Snow, heat, rain: NSW sees it all in a day

Wild storms have lashed Sydney, downing trees and power lines and cutting off power to thousands.
Wild storms have lashed Sydney, downing trees and power lines and cutting off power to thousands.

NSW was a "state of extremes" as severe storms lashed Sydney, downing trees and powerlines and cutting off power to thousands of homes while snow fell in Thredbo and parts of the state sweltered.

Wild weather hammered Sydney on Tuesday afternoon after the Bureau of Meteorology forecast a gusty thunderstorm warning for the region earlier in the day.

Winds reached up to 104 kilometres per hour at Fort Denison, closely followed by 96km/h in Holsworthy and 95km/h in Sydney Harbour, the bureau posted on Twitter on Tuesday afternoon.

Pea-sized hail even fell in the Sutherland region, it said.

NSW was a "state of extremes today", BOM tweeted on Tuesday afternoon.

"Currently snowing and zero at Thredbo... and reached a sizzling 39 degrees at Tocal in the Hunter (region)."

Other parts of the state also reached temperatures in the mid to high 30s, including 35.4C recorded in the heart of the city at the bureau's weather station on Observatory Hill.

About 51,500 homes and businesses lost power on Tuesday afternoon, Ausgrid said.

The company warned people to stay well away from fallen wired and debris as it responded to more than 1500 hazards.

By Tuesday evening, power had been restored to about 4000 customers with 48,000 still without power.

Those without power should plan to be without it overnight and into tomorrow, Ausgrid said in a statement late on Tuesday evening.

"Make alternate arrangements for tonight and breakfast as power won't be back until repairs can be made."

"Customers who rely on a continuous power supply for medical or life support equipment should contact family or friends to make alternative arrangements."

Endeavour Energy sent out similar messages after more than 25,000 of its customers also lost power due to the storms.

Another 2100 customers in parts of the Hawkesbury, Western Sydney and the Blue Mountains were still without power late on Tuesday evening, the company said in a statement.

"While we expect to restore more homes tonight, some customers in remote rural areas or where complex repairs are required will be without power overnight," the company said.

The severe weather also caused chaos for the afternoon commute.

Trains were stopped in sections of the North Shore and Central Coast and Newcastle lines, Transport for NSW said in a statement on Tuesday afternoon.

Those were running again by Tuesday evening while in Sydney's north, a number of road lanes remained closed due to fallen trees and traffic lights remain blacked out.

Buses were delayed in several areas including Pymble, Gordon, Chatswood, Roseville, Willoughby and Hornsby Heights.

Australian Associated Press