The first day of summer has brought more steaming hot weather to NSW with almost 30 bushfires burning and the possibility of severe thunderstorms across large parts of the state.
After a scorching weekend and a reprieve of just one day, inland NSW is bearing the brunt of the sweltering weather on Tuesday.
Total fire bans are active across seven areas including the state's north west, northern slopes, lower central western plains, central ranges, and the Riverina.
Coupled with windy conditions, the heat has elevated the fire danger across most of NSW to very high or severe.
At 1pm there were 29 fires burning at an advice warning level across the state.
Temperatures in the low 30s are forecast for coastal Sydney, but western Sydney and huge swathes of inland NSW will surpass 40C.
Most areas in the northwest corner of the state were already approaching or had reached 40 degrees by 9:30am.
The central west and northwest slopes and plains weren't far behind.
"West of the divide temperatures today are 10 to 16 degrees above average," Bureau of Meteorology forecaster Alex Majchrowski said.
The town of Bourke hit 46C just before 1pm, while Walgett was 44C, with Dubbo sitting around 39C and Griffith 38C.
Temporary relief from the heat will arrive for most on Wednesday, Mr Majchrowski says, but milder heatwave conditions will persist in northeastern NSW in the coming days.
"Temperatures (will be) starting to creep up again around Saturday, just ahead of the next cold front that will be making its way through," he said.
RFS crews battled more than 60 bush and grass fires across the state on Sunday, and RFS Commissioner Rob Rogers warned Tuesday could also be a tough day for firefighters in inland NSW.
Due to deteriorating weather conditions, the RFS is asking landholders undertaking harvest operations to stop and check weather conditions before deciding whether to continue.
Severe thunderstorms are also possible across large parts of the state on Tuesday, the weather bureau has warned.
A severe weather warning for damaging wind gusts of up to 90km/h has been issued for the elevated parts of the Snowy Mountains and the western ACT.
"Those storms are expected to kick off around the Riverina district, around Griffith, today around one or two o'clock, making their way east towards the coastline, with most of the severe storms likely south of Sydney," the bureau said.
"There is some potential for hail today, particularly about the southeast as well as possibly the mid-north coast and Hunter coast."
The extreme weather comes after a baking weekend which saw parts of Sydney - including the city - break the 40C barrier two days in a row.
Australian Associated Press