SINGAPORE - There is a risk of flash floods occurring at several areas in Singapore after heavy rain on Monday (July 12) filled drains and canals to near full capacity, the PUB warned.

In social media posts, the national water agency said water levels in drains and canals had reached 90 per cent at Upper Paya Lebar Road and Yio Chu Kang Road as at 6.13pm.

The public was to avoid the areas for the next hour due to the high flood risk.

PUB also said that as at 6.50pm, water levels had risen past 90 per cent at Jalan Boon Lay, as well as at the Sime Darby Centre in Bukit Timah Road.

The nearby Bukit Timah Canal, which is close to Blackmore Drive, also saw water levels rise past 90 per cent.

The Land Transport Authority, posting on its Twitter feed for traffic news, said flash floods have occurred on Dunearn Road, towards the city, after Jalan Anak Bukit, as well as on Bukit Timah Road, towards Woodlands, after Holland Link.

The Meteorological Service Singapore (MSS) said on July 1 that more thundery showers could be expected in the first half of July.

Prevailing south-west monsoon conditions mean low-level winds are expected to blow from the south-east or south-west.

Short-duration thundery showers had been forecast for the first week of the month, occurring mainly between the morning and early afternoon.

Prevailing winds in the region were also expected to converge over Singapore and its surrounding vicinity.

This could influence the development of Sumatra squalls - a line of thunderstorms - leading to widespread thundery showers and gusty winds over Singapore between pre-dawn hours and the morning.

In the second week of July, most of the thundery showers should be short and localised due to strong daytime heating of land areas, the MSS had said.