Bangkok faces 70% storm coverage as monsoon strengthens

Bangkok and surrounding provinces are forecast to experience thunderstorms across 70% of the area on Tuesday (August 11), with heavy rain in some places as a monsoon trough and a relatively strong southwest monsoon bring wetter conditions to much of Thailand.

The Thailand Meteorological Department said the monsoon trough extends across the upper North into a low-pressure cell over upper Vietnam and upper Laos. The southwest monsoon is also relatively strong over the Andaman Sea, Thailand and the Gulf of Thailand.

Heavy and accumulated rainfall could trigger flash floods and run-off, particularly in foothill areas near waterways and in low-lying communities, the department warned.

The forecast covers the 24-hour period from 6am on August 11 to 6am on August 12.

Bangkok and surrounding provinces

• Thunderstorms across 70% of the area, with heavy rain in some places
• Minimum temperature: 26-27C
• Maximum temperature: 32-34C
• Southwesterly winds: 10-25 kilometres per hour

Northern Thailand

• Thunderstorms are forecast across 70% of the region, with heavy rain in parts of Mae Hong Son, Chiang Mai, Chiang Rai, Lampang, Phayao, Nan, Uttaradit, Tak, Phitsanulok and Phetchabun.
• Minimum temperature: 23-27C
• Maximum temperature: 31-34C
• Southwesterly winds: 10-20km/h

Northeastern Thailand

• Thunderstorms are expected across 70% of the region, with heavy rain in parts of Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, Yasothon, Mukdahan, Amnat Charoen, Nakhon Ratchasima, Si Sa Ket and Ubon Ratchathani.
• Minimum temperature: 24-25C
• Maximum temperature: 32-34C
• Southwesterly winds: 10-20km/h

Central Thailand

• Thunderstorms are forecast across 40% of the region, with heavy rain in parts of Lopburi, Saraburi and Kanchanaburi.
• Minimum temperature: 25-26C
• Maximum temperature: 32-34C
• Southwesterly winds: 10-25km/h

Eastern Thailand

• Thunderstorms are expected across 70% of the region, with heavy rain in parts of Nakhon Nayok, Prachinburi, Chachoengsao, Chanthaburi and Trat.
• Minimum temperature: 24-27C
• Maximum temperature: 30-33C
• Southwesterly winds: 20-40km/h
• Waves: 2-3 metres, rising above 3 metres in thunderstorms

Southern Thailand — east coast

• Thunderstorms are forecast across 30% of the region, mainly in Phetchaburi, Prachuap Khiri Khan, Chumphon, Songkhla, Pattani, Yala and Narathiwat.
• Minimum temperature: 23-25C
• Maximum temperature: 32-34C
• Southwesterly winds: 20-35km/h
• Waves: 1-2 metres, rising above 2 metres offshore and in thunderstorms

Southern Thailand — west coast

• Thunderstorms are expected across 30% of the region, with heavy rain in parts of Ranong and Phang Nga.
• Minimum temperature: 24-28C
• Maximum temperature: 31-34C
• From Phang Nga northwards: southwesterly winds of 20-40km/h, with waves of 2-3 metres and above 3 metres in thunderstorms
• From Phuket southwards: southwesterly winds of 20-35km/h, with waves around 2 metres and above 2 metres in thunderstorms

Rough seas in upper Andaman and Gulf

The upper Andaman Sea and upper Gulf of Thailand are expected to have relatively rough conditions, with waves of 2-3 metres and above 3 metres in thunderstorms.

Mariners have been advised to proceed with caution and avoid areas affected by thunderstorms. Small boats in the upper Andaman Sea and upper Gulf of Thailand should remain ashore.