Weather map turns freakish purple colour
Temperatures will be "nudging into the low 40s" in parts of Queensland and New South Wales over the next few days as a low pressure trough directs desert air towards the coast.
Western suburbs of Brisbane are expected to hit 40C on Monday and Tuesday, while 36C is a possibility in the CBD. Those temperatures are far above the average and could lead Brisbane to have its warmest October day for almost 15 years.
Yet, it could not be more different further south as a cool front brings a return to "winter-like conditions" that could bring fresh snowfall and days not even managing to push above 0C in the Alps.
Severe fire danger is the concern in northern and eastern parts of Australia to start off the week.
"In the north, a low pressure trough is directing warmer westerly winds across NSW and Queensland," said Sky News Weather channel meteorologist Alison Osborne on Monday.
"Temperatures will be nudging into the low 40s".
Low pressure systems spin clockwise in the southern hemisphere and that's helping to dump hot air from Central Australia onto southern Queensland.
As a result, Brisbane's CBD will reach 34C on Monday and 36C on Tuesday. Ipswich is likely to experience two days of more than 40C to start the week - that's around 10 degrees above the October average.
As hot weather hits southern QLD this week, remember to keep cool, stay hydrated and look out for each other. Follow @BOM_Qld and @QldFES for up-to-date weather and fire info. pic.twitter.com/DieV0boarK— Queensland Health (@qldhealthnews) October 6, 2019
Due to a revised forecast, the North Western area is now under an Extreme fire danger rating today. Make sure you and your family know what you will do if fire threatens. Ask yourself - when will you go, what will you take and where will you go?#NSWRFS pic.twitter.com/mEzh7PakQO— NSW RFS (@NSWRFS) October 6, 2019
Severe fire danger is forecast for southeast Queensland away from the coast in the Darling Downs as well as the Central Highlands.
"In Brisbane, the 36C forecast for Tuesday would be the warmest October day since 2005 if it comes up," Bureau of Meteorology forecaster Kimba Wong told AAP.
"The maximum temperature record for October in Ipswich is 41.3C, so getting up to 40, 41C in Ipswich on Monday and Tuesday is certainly getting pretty close."
But by Wednesday a cool change will sweep through bringing down temperatures by 10 degrees, with 27C in the CBD and 30C in the west. The maximums should continue to tick down as the week goes on.
The hot weather will spread into northern NSW with 39C forecast in Moree for Monday with possible dust storms; Grafton could get to 38C.
An extreme fire danger warning is in place around Moree, Narrabri and Walgett with severe danger for northeastern parts of the state from the Hunter north.
It will be cooler in the big cities. Newcastle will peak at 27C on Monday and Tuesday, Sydney's CBD will reach 24C with 31C in the west and windy conditions on Tuesday.
Cooler conditions will then sweep through between Tuesday and Wednesday. Newcastle and Sydney will struggle to get above 20C on Wednesday and for much of the rest of the week.
For Canberra, a 24C day on Monday will drop to 16C on Tuesday with some rain. There will be a drop in overnight temperatures as well to just 1C at dawn on Wednesday and Thursday.
Heading into Victoria, and Sunday's warmer conditions are now a memory.
"A return to winter-like conditions is possible on Tuesday as a cool front and rain band pushes through the southeast," Ms Osborne said.
Melbourne is looking at a high of 18C today and then just 14C on Tuesday with showers, which will just about set the theme for the rest of the week.
"An air mass behind that is quite cold, so snow above 1200 metres across the Alps is possible with a return to winter-like conditions and temperatures below zero," Ms Osborne said.
Indeed, Mt Hotham will go from a maximum of 7C today to just zero on a snowy Tuesday with a dawn low of -4C.
In Hobart, a high of 17C on Monday will edge downwards to the mid-teens for the rest of the week with a low of just 5C on Wednesday morning and scattered showers.
Below average temperatures in Adelaide of 18C today and 16C on Tuesday are forecast - the latter 5 degrees below the usual October day. An overnight minimum is tipped of just 8C. There are possible light showers on Monday but it will be mostly dry for the rest of the week.
It's warmer in Perth with 26C on Monday rising up to 34C on Tuesday before a trough on Wednesday brings temperatures down to a more reasonable 27C. The city should remain dry.
It's hot and sunny in Darwin with highs of 34C and lows of 24C.