If you thought the winter blast this long weekend was the main feature, think again. A large stormy low will deepen and cross the country next week bringing rain, snow, gales and yes – another windy change.

In a nut shell the rest of today and is dominated by the cold polar change sweeping over New Zealand.

By Tuesday some regions will have sub-tropical northerlies once more, but it’s all ahead of a developing large Tasman Sea low.

This sub-tropical flow over New Zealand early next week, coupled with a cold southerly flow across eastern Australia, becomes the perfect set up to spin and deepen a low pressure system out in the Tasman Sea and that is precisely what is forecast to happen. This low will grow quickly on Tuesday with rain arriving on the West Coast later that day and strengthening northerlies for northern New Zealand.

By Wednesday this large low will cross the country bringing heavy snow in to the South Island, blustery to gale force winds in some parts of both islands (but also large areas of calm around the centre of this big low) and a burst of rain and showers, with possible isolated thunderstorms. At the same time cold southerly air feeds in making for heavy snow through the ranges and higher elevation areas. Snow levels may be lower than this weekend, with current data suggesting 150 to 200m above sea level. This is one to watch and we’ll have more details on Sunday.

As it departs NZ on Thursday the colder, windier, South West flow behind it will be made even worse by the huge high over eastern Australia. This will make for a very windy and colder Thursday, Friday and next Saturday across many parts of NZ due to this ‘squash zone’ of air pressure.

This set up may also create huge waves, over 9 metres, around the western coastline of the North Island and possibly some other coastal areas in the west too.

One to keep an eye on so check back for our updates in the days ahead.

– WeatherWatch.co.nz