J07
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there is surface high pressure shown between the two jets so the weather there would be fairly settled. More unsettled either side of the jets to the north of the sub tropical type and south of the polar.
Is that a diagram or an actual chart?
on this actual forecast chart for today, a significant weather chart for commercial flying, you can see that it can be even more complicated than what you showed.
It's a diagram I assume just for the general public, but why they label jet streams on them I don't know.
On the chart you showed- big triangle = 50kt, long line = 10kt and short line = 5kt?
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just about right I would think
Do you think this is a more interesting set up?
One jet is around about 38S, the other maybe 47/48S. I guess it is not normal for them to be so close together.
What sort of implications would this have for the weather?
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Can anyone say what this means? Polar Jet to the South, Subtropical Jet to the North?
(from www.weatherzone.com.au)
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NZ weather makes the BBC news
Rain lashes parts of New Zealand as drought summit called
by Steph Ball
Warnings were issued for Canterbury and the Kaikoura coast this morning as a slow moving depression moved east of the South Island. Flash floods triggered landslides making some Canterbury roads impassable, with 120mm (5 inches) of rain falling overnight. This is the first significant rain to have fallen here since last October.
As rain lashed the South Island, there were also disruptions to the play in England’s second One Day International in Hamilton, ending up as a much shortened game.
Meanwhile New Zealand’s Parliament was meeting up in Wellington for a summit on the country’s drought situation.
At present Waikato has been declared a drought area, although many other areas are currently experiencing very dry conditions. It was declared a drought area last month as the area experienced its driest January in a century.
While reservoirs are said to be full to two thirds of their capacity, the hot summer has seen an increase in water consumption which has worried government officials. There are concerns that lowering lake levels could eventually bring problems with power shortages as hydro electricity accounts for 65% of the countries supply.
More rain is forecast across New Zealand over the coming week.
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February has so far been quite different to last month. Has been more unsettled, with settled spells generally limited to 3 days at the most as opposed to 6-8 days last month. Also we have had some cold southerlies, knocking daytime highs back to about 16-17C.
The warmest part of the year has passed, it's all downhill now until the end of July
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Im sure with no wind and constant sunshine it felt like summer there.
I've often thought that, however, when you get to real summer you realise just how different it is. Main things would be the weakness of the sun in February, how low it is in the sky (less than 25 degrees at the moment!) and how short-lived these remarkably high temperatures are (eg a summer day of 18C max would probably be mild for much longer than a winter day of the same temperature, where it may only hold on relatively briefly- such as in this foehn wind).
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London may have hit 16.6C recently but I think 21C is a big one, and most likely won't happen until Mid-April. So I'm betting on April 11th.
I had a look to see what the equivalent date was for New Zealand, but unfortunately somewhere went and spoiled my fun by recording 22.4C on the first day of winter! (June 1st 2007...probably warmer than parts of the UK!). :-/
I remember reading somewhere about the "start of Spring". The person defined it as the first day that got to 16C? I thought that was a poor definition but according to that the UK is in Springtime now
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I love 2474, wonderful.
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Yes, but the irony of what you say about oceans trapping heat, is that during winter the oceans are last to cool while landmasses cool rapidly in the long nights/short days of the higher latitudes, so the warmer the oceans due to the warmer atmosphere from GW - the warmer the maritime climates will be in winter, that is what I was implying?
Ha, yes that is what you were implying. I see your point now, sorry!
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Personally I think the models are wonderful things, and they don't seem to get a lot of respect. I think they do a good job for what they are. But of course they will never be perfect. I'm not sure people realise the extreme non-linearity of the atmosphere! Open any textbook specific to meteorology and what do you see? Non-linear, non-linear, non-linear equation after equation after equation! And even these can just be approximations. There are many "fudges" going on when constructing a mathematical model of the atmosphere, some work pretty well but others can get quite strained. But if you don't use the "fudge" you may end up with something that is entirely unsolvable by analytic means.
That's where, thank God, we have computers. I wish I knew the ins-and-outs of the models and the actual mathematical differences between them, but I don't. However, you can get your bottom dollar that they do a heck of a lot of solving of highly, highly non-linear differential equations, and they do it numerically. These two things combined are never going to give you perfect results! Some simple looking equations are unsolvable analytically- consider the integral of exp(-x^2) dx. Simple looking, but cannot be solved without using erf(x), which I think (correct me if I'm wrong) is only defined numerically, not analytically. To be honest, I dread to think the absolute horrors that those poor computers are solving, second by second, minute by minute.
And the thing is, because they do this, they take heaps of calculation off the hands of people, allowing people to get on with what they are good at - THINKING*!
...hence pushing the science to higher and higher levels, which in turn goes on to improve the models, which in turn goes on to give us better results!
In other words, I think these computer models are great. People are learning all the time- this will improve the computers.
For a good example of non-linearity, the pendulum is easy enough. It's non-linear, but can be "fudged" to become linear. However, as this is an approximation, it's going to go wrong at some point. I don't know the details of that system in particular, but it's certain that at some finite (and possibly very large) time t, the fudged solution will diverge significantly from the actual behaviour. Now consider the atmosphere, how much more complex it is. Computer models aren't going to improve exponentially, they can only do it gradually, bar an absolutely mind-blowingly enormous breakthrough in analytic analysis of non-linear equations (not to mention chaos....partial differential equations....and so on).
* I should also mention moaning.
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You could effectively extend Summer and push Autumn back and Spring forward and remove or and then shorten offical Winter. What do you think??
Extend summer? Nah. Summer is often going to be limited by aspects such as sunshine hours, strength of the sun (it's far, far too weak in September for that to be a summer month, IMO) as opposed to just temperature. Last autumn was odd, quite dry and mild for a long period, but I don't believe it really "extended" summer at all. There are natural limits that we can't overcome by increasing temperatures. I know in an exceptional year we may get 21C in October, that also I think doesn't extend summer- it's just an autumn bonus.
I've personally always considered mid/late May to be summer simply because of very mild/warm temperatures, extremely long days and decent sunshine hours with sun that actually has some kick to it (unlike September).
as ocean temps rise due to global warming, be at the forefront of any impacts caused by GW, as oceans tend to be the first to respond to global temp rises due to their large thermal capacity.This makes not much sense to me. The cause of global warming is increased energy being trapped in the atmosphere, this leads to increased air temperatures. But I would expect that oceans would be the *last* to respond due to their high specific heat- in other words they can absorb a lot of this extra heat without increasing much in temperature.
I would have expected land masses to be more susceptible to change.
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This is an exciting one. Thanks for the updates.
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Saw some pictures the other day of a DOC "office" on Raoul, the roof had taken a real battering and not much was left- but structurally it seemed to stand up fairly well. I don't know what the sustained winds speeds/gusts were there though.
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Drought worsens, despite a bit of rain earlier in the week. I swear I saw some new blades of grass the other day.
http://www.stuff.co.nz/waikatotimes/4391588a6004.html
Check this out:
Wow! Top picture is last August, second picture is 6 months on, February. Location is Scotsman Valley in central Waikato.
Forecast is for sunny weather and highs of 26-28C until Sunday/Monday when humid northerlies are hitting and will bring either rain or drizzle along with uncomfortable nights.
Waikato is now officially in the grip of a drought.The regional council yesterday declared the region a drought zone.
It is now officially the driest summer the Waikato has experienced since records began more than 100 years ago - and the first time ever such action has been taken.
Environment Waikato is urging all communities to conserve waterand plan for weeks more of dry weather.
Dairy farmers are the hardest hit, but the lack of rain is being felt by all - from horticulturists to small block owners and gardeners.
Environment Waikato chairman Peter Buckley, who also owns a 68-hectare dairy farm in North Waikato said he never thought he'd see the day.
"I've lived and farmed around here for 56 years and I've never seen it like this 1973/74 was pretty bad as was 1997/98 but nothing like this."
Ngarua dairy farmer Sue Fish said the situation was dire.
"There's nothing you can do, you're probably eating into supplements you would normally have fed (to animals) in autumn."
"It's a case of monitoring it from day to day, watching cow condition, and trying to make moves that will get you through it," said Mrs Fish.
She advised younger farmers who had not previously experienced current conditions to "hang in there, and talk to your bank manager".
Otorohanga dairy farmer Tony Van Grootel said the unrelenting dry conditions were getting pretty tough.
"I've just bought in 50 bails of silage, and it's getting pretty expensive. It's costing $100 a bail landed on the farm. A lot of the neighbours are in the same situation."
Mr van Grootel said if substantial rain did arrive, farmers would still need a month's worth of supplementary feed while grass grew back. If substantial rain did not arrive, he would begin drying off his cows. Low producing cows would also be likely to be culled. His stock had already begun to drop body weight due to the lack of pasture.
Matamata orchardist Stewart Broomhall said he agreed with Agriculture Minister Jim Anderton, who visited the Waikato this week, that the region was the brownest he had ever seen it in nearly 30 years.
"It's a long time between drinks, isn't it?
His orchard wasn't showing the effects of the drought to any great extent, but he feared a big dump of rain could affect the quality of fruit on royal gala apple trees, with fruit splitting near the stem.
Strawberries had also stopped abruptly because of the lack of water, he said.
Wearing his EW hat, Mr Buckley said the regional council's role was largely an advisory one at this stage.
"We will help people where we can, but one of the main areas for us is controlling water flows around the region. In a lot of places they are at dangerous and record lows. A lot of water inlets are getting stretched.
"We need people in the country areas and the city to use water a lot more conservatively."
By declaring the drought Mr Buckley hoped central Government would start to pay more attetnion to the region's plight. .
He said the Hauraki Plains, Matamata-Piako district and parts of Waipa were among the hardest-hit areas.
"We need steady rain over a number of weeks to get back to normal. We really are in the laps of the Gods now."
A drought response group has been set up and includes representatives of Dairy NZ, Environment Waikato, Federated Farmers, Meat and Wool, Ministry of Agriculture and Forestry (MAF), and the Rural Support Trust. The group's role is to ensure co-ordination of information and action and to represent the Waikato region at national level.
Rural Support Trust chairman Neil Bateup said the farming community should be pro-active about planning for the next couple of months.
"The lessons that we've learnt from areas like the East Coast are that the people who acknowledge that there is a problem are the ones that come out the other side better."
A national drought meeting of government officials and sector leaders is scheduled in Wellington on Tuesday.
*To contact the Rural Support Trust, call 0800 787 254 or 0800 RURAL HELP
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Going to miss NZ but I think the wind over the upper North Island is going to be increased as she tracks by. I wouldn't fancy being on Raoul Island at the moment though!
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Looks like Gene might head towards NZ, but there will be high pressure over the country by then. What's the chances of ex-TC Gene bringing rain to the North Island?
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Wow thanks for that JO
I lived in Westport (West coast S.I ) for a number of years and it was very green and lush. Canterbury was always drier, but don't remember it being quite so bad.
Do you think the mountain range has anything to do with it?
My daughter says it is very warm in Westport at present.
As a child in the 60's I remember there being hose bans in Auckland, it was so hot the ashfelt was melting on roads and the tar would stick to your shoes (jandals) ugh!
Want Switzerland? - See Queenstown.
Want New Zealand? - See Westport.
(Westport's fairly recent campaign to attract tourists
)I'd say the mountain range has everything to do with it- down in Hokitika, there's a catchment in the gorge that might record 12m of rain in a fairly wet year, a few dozen miles to the east, in Canterbury, they'd probably be looking at maybe 0.7m in the Mckenzie.
Think Wesport hit 25C today - and probably will be one of the better places to be in NZ right now as it's sheltered from the southerly.
As for your story about shoes sticking to the tar in Auckland- maybe that is why everyone wanders around the city barefoot now
:unsure: -
This season started off with a horrendous October- wet, cold and with many many high winds. Unseasonal late frost caused vineyard damage. Then suddenly November's second half made that month one of the warmest and driest in a long time. Not a good start to summer, unless you're a holiday maker (and plenty of those about!).
This transitioned into January which has ended so dry that I feel it may be worth a thread in extreme weather- since it may develop into something worthy of that description.
February has begun with hot, dry Nor'Westers starting fires in the south, followed by a cool southerly change bringing rain. Christchurch was up to 34C today, and in one hour dropped from 32C to 18C as the S pushed through.
There are some almost unbelievable stats coming out from Jan, which you can access here:
http://www.niwascience.co.nz/__data/assets...990/0801sum.pdf
A basic summary in my words:
Rainfall
This is the big one. Basically, for almost the entire population of New Zealand, rainfall has been below 50%. For perhaps 50% of NZ, rainfall has been below 25%. The worst hit area is the Waikato (this is an area south of Auckland, centred on the city of Hamilton). Anyone seen Lord of the Rings? Matamata, the green and pleasant vale where they filmed Hobbiton has only got 4% of its January rainfall. Various areas in the Waikato and east/central South Island have also got <10% of average rain. Considering the cumulative effect of the dry November, this has obviously created major issues. When you see pictures on the news, you have skinny sheep running across land that looks hot, barren, dusty and entirely infertile. Totally unsuitable for sheep farming. In other words- looks like Australia. But it shouldn't be like that at all. All the grass has died, all that remains is scrub.
NIWA are saying that even with normal rainfall, it won't be enough.
Media report:
http://tvnz.co.nz/view/page/1318360/1567903
As you can see from this, it's not just a dry January that is ruining things, it's that the dry weather is looking to run all the way from November until April (at this point), adding up to some major problems that many parts of NZ do not see as often as other countries.
Temperatures
Highest temperature is 35C. Not unusual, and not all that special at all. What has caused problems is the 3 weeks period where the South Island was hitting at least 30C every day (other than 2 or 3 days I think).
Alexandra in Central Otago has had an average January maximum of 28.2C. That is 4.5C above normal! Pretty extreme stuff. Will be interesting to see how this impacts on vines and fruit they grow up there.
Alexandra is the driest town in New Zealand, getting similar rainfall to Alice Springs.
In fact, many areas of NZ in general have been getting average maxima more akin to that of the Mediterranean (normally, NZ summers are cooler that there). An interesting one is Chateau Ruapehu, averaging 20.2C, 2.5C above normally. That is on the central plateau, I would guess at something like 1200m ASL.
Sunshine
Sunniest January ever for Southland and Otago. Above average everywhere else, except Northland (rubbish weather in January - wet, cool and cloudy). Some areas have been averaging 10 hours of bright sunshine per day.
Wind
Highest gust was 98 mph, due to ex-TC Funa.
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Further media reports:
http://www.stuff.co.nz/waikatotimes/4373371a6004.html
Please let it rain
A hot summer is bringing Waikato farmers to their knees as continuing dry weather costs tens of thousands of dollars in lost production.Paddocks have turned to dust and farmers are struggling to feed stock following one of the earliest and longest dry periods in the region in 15 years.
FarmWise consultant and Kereone farmer James Thomas said the situation was dire and the ramifications serious.
Mr Thomas said even if a farmer lost only five per cent on an average 100,000kg/milksolids farm, that equated to a loss of $35,000 in production, not to mention supplementary feed costs. "We only milk 180 cows and I've just bought 30 tonnes of feed and it costs $400 a tonne."
The lack of rain combined with a poor spring has resulted in a shortage of supplementary feed and the relief of maize silage is still two months away.
The cost of feed has skyrocketed, with grass silage bales up to about $100 each compared to $70 last year, and palm kernal up to $450.
"People are really getting into a situation where they're having to cull cows earlier or get rid of stock," Mr Thomas said. "If they haven't grazed calves out they're trying to do that. It could be very serious."
Farmers had hoped for "some decent" rain over the weekend but the drizzle that finally arrived was not enough.
"We need a huge amount of rain ... and follow-up rain. If it remains dry now there are huge ramifications," he said.
Matamata farmer Ross Sainsbury, who milks 220 cows, said the drought was hitting his herd. "If you listen, in the background you'll hear my cows crying out in hunger. It's pretty devastating listening to these animals making this noise.
"It's just a matter now of feeding what we can afford to feed, and then reducing numbers by getting rid of surplus animals to somewhere, which basically means we'll have to cull them."
Worse than that, Mr Sainsbury will have to stop milking his cows. "I'm going to have to take some drastic action in the next 10 days ... drying a significant proportion of the herd off. If you stop milking them it reduces their feed intake by about half."
http://tvnz.co.nz/view/page/423466/1563992
Drought hurting farmers
Drought hurting farmers and stock Jan 30, 2008 7:02 PMFarmers are becoming desperate for stock feed as drought conditions bite around the country and some have to spend thousands of dollars a week just to keep their animals from starving.
"Its getting quite serious...I mean I can see guys having to walk off," says Ken Tomlinson.
Tomlinson, an Omihi farmer, is determined not to let that happen to him, spending more than $2000 a week to keep his animals alive on his dry North Canterbury farm.
There has been some light rain in the past 24 hours for the farm, but it's evaporating almost immediately.
Its nearly five years since the area had any decent rainfall at all and even if the much needed rain does arrive by the autumn it's unlikely to penetrate the ground because it's so rock hard.
Farmers say many paddocks will have to be re-sown to get new grass in the future.
"The temperature's been getting up to 42 degrees Celsius, so no self respecting blade of grass is going to grow in that temperature," says Alec Baxter, another Omihi farmer. AFAIK, this 42C is unconfirmed, probably to remain that way.
In the North Island, the drought has seen milk production fall down 12% in the Waikato; some herds are even dry. There are so many sheep farmers wanting to quit stock that there are killing queues at the country's meat works.
http://tvnz.co.nz/view/page/423466/1568337
Canty fires
Canterbury dry conditions spark fires Feb 1, 2008 7:26 PMCanterbury's tinder dry conditions and one of the hottest days of summer have had firefighters stretched to the limit battling a series of blazes.
A scrub fire threatened homes near the North Canterbury town of Swannanoa on Friday and another broke out in nearby in Rangiora.
In Christchurch itself, smoke from two other fires drifted across the cty.
Helicopters were brought in to hit the multiple burning fires in a rural settlement north of Christchurch.
"The north-westers spread it throughtout the pine trees and the hedges it's just been fanned all over the place," says a firefighter.
The fire started in a paddock and quickly spread, threatening homes.
Forty ground crew from around North Canterbury took two hours to bring the blaze under control.
"It's got into a couple of plantations and it's crowned through them so it was definitly a building fire for a while," says Tim Sheppard, the Principle Rural Fire officer.
Just across the paddocks, 11 fire appliances were still battling a blaze in Rangiora.
Central Christchurch suffered too with firemen at the scene of a blaze near Hagley Park.
"What we're trying to do is hit these things hard and fast, because the country side is ripe for burning," says Sheppard
And while a southerly change has dumped some rain further South, the outlook is for more dry weather.
Wonder what February will bring? We are entering into the warmest 3 weeks of the year, and this is also the driest month. So it doesn't bode well at all, but who knows for sure?
The other problem is that March is generally considered to be a "summer" month, as it is warmer than December in a large number of regions. It also tends to have more settled weather.
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Beeb have done windchill for as long as I can remember:
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Hi,
I read in a Times column, a while back, that the highest levels of UV occur in Peru. I remember viewing this UV chart for Australia and seeing a 19 - http://www.bom.gov.au/weather/national/charts/UV.shtml
I sometimes look through the UV measurements in the UK to see what we can achieve in the summer months. http://www.hpa.org.uk/radiation/understand..._data/index.htm Camborne peaked at 9 a couple of years ago.
http://environment.newscientist.com/channe...-city-peru.html Found it...Cuzco, that's the one. A high of 25 where 300 000 people live up in the Peruvian andes.
Not too sure on all the calculations, sorry can't help you there. I have always just focused on the records.
Great links, thanks. The HPA site was good for a look, the sun really is extremely weak in the UK isn't it.
That reading of 25! :lol:
Wow....I can't imagine what that feels like. And, as you say, a decently populated area. Yikes.
On the subject, here is an interesting development:
Real-time UV Index display
First prototype at NIWA Lauder before installation at Alexandra swimming pool
Second prototype in use at the Goldrush Multisport Event in Central Otago
NIWA has developed a real time UV display in consultation with the Cancer Society and Sunsmart. The first prototype is currently installed at the new Molyneux Aquatic centre in Alexandra. Current UV intensities are sensed by a detector designed to measure the sun burning UV from the sun and sky that is incident on a horizontal surface. The signal is amplified and then displayed by means of servo technology that is used in model aircraft.
A large pointer displays the current intensity of UV, in terms of the internationally agreed UV Index scale. The scale is subdivided into 5 different regions corresponding to 5 different behavioural responses. For UVI values less than 3, the risk is “low” and the colour code is green. UVI values exceeding 10 are designated as “extreme” and colour-coded purple.
The display is solar powered, making it useful for outdoor sporting events (e.g., tennis, cricket, athletics, etc). We are seeking sponsors to cover the costs of calibrations. The UVI scale was originally used in Canada, where its maximum value was designed to reach 10. In New Zealand, the peak UVI can exceed 13 near midday in summer.
Basic units like the one shown here would cost about $3000. We are currently investigating other options including larger versions and double sided versions, and solar powered versions. All units would be offered with the option of an additional maintenance contract, which would include calibration of the display. All units would include the NIWA and Sunsmart logos, but there are spaces for two other advertisers (to effectively pay for the maintenance fee).
For more information please contact Dr Richard McKenzie at r.mckenzie@niwa.co.nz with a subject line containing the text “UVI Display”.
http://www.niwa.cri.nz/services/free/uvozone/uvi_display
Seems like a good idea to me. Who really checks the UV forecast before heading to the beach? To have something there it might perk people's attention to the danger....of course the onus would still be on them to act.
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I see "Bandwidth Exceeded - Upgrade to Pro"
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Hi all,
Today I was looking at the UV index, and apart from thinking "gosh that's high" and I started musing over records, and the effect of altitude.
If you look at the first photo, there's a cluster of three mountains at the bottom. The UV index for the nearest town is 13. UVI in NZ tends to be 40% greater than corresponding latitudes in the USA or Europe. This is for clear sky of course. I've also attached a "cloudy sky" UV forecast. I got these from www.sunsmart.org.nz and www.niwa.cri.nz/services/free/uvozone (both free for all).
For most areas cloud has not been having much effect.
Anyway, one of those cartoony mountains gets up to 2800m* , and at this time of the year, going up there is quite popular for serious climbers. There's also the most popular one-day walk in NZ which gets up to 2000m**, and in mid summer I expect it's like Oxford Street. You can bet your bottom dollar a number of people who go up there are not prepared for any mountain hazards, including high UV...as it is sold as an "easy" walk for everyone to do.
So, my question is, what sort of UV are these people exposing themselves to? Is there a simple way of calculating how it changes as you move upwards? Or even just an average approximation would be helpful. eg we can estimate lapse rate in the atmosphere under "normal" conditions to be between 0.6C and 1C....does something similar exist for UV?
This comes onto, what is the record UV index ever recorded? Wikipedia claims 17 for Carnarvon, Western Australia. I assume this is a sea level record. For an extreme example, surely if you go up the mountains in the northern Andes, you are going to be hit seriously hard.....even harder than 17 I would guess.
Or is there some kind of limiting factor on our planet which prevents the UV increasing without bound?
I suppose if we were looking for the place with the highest UV, it would be in the Southern Hemisphere, and at altitude. I would guess at the mountains of New Guinea.
Any input appreciated.
cheers
* Rumour has it that some people still think in "old money". I have looked this up and it is 9200 ft.
** Likewise about 6000 ft
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The amount of factual, synoptic and statistical detail contained in these old newpaper reports never ceases to amaze me, it seems to be something we lost somewhere around the late 1960s. I very rarely buy a newspaper ( although I do occasionally flick through one if it's lying around ) but I'm sure that even in the Daily Telegraph or the Times there isn't the amount of detail in weather related stories there used to be in earlier decades.
It seems the media now reduces everything to small, easily assimilable, bite size chunks and perish the thought that a 'technical' word might creep in to spoil things.
Surely we haven't all been reduced to the level of Harry Hill's t.v brother, Alan. 'If it's too hard, I can't understand it'
Honestly, I'm not sure those articles were all that technical. The weather forecast itself, yes. But the reports, not really. Yes, they go into more detail than we would expect now on the likes of time and quantity of snowfall, but there's nothing too brain taxing in there.
Weather still commands a lot of space in papers now. Frequently a double page spread. We still get detail on temperatures and rainfall, but not in for so many localities. The reports tend to nowadays look at how it has affected people. Sadly, this does mean that space is given to nonsense that some may spout, often along the lines of "we've never had it like this before", without any evidence, other than anecdotal, to back up the claim.
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http://www.metoffice.gov.uk/weather/impact...1/18433975.html
Blimey, that is uncomfortable. The rain looks like it's very welcome though.
weather.com reports Wellington at 28C, Dewpoint 18C and gusty northerlies. Such temperatures are rare around Wellington harbour, especially at 11AM!
Watching Sir Edmund Hillary's funeral, no sign of rain in Auckland yet, though the North of the SI is having heavy rain right now.
However, a southerly change is working its way up, only 10C in Stewart Island.
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I thought people might take an interest in a general, irregular report on the weather in New Zealand. Obviously, it is summer at the moment, with January being the equivalent of July in the Northern Hemisphere.
I often find that in the UK, the perception of NZ's climate can vary quite a bit. Some talk of it as though it's as hot as Australia (that's why they don't serve beer in pints, right?), whilst others are convinced it is more like Scotland- wet, windy, cold. Obviously, both are quite wrong as generalisations. I usually sum it up by saying it's similar to the UK only sunnier, with more reliable summers and milder winters. This is probably true for about 90% of both populations.
The recent weather has been mostly fine, with an exceptionally warm and dry November beginning the all too common summer drought for Hawkes Bay farmers.
Several areas recorded record November temperatures, along with sunny conditions and very little rain. This was after a generally cold and extremely windy October. December was a fairly average month, and January so far has been mostly anticyclonic.
It's a contrast to last year which had a wet and cool November/December (2006) and a slow start to January, all of which ultimately led into a good autumn and a classic Indian summer with May being the warmest ever. If I recall correctly, wellington only reached 14C on New Years Eve 2006, making it one of the coldest in history.
The current highest temperature of the summer so far is approximately 35C in Timaru. This is roughly 2/3 of the way down the South Island on the east coast, lying at about latitude 44S. The warmest part of the year is often the first two weeks of February.
Climate:
I personally find the climate of New Zealand very interesting. I may have been a little belligerent in the past when arguing this, I apologise for my tone in those cases. Without a nearby continent, initially it doesn't seem like there can be much interesting going on. But the topology of the country itself creates its own fun. Extensive mountainous areas, mixed with a maritime climate makes things very exciting at times. Lots of "highland" areas contribute to all-but guaranteed snow in winter for certain localities- something in the region of 70% of New Zealand is between 200m and 700m ASL.
The rain shadow effect can be very strong indeed. All who are fascinated by the Pennine Rain Shadow would enjoy the much greater contrast you can find here.
New Zealand is fortunate in being able to grow anything that grows in the UK, but also crops that would not really be commercially viable on a large scale in the British Isles, such as olives, grapes, tamarillos, kiwifruit, feijoas and citrus.
The capital city, Wellington, has an extremely temperate climate. In an average year, the summer highs will be about 21C and winter highs around 12C. For this latitude, the summers are very cool. Wellington itself is known for the wind. Most often it is from the North, being relatively warm and humid but never uncomfortable. Southerlies are most common in winter and tend to bring rain or squally showers followed by cool, sunny weather. Unfortunately, southerly changes also occur in summer, although they lack any real bite and rarely persist. They tend to lead to highs of 16C-19C. Temperatures rarely exceed 26C under any conditions. The city is clustered around the harbour on a narrow peninsular in close proximity to the extremely windy Cook Strait.
Suburbs to the North of the city have a different climate, being in valleys the summer temperature will quite often get over 28C. Recently, whilst the temperature in Wellington city was at a maximum of 23C, just up the valley in the suburb of Upper Hutt it was 32C.
The "dividing range", the Tararuas, rise to about 1800m and are known for their appalling weather, with something like 80 fine days per year and frequently getting hit with high winds. To the east, is the Wairarapa, one of the most "marginal" wine growing regions of New Zealand, which is quite a marginal country in itself. The area is quite windswept, and vineyards make great use of all sorts of technology to protect against the wind and dangerous late Spring frosts. Both cold southerlies and hot, dry north westerlies can hit here.
For a city that is roughly the antipode of Salamanca in Spain, people may be disappointed by wellington's climate, however it's not all bad. Firstly, there is the beautiful harbour and mountainous backdrop. But, as they say, if you want the views and the sun you must accept the wind. Wellington is New Zealand's sunniest "major" city. In 2007, it hit 2230 hours, which isn't bad considering so many people complain about the weather here.
Auckland is New Zealand's largest city and is warmer, more humid and wetter than Wellington. Summer highs are 24C. Winter lows about 14C. It rains a lot in winter, and a fair bit in summer also. January and February tend to be quite muggy, and warm temperatures tend to persist until the end of April. It is rare to see temperatures over 30C, due to the geography of the city. Summer sea breezes often converge from the SW and NE and produce a fair bit of cloud and sun showers. Winter is short and barely warrants the description, unless you live in a typically uninsulated kiwi house. So that'll be one million cold people then.
One of the best features of the city are the beaches. Straddling a thin isthmus of land, residents have access to both East and West coast beaches. So, a choice of golden sands and crystal waters or volanic black sand and wild, surf beaches. The water here is quite warm and good for swimming for much of the year.
The peninsula to the North is called...Northland and is similar to Auckland only warmer and more humid. This is where the smallest difference occurs between summer and winter temperatures. Warm weather persists until June. Certain regions grow pineapples and bananas. Whangarei (the only city) was the warmest location in New Zealand in 2007, with an average temperature of 16C. People say Northland has only two seasons - dust and mud.
Christchurch is the South Island's only major city. It exhibits a stronger seasonal change. Winter highs are about 10C, with cold nights, and summer highs about 22C. Frequently, it will be the warmest of the major cities, due to the foehn wind. The prevailing wind in summer is the NE sea breeze. However, all too often they suffer from the Nor'wester foehn. Anyone who has experienced a wind like this in the world does not need it described, however, the majority of people don't like it! I think it's OK in small doses, for the novelty!
The geography of Canterbury (the province of Christchurch) stretches from the sea to the Southern Alps. These stretch to a height of 3800m ASL. On the eastern side lies the MacKenzie country; a dry, relatively flat basin about 700m ASL. It is ringed by mountains on all sides, as further east you come to the Foothills of the Southern Alps, beyond which lie the Canterbury plains. Christchurch lies on the far eastern side of the plains, perfectly in the path of accelerating foehn winds. The mountains are "conveniently" oriented roughly North East-South West, meaning they form a natural barrier to the prevailing westerlies (NZ lies in the Roaring Forties).
On the Western side, the Alps, in only 20 miles can fall all the way from 3800m right down to the sea. This gives perfect conditions for tropical-like downpours on the West Coast, which is wetter than most places outside of the tropics, with similar rainfall to Vancouver Island in Canada. Due to this, rainfall can vary by a factor of 20 or more over less than 80 miles.
Christchurch is able to get snowfall in some winters, although usually this is reserved for more inland or highland areas.
The record high temperature for Christchurch is 42C, and the record low is -7C.
The other two "major centres" are Dunedin and Hamilton. Dunedin has a cooler climate again, whereas Hamilton is similar to Auckland but being inland has warmer summers and colder winters. It has recently had quite a warm period, hitting at least 28C for several days in a row.
Despite this, most amusingly, Dunedin recorded the highest temperature of anywhere during the winter months (22.4C), which would probably come as a surprise to most New Zealanders! The average summer high in Dunedin is 19C.
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At the moment, high pressure is in charge still, with the orientation giving south easterly winds to many areas. Certain locations get hit relatively hard by this, with Napier only reaching 19C under such conditions, more like a late Spring temperature.
Cyclone Funa may have an impact sometime in the week.
Daily highs across the country have been varying from 33C in the Bay of Plenty (North facing bay in the NI) to the likes of 14C in Southland.
I'm pretty sure there's the odd Kiwi on this forum, hopefully they could add to this and correct my mistakes.
The attached image (from www.metservice.com) I found interesting just for the obvious foehn wind effect. 21% humidity, 33C at 4PM with wind from the North west. This is followed by a southerly change. In winter the respective temperatures would be more in the region of 20C-22C in the NW followed by high single-digits in the S.
There is a range to the west of Blenheim (Richmond Ranges) which is causing this. It's not very big, gets to about 1800m, and is "the only bit of the North Island on the South Island".
I've also pointed out two lesser-known places on the rain radar map. The red blob on the SI is Blenheim, on the NI it is Napier.
(Not isolated heavy showers
)The only interest Blenheim holds to British people is that it's the centre of the Marlborough wine industry. So if you've ever had Marlborough Sauvignon Blanc, there you go.
Napier is the centre of the Hawkes Bay wine industry, probably not so well known in the UK, unless you're into your Gimblett Gravels.
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Jan 21st:
Ex bad-girl Funa has made the weather interesting of late.
Attached are the 10PM temperatures across NZ.
High humidity, high temperatures by day and pretty warm nights, but with very welcome rainfall for certain areas, which have been deprived recently.
http://www.metservice.com/default/index.php?alias=warnings
A deep depression, formerly Tropical cyclone Funa, lying about 420km west ofCape Reinga at 6pm Monday is moving quickly southwards and expected to turn
southeast on a track which will take it across northern Westland and Canterbury
during Tuesday afternoon.
The passage of the low is likely to be accompanied by a spell of
gales about central New Zealand from mid morning to late afternoon or
evening.
The strongest winds are expected in Taranaki,Wellington, Hawkes Bay
south of Hastings, Wairarapa the Kapiti Coast, Nelson, Marlborough
and north Canterbury. In these areas northerly or northwesterly wind
gusts of 110 to 130 km/h are possible. Winds of this strength have
the potential to damage trees, utility lines,and roofs, and make
driving hazardous.
Ahead of the depression humid tropical air with outbreaks of rain has
spread over the North Island and northern South Island. Heavy falls
are likely about Mt Taranaki and parts of Nelson, northern
Marlborough, Buller and Westland.
Between tonight and Tuesday afternoon 80 to 120mm could fall in the
ranges, and up to 160mm is possible about the Westland ranges.
People in these areas are advused to watch for rapidly rising rivers
and streams,surface flooding and slips.
Also a large northerly swell is expected to spread into Golden and
Tasman Bays which could produce abnormally high tides and, combined
with strong northerly winds and heavy rain in the Nelson region,
could threaten some lower lying coastal areas.
Currently, at midnight it is 22C, with a 17km/h North-west wind.
On the "media sensationalism" side, we have:
Best summer in 10 years? (It's barely started!) Almost continuous 3 week stretch of 30C temps for the South Island....grass no longer growing....sounds lovely.
http://www.stuff.co.nz/4365419a11.html
It's official it's New Zealand's best summer in nearly a decade. Niwa climate scientist Jim Salinger says the last time it was this dry and settled was during the summer of 1998-1999 - also one of the warmest years on the planet last century.The longest hot dry spell this summer has been in the east of the South Island which has had temperatures of at least 30C on all but two days from December 30. This beats the 2004-2005 summer when most areas had a 10-day stretch of at least 30C.
Grass has stopped growing in those parts of the country which have had two weeks without rain.
The end of the golden weather bringing relief to farmers is expected today in the North Island as Cyclone Funa brings moist air from the tropics.
MetService weather ambassador Bob McDavitt said the cyclone was likely to bring persistent and intense rain to much of the North Island and into Nelson tomorrow.
On Tuesday it is due to merge with another depression crossing southern and central districts, bringing widespread wind and rain.
McDavitt said the heat might return at the end of the month, and February's temperatures could be higher.
This month, temperatures were 1C above average, compared to 1.6C higher in January 1999. The hottest place so far this summer has been Timaru, which sweltered under 35C on January 7 and 12.
The Jet Stream and Us
in Spring Weather Discussion
Posted
OOC, how do they obtain the wind speeds for that high up? I am guessing that geostrophic and gradient wind theory only works roughly at sea level, so is there a way of modelling jet streams, or is it all observational data from balloons (or the like)?