A wave of heat sweeping across South Australia, Victoria and New South Wales this week is likely to be a near-record one for some inland areas. Parts of western and northern SA, northwestern Victoria and far western NSW, including Kyancutta, Woomera, Mildura and Broken Hill, should reach an average of 35 degrees for the week Sunday 19th to Saturday 25th. This is 11 degrees above average and within about a degree of their October records. Records go back 124 years in Mildura, 84 years in Kyancutta, 65 years in Woomera and 50 years in Broken Hill. Very little or no cooling is likely north and west from Woomera to Broken Hill to Bourke with the temperature reaching the high thirties by the end of the week just ahead of a cooler change. With temperatures rising from the mid thirties early in the week to high thirties late in the week heat-related stress is possible. Thankfully most nights will cool down to a comfortable level. On the coast more significant relief from the heat will arrive midweek. A cooler change will move through this Wednesday and another stronger change will arrive next weekend, dropping temperatures by as much as 12 and 15 degrees respectively. However, Adelaide may still get within a degree of its October record, a weekly average maximum of 31.7 degrees, set in 1914. The city should average a bit over 30 degrees this week, which would make it their hottest October week in 24 years. Melbourne is also on target for its warmest October week in 24 years with a forecast average maximum of 26 degrees this week. The early-season heat has been brought about by a reduction in the strength of cold fronts over Western Australia this month, allowing heat to build over the Pilbara and Kimberley with help from sunnier than normal days. The heat has been allowed to exceed average levels with the aid of a warmer-than-normal sea surface surrounding western and southern Australia. Marble Bar has averaged a maximum of 40 degrees this month so far, two degrees warmer than the October average and we are just entering the hotter part of the month.