Heavy thundery showers with gusty wind are expected between 5.55pm and 6.30pm.
The areas affected are the southern, western and central parts of Singapore.
PUB says flash floods may occur in the event of heavy rain.
For flash floods updates, visit PUB Facebook: http://www.facebook.com/PUBSg or PUB Twitter: http://twitter.com/PUBSingapore
For weather updates from AsiaOne, click here: