Almost all of Victoria will have begun a startling spell of heat by this afternoon with most of the state on target for at least 40 degrees or more during the next four days. Extreme heat has been making its way slowly around the nation, having brought heatwaves to western Queensland and northwest WA. Perth had its hottest day in six years and hottest night on record, whilst Adelaide and much of South Australia began its heatwave yesterday. Melbourne, and almost all of Victoria, is heading for over 40 degrees today, with the potential for four consecutive days. The city is forecast to reach at least 39 degrees for four consecutive days, something which it hasn't experienced since 1912. This heat won't make for easy playing conditions in the Australian Open of tennis either, where this spell of heat aligns more with the sweltering 2009 tournament. Some may remember the Australian Open in 2009, where a string of days rose above 35 degrees and three consecutive days reached above 43 degrees and one exceeding 45. On Friday afternoon, a cooler change should push through the region bringing significantly cooler conditions during the weekend, with temperatures in the mid 20's and the chance of a shower.