A complex low pressure system and associated cold front are moving across southeastern Australia, bringing a mix of severe thunderstorms, damaging winds, widespread rain, and a forecast for wintry conditions, including snow, over several days. Forecasts from various meteorological sources indicate a dynamic shift in weather patterns affecting multiple states.
Storm and Wind Timeline
On Thursday, April 9, a prefrontal trough is forecast to cross southeast Australia. This system has the potential to generate severe thunderstorms in parts of southern South Australia (SA), Victoria (Vic), and southern New South Wales (NSW). These storms are predicted to produce damaging wind gusts, with destructive winds possible in certain locations due to strong winds aloft.
Separately, a tightening pressure gradient is expected to cause strong northerly to northwesterly winds. Gusts may surpass 80 km/h in elevated areas and reach 90-100 km/h in the Victorian ranges, alpine regions, and parts of Tasmania (Tas).
Following the passage of the cold front on Thursday, a colder airmass is forecast to move across the southeast on Friday, April 10. A secondary trough and low pressure system will contribute to the transition to wintry conditions over the weekend. Wind speeds are expected to increase, with gusts potentially exceeding 100 km/h in exposed and elevated areas.
Current Severe Weather Warnings
As of Tuesday, a strong low pressure system centered over the eastern Great Australian Bight is moving eastward. Severe weather warnings for damaging winds are active in parts of Victoria, South Australia, New South Wales, and the Australian Capital Territory.
Recorded wind gusts include a reading of 133 km/h at Thredbo Top Station (NSW) overnight. Forecast wind warnings for specific regions include:
- South Australia: West Coast expects gusts up to 90 km/h; Flinders Ranges and Mount Lofty Ranges up to 100 km/h.
- Victoria: The alpine region is expecting gusts near 100 km/h.
- New South Wales: Damaging winds are expected along the Great Dividing Range up to the Northern Tablelands, with gusts exceeding 100 km/h likely in the Snowy Mountains.
Rainfall and Impacts
Widespread showers are occurring from Ceduna on the South Australian West Coast, across Victoria, northern Tasmania, and central and southern NSW to Sydney. Significant 24-hour rainfall totals to 9am Tuesday include:
- Victoria: Five locations in the Northern Country and North East districts topped 50 mm, with a high of 65.4 mm at Charnwood.
- South Australia: The Adelaide Hills received 52.6 mm at Warren Reservoir; Mount Gambier recorded 29.6 mm, its heaviest daily rainfall in over two years.
- New South Wales: At least three locations in the western foothills of the Snowy Mountains topped 25 mm.
Forecasting sources note uncertainty regarding the development of the low-pressure system, but some models indicate potential for heavy rain over Tasmania, Victoria, and New South Wales around Tuesday and Wednesday.
Snow Forecast
As the cold air intensifies, snow could fall at elevations as low as 600 meters in parts of Tasmania. Isolated snow flurries may also occur in the Victorian ranges above 1000 meters. While heavier snowfalls are forecast for Wednesday and Thursday, temperatures in the snowfields are currently too warm for snow accumulation; Thredbo Top Station recorded 1°C with drizzle at 10 am Tuesday. Cold air thunderstorms, possibly accompanied by small hail, are also a possibility.
Broader Weather Pattern
A large high-pressure system that had been shielding Australia from cold fronts is moving over the southern Tasman Sea. Two upper-level pools of cold air are expected to move over southern regions. The first will cross southern Western Australia and South Australia from Thursday to Sunday, then move over southeastern Australia. A second upper-level cold pool is forecast to reach the southwest around Wednesday or Thursday of the following week.
Residents in affected areas are advised to monitor forecasts and warnings from the Bureau of Meteorology.