New Zealand Weather

[J07]

I've held off on this because I like the seasons based on the sun, but for a few weeks now very Spring-like weather has been dominant, and even with a cold southerly on the way later this week the general hemispheric trend looks like Spring rather than winter. That means westerlies. Lots and lots of westerlies.

So far this month it's been pretty damn mild/warm for many areas. Wet in the west. Dry in the east. Sunny for most places. We'll be close to 170 sunshine hours when August ends, which is really good but still not a record (2007 was sunnier).

Temperatures of interest so far this month:

Wellington's warmest ever August day with 20C recorded at some valley stations.

Napiers possible warmest ever August day with 24C.

Yesterday 9 towns hit or exceeded 20C.

A warm windy situation affects NZ today. Gusts to 140km/h from the northwest. Warm in the east, and mostly dry, with plentiful high and mid level cloud. Humid in the north, with dewpoints up to 18C recorded.

http://www.stuff.co.nz/national/2779025/Start-of-the-golden-weather

(from 23rd August)

If you thought there was a hint of spring in the air, you're right. After an extremely cold winter, temperatures for the first few weeks of August have been one to two degrees warmer than normal around the country.

Last week, magnolias and cherry blossoms were out in style in Auckland, and daffodils and other spring bulbs were bravely beginning to bloom in Wellington and Christchurch.

And the good news is that the outlook is stable. Average temperatures and rainfall - including everything from Nelson's 200-odd hours of sunshine and 90mm of rain for a typical October, to Milford Sound's 690mm of rain, or Dunedin's paltry 145 hours of sunshine - are expected over the next three months.

Senior climate scientist Georgina Griffiths from the National Institute of Water and Atmospheric Research (Niwa) said that after the record-setting cold month of May, and a chilly June and July, spring was beginning. "Spring has sprung a wee bit early and the expectation is everything is back to normal."

Spring is usually considered to start in September and go through to November.

But it may not be such good news for summer and the Christmas holidays. Waiting in the wings is an El Nino weather pattern - a temporary increase in sea temperatures in the Pacific that arrives at irregular intervals every few years and causes weather changes around the globe. Griffiths said Niwa was watching the seas in the tropical South Pacific and the corresponding changes in the atmosphere, which were currently looking "El Nino-like".

If the El Nino conditions continue to intensify it would mean more frequent and stronger south-westerlies, and the possibility of drought for the northern and eastern areas of both islands as higher temperatures and the wind dried out the soil.

Not every El Nino is the same but the weather pattern generally means cooler summer air and sea temperatures for most of New Zealand - which could be a dampener for holiday makers. "Going swimming in an El Nino can be notably cooler," said Griffiths.

But some areas are likely to escape the cool El Nino weather, especially northern and eastern regions including Gisborne, Hawke's Bay, Nelson, Marlborough and Canterbury, because the wind tends to become dry and warm up as it travels over hills.

Other areas that may experience a warmer summer compared to the rest of the country include Northland, Coromandel, Wairarapa and the Bay of Plenty. It could be wetter than normal in Buller, Westland, Fiordland and possibly Southland and Taranaki.

Predicting weather a long time in advance was difficult and forecasters said that in around six weeks they would have a better idea of what summer would be like.

But around the country it seems spring fever has already hit. There has been an influx of visitors at the Auckland Botanic Gardens, which features a "spring valley" walk with magnolias, camellias, blossoms and daffodils.

Visitors were last week also enjoying spring blooms in Wellington, while in Christchurch the daffodils were just beginning to poke their heads through the ground and the magnolias were out. Wellington visitor service officer Charmaine Scott said the fragrant walk in the Botanic Garden was living up to its name and the magnolias had come out early.

"I think spring is here a month early."

And the warmer weather also brings more activity on the exercise front: gyms around the country are reporting customers coming in to prepare for bikini season.

[J07]

Temperatures a few degrees below average for pretty much everywhere, but also pretty much sunny for the whole country. Conditions not expected to change over the next few days.

Edited September 5, 2009 by J07

[J07]

Warmest day nationwide since April. Most places hit 20C. 17C here, but sunny all day.

Tomorrow some warm air from Aussie makes its way over. 30C was recorded in Melbourne (almost a Sept record). Records may fall in the South Island tomorrow.

[J07]

Phew, what a scorcher. As expected records fell today. New September record maxima on the South Island for Alexandra and Timaru, which hit 29C and 27C respectively.

At 6PM it was still 22C in Christchurch. They've had 6 days so far this month over 20C and no rain at all. It's only the first month of Spring.

Relative humidities have been very low and there's been plenty of dust about. RHs varying from around 8% to 20% during the foehn, and temperatures above 20C at the same time. Winds have gusted to 50 knots in exposed places. Essentially all this is drying things out very early in the season, and with an El Nino summer on the way eastern areas are quite likely to have some real struggles on their hands. Come December we could well see dessicating nor'westers blowing all the top soil in Canterbury out to sea. Unless something changes, that is.

As it stands, the nights are still longer than the days....and there's another blast of warmth heading for SE Australia and then us early next week.

[J07]

Not looking good if they're talking about this already....

Apparently a few fires have been underway down south due to strong, warm dry winds. Not helped by Dunedin hitting 23C at 2AM one morning- so much for "the Scottish City"!

http://www.stuff.co.nz/the-press/news/christchurch/2868349/Canterbury-drought-likely-say-forecasters

High temperatures and strong winds are drying Canterbury out and bringing the threat of drought closer.

Forecasters say there is little chance of any significant respite over the next few months from the increasingly dry conditions.

Barely any rain has fallen along the South Island's east coast this month, with only 0.2 millimetres recorded in Christchurch and none in Kaikoura and Oamaru.

The dry start to September follows three months of below-average rainfall. Christchurch has had just 111.8mm of rain since June 1, about 100mm less than, and only 53 per cent of the long-term average.

Temperature records have also been broken as warm northwesterly winds bring temperatures more like summer after the country's warmest August on record.

Timaru had its hottest September day in 124 years of records on Monday, when the temperature soared to 28.2 degrees Celsius, beating the previous highest September temperature of 26.4C, recorded last year.

Other temperature records broken on Monday include Orari with 27.5C and Cromwell with 26C. Oamaru had its second-highest September maximum of 26.4C, as did Dunedin with 25.4C.

The Australian desert dust that blanketed Canterbury on Monday played tricks on Environment Canterbury's (ECan) pollution monitoring network.

Rangiora, Ashburton, Timaru, Waimate and Geraldine recorded their highest pollution levels of the year on Monday night, only it was not smoke and particulates but dust.

Blue Skies Weather forecaster Tony Trewinnard said predominantly dry weather expected through to the end of the year would probably leave Canterbury dusty enough without the help of dust from Australia.

An El Nino bringing westerly winds, coupled with an apparent shift in seasons, was to blame.

"I think it is a dry outlook and I think that horrible D word [drought] will be close to people's lips by the end of the year," Trewinnard said.

"Everything's early. That's been the case with all our seasons this year.

"Our autumn started early, winter started early with that cold, stormy May, spring started at the end of July or beginning of August, and now we're getting almost summer temperatures and it's only September."

He expected warm west to northwesterly weather this month, but more settled weather was possible next month.

"I still expect it to stay quite dry; then in November I suspect the north-westerlies will crank up again," he said.

"Where we head to after that, I wouldn't mind betting December remains drier and that people will be starting to talk about drought.

"By then we'll have had three or four months of low rainfall, high temperatures and sunshine and northwest winds."

National Institute of Water and Atmospheric Research senior climate scientist Georgina Griffiths said soil-moisture levels in the eastern South Island were starting to fall.

"The last three months have been quite dry and all of a sudden August was record warm, and with all those nor'westers the temperatures ramped up heaps and we are now starting to see the effects of that on soil moisture, certainly in the last few days," she said.

MetService spokesman Bob McDavitt said there was no useful rain likely for Canterbury during the next week.

http://www.stuff.co.nz/timaru-herald/news/2872513/Fire-watch-as-green-drought-nears

The head of the district's rural fire service says it will be several weeks before a decision is made whether to bring in early fire restrictions.

South Canterbury principal rural fire officer Rob Hands said he was closely watching the increasingly dry conditions, which almost have the district in a green drought.

"It is definitely drier now than the same time last year, [but, restrictions] will be determined over the next few weeks."

Mr Hands said the region would need several significant rainfalls to prevent early fire restrictions, which would normally come in during the shoulder periods to Christmas.

What was green at the moment was dry enough to burn, he said.

If there were to be burn-offs, Mr Hands said they should be well-planned and take "the commonsense approach".

It included having a system to contain the fire if it got out of control and making a courtesy call to neighbours and the local fire brigade before setting fire to paddocks, he said.

A fire in a pine plantation was still burning two days after it started from an old burn-off.

Mr Hands said firefighters had been keeping an eye on the area and found about six hotspots yesterday, though it was not causing "any grief", unlike the day before.

Two helicopters were used to fight the fire in the 6ha plantation.

Mr Hands estimated only 20 to 30 per cent of the pine trees were unscathed.

[J07]

A strange Spring here with a lack of "normal weather". After a warm and dry September, and the warmest August ever, we had the coldest October since the 1940s.

November has been mostly dry, and now some warmth is heading our way.

Today Timaru hit 29C, which makes this the warmest day since September 14th!

Tomorrow, somewhere will reach 30C, for the first 30C of the season. (3 weeks later than last year).

Gisborne should be glorious the next few days.

[J07]

Today, 3 locations reached 30C.

Of those, the most interesting was probably Oamaru, which reached 24C at 6AM, rose to 30C early afternoon, then in 30 mins fell to 12C with a southwest change.

[J07]

Todays highs were 31C at Alexandra and Dunedin Airport. This is the warmest day since February.

The cold front at 9PM was clearly between Timaru and Christchurch. Still 24C at Le Bons Bay (9PM), but that should drop quickly as the front goes through.

[J07]

Two places hit 32C today, and dewpoints were also high in those locations (around 18C). A warm and humid day for pretty much everyone, except east coast of the South Island where temperatures inland were in the low 20s and dewpoints below zero.

There also were severe thunderstorms this afternoon, with a very high tropopause (14km apparently).

[J07]

Highest temperature this month will turn out to be the 32C in Whakatane (new November record) and Kawerau (not a November record).

Today a weakening trough is moving north, followed by a dramatic change to recent weeks with the southerly behind it. Temperatures in the south island more like mid teens rather than mid-high 20s.

I am quite happy to get some rain here, but it's rather too cold for the tomatoes....

[Buzzit]

In the North Island at the moment is a great example of a thunderstorm band meeting up with a stationary torrential rain front

http://www.metservice.co.nz/national/maps-rain-radar/rain-radar/all-nz-rain-last-6-hrs

Edited December 4, 2009 by Buzzit

[J07]

Yeah, that was a real beauty up there yesterday! There was a severe thunderstorm warning issued for those.

There's been some very humid air hanging around, which has made conditions more like February up in Northland. Day after day they've been getting highs of mid to high 20s, with dewpoints of 19C-21C. Despite all that, most places barely got any rain. But those that got it...really got it.

Mean 24 hour temperatures in Whangarei since last Sunday:

21C; 22C; 23C; 22C; 21C; 19C. Today will be much fresher.

Pretty terrible start to the summer for eastern areas though. Cold, grey and miserable in Wellington for far too many days.