A cold southerly change predicted by WeatherWatch.co.nz last month still looks set to happen later this weekend as the North Island’s current low moves east and deepens quickly on Sunday.

The prediction was made last month as part of our monthly weather and climate forecasts prepared for dairy giant Fonterra – and was shared with readers at WeatherWatch.co.nz.

Based on models by MetOcean and GFS – and our experience with similar set ups in the past – we could see a high over Tasmania and the Tasman Sea working in harmony with a deepening low east of New Zealand – together dredging up cold southerlies around mid-July.

We don’t always trust the models either – sometimes ignoring their predictions in favour of our own forecasts, but in this instance everything seemed to point towards this likely southerly change.

The prediction was that between July 9 and 13 the weather in New Zealand would significantly cool down following a very mild start to the month, with a cold southerly really pushing in around the 13th.

Now two weeks later the forecast remains almost identical – but the main southerly change is running just a day late. 

At this stage WeatherWatch.co.nz predicts a cold southerly will push up the South Island starting early on Sunday morning and pushing north up both islands as the day moves on.

By Monday things will be easing for some South Island regions while the North Island has to wait until Tuesday before conditions ease further.

More snow is predicted to low levels, possibly a couple of hundred metres for a time in the south.

The Desert Road is again likely to see snow late Sunday and Monday – and may well close the highway again.

Despite this next wintry snap WeatherWatch.co.nz believes it won’t cause too many headaches.  “It will be another 48 hour period with more wind and cold and snow on hills – but this isn’t a major storm or anything like that, just another noticeable cold snap” says hyead weather analyst Philip Duncan.

But the news will be welcomed by skiers and boarders – especially with sunny, calm, weather expected for many of our ski fields later next week.

A high is forecast to move in later next week and last for at least a few days.

– WeatherWatch.co.nz