Hundreds without power as Sydney braces for more rain

Hundreds have been left without power after a storm cell smashed Sydney overnight.

Over 600 residents are still without power this morning, though Ausgrid has been providing updates on Twitter and is working to restore electricity to affected homes.

The SES has received 377 calls for assistance in the 24 hours to 5am, including 11 flood rescues in Sydney.

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They said most of the rescues involved cars driving into floodwaters.

There's more rain to come today with the Bureau of Meteorology forecasting a 70 per cent chance of further showers in Sydney, with the likelihood decreasing into the early afternoon.

Thousands of students will also stay home for the day, after two schools in Annangrove, St Madeleine's and Marian College, were closed due to a tree falling on a powerline.

Drivers warned on rain-hit roads

All northbound lanes have reopened on the Pacific Highway at Chatswood following a fallen tree and low hanging wires at Victoria Avenue.

The highway had been closed northbound.

Motorists should continue to allow extra travel time as heavy traffic eases through the area.

From Oxford Falls to North Narrabeen, Wakehurst Parkway remains closed in both directions.

Oxford Falls Road is also closed at Oxford Falls.

In the Royal National Park, Audley Weir is closed between Audley Road and Sir Bertram Stevens Drive, due to flooding.

Motorists should continue to exercise caution on roads affected by flooding and adverse weather, and allow plenty of extra travel time.

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Record rainfall in Sydney

Terrey Hills, in Sydney's north, copped a record drenching with 121mm registering in the gauges since 9am Tuesday.

That smashed a 13-year February rain record of 90.2mm, which fell in 2010.

Elsewhere in the state, 88.6mm fell in Canterbury, 64.8mm at Sydney Airport and 49.4mm in Richmond in Sydney's west.

As of 3am AEDT today the strongest falls were towards Gosford, where so far they've seen 48.2mm since 9am yesterday with the rain continuing.

The intense storms left the carpark at Woolworths Neutral Bay inundated, while some residents posted images of a water spout that formed near Dee Why on the Northern Beaches just after 6.30pm.

A massive tree was brought down in Pymble.

The rain also brought about a drop in temperatures, after parts of the city hit highs of around 30 degrees in the early afternoon. Most observation stations had dropped to about 21 degrees by 7.30pm.

Sydney's downpour came after a severe thunderstorm hit other parts of the state, with flash flooding inundating the NSW town of Orange this afternoon.

It came shortly after warnings from the BoM about heavy rainfall, damaging winds and large hailstones for the Central West region and the Australian Capital Territory.

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The warnings and road weather alerts have since been cancelled.

"A southerly change is moving through a high-moisture environment in eastern NSW today," the BoM said.

"Severe thunderstorms are likely to produce heavy rainfall that may lead to flash flooding, damaging winds and large hailstones in the warning area over the next several hours."

Canberra's strongest wind gust of 87km/h was recorded at 3.06pm.

The wet and stormy conditions came as yet another fresh batch of heatwave warnings were issued while much of the country is also set for a lashing by intense winds.

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