A month's worth of rain is set to fall in Melbourne and other parts of Victoria by Wednesday, with a wider severe weather warning issued for the state.

Thunderstorms swept over Melbourne's north and areas around Sunbury and Whittlesea on Monday night.

In Strath Creek, north of Melbourne, 54 millimetres of rain fell in just 30 minutes around 7pm.

Widespread rain and isolated thunderstorms are expected to develop across most of the state overnight, as a low-pressure trough over South Australia moves across northern Victoria.