A low pressure trough over the New South Wales coast has delivered torrential rain to parts of the Illawarra and South Coast on Saturday, with more on the way.

In the 24 hours to 9am Sunday, rainfall totals exceeded 100mm across a number of locations. Beaumont (Illawarra, north of Nowra) recorded one of the highest totals with 197mm reaching the gauge. Mongarlowe and Bettowynd, both on the South Coast, weren’t far behind with 192mm and 181mm respectively. This adds to the significant falls the previous day. In the 24 hours to 9am on Saturday, 204mm fell at the Nowra Boat Shed, 159mm at Foxground and 143mm at Broughton Creek. This amount of rain is enough to cause riverine flooding, as a result, Major Flood Warnings in place for the Deua and Shoalhaven River catchments with Moderate and Minor Flood Warnings in place for other catchment areas.

The low pressure trough will deepen further through Sunday, bringing more rain to an already saturated region. There is also a significant risk of small-scale low pressure systems embedded within the trough bringing localised bursts of heavy rain and gusty winds. Widespread falls of 30-50mm are likely in the 24 hours to 9am Monday for the Illawarra and the South Coast, with higher isolated falls likely. Heavy rain and gusty winds are also expected to extend further north during the afternoon and evening to include Sydney and the Hunter Coast, though this is dependent on the development and movement of a low.

Image: Accumulated rainfall totals to 10pm EST Monday according to the ECMWF HRES model.

Showers will ease on Monday and the heaviest falls will shift further north to the Hunter Coast and Mid North Coast where falls of 15-30mm are expected. This easing trend will continue on Tuesday and the system moves away over the Tasman Sea.