Fire danger to rise as heat builds in Vic

Victoria is facing further heat and elevated fire danger this week.

Temperatures are expected to nudge 40C in northern Victoria and the low-to-mid 30s in the south on Monday ahead of a trough that will bring some relief to the state's south on Tuesday.

But temperatures will soar into the high 30s in the south and the mid-40s in the north on Wednesday, with strong northerly winds and severe fire danger expected over most of Victoria.

Bureau of Meteorology duty forecaster Michael Efron says a high pressure system is directing warm northerly winds over the state.

"Looking ahead, we'll see the warm conditions persisting into Monday with temperatures across the north of the state around 40C," he told AAP.

The trough will bring showers and possible thunderstorms at first in the east and west, then in central regions, by evening, and will cool the south on Tuesday.

Maximums, though, will stay around 40C in the north, with strong northerlies pushing that heat through to the south by Wednesday.

"It will be really hot in the northwest. We're expecting 44C in Mildura and Swan Hill, 43C at Echuca and in Melbourne we're expecting 38," he said.

"We will see northerly winds picking up across the state as well ahead of a cold front which will enter southwestern Victoria during the afternoon and move across central areas overnight."

Severe fire danger will extend to all western and central districts on Wednesday.

The change will bring rain, with five to 15mm expected in Melbourne by Thursday and higher totals in the eastern ranges.