'Supercell' storms, giant hail and damaging winds to lash eastern states

Storm season has arrived early with the Bureau of Meteorology warning a possible supercell could deliver giant hailstones and destructive winds.

A severe thunderstorm warning has been issued for much of NSW west of the Great Dividing Range.

Damaging winds, giant hailstones and heavy rainfall that may lead to flash flooding are possible on Wednesday for towns including Enngonia, Walgett, Cobar, Bourke, Ivanhoe, Lightning Ridge and Brewarrina.

The trough wreaking havoc will move across NSW, bringing showers and the potential for more severe thunderstorms to the east coast on Thursday and Friday, when the state's storm season begins.

Showers will be widespread, but storms will be less common, the bureau says.

Meteorologist Hugh McDowell said it won’t be “wall to wall” storms.

"It's not an Armageddon scenario. We're going to get some severe thunderstorms... you just need to keep abreast of the potential for those thunderstorms,” he said.

The weather should begin clearing up on Saturday, in time for people to make the most of the public holiday on Monday, he said.

"The long weekend ... is looking drier with sunny skies and temperatures warming up as well.

"We're likely to see temperatures on the east coast into the mid to high 20s and in the west, high 20s to perhaps the low 30s."

However parts of the state's north are expected to be spared much of the rain, prompting authorities to warn that fire danger could be heightened over the weekend.

"With the weekend temperatures warming up, the air drying out, and sunny skies - we're also seeing westerly winds - that is going to increase the fire dangers across parts of the North Coast, Mid North Coast, Northern Rivers district," Mr McDowell said.

Severe weather warnings for western Victoria and Queensland

Severe weather warnings are also forecast for western regions in Queensland and Victoria.

The bureau was forecasting wild weather for a large region of western Queensland late on Wednesday .

"Severe thunderstorms are likely to produce damaging winds and large hailstones over the next several hours in other parts of the Central West, Maranoa and Warrego and Darling Downs and Granite Belt districts," it said on Wednesday afternoon.

In Victoria warnings were issued on Wednesday afternoon for possible flash flooding in the Mallee and Wimmera a districts. Locations which may be affected include Ouyen, Murrayville, Rainbow, Walpeup, Warracknabeal and Nhill.

Storm season looms in NSW

NSW residents are being urged to prepare for the upcoming storm season.

The BOM has forecast spring is likely to herald above-average rainfall for people living in the east of Australia, as well as cooler days and warmer nights, after the wettest winter since 2016.

The NSW storm season officially starts on Friday.

Emergency Services Minister David Elliott welcomed the delivery of a deployable Mobile Incident Command Centre to deal with any disasters.

"It can be easily deployed to any location around the state, and further improves the NSW SES's prompt coordination and response to natural disasters", Mr Elliott said in a statement on Tuesday.

The SES is also getting new rescue vehicles, including six new 'Unimogs' which can operate in flood waters up to 1.2 metres.

The SES $56.4 million fleet replacement program was on track to deliver 270 vehicles, 124 marine vessels and 95 trailers to some of the state's most flood prone areas.

SES Commissioner Carlene York said her volunteers were preparing for a challenging storm season.

"The difference between now and last year's flooding is our dams are pretty full," she told Sydney radio 2GB on Tuesday.

"We've had a lot of rain over the winter so the ground is pretty saturated ... so it increases the risk of flash flooding."

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