Heavy rain is expected over southern and western Singapore on Wednesday (Oct 28) afternoon.In a weather warning issued at 11.34am, the Meteorological Service Singapore (MSS) said that moderate to heavy thundery showers are expected between 11.50am and 12.40pm.Checks of the service’s weather radar at 12pm showed moderate to heavy rain clouds over south-west Singapore.Meanwhile, national water agency, PUB has issued.