Forecasts show the mercury is tipped to hit at least 35 degrees for every working day next week, with Thursday to reach a scorching 40 degrees.

It may seem hot this weekend, with tops of 29 and 27 degrees forecast, but the working week will see the start of a stretch of truly sizzling weather.

Monday will hit 35, before maximum temperatures soar to 39 and 38 on Tuesday and Wednesday. However, it will be Thursday’s forecast top of 40 that could see Ballarat record one of its hottest days for years.

But, towns in northern and western Victoria are expected be even hotter. Mildura, Swan Hill and Horsham are among some of the towns that are forecast to hit 45 degrees on Thursday, with Melbourne’s hottest day to come on Tuesday, when 41 degrees is predicted.

The extreme weather has firefighters on high alert, with Fire Services Commissioner Craig Lapsley warning Victorians to prepare for what could be a disastrous week.

Visitng Greendale, near Ballan, yesterday to launch an offensive on arsonists, along with the government, CFA, DEPI and Victoria Police, Mr Lapsley said next week would be the “turning point” for what had so far been a relatively quite fire season.

“This will be the serious drying period for Victoria,” he said. “It will change the landscape to potentially become one of the most serious emergencies Victoria will see.

“All Victorians need to take heed about what is about to happen in Victoria in the next seven days.”

CFA chief fire officer Euan Ferguson said cool and wet spring weather had resulted in extra growth, meaning there was a lot of fuel for fires.

“Right around Ballarat, there are a number of areas that have potential to be the start fires so we are reminding people to be extra careful,” he said.

patrick.nolan@fairfaxmedia.com.au