Thailand issues heavy rain and flash flood warnings through August 21

Thai water and weather agencies have issued heavy-rain warnings for several provinces through August 21, cautioning that accumulated rainfall could trigger flash floods, run-off, landslides and flooding in low-lying areas.

Four subdistricts placed under 48-hour watch

The Hydro-Informatics Institute (Public Organization), under the Ministry of Higher Education, Science, Research and Innovation, has identified four subdistricts in three provinces as special monitoring areas for the next 48 hours because of the risk of flooding caused by accumulated rainfall.

The areas are:

• Nakhon Nayok: Hin Tang subdistrict in Mueang Nakhon Nayok district
• Nakhon Phanom: That Phanom and Nam Kam subdistricts in That Phanom district
• Kanchanaburi: Lai Wo subdistrict in Sangkhla Buri district

Northern districts face heavy rain from August 15-17

The Region 1 office of the Office of the National Water Resources (ONWR) has also issued a three-day forecast identifying northern districts at risk of heavy rain between August 15 and 17.

Residents have been advised to monitor local conditions because the rainfall could cause flash floods, landslides and waterlogging in low-lying areas.

Orange-alert areas are forecast to receive more than 90 millimetres of rain, while yellow-alert areas could receive between 35 and 90mm.

August 15

The orange-alert area is:

• Tak: Umphang

The yellow-alert areas are:

• Chiang Mai: Omkoi
• Uttaradit: Tha Pla, Nam Pat and Fak Tha
• Phrae: Mueang Phrae, Sung Men and Den Chai
• Nan: Mueang Nan, Mae Charim, Pua, Tha Wang Pha, Santi Suk, Bo Kluea and Phu Phiang
• Mae Hong Son: Mae Sariang, Mae La Noi and Sop Moei
• Kamphaeng Phet: Mueang Kamphaeng Phet
• Tak: Mae Ramat, Tha Song Yang and Mae Sot
• Phetchabun: Mueang Phetchabun and Lom Sak

August 16

The orange-alert area is:

• Tak: Tha Song Yang

The yellow-alert areas are:

• Chiang Mai: Hot, Doi Tao, Omkoi, Galyani Vadhana and Samoeng
• Mae Hong Son: Sop Moei
• Tak: Mae Ramat, Mae Sot and Umphang
• Phitsanulok: Nakhon Thai and Chat Trakan

August 17

The orange-alert area is:

• Chiang Mai: Chiang Dao

The yellow-alert areas are:

• Chiang Mai: Omkoi, Wiang Haeng and Phrao
• Nan: Pua, Tha Wang Pha and Thung Chang
• Mae Hong Son: Mae Sariang and Sop Moei
• Nakhon Sawan: Mueang Nakhon Sawan, Takhli, Phaisali, Lat Yao, Tak Fa, Mae Wong and Chum Ta Bong
• Kamphaeng Phet: Khanu Woralaksaburi
• Tak: Mae Ramat, Tha Song Yang, Phop Phra and Umphang
• Phetchabun: Mueang Phetchabun, Wichian Buri, Si Thep and Bueng Sam Phan

For accumulated rainfall over the three-day period, Tha Song Yang and Umphang districts in Tak have been placed under a red alert, with more than 200mm forecast.

Heavier rain expected from August 18-21

The Thai Meteorological Department (TMD) warned that heavy to very heavy rain was expected in some parts of Thailand from August 18 to 21, particularly in the North and Northeast.

The conditions will be caused by a monsoon trough extending across the North and upper Northeast, together with a rather strong southwest monsoon prevailing over the Andaman Sea, Thailand and the Gulf of Thailand.

People in affected areas have been advised to remain alert for heavy and accumulated rainfall that could cause flash floods and run-off, particularly on foothills near waterways and in low-lying areas.

Travellers should avoid routes with recurring flood problems, especially in low-lying locations where temporary waterlogging could occur.

Winds and waves in the upper Andaman Sea are expected to strengthen from August 19 to 21, with waves reaching two to three metres and exceeding three metres during thunderstorms.

Waves in the lower Andaman Sea and upper Gulf of Thailand are forecast at about two metres, rising above two metres during thunderstorms.

Mariners in the Andaman Sea and Gulf of Thailand should proceed with caution and avoid sailing in stormy areas. Small boats in the upper Andaman Sea should remain ashore during the period.