Vast expanses of thick cloud have been delivering heavy rain overnight across parts of southwestern WA, leading to some flooding. A deep low pressure trough aided by upper cool air has contributed to the distribution of large amounts of moisture over the Central West, Central Wheatbelt, Lower West, South West and Great Southern districts. A severe weather warning is currently in place for these districts, alerting against heavy rainfall. Impressive figures are coming out of places such as Gingin where 36mm was recorded between 8:30pm and 12:30am local time, 31mm of which fell within one hour. Wongan Hills has been one of the wettest locations statewide, collecting 91mm since 5:30pm on Friday, closely followed by Coorow West which picked up 60mm since 3pm. Rainfall of this magnitude presents the risk of flooding, with a number of flood watches already issued for the Central West, Lower West and South West districts. Catchments included in these flood watches the Greenough, Irwin, Moore and Hill Rivers, the Murray and Harvey Rivers and the Collie, Preston and Busselton Rivers. Rainfall is expected to ease as it spreads east on Sunday, however totals in excess of 20mm remain a risk over the Lower West, Southwest, Great Southern, Central Wheatbelt and Goldfields. By Monday, conditions should have stabilised, allowing skies to clear and any flooding to subside.