Thailand is under a heavy rain alert as the Thai Meteorological Department (TMD) forecasts widespread downpours and warns of potential flash floods and runoff across many regions. The warning is in effect for the 24-hour period from 6 a.m. on September 6 to 6 a.m. on September 7.
National Weather Outlook
The current weather pattern is influenced by a monsoon trough extending across the northern and upper northeastern parts of the country, linked to a low-pressure area over the upper South China Sea. This is combined with a moderate southwest monsoon affecting the Andaman Sea, mainland Thailand, and the Gulf of Thailand. This atmospheric setup is expected to bring significant rainfall nationwide, with the heaviest precipitation anticipated in the eastern Northeast region.
Authorities are urging residents in vulnerable areas, including the Mekong basin, hillsides near waterways, and low-lying zones, to remain vigilant. Particular attention is advised for locations that have a history of recurrent flooding. The TMD also cautioned against traveling on roads known to be prone to waterlogging, noting that even areas not typically affected could experience short-term inundation.
Regional Breakdown
Northern Thailand
Thunderstorms are predicted to cover approximately 70% of the North, with isolated areas expecting heavy rain. Provinces likely to experience significant downpours include Mae Hong Son, Chiang Mai, Lampang, Nan, Phrae, Uttaradit, Sukhothai, Tak, Phichit, Phitsanulok, and Phetchabun. Temperatures are expected to range from a low of 22-27 degrees Celsius to a high of 32-37 degrees Celsius, with winds blowing at 10-20 kilometers per hour.
Northeastern Thailand
The Northeast is also forecast to experience storms across 70% of its area, with heavy rain in isolated spots and very heavy rain specifically predicted for Ubon Ratchathani. All provinces in the region, including Loei, Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, Khon Kaen, Kalasin, Mukdahan, Maha Sarakham, Roi Et, Yasothon, Amnat Charoen, Surin, and Si Sa Ket, are expected to see rain. Overnight temperatures will be between 23-26 degrees Celsius, with daytime highs reaching 31-35 degrees Celsius. Winds will be from the southwest at 10-20 kilometers per hour.
Central Thailand
Around 60% of the Central region is expected to face thunderstorms, with isolated heavy rainfall possible in provinces such as Lop Buri, Saraburi, Phra Nakhon Si Ayutthaya, Kanchanaburi, Ratchaburi, Nakhon Pathom, and Samut Sakhon. Temperatures will fluctuate between 23-26 degrees Celsius at night and 35-37 degrees Celsius during the day. Southwesterly winds will range from 10-20 kilometers per hour.
Eastern Thailand
Storms are anticipated to cover 60% of the East, bringing heavy rain to isolated areas within Nakhon Nayok, Prachin Buri, Chachoengsao, Chanthaburi, and Trat. Expected temperatures are a low of 24-28 degrees Celsius and a high of 32-35 degrees Celsius. Southwesterly winds are forecast at 15-35 kilometers per hour. Sea conditions in the East will see waves of 1-2 meters, potentially exceeding 2 meters during thunderstorms.
Southern Thailand – East Coast
Thunderstorms are predicted for about 30% of the Southeast coast, primarily affecting Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, and Narathiwat. Temperatures will range from 23-26 degrees Celsius to 34-36 degrees Celsius. Southwesterly winds will be strong, between 15-35 kilometers per hour. Coastal waves are expected to be around 1 meter, increasing to 1-2 meters further offshore and over 2 meters in stormy conditions.
Southern Thailand – West Coast
Approximately 40% of the Southwest coast is likely to experience thunderstorms, mainly in Ranong, Phang Nga, Trang, and Satun. Overnight lows are forecast between 24-27 degrees Celsius, with daytime highs of 31-34 degrees Celsius. North of Phuket, southwesterly winds of 20-35 kilometers per hour will generate seas of about 2 meters, potentially rising above 2 meters during thunderstorms. South of Krabi, winds will be slightly lighter at 15-35 kilometers per hour, with seas ranging from 1 to 2 meters, and higher in stormy areas.
Bangkok and Vicinity
The capital and its surrounding areas face a 60% chance of thunderstorms, with isolated heavy downpours possible. Overnight temperatures are expected to be between 26-28 degrees Celsius, climbing to 34-36 degrees Celsius during the day. Southwesterly winds will blow at 10-20 kilometers per hour.
Maritime Safety Advisory
The TMD reported moderate wave activity across both the Andaman Sea and the Gulf of Thailand. Waves in the upper Andaman Sea are currently around 2 meters and are expected to exceed this height in areas experiencing thunderstorms. Mariners and small boat operators in both bodies of water are strongly advised to exercise caution and avoid sailing through stormy weather to ensure safety.
Residents in flood-prone areas are encouraged to stay informed about weather updates and take necessary precautions to mitigate risks associated with heavy rainfall and potential flooding.
