Hot Australian air will help kick summer into gear this weekend

Thursday, 27 December 2018

Keep an eye out for the nor'west arch over the Canterbury Plains at times over the next few days.

Canterbury's summer is just a day or so away.

It's true.

Sumner Beach could be packed over the weekend, with temperatures picked to reach 30C on Sunday.

Hard to believe as it may seem, the thermometer is expected to shoot up towards the 30s across the region this weekend, thanks to some hot Australian air blowing in on a northwesterly breeze.

The next few weeks could feature a repeating pattern of two or three warm days followed by a couple of cooler ones with some showers, breaking the cycle of the very wet and changeable November and December to date.

* Soggy start to summer likely after November deluge

* Canterbury's very wet November not over yet**

As well as having maximum temperatures in the high 20s on Saturday and possibly breaking the 30 degree Celsius barrier on Sunday, the first couple of days of 2019 should be almost as warm.

But don't get too complacent, as that may not be the way the rest of the summer plays out.

Blue Skies Weather forecaster Tony Trewinnard said the weather was finally turning the corner after a very unsettled and wet spell since the start of November.

'It will be changing for the better for most of the country. We will be leaving behind the colder, damper, rainier sort of weather and going into more the weather you'd expect for this time of year.'

Hot Australian air – bringing temperatures in the high 30s and low 40s to parts of South Australia and Victoria on Thursday – would start moving across the Tasman Sea towards New Zealand on Friday.

Warmer-than-normal ocean temperatures around New Zealand, combined with a phase of the Madden-Julian Oscillation in the tropics that favoured more northerly winds in the Tasman Sea, were also factors in the approaching weather turnaround, he said.

The generally fine spell of weather, dominated by anticyclones and westerly winds, would probably last for about three weeks.

'By the last third of January it looks like things might get unsettled again, bringing in a pattern with some more rain, colder temperatures and more low-pressure systems.

'So I wouldn't be too confident to say that the pattern we will see in the next couple of weeks will be with us through the rest of the summer and into the autumn,' Trewinnard said.

MetService forecaster James Millward confirmed temperatures would be on the rise for eastern South Island places this weekend. The northwesterlies could bring some welcome rain to the West Coast too.

Computer models showed a warm spell on the first two days of the new year.

New Year's Eve could well be wet in parts of the South Island but fine in the North Island, he said.