The Thai Meteorological Department has issued a weather alert for Monday (July 20), forecasting heavy to very heavy rainfall across much of the country due to the influence of Tropical Storm “Wipha.” Bangkok is expected to be hit especially hard, with a 70% chance of thunderstorms throughout the day.
In its 24-hour forecast, the department warned that intense downpours are expected in provinces including Bueng Kan, Nakhon Phanom, Chanthaburi, Trat, and Ranong.
Authorities have urged residents in these areas to remain on high alert for flash floods and water runoff, particularly in foothills, low-lying zones, and near waterways.
The worsening conditions are being driven by a strengthening southwesterly monsoon currently covering the Andaman Sea, Thailand, and the Gulf of Thailand.
Rough seas have also been forecast, especially in the upper Andaman Sea where wave heights are expected to reach between 2–4 metres, possibly exceeding 4 metres during thunderstorms.
The lower Andaman Sea and the upper Gulf of Thailand could see waves of 2–3 metres, increasing to over 3 metres in stormy areas.
Fishermen and marine operators are being urged to exercise extreme caution and avoid navigating through thunderstorm zones. Small boats in affected areas are advised to remain ashore until weather conditions improve.
As of 7pm on Sunday, Tropical Storm Wipha had made landfall in southern Guangdong province, China.
By 10pm, its centre was located over Maoming city and moving westward. The storm is projected to enter the Gulf of Tonkin before reaching northern Vietnam between July 21 and 22.
Thai authorities continue to monitor Wipha’s path closely, as it may bring further impacts to northern and northeastern regions of Thailand in the coming days. A nationwide advisory has been issued, valid from 6am Monday (July 20) to 6am Tuesday (July 21).
Regional Forecast Highlights
Bangkok and Surrounding Provinces – The capital and nearby areas are forecast to see a 70% chance of thunderstorms, with pockets of heavy rain expected.
– Temperatures: 25–27°C (low) and 31–33°C (high)
– Winds: Southwesterly, 10–25 km/h
Northern Region – Thunderstorms are likely in 60% of the region, with heavy rainfall forecast in Chiang Rai, Phayao, Nan, Phrae, Uttaradit, Tak, Kamphaeng Phet, Phichit, Phitsanulok, and Phetchabun.
– Temperatures: 22–25°C (low) and 31–34°C (high)
– Winds: Southwesterly, 10–20 km/h
Northeastern Region – Around 60% of the region is expected to see storms, with very heavy rain in Loei, Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, and Mukdahan.
– Temperatures: 22–25°C (low) and 30–34°C (high)
– Winds: Southwesterly, 10–20 km/h
Central Region – Rain is forecast in 70% of the area, with heavy showers expected in Nakhon Sawan, Uthai Thani, Chai Nat, Lopburi, Saraburi, Singburi, Ang Thong, Ayutthaya, Suphan Buri, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram, and Samut Sakhon.
– Temperatures: 23–25°C (low) and 31–34°C (high)
– Winds: Southwesterly, 10–25 km/h
Authorities urge the public to monitor weather updates closely and take precautions as Thailand braces for potentially hazardous conditions brought by Tropical Storm Wipha.
