After a sensational stretch of sunny skies, Melbourne has woken to a drenching Sunday.

Severe rain and thunderstorms have lashed the state overnight, with flash-flooding expected across metropolitan Melbourne.

The mammoth rainband — which stretches as far as Rainbow in the northwest, south to Colac, across Melbourne to Leongatha in South Gippsland — is slowly travelling east today.

The western suburbs copped the brunt of the overnight rain recording a total of 25mm to 40mm, while the eastern suburbs saw 25mm to 30mm fall within 24 hours.

Some regional areas recorded more than 40mm of rain since 9am Saturday, including Geelong (42mm), Mount Mercer, near Ballarat, (41mm) and Upper Lang Lang (40mm) and Athlone (41.4mm) in Gippsland.

Dramatic footage shows a downpour of hail and extreme winds that hit Leongatha on Saturday.

In the video, a man yells “that is actually a tornado”, as winds and rain lash his property.

Some Leongatha locals have reportedly lost power for more than 16 hours and are predicted to be without power until 4pm Sunday afternoon.

This comes after a 4.8 magnitude earthquake rocked the suburb earlier this month.

Bureau of Meteorology senior meteorologist David Crock said more rain was on the way.

“Rain is expected on and off all day through Melbourne with 20 to 40mm on the forecast, and the wet weather not really clearing up until later in the evening,” he said.

Severe thunderstorms are also expected in the city’s northeast this afternoon and evening.

“Towns like Wangaratta, Albury-Wodonga, and the alpine resorts as well are likely to see severe thunderstorms on Sunday afternoon and evening, which may bring heavy rain and may also bring destructive wind gusts of over 125 km/h,” Mr Crock said.

“This amount of rain is more than enough to cause significant impacts across Melbourne,” Mr Crock said.

There is already a lot of water on the roads and people are advised that there will be flash flooding in Melbourne today.

“Don’t drive into floodwaters,” Mr Crock said.

An additional 10–20mm is expected for the rest of Sunday.

Severe thunderstorms are also predicted to dominate northeast Melbourne this Sunday afternoon and evening.

These thunderstorms “could become strong enough to produce destructive winds of 125km/h.”

VicEmergency issued a warning on Saturday night advising people in East Gippsland of a high risk of epidemic thunderstorm asthma in the area on Sunday.

“Be aware of an increased chance of experiencing breathing difficulties or an asthma attack.

“Prepare now – carry your asthma reliever puffer with you at all times on Sunday,” the statement read.