Bom climate drivers

The Bureau of Meteorology BOM has declared two major climate drivers linked to hot, dry conditions are officially underway in Australia, prompting further warnings that extreme heat could hit this spring and summer.

Victoria is well known for its variable climate. From year to year, four global climate processes vary their behaviour, potentially resulting in wetter or dryer seasons. From a farmer's perspective when they're are behaving they bring moisture from the oceans and allow it to fall over Victoria as rain. Hopefully delivering the right amount at the right time. But they don't always work the way we'd like them to and can sometimes scatter the mob, effectively chasing rainfall away from Victoria. Over recent decades some of these dogs have changed their behaviour contributing to our extended dry spell and the changing weather patterns that many farmers have noticed. While we can't control what these dogs are up to the Bureau of Meteorology and the Victorian Department of Primary Industries have new and valuable tools that can assist farmers in keeping track of these climate dogs helping to predict the likelihood of rain over the coming season and manage climate risk.

Bom climate drivers

But it wasn't until three months later, in September, that the event was officially declared underway. BOM climate researcher Matthew Wheeler, who co-authored a recent report proposing changes to the index , said this year was the "perfect example" of why the system was no longer the best fit. The event, which takes place over the Pacific Ocean, is characterised by a complex interaction between the ocean and the atmosphere which causes the two systems to effectively team up to start rearranging where rain falls. The "coupling" between the two systems is a crucial part of the event, as it leads to the event being locked in for a prolonged period of time. For the ocean component, the bureau compares temperatures in a certain part of the Pacific with the average. Other agencies, such as the US, have a slightly softer criteria and often tend to put more emphasis on the ocean indicators. Dr Wheeler said the ocean and atmospheric indices usually tipped over the thresholds "about the same time". The index doesn't just take into account how hot the temperatures are in the eastern Pacific, but how hot they are compared to the anomalies being experienced by the entire planet's tropical oceans. When all of the oceans are warm everywhere, as was the case this year, temperatures in the eastern Pacific must become even warmer to trigger a change in the atmosphere. However, it noted there was still a "weak ocean-atmosphere coupling" at the time. While it is only a proposal at this stage, the bureau's head of climate monitoring, Karl Braganza, said it was likely the bureau would make the switch over coming years.

View feature articles. Supplied: Bureau of Meteorology. One other Climatedog explaining other climate features that can affect rainfall in Victoria is Mojo.

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This update confirms the wet conditions are likely to remain for at least a while longer. The update comes as a low pressure system lingers off the southern New South Wales coast, causing yet more rain in the south-east. Showers and storms are expected to continue for the rest of south-east and eastern Australia with potentially severe thunderstorms for coastal areas between Townsville and Wollongong. The BOM is predicting that heavy rainfall will be the primary risk, but warns damaging winds and large hail are possible. Five of the models are predicting the phenomenon to persist until at least the end of the year. Conditions are primed for widespread flooding even beyond what we have already seen over the last few weeks. Saturated catchments mean it is taking relatively little rain to trigger flooding. The update shows all but one climate model indicates that negative IOD conditions are likely to continue through November. The Indian Ocean Dipole typically breaks down as the monsoon moves south at the beginning of summer. It is therefore not surprising that all the models predict the IOD will be gone by December.

Bom climate drivers

So what's next? It's the climate driver generally responsible for cooler, wetter conditions. That has coincided with widespread flooding across Australia in the past couple of years. Flooding continues in South Australia. It now appears that the weather driver which results in wetter conditions is easing rapidly, says BOM meteorologist Pieter Claasen. The latest BOM outlook, released on Wednesday, suggests there is a chance that could change next summer. It's complicated, but the weather drivers depend on water temperatures in the Pacific Ocean. This can lead to a major shift in weather patterns across the Pacific.

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While we can't control what these dogs are up to the Bureau of Meteorology and the Victorian Department of Primary Industries have new and valuable tools that can assist farmers in keeping track of these climate dogs helping to predict the likelihood of rain over the coming season and manage climate risk. This is Ridgy, or as scientists like to call him, the Sub-tropical Ridge. But Mr Webb said it didn't need to be a Black Summer to be dangerous. CoastExchange CoastExchange was CoastAdapt's online forum in which users could interact with their peers to share ideas, approaches, opportunities, and more. Footer ABC News homepage. If we take a look at the southern ocean we can see westerly winds circling around Antarctica throwing out cold fronts of stormy wet weather. The major climate driver is characterised by a shift in warm waters and cloud from the western Pacific to the central Pacific, which leads to a reduction in rain over Australia and increased temperatures. The previous record in occurred during a compound event. But Enso's behaviour can vary from year to year. Share Copy link Facebook X formerly Twitter. He influences Victoria's rainfall in winter and spring. Southern Australia is affected by a large-scale circulation feature known as the sub-tropical ridge. You can find more information on Impacts of cyclones and wind storms.

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Read More. Eastie can appear all year round but typically prefers the seasons of autumn and winter. Historically Indy has been a significant source of rain. Share Copy link Facebook X formerly Twitter. Southern Australia is affected by a large-scale circulation feature known as the sub-tropical ridge. The "coupling" between the two systems is a crucial part of the event, as it leads to the event being locked in for a prolonged period of time. Saved pages. Footer ABC News homepage. Together, warmer temperatures and reduced rainfall can prove challenging for the southern part of the continent, with already hot and dry summer conditions amplified by these events. The previous record in occurred during a compound event.