An impending rain event scheduled for the opening days of spring continues the pattern of wet weather which has gripped eastern Australia during winter. Most of New South Wales received above average rain this winter, with some areas picking up more than three times their seasonal average. Standout locations were Wanaaring (Upper Western), Nyngan (Central West), Camden (Sydney) and Bankstown (Sydney), which all had their wettest winter on record, more than 125 years of records for Wanaaring and Nyngan. Sydney had its wettest winter in nine years. In Queensland, it was the wettest winter on record for Richmond (Northern Goldfields), Longreach (Central West), Isisford (Central West) and Boulia (Channel Country) and their wettest in 69 years for Charleville (Maranoa). All of these locations have data available for more than a century. Brisbane had its wettest winter in 17 years. Abnormally heavy rain during the last three months was driven primarily by above average sea surface temperatures surrounding Australia. Warm oceans contribute more moisture into the atmosphere through evaporation. The greatest influence came from one of the strongest negative Indian Ocean Dipole (IOD) events ever recorded, which helped pump moisture across the country from the northwest. Despite this negative IOD weakening progressively since its peak in July, spring will start out on a similarly wet note for New South Wales and southern Queensland. A band of cloud being fed by Indian Ocean moisture will spread across New South Wales from Thursday to Saturday. Parts of New South Wales and southwest Queensland could see their heaviest rain in a couple of years during the first two days of spring. Some catchments are still saturated from prolific winter rain, so riverine flooding is a high risk during this event. Flash flooding is also a risk during the heavier bursts of rain. Rainfall totals in the 20-50mm range are likely for a broad area stretching from southern Queensland across to the slopes and ranges in New South Wales. Isolated totals are expected to reach 100mm during this three-days spell. Parts of the Central West Slopes and Plains and Upper Western in New South Wales and Channel Country in Queensland could see the heaviest rain in about one or two years. Towns in this boat could include Thargomindah, Bourke, Coonabarabran and Mudgee. The eastern seaboard will miss out on the heaviest falls, due to air becoming drier as it passes over the Great Dividing Range. Both Sydney and Brisbane will see some rain, mainly on Friday in Sydney and Saturday in Brisbane. Looking ahead, rain will clear on Saturday as the cloud band moves into the Tasman Sea, allowing drier weather to return by the start of next week.