Heavy rain forecast across four regions, thundershowers to cover 60% of Bangkok

The Thai Meteorological Department has warned of isolated heavy rain across four regions over the next 24 hours, with residents in vulnerable areas advised to prepare for flash floods, run-off and overflowing waterways.

In its forecast issued at 5pm on Wednesday (July 15), the department said a moderate southwest monsoon was prevailing over the Andaman Sea, Thailand and the Gulf of Thailand, while a low-pressure cell covered upper Vietnam.

The conditions will bring heavy rain to parts of the North, Northeast, East and southern west coast. People living near foothills, waterways and low-lying areas should remain alert to hazards caused by heavy rain and accumulated rainfall.

The regional forecast is valid from 6pm on Wednesday to 6pm on Thursday (July 16).

Eastern provinces face widespread storms

Thunderstorms are forecast across 60% of the East, with isolated heavy rain in Nakhon Nayok, Prachin Buri, Chanthaburi and Trat.

Temperatures will range from lows of 24-27°C to highs of 31-34°C, with southwesterly winds of 20-35 kilometres per hour.

Waves will be about two metres high and may rise above two metres during thunderstorms.

Heavy rain expected in North and Northeast

In the North, thunderstorms are forecast across 40% of the region, with isolated heavy rain in Mae Hong Son, Tak, Phitsanulok and Phetchabun.

Temperatures will range from 23-25°C overnight to daytime highs of 32-35°C.

The Northeast will also see thunderstorms across 40% of the region, with heavy rain expected in Bueng Kan, Sakon Nakhon, Nakhon Phanom, Mukdahan, Amnat Charoen and Ubon Ratchathani.

Temperatures are forecast to range from lows of 23-25°C to highs of 33-35°C.

Central region to see scattered thunderstorms

Thunderstorms are expected across 40% of the Central region, mainly in Nakhon Sawan, Uthai Thani, Chai Nat, Suphan Buri, Ayutthaya, Saraburi, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram and Samut Sakhon.

Temperatures will range from 23-26°C to highs of 34-36°C, with southwesterly winds of 10-20kph.

Heavy rain targets Andaman coast

Thunderstorms are forecast across 60% of the southern west coast, with isolated heavy rain in Ranong, Phang Nga, Phuket and Krabi.

From Phuket northwards, southwesterly winds will reach 20-35kph, with waves of about two metres. From Krabi southwards, winds will reach 15-35kph and waves will be one to two metres high.

Waves may rise above two metres in areas affected by thunderstorms.

On the southern east coast, thunderstorms are expected across 40% of the region, mainly in Chumphon, Surat Thani, Nakhon Si Thammarat, Pattani, Yala and Narathiwat.

Mariners warned to avoid thunderstorms

Waves in the upper Andaman Sea and upper Gulf of Thailand will be about two metres high, while those in the lower Andaman Sea and lower Gulf will range from one to two metres.

Waves may exceed two metres during thunderstorms. The department advised all vessels to proceed with caution and avoid stormy areas.

Thundershowers forecast across 60% of Bangkok

Bangkok and surrounding provinces can expect thundershowers across 60% of the area.

Temperatures will range from overnight lows of 25-27°C to daytime highs of 33-35°C, with southwesterly winds of 10-20kph.