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Written by Beth Askham

How can we predict extreme weather events like the Sydney storm in Australia last week?

The wild storm that hit Sydney was the result of a weather system called an east coast low.

East coast lows are intense low pressure systems that form off the eastern coast of Australia. They can bring intense winds, flooding events, severe thunderstorms and unusual inland snowfalls. They can cause damage to coastal infrastructure and wreck or beach ships.

The problem is that these systems are hard to predict. They can form very rapidly and they will often form at night.

Lloyds Register Foundation funded research to help predict these extreme events by looking at ocean temperatures.

They supported researchers to study these events, including the east coast low that brought the massive coal ship, the Pasha Bulker, to ground at Newcastle in 2007.

Chris Chambers, an author of this study, says ocean eddies are large features in the ocean that contain huge amounts of warm water. “They rotate and move gradually southward down the coast bringing warm water in huge pockets to the regions just offshore. Each of these pockets provide an enormous source of heat and water vapour to the atmosphere.”

“Next to one of these warm eddies there might be a cold eddy. This means that the ocean temperatures might change very quickly over a short distance. This also has an effect on the atmosphere and can strongly affect the rainfall.”

Researchers are now working on improved models of ocean eddies. Simulations of these eddies might help us predict east coast lows and other types of extreme weather.

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