CANBERRA, Jan. 13 (Xinhua) -- Large part of southern Australia is expected to experience severe to extreme heatwave conditions throughout this week, the Bureau of Meteorology (BoM) warned on Monday.
An extremely hot air mass over western and inland Australia is forecast to spread across the southeast on Monday, directing very hot northerly winds over South Australia, Victoria, New South Wales (NSW) and Tasmania.
Temperatures are forecast to reach the mid-40s degree Celsius in many inland areas. South Australian capital city Adelaide is forecast to reach 40 degree on Monday, and Melbourne, the city hosting the Australian Open tennis grand slam, is forecast to reach 41 degree on Tuesday.
Sydney will be spared the worst of the conditions with temperatures in the high 20s in the city, and high 30s in the west. Perth will be milder during the week, but will see temperatures reach the high 30s again on the weekend.
Assistant Director for BoM Weather Services, Alasdair Hainsworth, said the bureau had launched a new pilot heatwave forecast service, which provides a measure of the intensity of a heatwave and complements the official temperature forecast.
"What is unusual about this event, which the pilot heatwave forecast shows, is that when high maximum temperatures and above average minimum temperatures are sustained over a number of days, there is a build-up of 'excess' heat. Extreme heatwave conditions can be seen in southern NSW, Victoria and Tasmania," he said.
The new service is able to map the level of intensity of each heatwave event, indicating areas of "severe" and "extreme" heatwave at the upper end of the scale.
The current event shows large areas of southern Australia will reach severe to extreme heatwave conditions, Hainsworth said.
"The heatwave service provides a more advanced indicator than temperature alone in anticipating the impact of heat stress. Hainsworth warned that the elderly are particularly vulnerable to the effect of heat stress.
"When average conditions are exceeded over a period of time by continuously high night-time and day-time temperatures, heat stress becomes a critical factor in human survival and infrastructure resilience," Hainsworth said.
Earlier this month, the BoM has confirmed that Australia has recorded its hottest calendar year on record in 2013 with average temperatures being 1.20 degrees Celsius above the long-term average of 21.8 degree and breaking the previous record set in 2005 by 0.17 degree.