Half of Victoria is facing extreme fire conditions tomorrow, with storms forecast to follow a hot and gusty day.

Authorities have declared a total fire ban from midnight in the Wimmera, South West, North Central, Central, and West and South Gippsland districts.

The Bureau of Meteorology said much of Victoria would experience temperatures in the mid-30s degrees Celsius, with north to north-westerly winds reaching 30-to-40 kilometres per hour from dawn around the Central Ranges and the Otways in the state’s south-west.

Senior meteorologist Briony Macpherson said the winds would begin picking up across western and central regions during the afternoon, gusting up to 60 kph.

A map of Victoria with four districts shaded yellow where for a high fire danger and five in orange for an extreme danger.

Five districts are forecast to be at extreme fire danger on Tuesday while three are at high fire danger. (Supplied: Country Fire Authority)

“Those winds combined with hot, dry air is what’s elevating our fire dangers tomorrow,” Ms Macpherson said.

But she said the danger would peak when the cool change brought the chance of severe thunderstorms, lightning strikes and damaging winds of up to 90 kph in some parts. 

“Even though the wind change will bring quite a bit of relief temperature-wise — we could see temperatures dropping 10 degrees or so in a fairly short period of time, particularly through places like Melbourne — it will make fires hard to fight if any do start,” she said.

“We are expecting that change to come through the far south-west of the state in early afternoon and then push through western districts during the afternoon, reaching Mildura, Ballarat, Geelong around about 5pm. 

“It should push through [Melbourne] between about 6 and 8pm and then pushing through the north of the state and through Gippsland overnight.”

A car travels along a wet highway under stormy grey clouds hanging low over trees.

Thunderstorms are expected to develop in Victoria’s west on Tuesday afternoon and move across central districts tomorrow night. (ABC News: Peter Healy)

Emergency Management Commissioner Tim Wiebusch said authorities were concerned about all areas from Victoria’s west through to West and South Gippsland.

He said that included areas of grassland between Melbourne’s north-west suburbs and Geelong out to the Inverleigh area.

He said there could be more fast-moving fires breaking out near populated areas, like Friday’s Clarkfield blaze that destroyed and damaged caravans in a storage facility north-east of Sunbury.

“We still have a lot of grassland fire load in our landscape and we know it’s very dry,” Mr Wiebusch said.

“The whole state is still a tinderbox.”A dirt road winds around a bend where smoke rises from burnt ground and trees.

Tim Wiebusch says large amounts of dry fuel remain scattered around Victoria. (ABC News: Danielle Bonica)

Fire Rescue Victoria Commissioner Gavin Freeman said it was crucial all Victorians living in fire risk areas — including those living in towns and cities — revised their bushfire plans ahead of tomorrow.

“It doesn’t matter where you live in the state, the best chance of us being able to help you is you knowing how to respond yourself,” Mr Freeman said.

“If you’re undertaking any activities in the outdoors, think about whether it could start a fire or not and if the answer is, ‘Yes it could’, don’t do it.”

Regional rail operator V/Line said services would run on extreme heat timetables on the Ararat, Ballarat, Geelong, Maryborough, Seymour, Shepparton and Warrnambool lines.

That means some trains will travel more slowly in case tracks have expanded, and some services will be replaced by air-conditioned buses.

Emergency resources

With fires and floods occurring simultaneously, and overlapping with international deployments, sharing critical resources is becoming an increasingly complex task.

V/Line said partial extreme heat timetables would apply to the Bendigo, Echuca and Swan Hill lines and speed restrictions could be implemented on other lines if temperatures exceeded 36C.

Meanwhile, Mr Wiebusch revealed the Walwa bushfire in the state’s north-east and the destructive Longwood blaze in central Victoria, which have both burned for more than a month, have now been controlled.

He said community recovery operations were continuing, including by teams from Disaster Relief Australia and BlazeAid in Longwood and Harcourt.

Mr Wiebusch said a fire in the Otways was the only blaze that was yet to be contained, but crews were hopeful that would happen by the end of this week.