Weather Advisory
Subject: Storm “RAGASA”
and heavy to very heavy rain in Thailand
No.4 (252/2025)
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At 10.00 a.m. LST (23 September 2025), typhoon “RAGASA”, over the upper South China Sea or at latitude 20.2 degrees north and longitude 117.6 degrees east with maximum sustained winds about 195 km./hr. This storm is moving west-northwest with a speed of 20 km/hr. It is expected to move near Hong Kong, China and move closer to the coast of southern China, passing through the Gulf of Tonkin on 25 September 2025. It is expected to weaken into tropical storm before making landfall over upper Vietnam. Storm “RAGASA” is forecast to downgrade rapidly due to the extending of the high-pressure system of China during 25 – 26 September. This storm is not move to Thailand.
The storm “RAGASA” effects to the monsoon through which lie across the North and the upper Northeast and southwest monsoon which prevail over the Thailand more strength. Heavy to very heavy rain will occur in the North, the Northeast, the Central, the East including Bangkok and vicinity during 23-26 September 2025. People in the country should beware of heavy to very heavy rain and accumulation that may cause flash floods and overflows especially along the waterways near foothills and lowlands. The wind force waves in the upper Andaman Sea up to 2-3 meters high and above 3 meters high in thundershowers. All ships in the Andaman Sea should proceed with caution. Small boats in the upper Andaman Sea should keep ashore during 24–26 September 2025.
This advisory is in effect on 23 September 2025, at 11.00 a.m.
This next issue will be on 23 September 2025, at 05.00 p.m.
(Signed) Sugunyanee Yavinchan
(Miss Sugunyanee Yavinchan)
Director-General
Thai Meteorological Department