Australia Long-Range Outlook

Outlook for April, May and June

Severe drought led to wildfires in Australia this past austral spring into early summer. The severe drought was brought on by the strongest positive Indian Ocean Dipole on record during austral spring. The +IOD was characterized by cooler-than-normal waters off Indonesia and off northwest Australia. The effects of the +IOD was magnified some by the the development of a weak central Pacific El Nino or warm pool of water near the International Date Line.

Taking a look at the current sea-surface temperature anomalies, we can see water temperatures have since warmed above normal off Indonesia and northwest Australia which led to improved rainfall, especially in eastern Australia in early 2020. The warm pool persists near the Date Line over the equatorial Pacific.

The warm water off northwest Australia is expected to persist through the remainder of austral autumn into austral winter as the Indian Ocean Dipole (IOD) is expected to remain close to neutral. However, some teleconnections point toward the IOD trending toward weakly negative heading into austral spring. A -IOD is characterized by warmer-than-normal waters off Indonesia and usually means normal to above-normal rainfall across Australia.

The waters across the equatorial Pacific, or ENSO, still show a warm pool near the Date Line as referenced above, but several long-range models as well as some teleconnections suggest there can be a trend to La Nina late in 2020. However, the trend to La Nina is not expected until late austral winter or austral spring, so there will be no impact over the next few months.

APEC multi-model ensemble

A trend to La Nina could mean good news for rainfall across Australia heading into next austral summer and a lesser chance for a repeat of the drought and wildfires that impacted Australia in 2019.

Taking a look at our analog years, we can see more favorable prospects for precipitation through the rest of autumn, owing in part to the warming of the waters off northwest Australia.

Our top analogs show a similar pattern and, after studying several long-range climate models, our outlook for the next 90 days (April through June) can be seen below.

We will do an update for the upcoming austral winter forecast in a couple of months.