'Most significant' heatwave in six years brings temperatures in Australia above 45C

By weather reporter Tyne Logan, ABC News Photo: Unsplash Parts of southern Australia are forecast to hit temperatures above 45C for multiple days in a row this week, as intense heat makes its way across the country. It comes as the Bureau of Meteorology (BOM) warns of what is likely to be the "most significant" heatwave south-eastern Australia has seen in six years. Large swathes of the country, spanning more than 3500km from WA's north-west to Tasmania's north-east, have been placed under severe to extreme heatwave warnings from Wednesday to Saturday. "It is looking like … the most significant burst of heat for south-eastern Australia, particularly in terms of multiple days in a row of mid-40 temperatures, since the summer of 2019-2020," senior forecaster Dean Narramore said. The extreme heat has also raised warnings of extreme fire danger, with wind and dry lightning forecast to add to the risk by Friday for parts of South Australia and Victoria. Photo: ABC News Multi-day heat to begin Wednesday While Tuesday is set to see hot temperatures near the southern WA and SA border, it is on Wednesday that the heat is forecast to really ramp up, particularly for the south-east, setting the scene for "multiple days" of heat across the region. As is often the case this time of year, the heat is originating from northern WA and the NT - an area often referred to as the 'heat engine' of the country. For weeks, heat has been building across the region. That hot air is now being dragged down into the opposite end of the country by a trough, leading to temperatures well above average. Between Wednesday and Friday, much of Victoria, South Australia and south-eastern New South Wales could see temperatures between 8 and 16 degrees above average for January. Port Augusta, for example, could see three days in a row above 45C, including a forecast top of 46C on Thursday. Towns along the Murray River, such as Mildura and Echuca, are also forecast to see multiple days at 44 or 45C between Wednesday and Friday. Narramore said these regions had the potential to topple January records. "January is one of the hottest months of the year, but there are a few places that are at least approaching or getting pretty close to records, particularly in north-west Victoria," he said. The biggest deviations from normal, however, will be further south. Coastal parts of SA and Victoria, where temperatures generally average the high 20s, are also forecast to reach or near 40C for several days in a row. Adelaide, for example, is forecast to reach 41C on Wednesday and 39C on Thursday. Melbourne is not far behind with a forecast top of 41C on Wednesday and 38C on Friday, with a brief drop in temperatures forecast on Thursday for coastal parts of SA and Victoria. The heat will progress further eastward by the weekend, with Sydney also forecast to reach a top of 39 on Saturday and Canberra hitting temperatures between 36-39C for several days in a row. Though not as exceptional as the other states, Tasmania is also looking at temperatures much warmer than usual for this time of year, with daytime temps 6-10 degrees above average on both Wednesday and Thursday. 'Block' triggers multiple days above 40C While temperature spikes into the 40s are not uncommon for January, Narramore said what set this event apart was how long the high temperatures were lasting - especially for the south coast. "Normally … we'll see temperatures for a day or so spike into the mid 40s," he said. "But now we're looking at three, and in some areas four, consecutive days where the temperature will be sitting somewhere between 10 and 15 degrees [above average] through inland parts of south-eastern Australia." Narramore said the culprit for the long-lasting heat could be found to the east of Australia, where a strong high-pressure system was causing a jam in the flow of weather. This was preventing the heat from moving swiftly from west to east, instead leading to days upon days of warmth. "So it's just going to be hot, it's going to be sunny, and it's going to sit there for three days before that high weakens in the Tasman Sea, and then a stronger front comes in and pushes that trough through south-eastern Australia," he said. 'Extreme' heatwave fuelled by warm nights It's that lengthy period of heat that has prompted warnings of severe to extreme heatwave conditions for many. To trigger a heatwave warning, the combined day and nighttime temperatures must be unusually warm for a particular location for at least three days. In this case, Narramore said the nights were also forecast to be 8 -14C above average, particularly through inland areas. Having no reprieve from the heat can make it harder for the body to recover, as well as putting extra strain on infrastructure like transport and electricity. Narramore said the people in "extreme" warning areas should take particular care, especially toward the end of the heatwave. "[Extreme...

'Most significant' heatwave in six years brings temperatures in Australia above 45C

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