THIS week will see parts of the Upper Hunter crack 40 degrees on the temperature gauge and 38 degrees in Newcastle.
Despite the southerly change on Monday and Tuesday, cooling things off after a hot weekend across the coast, the mercury will climb once again from Wednesday.
A Bureau of Meteorology spokesperson said on Tuesday afternoon the heatwave warning had been upped to extreme for the Hunter heading into Australia Day.
"We will experience really hot temperatures, plenty of those high 30s and into the 40s throughout the Hunter," they said,
The notable maximum temperature for Newcastle will be 39 degrees across both Thursday and Friday.
"We've got a consecutive run of 40s in the Hunter, we've got 41 in Maitland on Thursday and 42 on Friday," the spokesperson said.
They said there is likely to be a southerly wind change very late on Friday afternoon into the early parts of Saturday pushing up the coast, bringing a cooler change.
"We will see a 13 degree drop from Friday into Saturday for maximum temperatures so it could be gusty, and we could see some storms with that southerly change."
The spokesperson said there is yet to be a Total Fire Ban released by the RFS but there was "certainly an incease in fire danger" in the later part of the week.
"Be proactive and smart about what you're doing in these hot conditions and how you tackle Thursday and Friday in particular," they said.
The State Emergency Operations Controller, Deputy Commissioner Peter Thurtell APM has urged residents and visitors of New South Wales to look after their health as a wave of hot weather crosses the state this week.
"We know many people will want to head to the beach, a local swimming hole or swim in your backyard pool. Please be careful. Keep a watchful eye over children especially when they are near the water - all children need to be supervised," he said.
NSW Health has advised to avoid being outside in the hottest part of the day, stay hydrated, wear sunscreen when outdoors and keep homes cool with air conditioning and fans and limit your physical activity to early in the morning when it's coolest.
If you experience heat exhaustion get to a cooler area, loosen or remove clothing and drink water. If you are concerned about heat stroke immediately call Triple Zero (000).
Fire agencies are urging those that live or are visiting bush fire prone areas to know the Fire Danger Rating and have a plan of action in the event a bush or grass fire threatens. Report all unattended fires to Triple Zero (000) immediately.
