Australia set for a tale of two summers

Summer is to be wet in the east and dry in the west, with the Bureau of Meteorology forecasting significant rainfall along coastal NSW, most of Victoria, large areas of Queensland and northern and eastern Tasmania.

“That brings potential for widespread flooding as rivers are already high, dams are full and catchments are wet,” the Bureau said.

Cooler days are likely for most of NSW, part of southern Queensland and into Victoria, while days are likely to be warmer than average across most of WA and the NT, north and central Queensland coastal areas and parts of the south.

Ocean temperatures around northern Australia are well above average, increasing the risk of tropical cyclones and heavy rain events from systems drawing moisture from the Coral Sea.

The Bureau said today severe thunderstorms are possible across northern, eastern and central Queensland over the next 24 hours, with a chance they will strike parts of the metro areas of south-east Queensland into Tuesday. It warned of heavy rainfall, large hail and damaging winds.

On Wednesday, a potential low will form near the central east coast bringing the risk of widespread rain, thunderstorms in the eastern half of the state, while damaging wind gusts and offshore gales over the southern coast are possible on Thursday and Friday.

In the far north a trough is likely to form and induce monsoon like conditions across parts of the northern tropics through the latter part of this week.

In its summer outlook, the Bureau said there is increased risk of prolonged heatwaves with higher humidity in southern areas, and coastal flooding in the east and north. Unusually high tides are forecast around January 23 and February 20.

Contributing to the wet outlook in the east are La Niña in the Pacific Ocean and a positive Southern Annular Mode. A negative Indian Ocean Dipole event is weakening and will likely come to an end by early summer. La Niña may start to ease in early 2023.

Senior Meteorologist Jonathan How says heat waves may last longer, be warmer overnight, and be more humid. Sea temperatures are expected to be warmer than normal for an extended timeframe, and floodwaters from the Murray River are not expected to peak in SA at Renmark until around mid December and at Murray Bridge around early January.

This season, there is an increased chance of an above average number of tropical cyclones, including tropical lows in Australia and the surrounding region. Typically, the Australian region has nine to 11 tropical cyclones during the peak cycle and season, usually between November and April.

“There is an increased chance that the first tropical cyclone in the Australian region is likely to be earlier in the season,” Mr How said. “It’s likely to be a wetter summer than usual for large areas of Queensland, where there’s a high chance of above average rainfall, particularly in the far north and along the east coast of the state.”