Australia Weather News

Australia is in its peak severe weather season and there are warnings of dangerous supercell storms along the east coast this weekend.

A supercell is capable of producing 125 kilometre per hour winds, giant hail, flash flooding and tornadoes.

So what makes them different to a regular storm and how do they form?

What makes a supercell storm?

A supercell storm can be identified by the shape of the cloud mass.

If the outer wall of a thunderstorm appears to have horizontal ridges and grooves, it is rotating.

It is that rotation and tilt – which makes for a longer-lasting, particularly powerful storm – that separates a supercell from a typical storm.

Warm, moist air at the surface is given an initial lift into an unstable atmosphere by a force such as a cold front, a mountain, or the heat of the day.

As it rises through the atmosphere, the warm, moist air cools and condenses into clouds and rain.

A regular storm's updraft, which supplies moisture and energy, is obstructed by the downdraft, which contains the rain that weakens it.

But a supercell storm's updraft and downdraft are separate, which allows it to intensify.

Why supercells so dangerous?

Supercell thunderstorms, which can produce tornadoes, are the least common but most dangerous type of storm.

They are powerful enough to topple trees and destroy homes and are responsible for the vast majority of storm damage in Australia.

A regular storm usually has a life span of less than an hour, but supercells can last up to six hours.

The storm can move towards the left or right regardless of background movement.

Supercell thunderstorms can also be extremely hard to predict.

Where do supercell storms form?

Given the right conditions, supercell thunderstorms can occur all over Australia and appear several times a year.

New South Wales, Queensland and Victoria are most at risk.

The NSW north-west, central and southern inland, along with north-east Victoria are most likely to be in the path of supercells.

The peak severe storm season in Australia is from October through to January, which is when most supercell storms occur.