Warning over deadly weather event forecast today

Health authorities are pleading with asthma sufferers to stay inside with overwhelmed hospitals dealing with Victoria's Delta outbreak short on resources to handle the state's first thunderstorm asthma alert of the season.

Melbourne and the state's central regions have been identified as a moderate risk area for Thursday, while the state's South West, Wimmera and Mallee are all high risk.

Large parts of the state are to be hit with severe thunderstorms including heavy rainfall and damaging winds – a dangerous combination during grass pollen season.

The situation could be compounded by the more than 24,000 active Covid cases in Victoria.

Five years ago a similar event killed nine people and left thousands more hospitalised, with health authorities fearing the Covid pandemic will leave asthma sufferers without the treatment they need.

"Our hospitals are experiencing significant demand due to Covid-19, so it's important you stay well," the Department of Health said in a warning.

"The combination of forecast high grass pollen levels and severe thunderstorms with strong winds means that there is a chance that a large number of people may develop asthma symptoms over a short period of time."

Those at risk are being advised to avoid being outdoors during storms and the winds that precede them, and remember to take preventative medication.

The Department of Health also advises asthma sufferers to monitor the epidemic thunderstorm asthma risk via the VicEmergency app.

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The eastern areas of North East, East Gippsland and West and South Gippsland are deemed low risk.

The department has also urged asthma sufferers not to dismiss Covid symptoms to the increased asthma risk and seek testing when appropriate.

Bureau of Meteorology meteorologist Sarah Scully said the weather conditions would intensify on Friday.

"It's on Friday that we will see the peak severe thunderstorm and the super cell development. Showers and storms will affect much of eastern Australia," she said.

Northern parts of the state could even face hail, BoM have warned.

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