Dramatic weather for long weekend

Snow as far north as the Kaimai Ranges and Coromandel Peninsula, waves the height of power poles near Cook Strait, daily highs as low as 3 or 4 degrees...sounds pretty dramatic for our Queens Birthday weekend but those really are the extremes. Most places will see rain and wind but also some sun and calm spells.

Just to give you a brief time line, from last Friday to Monday the computer models were predicting a cold blast straight off the Antarctic ice shelf. On Tuesday and Wednesday it back completely off that idea and instead predicted that the high in the Tasman Sea would grow so big and strong that it would keep the southerlies well south of New Zealand. Over the past 24 hours the computer models have moved back to the polar blast scenario with a large high to the west and a strong southerly flow spreading up the country starting late on Saturday and peaking in the 24 hours of Sunday.

The air is coming from further south than last weeks wintry blast. It's very close to the ice shelf which is why the computer data was suggesting highs of 4 degrees for places like Timaru and Christchurch this Sunday. The freezing level is going to plummet, as low as sea level in the South Island. The cold air in the North Island, mixed with a rain band moving through on Saturday and Sunday means rain will turn to snow, quite likely heavy snow, on the Desert Road. Other highways in the central North Island may also be affected so if you're driving through on Sunday or Monday you'll want to be up to date with driving conditions.

The good news for travellers is that the winds should quickly move through and hopefully blow away the snow clouds in time for motorists returning home on Monday afternoon and evening - in both islands.

This cold air means that a dusting of snow is quite possible on the Kaimai and Coromandel ranges...it won' be heavy but during Sunday or Sunday night we may see flurries down to 7 or 800metres. So if you're going tramping ANYwhere in New Zealand be prepared for really wintry conditions. Even if it's not snowing it's going to be bitterly cold in a number of places on Sunday and Monday. Winds are likely to be gale force above a few hundred metres in a number of regions too.

The strong winds will whip up the seas, probably not to the levels we saw last weekend which cancelled all the Cook Strait ferries, but strong to gale southerlies are likely again late on Sunday and early Monday. This may impact sailings ... it's hard to know this far in advance. Definitely something to be aware of if you're crossing the Strait. Swells may be higher than 6 metres within Cook Strait itself.

As I said, snow is likely to low levels in the South Island. Dunedin and Queenstown will certainly see a few flakes and snow is also likely to low levels in Canterbury on Sunday - especially early Sunday further south.

The southerly that follows on Monday will be bitterly cold. I think highs around 9, 10 and 11 will be common place right across New Zealand but wind chills will be closer to zero for much of the day in many south coastal areas of both islands. The southerly should bring clearing skies to most places though, especially northern and western New Zealand.

The place to be this long weekend? The West Coast. Perhaps a few showers early on Saturday otherwise blue skies... the gusty southerlies may also keep west coasters a few degrees higher than their east coast neighbours.

We will have extensive travel and land forecasts across the long weekend including a current 3 day forecast for all regions across New Zealand, independent of MetService, which you'll find here. This link will be updated morning and night. Also, check www.weatherwatch.co.nz for all the latest news on this system - and we'd love to see your photos of the wild weather.

Happy Birthday Betty! I'll have a mulled wine for you on Monday.