The Thai Meteorological Department (TMD) has warned of heavier rain across Thailand on Wednesday (August 19), with thunderstorms forecast to cover 70% of Bangkok and surrounding provinces, the North and the Northeast.
Heavy to very heavy rain is expected in parts of the upper North, upper Northeast and East during the 24-hour period from 6am on August 19 to 6am on August 20.
The conditions are being driven by a monsoon trough extending across the upper North and upper Laos towards a low-pressure area along the coast of upper Vietnam. A relatively strong south-westerly monsoon is also prevailing over the Andaman Sea, Thailand and the Gulf of Thailand.
The monsoon trough and strengthening south-westerly monsoon have repeatedly brought heavy rain and rough seas across Thailand this month.
Residents in affected areas have been advised to watch for heavy and accumulated rainfall, which could trigger flash floods, forest run-off and overflowing waterways, particularly on foothill slopes near waterways and in low-lying areas.
Rough seas warning
Winds and waves are strengthening in the Andaman Sea and Gulf of Thailand.
- Waves in the upper Andaman Sea and upper Gulf are forecast at two to three metres.
- Waves may exceed three metres in thunderstorm areas.
- Mariners should proceed with caution and avoid areas experiencing thunderstorms.
- Small boats in the upper Andaman Sea should remain ashore during this period.