SINGAPORE: National water agency PUB warned on Monday (Mar 17) that flash floods could occur, with wet weather forecast for later in the week.

A monsoon surge is expected between Mar 19 and Mar 21, bringing moderate to heavy rain across Singapore, said the Meteorological Service Singapore (MSS).

In addition to the rain, the Met Service predicted that the surge would also bring about windy and cooler conditions, including lower daily minimum temperatures of about 22 degrees Celsius.

Subsequently, daily temperatures may range between 24 and 34 degrees Celsius on most days in March.

The monsoon surge comes as north-easterly winds strengthen over the South China Sea, which will cause extensive rain clouds to form over the surrounding region.

"Intense rainfall may overwhelm our drains and canals temporarily, causing flash floods," said PUB in a Facebook post, advising the public to subscribe to its flood alerts and adjust any planned travel routes accordingly.

There will also be short thundery showers in the afternoon for the rest of the fortnight in March, said MSS in its forecast. 

It added that it expects the overall rainfall for the second half of the month to be "above average" over most parts of Singapore.

The average rainfall for March is 151.7mm, according to historical data between 1991 and 2020.

Earlier in the year, Singapore experienced a monsoon surge from Jan 10 to Jan 13 that, according to the Met Service, was "one of the longer and more intense" ones in recent years. 

The surge brought moderate to heavy rain and led to flood risk warnings in various locations. Flooding occurred along a stretch on Jalan Seaview on Jan 10, which PUB said then was due to "heavy rain coinciding with high tide".

Twelve flights were also diverted from Changi Airport due to poor weather conditions arising from the monsoon surge and resulting prolonged rain. 

Changi had recorded the highest total amount of rainfall at 255.2mm from Jan 10 to Jan 11, more than Singapore's average monthly rainfall of 222.4mm in January, said PUB then.

PUB later said it expected another monsoon surge from Jan 17 to Jan 19 to bring about "prolonged rainfall".