rain expected (May 25–26).
Greater Bangkok: 70–80% chance of thunderstorms, with localised intense rainfall (May 25–27).
Source: Bangkok Post