A fast-developing coastal low off the NSW coast is expected to bring damaging winds, heavy rain, flash flooding, coastal erosion, and storm damage. The system is currently affecting the Mid North Coast with widespread rain, thunderstorms, and surf.
Widespread rainfall totals of 50-150mm are likely and isolated intense falls in excess of 200mm in a 24hour period are possible, which is expected to cause flash flooding.
Forecasts predict wind gusts up to 125km/h and six-hour rainfall totals of 70–90mm, possibly reaching 120mm in some areas. The system will move south towards Sydney, the Illawarra, and the South Coast on Tuesday afternoon, bringing wind gusts up to 125km/h and a continued risk of flash flooding.
Flash flooding is particularly likely between Newcastle, Sydney, and the Illawarra due to intense, short bursts of rainfall. Minor to moderate riverine rises in coastal catchments and throughout the Hawkesbury Nepean Valley are also possible.
The event is more dynamic and faster-moving than recent storms.