Rain and thunderstorms will spread over southeastern and eastern Australia during the next three days, dumping more water into already flooded rivers across several states.

Since the beginning of September, a series of rain and storm-bearing low pressure troughs have delivered two-to-four months’ worth of rain in parts of eastern Australia.

This frequent and substantial rainfall has caused flooding in several states, with numerous flood warnings currently in place from southern Qld down to northern Vic, including a large swathe of NSW.

The map below shows the month-to-date rainfall percentages, with blue shading representing areas that have already seen more than 200 percent of their average rainfall so far this month.

Image: Observed September month-to-date rainfall percentages. Source: Bureau of Meteorology.

A cut-off upper-level low and an associate surface trough will interact with moisture-laden air to cause widespread showers and storms in parts of SA, NSW, the ACT, Qld, Vic, Tas and the NT between now and Wednesday.

The heaviest rain from this system is likely to fall over Vic and southern NSW, where renewed river level rises may cause flooding. There is also potential for severe thunderstorms in several states during the next three days.

Image: Forecast accumulated rain between Monday and Wednesday according to the ECMWF-HRES model.

Be sure to check the latest flood and thunderstorm warnings for the most up-to-date information as this event unfolds.