Australia Extreme Rainfall Shifts Back into Victoria Next 10 Days

Highlight: Next round of storms to bring excessive rainfall and additional flooding to Victoria.

Fig. 1: Australia rainfall for the week ending Oct. 24, 2022.

Discussion: Areas of 150-200 mm. (6-8 in.) were observed in parts of East Australia for the week of Oct. 18-24, 2022. Hardest hit zones were in northeast New South Wales and southeast Queensland (Fig. 1). Current weather satellite view indicates the culprit, an occluded low-pressure area over Victoria and new low-pressure area forming off the northeast coast of New South Wales (Fig. 2). A widespread area of rain of which some is heavy in intensity covers Victoria and the southeast/east portion of New South Wales and the southeast coast of Queensland.

Fig. 2: Current weather satellite view of Australia into the South Pacific.

The forecast indicates the low-pressure system off northeast New South Wales will drift southward into Victoria during the next 2-3 days and strengthen. The result is another excessive rainfall event centered on central and eastern Victoria to Tasmania where several inches of rain including high spots of 6 inches could occur (Fig. 3). Early in the 6-10-day period, another storm rolls across southern Australia and causes several inches of rain from near Brisbane eastward to Victoria (again). High spots of 5-6 in. of rain can occur in this zone (Fig. 4). The set of storms clearly targets Victoria for flooding rainfall.

Fig. 3: ECM day 1-5 rainfall forecast for Australia.

Fig. 4: ECM day 6-10 rainfall forecast for Australia.

The extreme rainfall pattern in the East/Southeast may temporarily ease Nov. 4-13 although most of the continent will average wetter than normal. However, the extreme wet weather risk returns to East/Southeast Australia in the week 4-6 outlook according to ECM (Fig. 5).

Fig. 5: ECM week 4-6 rainfall anomaly forecast for Australia.