Over 500 calls for help as storms hit Melbourne and Geelong

The weather bureau had predicted large hailstones across the state, ranging from the size of a marble in Melbourne to the size of a golf ball in northeastern Victoria.

Senior meteorologist Joanna Hewes said a deep low pressure area over southwest Victoria pushed a band of rain late on Friday morning.

“Broadly speaking, what we're expecting across much of the state today is the potential for large hail – that is, hail that's an inch or more in size,” Hewes said. “But up in north-east Victoria there is the potential for what we classify as giant hail… which is more like golf ball sized hail.”

The State Control Center reiterated the bureau's warnings, saying: “Destructive winds, huge hail and heavy rains are possible in the northeastern and eastern parts of the northern country and in the north-central districts.”

“There is a potential for tornadoes to form in this area. Otherwise, damaging winds, large hail and heavy rainfall are possible across most of the state, with the exception of western parts of Mallee and north-eastern parts of East Gippsland.”

Rainfall of up to 40 millimeters was expected for Melbourne on Friday, but areas southwest of the city, including Avalon and Werribee, were the worst affected by 11am.

The Bureau of Meteorology's Kevin Parkyn said unique winds caused supercell thunderstorms to form in western Victoria on Wednesday, dropping hail “the size of cricket balls” on the small town of Casterton.

Ahead of Friday's storms, Parkyn warned of heavy rains that could lead to flash flooding and damaging winds “that could rip trees from the ground.”

“Unfortunately (the storms) don’t have a timetable; They don’t even have a platform,” he said.

On Thursday, Victoria SES commander David Baker urged motorcyclists heading to the MotoGP at Phillip Island to reconsider their travel plans if they wanted to be out on Friday afternoon.

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