Spring is certainly here and we’re experiencing what I think is a classic September weather pattern, dominated by storms over the Southern Ocean and strong to gale-force westerly winds surging off and on.  

The storms south of New Zealand remain enormous – both in size and depth of air pressure. Most lows south of the country have been around the 940 to 950 hPa range now for several weeks. Usually we get a few like that, then that’s it. 

You’ve probably seen and heard the words “polar vortex” used a lot this year. The polar vortex is like elastic holding the cold in place around Antarctica – and this year it’s lost that tightness and has more of a wavy shape to it. 

Each time the wave goes up from Antarctica it shifts the boundary of cold air and low pressure into the NZ area – and this week that produced a significant winter outbreak over the country with hail, snow and bitterly cold wind chill for newborn livestock.

There is no sign of these storms coming to an end any time soon. The lower air pressure to the south of NZ and Australia isn’t just there only – it exists all the way around coastal Antarctica, with low air pressure storms south of South America and South Africa. 

With so much low pressure south of us it means more isobars on the weather maps in our part of the world – and that’s why we’re experiencing the windy westerlies much more this year. They tilt northwest, we get warmer and windier days. They tilt southwest and the Southern Alps get another dusting of snow and Southland and Otago shoulder the colder gloom again for most of the country.

Over the coming week the weather pattern takes a bit of a breather – at least to start with. High pressure looks to briefly cross the country bringing a spell of calm after so many weeks of wind. But it’s short lived, and by later this week the severe gale nor’westers return with the chance of more rain and cold fronts. 

While not locked in at the time of writing this, there was evidence in the long-range maps that by next weekend a low will form over NZ as another colder, wintry, southerly comes back in. 

There is some good news for those who want a break from the unsettled weather. Long-range data does hint that as October arrives so too does high pressure from Australia. I’m reluctant to lock it in just yet, but GFS modelling out of America suggests New Zealand may well get a calmer period of weather to kick off October thanks to a powerful anticyclone that may be closer to 1040hPa. We shall see. Always good to have a silver lining amongst all this chaos. 

Upcoming Highlights from September 23:

• Brief high pressure

• Windy nor’westers and rain

• Possible weekend low

• Possible powerful high-pressure zone moving slowly across NZ next week

A spike in lamb casualties and a shortage of feed supplies are worrying Southland farmers amid spring snowfalls and an uncommonly wet September.

Slink skin processor NZAGRI Development technical adviser Eddie Zhi said wet weather and recent snow in Southland meant an increase in lamb casualties.

Since he set up shop in August, Zhi said, collectors have brought him over 70,000 lambs – but more than 25,000 of those were collected this week alone after snow hit the region.

Collectors usually collect lambs once a day, but this week collectors have been out on two collection runs a day because of increased casualty rates, he said.

Rates increased so much he is now looking for extra collectors.

A spokesperson for Environment Southland said in the first 16 days of September, parts of Southland had already recorded 200% more rain than the long-term average for the entire month.

A MetService spokesperson said Lumsden had received 131mm of rain so far this month, while the September average is 66.2mm, based on data from 1991-2020.

Winton dairy farmer and dairy chair for Federated Farmers Southland Bart Luijten said the branch has been receiving calls from farmers wanting to offload cows in the short term, so they can minimise damage to land during wet soil conditions.

Despite the province having a feed surplus for much of the year, feed supplies are now low in some regions of Southland, Luijten said.

Some farmers are milking once a day because of low feed supplies, he said.

Farmers are trying to mitigate the impact of current weather and feed conditions in any way they can.

There is some hope as rains are predicted to ease over the next couple of days, he said.

He advised farmers to talk to friends and not isolate themselves when times are tough.

“Everyone is in the same boat. We’re trying to do our best, but there are things out of our control.  You might just have to lower expectations and make decisions day by day.”

Luijten said the Southland community is rallying to help each other, with silage contractors who can’t work because of wet weather helping farmers feed out so they can have a day off.

A Facebook post for the branch asked anyone with spare feed or the ability to take on cows to let the branch know so they can be put in contact with farmers wanting to shift cows for the short term.

Balfour arable farmer Blair Drysdale said the wet weather has been holding up growers’ ability to apply fertilisers.

He said there is a small window to apply growth regulator to autumn-sown wheat and barley, and he is considering using a helicopter to apply it as it is hard to get machinery into paddocks.

Crops have had “wet feet for too long” and might drown, Drysdale said.

He also runs sheep and is feeding out as he has feed shortages.

Head weather analyst and owner of WeatherWatch.co.nz Phil Duncan said soil moisture maps from NIWA don’t show anything too alarming, but some parts of northern Southland might be wetter than usual.

“Snow events in Southland are quite common in September. The Southern Ocean weather is especially stormy this year with particularly low air pressure. This means stormy lows normally parked nearer to Antarctica have the ability to shift much closer to southern NZ. This September and Spring have a higher than normal chance of winter outbreaks, so Southland and Otago are clearly in the firing line for that when it does happen,” he said.

In Focus Podcast | Sheep outlook: the future of our flock

Sheep farmers are doing it tough right now, with farmgate returns dropping back after a few good years and input costs rising. Add to that the march of pine trees across the land, and there’s talk of an existential crisis. Bryan asked AgriHQ senior analyst Mel Croad to give him the lay of the land and asked her what the sector needed to do to find prosperity again.

One of the messiest weather patterns so far this year is now tracking around New Zealand and it means a changeable forecast – for some, a highly repetitive one. Messier doesn’t mean stormier – but it does mean we’re not in a settled, calm period. 

Over winter we had a season of “big” weather systems from at least two large low-pressure systems that engulfed the entire nation for several days at a time, to the most powerful high-pressure zone ever recorded in New Zealand. Big weather systems can take weeks to move through.

Fast-forward to September and while this new season looks to also be a season of “big”, this month in particular also looks to be the month of “changeable”. That’s because weather systems (anticyclones and depressions) are moving through much faster now – classic spring! 

There are two things standing out about our weather pattern this month: One, just how very powerful the storms over the Southern Ocean are this year. In recent weeks most storms have had air pressure between 920 and 950hPa, which does happen at this time of year but it’s the frequency and large number of storms reaching this depth that is standing out to WeatherWatch this year. And two, the warmer-than-average airflows in the mix. 

The warmer-than-average weather won’t be consistent – the volatile weather south of NZ and the generally faster-moving, more chaotic pattern we have means NZ will still get regular cold injections – but because things are moving fast from west to east, these cold air injections may not linger long, and may struggle to go north – limiting northern frosts.

Storms south of NZ will send several cold fronts into NZ so the lower South Island in particular may feel winter this year is taking longer to ease, while those in northern NZ may be talking more about how fast the grass is now growing as an early spring starts to establish itself.

High pressure may cross NZ giving us a pause from this all – and a return to cold nights with a heightened frost risk. At the time of writing this, high pressure was forecast to cross NZ on Monday September 3 – but modelling was conflicted about if it would linger very long or directly affect both main islands. Outside of that, many highs may skirt to our north for a time, allowing for more cold fronts to come in from the west and south.

Due to the dominating westerly flow, rainfall over the next 15 days looks to be mostly on the West Coast with over 300mm likely around mid to south Westland, and around 100mm for parts of the western North Island, like Taranaki and Waitomo. Gisborne and Northern Hawke’s Bay may have the lowest totals.

Upcoming Highlights:

• Monday/Tuesday kicks off colder with a southwesterly flow across NZ

• Wednesday/Thursday has milder west to northwest winds returning

• Another cold front moves up NZ on Friday/Saturday

• Most wet weather in the west to southwest of both main islands

In Focus Podcast: Full Show | 13 September

Heavy snow has caused power outages and concerns about feed reserves in Otago.

Federated Farmers high country chair Andrew Paterson, who owns Matakanui Station near Omakau, said they have had three inches, or 7.6cm, of snow since Thursday night “and it is still falling and forecast to keep snowing today”.

Paterson said he is concerned about feed, as the area had a poor autumn and winter.

“Most of us have had a tough winter, and we are short on feed supply.  Normally you get to this time of the year and the grass is growing and winter is over. We’ve had a really tough winter and autumn with the drought. Now we’ve got snow with essentially no or little feed reserves left.”

Paterson had been shearing hoggets and had to stop because of a power outage on the farm.

“All the sheep that we’ve shorn from the latest shearing we’re putting back into the wool shed and under cover,” he said.

Aurora Energy reported power outages in Queenstown, Cromwell, Alexandra, Omakau, Glenorchy and Wānaka.

Media reports said at 7am this morning power was cut to 3500 homes in Otago.

Paterson said because the area often has snow in the first week of October he does not start lambing until then, with most in the area not lambing until late September.

Head weather analyst and owner of WeatherWatch.co.nz Phil Duncan said Otago is more exposed to moisture from low pressure nearby and had a higher risk for snow this morning.

“The low-pressure zone will create some areas of more moisture today. Otago is getting more snow because weak low pressures can be more unpredictable, but add more moisture into the colder air. Snow showers are no different to rain showers and our hills and ranges can make some heavier, others miss out.”

There will be winter weather conditions in the lower South Island over Sunday and Monday and with wind chills below 0degC, he said.

“The whole system is slowly moving northwards today and weakening. Conditions will clear from the south today,” Duncan said.

In Focus Podcast: Full Show | 13 September

Heading into in the second week of September, New Zealand’s early spring weather continues. Monday, September 9, kicks off with yet more windy westerlies, which will be strong and gusty and may even reach severe gale in some places, south of the lower North Island.

Heavy rain on the West Coast and rain or showers for many other western and southern areas. Tuesday is similar, although it becomes colder in the South Island with snow levels lowering for a time around the mountains and ranges. Wednesday may be another windy day for some of you in the south of the country. 

After more than two weeks of strong winds coming from the west these conditions will finally ease by late next week. But the weather pattern beyond this is starting to look messy. 

As we’ve been saying for a number of months now, we’re in a “neutral” season and while there is a lot of chatter going on about a possible La Niña, that doesn’t mean that our weather here in New Zealand is going to be affected yet. (And it’s possible La Niña may still not even officially be declared this year.) 

The Southern Ocean has been especially stormy this year, creating one major storm after the other. Storms in late winter/early spring are normal, but this year it is the frequent nature of so many deep air pressure lows that’s made things different. 

Not only that, but many of these storms and low-pressure zones have been brushing the lower part of NZ – they haven’t all been well south down towards Antarctica. In fact next week some of the severe gales around NZ are due to more deep low pressure just south of Stewart Island.

I’ve said a few times that winter this year was defined by the word “big”. We had big high-pressure zones and big low-pressure zones and many of them lasted for two weeks in the NZ area at a time. 

Now that we’re going through September we are still seeing big systems, perhaps not lingering as long as they did in the depths of winter, but they are still large and we are seeing large lows around Australia and around New Zealand coming up too – whether they hit us is a different question, but they are likely to be around.

Earlier this week, WeatherWatch issued our September ClimateWatch update where we track things like La Niña and temperature trends and rainfall trends for the month ahead. The month of September is looking generally warmer than average but with an increased risk of a snowstorm or frost event this year, and while that’s normal most springs, the chance of one being a strong one is a little elevated due to the storms south of New Zealand.

Spring may be a bit warmer than average but could still bring some stormy and severe weather at times, which hasn’t always been the case in recent years.

The season of stress is upon us! Spring weather brings all sorts of challenges to many of you (and to us as weather forecasters, too). Of course, one of the biggest issues in early September is dealing with snowstorms for newborn livestock and frosts for those that don’t want damage to plants, vines and buds. Many of us are in a heightened sense of alert for the next couple more months. 

The weather pattern at the moment is highly chaotic. Major storms down over the Southern Ocean have helped dominate our weather pattern for the past week and look to continue for September’s first week.

These storms have had central air pressure down around 920 hectopascals, which is incredibly low. But high-pressure zones over Australia, the north Tasman Sea and near New Zealand put the lid on just how far north those storms can go – and that’s what creates those gigantic windy westerlies that stretch all the way from south of Australia across the Tasman and then over New Zealand.

We said goodbye to El Niño back in April and we’ve had a “neutral” winter season, evident with the huge high-pressure zones that we had and the many large low-pressure zones too. 

I’ve said a number of times that this has been “the winter of big air pressure”. Now that spring is here (at least on the meteorological calendar), will we still get these “big” weather systems? It certainly appears for the start of September that, yes, they will continue with big storms south of us and large highs out over Australia putting NZ on the edge of it all. 

At the time of writing this column the climate driver update from Australia’s Bureau of Meteorology suggests that we’re still in a neutral season but that we are getting closer to a possible La Niña. 

It’s worth noting when you look at the various models from all around the world it still shows that the mean average keeps conditions in “neutral” for the rest of 2024, although it does certainly flirt with La Niña during spring (especially October and November). 

But those same long-range models suggest that we’re heading back into neutral as we head towards summer. 

To make sense of all of that confusion, it basically means not a lot is going to change with our weather pattern. There might be a bit more life to the north of New Zealand and we’ve certainly seen a few low-pressure zones over the past two weeks (and they are worth keeping an eye on because the wet season in the tropics doesn’t normally start for another month or two, so this may well be a sign of a very weak La Niña forming). 

Either way, New Zealand remains two small mountainous islands partially stuck in the Roaring Forties … in other words, don’t get too hooked on what might happen months from now, but my general feeling is more chaos before there is a stronger pattern emerging.

In Focus Podcast | Rewiring rural New Zealand’s approach to power

Rocketing power prices and uncertainty about generating more are keeping many people up at night, but Mike Casey reckons farmers have everything they need to power up right now. The chief executive of Rewiring Aotearoa has transformed his cherry orchard into a solar powered operation and he reckons every farmer should do the same. 

To Mike, it’s just a sound business decision as his power bills have plummeted, the capital outlay will be repaid in five years and he’s sorted if a storm knocks out the regional power supply.

North Canterbury farmers who have been facing drought conditions for months will have to continue to carefully manage their feed stocks, but there is hope for improvement on the horizon.

In March Farmers Weekly reported drought conditions. A medium-scale adverse event was declared for the top of the South Island.

By June some farmers had received only had 40mm of rain for the year. Drought, poor returns and high transport costs left Hurunui farmers scraping the barrel for feed, with animal welfare becoming a major concern. 

North Canterbury Federated Farmers president Karl Dean said at the time that, apart from a lack of rain, the biggest challenge at that stage was the cost of bringing in supplementary feed.

Earlier in August, Rural Communities Minister Mark Patterson announced the government is providing $20,000 towards specialist veterinary care for farmers in the district.

But now there is hope on the horizon as normal rainfall and normal soil moisture levels are predicted for September and October.

General manager catchment implementation at Environment Canterbury Judith Earl-Goulet said in the past month soil moisture levels have improved.

In all, “65mm to 130mm of rainfall was recorded at our monitoring sites across the region. However, groundwater levels are still low,”  Earl-Goulet said.

“Following dry conditions, any rainfall will improve soil moisture first. If there is excess, it will add to groundwater and river levels.   

“The recent rains, coupled with warmer temperatures, are resulting in some pasture growth, which is expected this time of year,” she said.

“Rain over the next few weeks will be vital for predicting how the region will fare in the summer ahead.

“Without sufficient rainfall for recharge in coming weeks, it may be necessary for irrigation restrictions to be put in place earlier than usual.”    

Irrigation restrictions are determined by the source of irrigation water,  groundwater availability and the conditions that apply to the irrigator’s consent, Earl-Goulet said.   

She said NIWA’s drought index shows conditions are easing.

Head weather analyst and owner of WeatherWatch.co.nz Phil Duncan said the country is in a neutral weather pattern. 

“We don’t have El Niño and we don’t have La Niña. This means our weather pattern is highly chaotic.” 

This tends to suggest that Canterbury may lean warmer than average and slightly windier than previous years, Duncan said.

“Heavy rain on the West Coast will to some degree spill over into Canterbury waterways and potentially to farms in lower foothills. For those nearer to the eastern coastline, we expected it to be dry and milder,” Duncan said.

“Because of the extremely stormy nature of the Southern Ocean weather pattern this year we have an elevated risk for a brief-lived snowstorm or frost event this September and October.  

“Soil moisture levels in Canterbury will be lower the further east you are, unless there’s a surprise easterly rain event,” he said.

North Canterbury meat and wool chair for Federated Farmers Sara Black said most farmers are not out of the woods yet.

However, she said, there was a glimmer of hope at a Hurunui Adverse Events Committee meeting held on Tuesday night.

“We had a little bit of rain and snow last week.  Any moisture is gratefully received. Totals from around the district show 30mm to 50mm of rain,” Black said.

Farmers were still under a lot of feed pressure, especially as lambing approaches.

“We’re very much in a holding pattern at this stage.”

She said many farmers have been feeding out since January and are under financial pressure as a result.

“There’s no money coming in, especially for sheep farmers until they get lambs grown out. Even though there’s been a recent spike in the sheepmeat price it’s hard to see where the lamb price will be, especially for store lambs,” she said.

“People are still stressed. We haven’t got to the end of anything. We’ve had a little bit of rain, but there’s still that uncertainty. It’s long haul now”.

Sheep entered the next season leaner than they should have been, she said.

Black said more funding for the North Canterbury Rural Support Trust could help support farmers through “this tricky period”.

This week, New Zealand weather kicked off with a southerly off Antarctica. Three days later, the airflow coming into NZ was from out of Australia. There aren’t many parts of the world that get the weather off two continents in such a short time – especially two very different ones (one super cold, the other fairly warm). 

Most Kiwis might see this week as more winter weather, but I see it as a sign of spring: the cold blast, the windy weather, then the uptick in temperatures that pushed NZ above average by mid to late this past week. 

But to me, the biggest telltale sign that spring’s weather pattern is coming in are the windy westerlies. 

We’re now heading into the final week of August. September kicks off next Sunday and so too does the start of spring on the meteorological calendar (with spring not starting until September 23rd on the astronomical calendar). Also, our coldest weather is in June, July and August – leaving September about a degree milder and giving us a bit more spring in our step. 

September is also the month that gains a lot of sunlight. About 20 minutes of extra daylight every week, meaning we gain one hour more daylight in September. Then, of course, we get daylight saving towards the end and that gives us another hour of daylight in the evening. 

Although daylight saving has absolutely no effect on the weather (obviously!) it is a sign that in just a month’s time we’ll have turned another big corner on winter.

In my view spring this year comes with a higher-than-usual risk of a snowstorm or frost event. This is due to the extra stormy weather over the Southern Ocean and south of NZ lately. 

In fact, at time of writing, there is a storm that computer modelling was picking central air pressure to be between 916 and 926hPa for next week. That’s more powerful than most Atlantic hurricanes. Thankfully the storm itself will be near the ice shelf, but the winds will stretch up to Aussie and NZ. 

Storms like this that far south tend to produce gale westerlies from Tasmania to New Zealand. Looking at long-range maps that sure seems to be the pattern off and on for the next two weeks. Westerlies streaming into NZ, sometimes with airflows out of Australia, sometimes the subtropics north of NZ, and other times a cold south to south-wester. 

The good news is that this set-up should drive in plenty of rain to the West Coast and spill over into our low hydro dams. Several hundred millimetres or more of rain will fall there over the next week or two. 

The bad news? Windier, drier westerlies for Canterbury, and a heightened risk of a sudden severe snow or frost event in September. The milder and windier spring westerlies may arrive early this year – but remember: the cold air south of us has only just peaked and hasn’t gone away yet.

Next week kicks off with an Antarctic blast for some, but for the rest of August a new pattern is forming – a spring weather pattern. This is different to the astronomical seasons, which are evenly spread around the year as the earth rotates around the sun. 

Instead, a spring weather pattern is when we as weather forecasters start to both see and feel a shift from the “dark and dormant” winter to the “windy westerlies and injections of warmth” that spring brings.

In previous years we have declared the spring weather pattern to be here by late July. This year we’re running a few weeks later, which, to southerners especially, won’t come as much surprise. 

One of the biggest pushbacks we get to any early spring weather declaration is that any snow or frost is “proof we’re still in winter”.  But that’s not proof of winter. Winter is defined as a season with death and decay and the coldest weather …  spring is defined as “moving, rising, life beginning, blossoms, buds, newborn animals”.

In the northern hemisphere some of the biggest snowstorms in places like Canada or Russia or northern Europe can occur in early spring. This is due to the coldest air of the year now meeting longer hours of daylight and more warmth. After all, we’re now officially out of the solar winter – the three months of the year with the least amount of available sunlight. No wonder you’re noticing the longer, brighter, early evenings now.

As Reserve Bank Governor Adrian Orr said this week, “it’s darkest before dawn … and it’s dawn now”. That sums up the current weather pattern. We’re still in winter technically, but we’re seeing hints of spring’s weather arriving. 

So what is a “spring weather pattern”? I define it as being dominated by more westerlies, more injections of Australian and/or subtropical airflows, and still stormy at times. In winter we tend to have more southerlies, more injections of sub-Antarctic air.

It does feel a bit weird to be writing about spring weather when, at the time of writing this, a significant Antarctica blast is possible on Monday. But to anyone who says “so much for spring” when you get a frost or heavy snow, that is PART of spring! 

If spring was warm, dry and sunny it would be summer. If it was snowy, cold, and had little plant life or growth, then we’re in winter. But I think many of you will see over the rest of August that we do have a more westerly-driven, milder at times, weather pattern – but spring brings that added risk of moisture + cold, which can lead to snowstorms and sudden severe weather events. 

We generally usually see New Zealand’s weather pattern calm down in two months from now, by late October. 

So we’re in a moderate to high risk for frost and snow events until then – but the weather is likely to have more of a spring in its step moving forward.

Farmers impacted by the ongoing drought in North Canterbury have been given a financial boost by the government.

Rural Communities Minister Mark Patterson said a lack of rain has left farms short of feed, with pasture and crops failing to grow.

“Prolonged dry weather and challenging financial conditions have made circumstances extremely tough for farmers in the Hurunui District,” Patterson said.

Many farmers have been using good management practices, such as reducing livestock numbers, to get through the drought. As lambing and calving gets underway, extra one-off support is needed.

During his visit to affected farms, Patterson announced the government is providing $20,000, with the Farmers Adverse Events Trust, Veterinary Association and Boehringer Ingelheim contributing an additional $18,000, to deliver specialist veterinary support to drought-affected farmers in the Hurunui District.

“A further $30,000 contribution will go to the Hurunui Mayoral Fund to ensure targeted assistance is available to those farmers identified the most critical in need.”

The latest support comes on top of funding provided to the region earlier this year.

In March, extremely dry weather conditions were classified a medium-scale adverse event across multiple regions. That classification unlocked around $170,000 in extra funding for Rural Support Trusts to provide early on-the-ground support for affected farmers.

“Tax relief is available through the Income Equalisation Scheme, which is designed to help with on farm cashflow.

“The Ministry for Primary Industries’ On Farm Support service will continue to work closely with farmers and growers to determine where support is required.”

Patterson encouraged farmers across the district who need support to contact their local Rural Support Trust on 0800 787 254.

In Focus Podcast | Platform to power farm succession

Two South Island farmers have launched an online platform, Landify, which helps young farmers looking to get into farm ownership find investors and sellers. 

Co-founder Sarah How tells Bryan that while the sector has talked about the problem of succession for years there has been relatively few tools developed to deal with the problem.