An Update on Australian Drought

An Update on the Australian Drought

Australia: The exceptional drought across Australia as 2019 closes is the result of a 24-month period of very dry climate across most of the continent. The catalyst to the long-term dry pattern has been periods of positive phase Indian Ocean Dipole and borderline El Nino-like Nino34 SSTA (Fig. 1). The +IOD pattern has reached historical intensity although forecast to weaken into early 2020 (Fig. 2). The rainfall deficit ranking remained profoundly dry the past 3 months across New South Wales worsening the drought condition (Fig. 3). The rainfall needed to bring the long-term rainfall amount out of the 10^th lowest percentile is an incredible “very much above normal” to “exceeds highest on record” which represents 2 to 4 times normal (Fig. 4-5).

Fig. 1: +IOD and +Nino34 SSTA contribute to Australian dry climate.

Fig. 2: The historical +IOD intensity peaked in October but is forecast to fade in early 2020.

Fig. 3: The drought has intensified the past 3 months especially across New South Wales.

Fig. 4: Removing the rainfall deficits caused by the APR-SEP 2019 dry period in decile ranges.

Fig. 5: Removing the rainfall deficits caused by the APR-SEP 2019 dry period in percentage of normal rainfall.