If Thursday hits its predicted peak it will be the ACT's longest March heat spell on record.

A severe storm is expected to narrowly miss Canberra on Monday afternoon.

Temperatures in Canberra reached 38.5 degrees as the region's first heatwave of the year peaked on Wednesday.

The trough that brought a series of storms to Canberra on Saturday is expected to affect the region until Monday.

A fierce blast of winter has prompted a severe weather warning for most of southern NSW, including Sydney.

It will snow in the ACT tonight as a cold front moves over the region, the Bureau of Meteorology says.

The impacts of the monster El Nino in the Pacific are likely to intensify across much of Australia, including worsening drought and an elevated bushfire threat, after conditions that were nullifying its effects suddenly retreated.

Sydneysiders can expect more rain to fall tonight before it clears to a cloudy but chilly Monday morning.

Sydneysiders can expect several days of rain-soaked commutes after an early morning downpour ended three weeks of uninterrupted sunshine.

Prepare for hotter days and a worsening drought - a ''substantial'' El Nino event is underway.

Coogee Beach looked like a construction site - or a popular holiday destination for heavy machinery - as 12 large earth movers, two vacuum trucks and a crew of 35 worked to restore the beach to its pre-storm glory.

Broken Hill's water reserves are down to about 4 per cent amid forecasts the town will be without water by the end of the year.

Sydney in for scorching weather on Friday as a slow-moving high-pressure system steers a huge hot air mass formed over Australia's Red Centre to the country's south-east.

Unless you've been inside a 200kmh blast of wind it's hard to imagine the tremendous natural force behind it.

The state's second east coast low in as many weeks is likely to bring further heavy rains to north-eastern NSW but largely skirt flood-hit areas around Sydney and the Hunter Valley, meteorologists say.