Arya News - The department attributed the wetter conditions to a strengthening southwesterly monsoon prevailing over the Andaman Sea, Thailand and the Gulf of Thailand, together with a low-pressure cell covering upper Vietnam.
BANGKOK – Thailand is expected to see increased rainfall over the next 24 hours, with isolated heavy downpours forecast for the North and upper Northeast, the Thai Meteorological Department said at 5pm on Tuesday, July 21.
The department attributed the wetter conditions to a strengthening southwesterly monsoon prevailing over the Andaman Sea, Thailand and the Gulf of Thailand, together with a low-pressure cell covering upper Vietnam.
Residents in northern and upper northeastern provinces have been advised to watch for hazards caused by heavy rain and accumulated rainfall, particularly in vulnerable and low-lying areas.
Heavy rain expected across northern provinces
Thunderstorms are forecast across 60% of the North, with isolated heavy rain expected in Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Nan, Lamphun, Lampang and Tak.
Temperatures will range from lows of 21-26 degrees Celsius to highs of 28-35°C, with southwesterly winds of 10-20 kilometres per hour.
In the Northeast, thunderstorms are expected across 40% of the region. Heavy rain is forecast mainly in Nong Khai, Bueng Kan, Sakon Nakhon and Nakhon Phanom.
Temperatures will range from 23-25°C at night to 32-36°C during the day, with southwesterly winds of 10-20kph.
Bangkok faces afternoon and evening storms
Bangkok and surrounding provinces have a 40% chance of thunderstorms, mainly between the afternoon and evening.
Minimum temperatures will range from 26-28°C, while maximum temperatures are expected to reach 35-37°C. Southwesterly winds will blow at 10-20kph.
The Central region also has a 40% chance of thunderstorms, mainly in Nakhon Sawan, Uthai Thani, Chai Nat, Lop Buri, Saraburi, Kanchanaburi and Ratchaburi.
Temperatures in the region will range from lows of 25-26°C to highs of 35-37°C.
Rough seas pose risk to mariners
Waves in the upper Andaman Sea and upper Gulf of Thailand are expected to reach one to two metres, while waves in the lower Andaman Sea will be around one metre high.
In areas experiencing thunderstorms, waves may rise above two metres.
The department advised mariners to proceed with caution and avoid sailing in stormy areas.
The eastern region has a 40% chance of thunderstorms, mainly in Chachoengsao, Nakhon Nayok, Prachin Buri, Rayong, Chanthaburi and Trat.
Southwesterly winds will reach 15-35kph, with waves of one to two metres and higher than two metres during thunderstorms. Temperatures will range from 23-27°C to 33-36°C.
Rain forecast on both southern coasts
On the southern east coast, thunderstorms are expected across 30% of the region, mainly in Phatthalung, Songkhla, Pattani, Yala and Narathiwat.
Temperatures will range from 22-25°C to 32-36°C. Waves will be around one metre high, rising above one metre offshore and exceeding two metres in stormy areas.
The southern west coast has a 40% chance of thunderstorms, mainly in Phuket, Krabi, Trang and Satun. Temperatures will range from 23-25°C to 32-35°C.
From Phang Nga northwards, waves will reach one to two metres and exceed two metres during thunderstorms. From Phuket southwards, waves will be around one metre high, rising above two metres in stormy areas.
Pacific system could develop into depression
The Meteorological Department is also monitoring a strong low-pressure system over the Pacific Ocean that could intensify into a tropical depression.
The system is expected to move across the northern Philippines between July 24 and 25.
The department has not yet indicated a direct impact on Thailand, but developments will be monitored because the system could influence regional weather conditions.
Farmers warned of saturated soil and waterlogging
In its 10-day agricultural weather outlook for July 21-30, the department forecast widespread rainfall across much of Thailand.
SPEI and MAI drought and moisture indices show increasingly wet conditions across most of the country, although pockets of dry soil remain in parts of the Central region.
Farmers in the South, upper North, upper and eastern Northeast, and East were warned that soil moisture was approaching saturation.
They were advised to clear drainage channels to reduce waterlogging, protect crops from root rot and closely monitor fungal diseases.
In the Central region, lower North and central Northeast, rainfall may still be insufficient to reach deeper root zones. Farmers were advised to continue mulching around plants to retain moisture and prepare channels or storage areas to capture rainwater.
The forecast covers the period from 6pm on Tuesday to 6pm on Wednesday.