TMD warns Thai South of heavy rain as Bay of Bengal storm develops
A monsoon trough and a low-pressure area raise flash flood and landslide risks in southern Thailand as a depression is forecast to head towards India or Bangladesh.
- The Thai Meteorological Department has warned of heavy to very heavy rain in central parts of southern Thailand for the next one to three days.
- The warning is linked to a developing storm in the Bay of Bengal, which is expected to become a cyclone but is not forecast to hit Thailand directly.
- The heavy rain is caused by a monsoon trough and a low-pressure system over southern Thailand, which are being influenced by the larger storm in the Bay of Bengal.
- Residents in the affected areas are advised to be on alert for potential flash floods, rapid run-off, and landslides due to the sustained rainfall.
The Thai Meteorological Department has issued a weather update warning residents in central parts of southern Thailand to prepare for continuing heavy to very heavy rain over the next one to three days.
The department is closely monitoring a depression in the Bay of Bengal that is expected to strengthen into a cyclone but is not forecast to move directly into Thailand.
The developing weather conditions have drawn considerable public attention and concern in the South, where several weather factors are combining and could significantly affect daily life, travel and agricultural land.
Bay of Bengal depression forecast to head towards India or Bangladesh
The department’s weather monitoring and forecast models on the morning of Sunday (October 25, 2026) indicated that the depression in the Bay of Bengal had maintained the same strength and speed.
It was expected to intensify into a “cyclone” within the next few hours.
The storm is forecast to move northwards towards India or Bangladesh. The department stressed: “This storm is not expected to move directly into Thailand.”
Thailand would therefore avoid a direct impact from the storm’s centre.
Nevertheless, the development of a large storm in the Bay of Bengal affects wind patterns, the monsoon trough and the distribution of moisture in neighbouring areas.
Two weather systems bring heavy rain to southern Thailand
Although the storm’s centre is not expected to enter Thailand, southern residents still face unsettled weather and heavy to very heavy rain.
The department identified two main factors working together:
- The monsoon trough, referred to in the update as the Intertropical Convergence Zone (ITCZ), extends over central parts of southern Thailand and draws moisture into the Gulf of Thailand and the Andaman Sea. The trough is also being drawn towards the depression in the Bay of Bengal, contributing to a sustained build-up of dense rain clouds.
- A low-pressure area also covers central parts of the South, encouraging thundershowers, rapid rain-cloud development and heavy rain in several provinces.
Together, these systems are bringing monsoon conditions and extensive rain clouds to central parts of southern Thailand.
Flash flood and rapid run-off risks over the next one to three days
The department warned residents in central parts of southern Thailand, particularly those in vulnerable locations, to watch for heavy rain and continuing rainfall accumulation over the next one to three days. The period was given as October 25 to 27 or 28.
Heavy rainfall accumulating over a short period could create several hazards:
- Flash floods and fast-flowing run-off from forested areas, particularly near foothills, waterways and mountain ranges.
- Flooding in urban and low-lying areas, where heavy rain could slow drainage, leaving standing water on roads and in urban communities.
- Landslides and mudslides, as several consecutive days of rain could saturate the soil and increase the risk of slopes giving way.
Residents advised to check vulnerable areas and monitor water conditions
For their safety, residents in central and lower parts of southern Thailand should look out for warning signboards and closely monitor water conditions.
Safety advice
- Closely follow weather forecasts and updates from the Thai Meteorological Department, the Department of Disaster Prevention and Mitigation or government agencies in the local area.
- Households in low-lying areas or places with a history of flooding should move possessions, household items and electrical equipment to higher ground.
- Check drainage around homes and remove leaves, rubbish and other obstructions from drains to help water flow.
- Motorists should drive cautiously because of poor visibility and possible standing water on roads.
- Seafarers and marine tourism operators should check forecasts before setting out and avoid sailing in areas with thundershowers, where waves may exceed 2 metres.
The morning outlook on October 25 was for the Bay of Bengal depression to strengthen into a cyclone and head towards India and Bangladesh without directly affecting Thailand.
However, the monsoon trough and low-pressure area over central parts of southern Thailand mean southern residents should remain on high alert for heavy rain, rainfall accumulation, flash floods and fast-flowing run-off from forested areas over the next one to three days.
The department’s website and the 24-hour weather forecast hotline on 1182 are listed as contact channels for further weather information or emergency reports.
