BANGKOK, Thailand — The Office of the National Water Resources (ONWR) has issued urgent warnings for heavy to very heavy rainfall across parts of upper Thailand through July 8, raising severe risks of flash floods, forest runoff, and landslides. The deteriorating weather conditions are driven by the combined forces of a persistent monsoon trough and a relatively strong southwest monsoon sweeping across the country.

Tropical Storm Maysak Lashes Thailand with Torrential Rain and Sea Alerts

Meteorological officials explain that the active monsoon trough extends across the upper North and upper Laos, directly linked to the residual effects of severe tropical storm Maysak. Concurrently, a strong southwest monsoon is prevailing over the Andaman Sea, Thailand, and the Gulf of Thailand. While rainfall is expected to gradually ease in parts of the Central, Eastern, and Southern regions, the upper North and upper Northeast are forecast to endure heavy to very heavy rain through July 9.

In response to the severe weather threat, authorities have placed sixteen provinces under strict heavy-rain monitoring through July 8. The affected areas span multiple regions, including Tak, Mae Hong Son, Chiang Rai, Nan, and Phayao in the northern and western zones, alongside Nong Khai and Bueng Kan in the Northeast. Additionally, coastal and southern provinces such as Chanthaburi, Trat, Kanchanaburi, Chumphon, Ranong, Phangnga, Phuket, Trang, and Satun remain on high alert. Residents in these vulnerable areas have been strongly urged to prepare for potential flash floods, forest runoff, landslides, and urban flooding, as local drainage systems may easily become overwhelmed by the intense precipitation.

Thai authorities have warned that heavy to very heavy rain will continue across parts of northern Thailand and other areas, with risks of flash floods, landslides and urban flooding. The weather is being driven by a monsoon trough and a strong southwest monsoon affecting… pic.twitter.com/Azd4fzy1ed

— Bangkok Post (@BangkokPostNews) July 7, 2026

The relentless rainfall has also pushed the nation’s water infrastructure to critical levels. The ONWR reported that three major northern reservoirs—Mae Ngat, Kiu Lom, and Mae Chang—have already exceeded their maximum storage capacities. Furthermore, 33 medium-sized reservoirs nationwide are currently operating at more than 80 percent capacity or have surpassed their safe operational thresholds, necessitating careful water release management to prevent structural stress and downstream flooding.

Providing broader context regarding the increasingly severe weather patterns, marine and environmental expert Thon Thamrongnawasawat noted that Super Typhoon Bavi, recognized as the strongest storm of the year, exemplifies a disturbing global trend toward more powerful cyclones driven by climate change and El Niño conditions. He explained that unusually warm sea surface temperatures are allowing these storms to intensify with greater ease and speed. Highlighting the impact of rising global temperatures, he pointed out that the most intense typhoons ever recorded have all occurred within the past twelve years.

Heavy Rainfall Triggers Widespread Flash Flooding Across Phuket

As the monsoon season continues to batter the region, local authorities and disaster prevention agencies are maintaining a state of high alert, monitoring water levels and preparing emergency response teams for potential evacuations.

-Thailand News (TN)