Second monsoon surge from Jan 17 to 19 expected to be less intense: MSS

SINGAPORE - The spell of prolonged rain that is forecast to hit the Republic from Jan 17 to 19 is expected to be less intense and shorter than the previous four-day event.

The National Environment Agency’s Meteorological Service Singapore (MSS) said this on Jan 17, in response to queries from The Straits Times.

But it added that it is difficult to predict the extent and intensity of a surge event as its strength depends on many different factors. These include wind direction and speed, and how far cloud clusters are from Singapore, said MSS.

The agencies had

warned in the fortnightly weather outlook on Jan 16

that the Republic would experience its second monsoon surge in the month, bringing windy and cooler conditions with occasional spells of moderate to heavy thundery showers over Singapore and the vicinity.

Coastal areas could see more flash flooding during this surge, as tides are expected to be higher compared with those during the previous surge that happened between Jan 10 and 13.

During periods of seasonal high tides, it is common for low-lying areas along East Coast Park to get flooded even without incessant rain.

When ST visited the park at 1pm on Jan 17, when the highest tide was recorded for the day at 3.2m, light rain fell for about five minutes before the skies cleared.

There were full drains and pools of water at grassy areas near the coast – likely owing to high tides – but water did not spill over onto the pavements.

Most people at East Coast Park whom ST spoke to were not aware of the impending monsoon surge, but all said they had checked the weather forecast before heading out.

A Tampines resident, who wanted to be known only as Ms Ida, 34, and her husband took their 2½-year-old daughter to the park’s Coastal Playgrove around noon.

As rain was forecast only in the late afternoon, they went out without umbrellas or ponchos.

“I know that it’s monsoon season, but the rain hasn’t been that heavy over the past few days. It’s on and off,” said Ms Ida, who works in administration. She added that she trusts Singapore’s drainage system to prevent floods.

A retiree in his 70s fishing at a pier in the park, who gave his name only as Mr Wee, heard about the second monsoon surge from the news.

The Hougang resident, who is a former shipyard worker, said it did not affect his twice-weekly cycling and fishing plans. He said in Mandarin: “If I’m caught in the rain, I can just go home and wash up.”

Marketing agent Steven Liu, 36, was on a seaside excursion with his parents and son, after recently frequenting indoor places such as shopping malls because of the rain.

He said: “Even when we go outdoors, we choose places where there is shelter nearby, in case of rain.”

Residents at Jalan Seaview in Mountbatten braced themselves for a second surge – their landed estate was

affected by flash floods during the first monsoon surge

on Jan 10 as the deluge coincided with a high tide of 2.8m.

A homemaker in her 50s, who wanted to be known only as Mrs Phan, said flooding has been a common occurrence in her past two decades living in Jalan Seaview. Mrs Phan said in Mandarin: “Sometimes, the flooding is so bad, we cannot drive our car out.”

Gesturing towards a slope in front of her front gate, she added: “After 20 years of dealing with floods, we had to build this slope ourselves in order to stop the flood water flowing into the house.”

Mrs S.Y. Chen, a resident who moved into the estate in August 2024, said her son saw news online about the second surge. Her family is “definitely worried”.

The 48-year-old hotel manager added that they are not familiar with flood prevention measures, but hopes the drain at their front yard will be able to channel away the excess water.

Singapore is in the wet phase of the north-east monsoon – which tends to last from December to January – and spells of monsoon surges are common during this season.

A monsoon surge refers to bursts of cold air from the north-east, such as Central Asia, which flows over the South China Sea before bringing widespread rainfall, strong winds and cooler weather to Singapore.

When regions up north, such as Siberia, experience extremely cold weather in the winter months, the cold air occasionally sweeps southwards to the South China Sea, and is blown towards the tropics. The air then warms and picks up moisture, leading to the formation of dense rain clouds. This brings increased rainfall near the Equator. 

Singapore experiences two to four monsoon surges each year, on average.

As at Jan 15, Singapore’s islandwide average rainfall for the month had reached 376.8mm, or 69.5 per cent above the month’s long-term average, said MSS.

The agency said: “While it is too early to determine if there will be record-breaking rainfall, January 2025 will likely rank as one of the wettest Januaries.”

According to

Singapore’s third national climate change study (V3),

climate change is expected to bring heavier, more intense and frequent storms. This could lead to more flash flooding.

In the low-carbon emission scenario, the rainy season between November and January is expected to get wetter by up to 58 per cent, said the study, which was released in 2023.

Climate change is also expected to cause land ice at the Poles to melt, causing sea levels to rise.

Higher sea levels, when coupled with high tides, could cause coastal flooding to increase.