The rollercoaster that is Melbourne's weather will continue today, with steady rain expected to drench the city for most of the morning and the top temperature expected to hit only half of yesterday's maximum.
A cold front moving through Bass Strait has delivered a large band of rain across the metropolitan area, with up to 15 millimetres of rain expected to fall by this afternoon.
Mercury plunges as rain pummels state
The rollercoaster that is Melbourne's weather will continue today, with steady rain expected to drench the city for most of the morning.
Bureau of Meteorology senior forecaster Richard Carlyon said a top of 17 degrees was forecast in Melbourne, about half of the 30.2 degree warmth the city experienced yesterday.
Central Victoria and West Gippsland are expected to be the wettest areas in the state.
"The rain will contract eastwards, with just a few showers to follow this afternoon," Mr Carlyon said.
"They will become isolated tonight, so it will be an easing trend through the afternoon but it looks like steady rain persisting for the bulk of the morning."
The next high-pressure system will move south of Victoria late on Thursday and will extend a ridge towards Victoria on Friday, delivering sunny conditions and a top of 21 degrees for Melbourne on Derby Day.
Police warned motorists to be careful on the roads during today's rain, particularly on the Hume Freeway where emergency services were cleaning up a three-kilometre diesel spill that caused a B-double truck to jackknife.
The crash occurred on the south-bound lanes of the freeway at Beveridge about 6am. A car is also believed to have slid off the road on the diesel.
One south-bound lane of the Hume Freeway has been closed, and police may have to close all south-bound lanes while the truck is removed.
The Western Highway at Beaufort has also been closed after two semi-trailers crashed head-on just before 3.30am.
One truck burst into flames and both drivers were taken to Ballarat Hospital, one with serious injuries.
The Western Highway is expected to remain closed until mid-morning.