El Nino's Impact on Australia's Weather: A Complex Tale of Heat and Rain
The recent record-breaking heat in Australia during June has been a surprise to many, especially given the newly-declared El Nino event and the Bureau's Long Range Forecast maps. But what's the story behind this unexpected weather phenomenon? In this article, we delve into the complex interplay of climate drivers and their impact on Australia's weather patterns.
The Ocean's Role
The oceans surrounding Australia have played a crucial role in the recent weather patterns. The Indian Ocean, in particular, has been warmer than usual off Australia's northwest coast, contributing to the formation of the northwest cloudband. This region is a key player in one of Australia's most famous weather events, and the cloudbands that have crossed the country this month have tapped into the extra moisture in the air above these warm seas.
But it's not just the Indian Ocean that's influencing the weather. The Southern Ocean has also been a driving force, with the Southern Annular Mode (SAM) becoming extremely strong and positive. This mode, which is on par with the record set briefly in 2016, has led to higher than usual pressure closer to Australia, resulting in onshore winds guiding showers onto the east coast and some moisture feeding inland to aid inland rainfall.
The El Nino Effect
El Nino has started stronger and earlier compared to most events, with both the ocean (Relative Nino) and atmosphere (Southern Oscillation Index - SOI) being the strongest for June since 1997. That year was infamous as the beginning of the equal strongest El Nino on record, and there's still plenty of time for El Nino to influence Australia's weather patterns.
Typically, El Nino influences the other oceans, with the Indian Ocean often cooling near Australia's northwest into our springtime. The Southern Ocean typically shifts towards a more negative SAM by summer, which is part of the reason why El Nino's typically have their greatest influence on Australia's rainfall patterns from August to October.
The Complex Interplay
What makes this situation particularly fascinating is the complex interplay of climate drivers. The two oceans, the Indian and Southern Oceans, have both worked to counteract the drying influence of El Nino. But this balance is not likely to last, and the strong start to El Nino is a sign of things to come.
The Impact on Ski Fields
The combination of warm and wet weather in the southeast has been terrible for the ski fields. The resorts are still seeing their equal worst start to a ski season on record, and while snow is coming on Friday, further warmth and rain in the following week could produce the outright worst start to a season.
Conclusion
In conclusion, the recent record-breaking heat in Australia during June is a complex tale of climate drivers and their impact on weather patterns. The oceans, El Nino, and the SAM have all played a role in this unexpected weather phenomenon, and it's a reminder of the intricate and dynamic nature of our climate system. As we move forward, it will be fascinating to see how these climate drivers continue to influence Australia's weather patterns.
