If you tossed and turned through the heat overnight, you won’t get any relief on Friday as Victoria breaks through 40 degrees.

Weatherzone meteorologist Graeme Brittain said Melbourne was likely to hit 30 degrees by 9am on Friday, before climbing to a predicted top of 42.

Meanwhile, Swan Hill and Horsham are expected to reach 44 degrees on Friday.

It comes after a sweltering night. Bureau of Meteorology on Thursday predicted Melbourne would stay above 25 degrees overnight.

“It will be potentially 30C at midnight in Melbourne, so it’s a hot night,” Emergency Management Commissioner Craig Lapsley had warned on Thursday.

“The fire risk is real and the fire risk only gets worse with the fact that there’s no respite across the state tonight.”

Mr Lapsley said central and western Victoria were most at risk of bushfire, with blazes already burning near the SA border and Geelong on Thursday.

Total fire bans are in place on Friday for Mallee, Wimmera, South West, North Central and Central districts. The Country Fire Authority warned Mallee, Wimmera and South West residents to activate their bushfire plans.

Bureau of Metereology’s state manager Andrew Tupper said there would be a risk of dry lightning, which occurs when electrical storms hit without rain managing to make it to the ground.

Total fire bans are in place for Mallee, Wimmera, South West, North Central and Central districts. Photo: Country Fire Authority

The northern districts are not predicted to get relief from the heat until next week, while Melbourne and coastal regions are expected to get some relief late on Friday afternoon.

“We’ll see cooler conditions moving in from the south bringing relief to coastal parts. However, northern parts of Victoria and border regions, that heat is going to remain,” Weatherzone’s Mr Brittain told The New Daily.

Melbourne is predicted to be a cooler 26 degrees on Saturday with possible showers and 29 on Sunday.

Despite extreme heat warnings, Chief Health Officer Charles Guest said there’d been reports on Thursday of nine children being left in parked cars.

“We know that leaving children in parked cars can lead to death. I’m glad to say this hasn’t happened this summer so far,” he said.

Agriculture Victoria warned pet owners to be alert to heat stroke in animals. Leave two bowls of water out and do not under any circumstance leave a pet locked in a car.

An stagnant weather pattern is expected to cause a prolonged spell of heat across a large portion Australia during the second half of January. More here: https://t.co/xL6GfWOT27 pic.twitter.com/pfbyq7dVwn

— Weatherzone (@weatherzone) January 17, 2018

More than 1000 properties in Beaufort, near Ballarat, were left sweltering without fans and air-conditioners because of a power failure before operator Powercor restored electricity.

Dr Guest said people without access to air-conditioning or at risk of heat exhaustion were advised to head to shopping centres or cinemas to cool down.

The heat comes just weeks after Melbourne reached 42 degrees on January 6. Swan Hill reached 43.9 degrees on the same day. The state high was 45.2 degrees in Walpeup.

“It might only be the hottest day [on Friday] since then for some places, but there’s a chance that it could exceed the previous highs seen earlier this month,” Mr Brittain said.

“The spikes of heat that we’ve seen so far this month, generally oscillations like that are quite common in summer but the magnitude of spikes in heat are quite significant.”

Emergency Services Minister James Merlino earlier said the state was as prepared as possible but he urged Victorians, particularly the elderly, to stay cool.

“This is a very hot period and a period of high fire danger,” he told reporters.

“It’s important people stay cool, particularly if you are elderly or if you have a medical condition.

“Look after your neighbours and please be aware of your surroundings.”

-with AAP