The Bureau of Meteorology has been forced to introduce new colours to some of its charts because of recent extreme heat in Central Australia.
Shades of deep purple and magenta have been added to the forecast map for temperatures up to 54 degrees Celsius.
The temperature range was previously capped at 50C.
The changes occur on the Bureau's interactive maps which are generated by computer models and are used to produce the official forecast.
The maps for Sunday and Monday show an area shaded deep purple over the outback.
Paul Lainio from the bureau says the colours were introduced after temperatures climbed above 47C in parts of South Australia.
"We noticed over the last couple of days that those charts were indicating temperatures in excess of 50 degrees and our colour scale we had didn't match that," he said.
"We added the new colours so we could highlight where those extremely hot temperatures were predicted by the computer model.
"Forecasters use a whole range of computer models, the observations we receive and they come up with the most likely forecast and that could be different to those, and in fact is different at the moment to those maps."
He says he hopes the new colours are rarely called into play.
"It's certainly a worrying sign when we see day after day after day of temperatures in the mid-40s.
"The official forecast, from the maps that are available for South Australia for instance, we've got temperatures up around 49 degrees, up in the high 40s for the north of the state.
"So absolutely scorching temperatures through much of the north of South Australia and also into some of the other states as well."
© ABC 2013
21:52 EST Parts of Sydney and the Blue Mountains have been blanketed by large hailstones as a severe thunderstorm moves across the area.