Monsoon surge raises flood risk across Thailand: 47 provinces on high alert

Swelling rainfall across Thailand, spurred by the increasing strength of a monsoon coupled with an area of low atmospheric pressure, has compelled the Thai Meteorological Department (TMD) to warn that 47 provinces could face potentially hazardous situations. Over the next 24 hours, it predicts 60% of their areas will face heavy rain, with the severity being the most significant in the northern and northeastern regions of the country.

Meteorologists at the TMD have attributed this increase in rainfall to the interaction of a trough of the southwestern monsoon as it crosses Myanmar and enters the northern region of Thailand, toward a pocket of low atmospheric pressure in Laos and North Vietnam. This system is underpinned by a southwestern monsoon, which intensifies over the Andaman Sea, Thailand, and the Gulf of Thailand.

The TMD cautioned that these phenomena, once converged over Thailand, will lead to higher rainfall and heavier showers in some parts of the country notably in the east. Altitudes in the north and northeast of the country are projected to experience intense rain and accumulated rainfall. This has the potential to cause sudden floods and forest runoff.

People in these regions, particularly near uphill areas, waterways, and lower plains are urged to be cautious of potential dangers. In the upper Andaman Sea, waves are expected to be 1 to 2 metres high and in areas with stormy weather, waves may rise above 2 metres. Fishermen are asked to navigate boats with caution and avoid regions with thunderstorms entirely.

Weather forecasts for Thailand from 6am today until 6am tomorrow show that the northern region will experience thunderstorms with 70% of the area affected, with heavy to very heavy rain in some parts, particularly in the provinces of Chiang Mai, Chiang Rai, Phrae, and Nan. Minimum temperatures range from 23 to 26 degrees Celsius, with maximum temperatures of 32 to 35 degrees. Southeasterly winds will be blowing at a speed of 10 to 25 kilometres per hour.

The northeastern region is also set to have thunderstorms with 70% of the area affected and heavy to very heavy rain in some parts of the provinces notably Khon Kaen, Udon Thani, Maha Sarakham, and Nakhon Ratchasima amongst others. Minimum temperatures will be around 23 to 26 degrees Celsius, maximum temperatures at 31 to 36 degrees, and southeasterly winds at a velocity of 10 to 20 kilometres per hour.

In the central region, thunderstorms are predicted in 60% of the area, especially in the province of Ayutthaya, Kanchanaburi, and Nonthaburi. Minimum temperatures will likely fall to around 25 to 27 degrees Celsius, maximums at 34 to 36 degrees and moderate westerly winds at 10 to 25 kilometres per hour.

The initial instance of a thunderstorm in the eastern region, covering 60% of the area, with heavy rainfall in some parts, includes the provinces of Nakhon Nayok, Chachoengsao, and Rayong to name a few.

The lowest temperatures will likely be around 25 to 27 degrees Celsius, the highest at 32 to 35 degrees, and moderate westerly winds shall prevail at a speed of 15 to 30 kilometres per hour. Sea waves are expected to be about 1 metre high, rising to 1 to 2 metres in thunderstorm-hit areas.

The southern region, including Phetchaburi, Prachuap Khiri Khan, and Trang, is expected to see thunderstorms in 40% of the area, while the western coastline of the region, including Ranong and Phuket, may see elevated thunderstorm activity across 60% of the area. The sea waves in these areas are expected to range from 1 to 2 metres, rising beyond 2 metres in areas experiencing thunderstorms. The winds will primarily be from a south-westerly direction, ranging in speed from 15 to 30 kilometres per hour.

In Bangkok and the surrounding areas, thunderstorms are predicted across 60% of the area. Temperatures in the region will range between a low of 25 to 28 degrees Celsius and a high of 34 to 36 degrees Celsius. Wind will be blowing in a southeasterly direction at a speed of 10 to 25 kilometres per hour.

The Meteorological Department has issued a warning, stating that over the next 24 hours, 47 provinces across Thailand are expected to experience increased rainfall, with 60% of these regions expected to experience heavy rainfall.