The mid-summer heatwave baking much of NSW has given parts of Sydney their hottest start to a year in at least decades, and may have as long as another week to run.
While outback towns including Bourke climbed into the mid-40s on Monday, Sydney's western suburbs weren't far behind. Penrith reached 43.2 degrees and Richmond 42.
The Bureau of Meteorology issued a fire weather warning for Monday for the Sydney, Hunter, southern ranges and central ranges regions. The NSW Rural Fire Service also issued total fire bans for those areas amid "severe" fire danger ratings for the day.
There is also thunderstorm activity in the city's west, with the bureau issuing a warning for a severe storm including the possibility of large hailstones.
A Severe #Thunderstorm Warning has been issued for parts of Blue Mountains, Hawkesbury and Sydney Metro areas. Large hail and damaging winds likely. Latest warnings at https://t.co/aRHYRvsH6t #SydneyWeather pic.twitter.com/99SToxw8RC??? Bureau of Meteorology, New South Wales (@BOM_NSW) January 22, 2018
For Tuesday, the areas of most on concern will be the southern ranges and slopes, where total fire bans will be place.
Monday's maximum in Sydney's CBD fell short of the predicted top of 33 degrees as coastal breezes kept the mercury just under the 30-degree mark for most of the afternoon.
"There's not much cooling for Sydney for the next week," Graeme Brittain, a meteorologist with Weatherzone, said. "There's no significant cold front coming through."
Sydney's daily maximums should hover around the 29-31 degree mark until early next week.
Relief for places like Penrith will be at least as long in coming, with 38 degrees predicted by the Bureau of Meteorology on Tuesday, and 37 degrees for each of the following three days.
Monday's temperature top above 40 degrees was the fourth such day in a row for the suburb, the first such run since records began at the site in 1995.
Both Penrith and Richmond - as measured by the site at the airforce base since the early 1990s - have had their warmest start to any year, Mr Brittain said.
Wilcannia in the state's far west was the hottest location on Monday, with 46.4 degrees reported just after 4pm. (See bureau chart below of the forecast hottest spots for NSW on Monday.)
Big sweat
With increasing cloud cover and greater humidity, the most trying days for many could come on Thursday and Friday.
Most areas of Sydney won't get a night with the mercury falling below 21 degrees this week, the bureau said.
"It's going to get quite uncomfortable, especially with these overnight temperatures," Mr Brittain said.
Those muggy conditions will most likely be widespread, and will also affect Melbourne, where tennis players at the Australian Open are likely to be playing their finals in extreme conditions by the weekend.
Melbourne's top for Saturday and Sunday is forecast to reach 39 degrees on both days, with little chance of a rapid cooling on both evenings when the singles finals will take place, Mr Brittain said.
Rising frequency of extremes
Many sites around Australia have recorded an increase in the frequency of very hot days.
In Sydney, for instance, there was just one day of 42 degrees or warmer conditions in the 1998-2007 period.
In the following decade, there were two such days, and in 2018 there has already been a third, the bureau said.
In Penrith, there were 14 days of 42 degrees or hotter weather in 1998-2007 and 24 in the following decade. With 2018 just over three weeks old, there has already been another six such days.
Similar patterns are evident in regional areas too.
Moree in the state's north had four days of 42 degrees or warmer weather during 1998-2007 but 21 in the 10 years since. It is yet to add to the tally in 2018.
Weatherzone is owned by Fairfax Media, publisher of this website.
