Temperatures to reach sub-zero

A cyclist negotiates wild weather which caused flooding along Tamaki Drive in Auckland on Tuesday. Photo / Brett Phibbs

A blast of wintry air is set to bite this weekend - with temperatures plummeting as we head into the second week of spring.

Meteorologists say the forecast is looking anything but spring-like, with snow on the cards for much of the south.

Auckland and Northland are in for some rain tonight which should clear by Saturday morning as the chilly weather sets in, MetService meteorologist Tom Adams said.

"There's already some pretty good thunderstorms out in the Tasman Sea, they're unlikely to be as heavy on land but there could be some heavy downpours for Northland.

Auckland is going to see some rain, but the worst of it is north.

"Auckland is the southern end of it ... but it is a developing situation. There has been some uncertainty about how far south its effects will be felt."

A "wintry, southerly feel" will envelope the whole country by Saturday - kicking off today in the South Island with a front currently causing a few issues on Queenstown roads.
Another, larger front is ready to hit on Saturday.

Noon Sunday wind map: Here comes the southerly flow (red means strong to gale force winds) blowing up from Antarctica to NZ. Note the calm weather out to the west in the Tasman (incoming high for next week). Photo / WeatherWatch

Auckland will see a dip from its minimum temperature of 8C tonight to 4C on Monday.

In Christchurch the minimum temperature will reach -2C tonight and sub-zero temperatures are expected into early next week, Mr Adams said.

It would be a similar story throughout most centres as a series of fronts drag the cold air up from the south, he said.

Frosts would return in force and snow was expected to about 500m in places, including a "top up" expected for Mt Ruapehu.

A weather watch is being issued for Canterbury with southerly gales expected in the region throughout the weekend.

"Temperatures are going to be very cold. The whole country will be feeling quite chilly," Mr Adams said.

"It's subjective. Ski areas are going to be loving it, but farmers are not."

Next week is expected to be fairly settled with only a bit of rain on the radar for the west coast, he said.

WeatherWatch head analyst Philip Duncan said the cold snap could be bad news for farmers.

Snow could be expected as low as 100m around Southland and Otago but hopefully would be short-lived, he said.

The southerly blast was coming from Antarctica and was expected to peak across New Zealand on Sunday, he said.

"[Farmers] with newborn lambs don't want to hear of polar blasts - but we have somewhat of a polar snap this weekend, starting in the deep south on Saturday...and spreading across most of New Zealand on Sunday."

MAIN CENTRES FORECAST:

• Whangarei - Mostly cloudy, rain developing on Saturday. High 15C, Low 11C. On Sunday, rain easing to showers. High 16C, Low 9C

• Auckland - Cloudy, few showers. High 15C, Low 8C. Rain easing to showers on Sunday. High 15C, Low 9C.

• Hamilton: Mostly cloudy, few showers on Saturday. High 14C, Low 4C. Cloudy periods on Sunday, with a chance shower. High 15C, Low 6C.

• Wellington: Showers develop on Saturday, strong northwesterlies turn southerly. High 13C, Low 5C. On Sunday, cloudy periods, evening showers. High 12C, Low 6C.

• Christchurch: Fine spells, morning rain on Saturday. High 11C, Low -2C. Showers develop on Sunday, with northwest winds. High 16C, Low 0C.

• Dunedin: Few showers on Saturday, fine afternoon. High 9C, Low 3C. Sunday will see showers, northwest changes to southwest winds. High 12C, Low 2C.

• Queenstown: Morning rain, with a chance of a shower on Saturday. High 9C, Low 0C. Occasional sleety showers on Sunday, chance snow. High 10C, Low -2C.

(Source: MetService)