Heatwave across southern Australia will challenge record books, says BOM, as shark sightings close beaches on Christmas Day

The heatwave enveloping SA may break records, according to the BOM, which explained the weather phenomena pushing up the high temperatures. It comes as shark sightings briefly closed two beaches on Christmas Day.

• Full state weather forecast

The heatwave enveloping SA may break records, according to the Bureau of Meteorology, which explained the weather phenomena pushing up the high temperatures.

As thousands head to the beach, where shark sightings forced the temporary evacuation of two SA beaches on Christmas Day, the bureau said a blocking system off the east coast was trapping the heat.

“This heatwave that’s developing now over southern and southeastern Australia is going to be challenging the record books,” Sky News senior meteorologist Tristan Meyers said.

“This is not only due to how hot individual days are going to be — for example 45C, 46C, and potentially 47C in parts of western, southern NSW, northern Victoria and South Australia — but also how prolonged it’s going to be.

“For some areas we’re going to see a week or more of 45C-plus temperatures and that hasn’t ever happened before — particularly in December, but potentially all time.”

TEMPERATURES ACROSS THE STATE

Mr Meyers said this unusually hot festive period has been caused by a “special” high-pressure system — called a blocking system — brewing off the east coast.

“It’s not really moving anywhere,” he said. “It’s waxing and waning in intensity over the next week or two, but it’s kind of sticking around the same position.”

This means it will continue to swirl and throw incredibly hot northern air onto the heavily populated coastal areas of Australia, causing a sustained heatwave across much of the country.

Shark sightings forced the temporary evacuation of Brighton and Henley Beach on Christmas Day as thousands flocked to the water to cool off.

About 3.30pm a 2m shark spotted 70m off the southern end of Sellicks Beach forced the evacuation of the beach.

For a short time, the beach near Brighton Jetty was evacuated after a 3m shark was sighted 20m offshore.

Just before 6pm a shark swimming near Henley Jetty forced swimmers from the water.

Health officials are urging South Australians to keep an eye on the elderly and vulnerable as temperatures soar across the state this week.

The Bureau of Meteorology has revised its prediction for on Thursday and Friday, increasing the forecast temperature and risk of fire.

Adelaide will swelter through 37C on Wednesday, 41C on Thursday and 39C on Friday before temperatures drop on Saturday — but won’t get below 30C.

South Australian Ambulance Service operations manager Anthony Pryzibilla encouraged people to stay inside where possible.

Beach weather! Take care if you are going out in the sun and the heat. Heading out on the water? Check the marine forecast: https://t.co/m2Aee7x6IR pic.twitter.com/liQRr9toML

— Bureau of Meteorology, South Australia (@BOM_SA) December 25, 2018

“Anytime the temperature starts climbing people in our community, particularly those vulnerable members such as the elderly, are at risk and are really needing family members to keep a close eye on them,” Mr Pryzibilla said.

“If you’ve got a neighbour or relatives nearby this is a good time of year to drop in and check on them.”

Adelaide sweltered through a maximum temperature of 36.2C at 2.30pm on Tuesday after reaching a maximum of 34C on Christmas Eve.

The highest temperature recorded in the state yesterday was at Marree in the far North where the township reached a high of 42.8C at 3.13pm.

Total fire bans are likely to be declared across large swathes of the state later in the week but only the Mt Lofty Ranges has been declared a severe fire risk today.

However, the weekend now will be cooler than expected, with the temperatures expected to reach 30C on Saturday and Monday.

Kristina Fuller, of Klemzig, said she and her husband Glenn had cancelled their family’s plans to holiday at Wallaroo because of the heat.

“We decided to stay home because we have a pool and it’s also too hot to go to the beach,” she said.

Her children Georgia, 14, Sam, 12, and Ruby, 8, and their friends Lukas, 11, and Olivia, 9, were more than happy to spend Christmas Day in the pool, Ms Fuller said. “They’ve been in there a lot of the time, except for when they were having lunch and unwrapping presents,” she said, adding they were also “sun smart”.

Ruby Fuller with best friend Olivia kept their cool in the pool in Klemzig. Picture: Naomi Jellicoe

“We always encourage them to use sunscreen and they wear rashies,” she said.

Emergency services were kept busy yesterday by a fire which destroyed a hectare of scrubland and endangered houses in the eastern suburbs.

The fire was spotted by neighbours on Bishop St at Skye just before 3.30pm as black smoke billowed from nearby scrub. The fire was contained in just over an hour but the cause was last night unknown.

Shark sightings forced the evacuation of Brighton and Henley Beach on Saturday.