10pm Thursday Update

Stormy weather is on the way for two thirds of New Zealand this weekend as another large low pressure system moves across us.

The low, which is literally several times the size of New Zealand, is churning through the Southern Ocean and will bring torrential rain and severe gales to both islands this weekend.

WeatherWatch.co.nz head weather analyst Philip Duncan says the centre of the low won’t cross the country but the strongest winds associated with it will.  “Gales will stretch from the Southern Ocean, over Tasmania across the Tasman Sea and will then be funnelled through Cook Strait and of course over the Southern Alps”.

Mr Duncan says those around Wellington, Masterton, Blenheim, and Kaikoura will be most exposed to the severe gales this Saturday and Sunday.

“Gales are also likely to affect motorists driving through the Southern Alps and over the Hawkes Bay ranges”.

As of 10pm mild weather was covering the country. “It’s out of habit that I’ve lit my fire tonight” says Christchurch based weather analyst Richard Green.  He says at 7pm it was mild with 15 degrees.

However by 10pm it had dropped to 7 although it was a mild 12 degrees in Akaroa and Kaikoura.

Gusty northerlies in Wellington meant it was still around 14 there. 

In Auckland it was 10 degrees at 10pm.

Heavy rain is expected to move in to western areas of the South Island and MetService has issued several rain warnings.  

The government forecaster also has high confidence of severe gales.  “A very strong northwest flow and gales are expected in many eastern areas from Southland to Wairarapa on Saturday, spreading to inland parts of Hawkes Bay and Gisborne by Sunday morning.  Forecasters have increasing confidence of severe gales in some inland areas, especially from north Canterbury to Wairarapa also Wellington”.

Another cold snap?

It may not be a big snow maker but following this large low is the often predictable cold snap – and the entire country may be affected.

The polar jet stream is predicted to rise north allowing the cold Antarctic air it holds behind it to lift up over New Zealand.  Cold southerlies are likely to move in early next week in the far south and reach northern New Zealand by Wednesday. 

Daytime highs in the South Island and Wellington are unlikely to climb above single digits with wind chills closer to zero.  For the rest of the country highs between 10 and 13 are expected to be common place around Wednesday next week.