It's likely to be a wild week from the weekend onwards for the southern states of Australia where there will be the potential for multiple days of damaging winds and gales to occur. These gales will begin over Western Australia on Saturday and gradually extend eastward into next week. Meanwhile, the north will bask in unseasonal heat, resulting in elevated bushfire dangers. In contrast, Tasmania may face heavy rainfall, flooding, and even blizzard conditions.
EC max 850mb winds for the next 10 days - shows an approximation of estimated maximum surface wind gust potential in ideal conditions. Source: Weatherwatch MetCentre.
Intense Polar Cyclone Responsible - Pressure May be Comparable to TC Yasi!
The culprit is expected to be a slow-moving but intense polar cyclone in the Southern Ocean. Polar cyclones (not to be confused with tropical cyclones) are not unusual in the Southern Ocean. However, this polar cyclone is expected to be unusually intense and slow-moving, with forecast pressures as low as 931mb! For comparison, TC Yasi, a Category 5 tropical cyclone that devastated parts of northern Queensland in 2011, had a pressure of 929mb at its most intense.
EC minimum sea level pressure. Shows an intense low (sub 935mb) tracking across the southern Ocean. Source: Weatherwatch MetCentre.
Fortunately, polar cyclones have much broader pressure gradients than their better known tropical counterparts, so they tend not to produce the intense winds that tropical cyclones generate. Unfortunately, since the pressure gradients are broader, they can impact larger areas, with damaging gales potentially extending more than 1000km from the center. This is why such strong winds can be generated over Australia, even from a long distance away.
Impacts on Southern States
Victoria & Southern NSW—Days of Severe Wind Warnings Possible
Victoria and Tasmania may be hardest hit by this system, with days of damaging wind gusts possible starting Sunday—particularly along coastlines exposed to the west and south, and elevated areas such as mountain ranges. In fact, some locations could remain at risk for 6-7 consecutive days of damaging gales, though this longer-range outlook is subject to change. In southern NSW, initial strong winds and cold fronts rotating around the low may peak further south, but early indications suggest an increase in winds late next week.
EC max 850mb winds for the next 10 days - shows an approximation of estimated maximum surface wind gust potential in ideal conditions. Source: Weatherwatch MetCentre.
Tasmania —Heavy Rain & Flooding to Add to The Threat of Damaging Winds
The increase in strong westerly winds will also enhance rainfall and possibly even alpine snow, particularly for western Tasmania, where falls of 200-300mm are possible. At this stage, heavy falls are less likely over the mainland, though if they do occur, they would likely be in southwestern Victoria and the northeastern ranges, which are typical locations for heavier falls in these conditions.
Weatherwatch MetGraph showing forecast accumulated rainfall for western Tasmania until the following weekend. Source: Weatherwatch MetCentre.
South Australia
Significant impacts in South Australia will mostly be confined to the populated southeastern corner of the state, including the Eyre Peninsula. Gales are expected to commence on Sunday, with current indications supporting the development of damaging wind gusts. Winds may briefly ease on Monday before increasing again on Tuesday, with gales remaining possible until late Friday. For South Australia, the impacts of cold fronts are often slightly tempered compared to Victoria and Tasmania unless a small cut-off low develops. Fortunately, there’s no indication of this occurring, but we’ll be monitoring closely for any changes.
Western Australia
Western Australia will see the first impacts of this system, with widespread damaging winds possible across southern areas of the state on Saturday. Saturday is expected to be the worst day, though multiple days of strong winds with locally damaging gusts are likely to persist until mid-next week. Saturday’s setup is particularly concerning due to the added threat of severe thunderstorms, which may produce locally destructive winds. The setup is also conducive to coastal tornadoes or waterspouts, which, while a threat in any decent winter cold front, may be a slightly elevated concern with this front.
ACCESS forecast sounding for Bunbury on Saturday. This shows weak levels of instability in the surface-600mb layer with strong linear wind shear. This setup is often conducive to small tornadoes or waterspouts occurring but remains a very isolated occurrence. Source: Weatherwatch MetCentre.
Impacts on Northern States
Queensland & Northern NSW
The primary concern in Queensland and Northern NSW is the elevated bushfire danger, particularly late next week. It’s too early to definitively predict conditions 6-7 days out, but based on patterns across southern Australia and the unseasonal warmth building in the north, this provides the perfect recipe for heightened bushfire risks. Strong cold fronts sweeping across southeastern Australia frequently generate strong and gusty winds in southern Queensland and northern NSW. While these winds may not be severe or damaging, when combined with temperatures well into the 30s and low humidity, they generate elevated bushfire dangers. Fortunately, recent rainfall will temper bushfire concerns in some areas, but recent rains have been quite coastal, and the strongest winds and highest temperatures are likely to remain inland, where rainfall has been lower.
While still 7 days ahead, most models indicate not only the presence of unseasonal heat across the Northern Territory and Queensland, but strengthening WNW winds which would increase fire dangers however this is subject to some variation. Source: Weatherwatch MetCentre.
Northern Territory
Similar to Queensland, the long-term outlook is subject to change, but preliminary indications support the potential for increased winds and bush or grass fire concerns in southern to central areas of the Northern Territory during the second half of next week.
How Can You Prepare?
At Weatherwatch, we’ve been advising businesses on weather risks since 1976. If you’re looking for expert guidance to navigate Australia’s extreme weather, please reach out to our team! However there's plenty you can still do for your own home:
For southern states, strong winds can bring down branches, trees, and powerlines. Power outages are never fun, but having spare batteries or ensuring your charging banks are full can help ensure you have torches and a phone during any outage. If possible, it's a good idea to park your car in the garage rather than on the street, especially if you live in a tree-lined area.
In northern states, it’s a reminder that bushfire season is here. The most important thing is to have a plan ready should your property be impacted by bushfires (remember, you might be at work too, so you should plan for this as well). You may only have minutes to act, so having a plan ensures you know exactly what to do.
It’s also time to ensure your property is cleared and well-maintained, with no dead branches or trees lying around that could provide extra fuel for a fire.
