Met Society Newsletter

NOVEMBER WEATHER CLIPPINGS

For a printable pdf of this newsletter : http://metsoc.rsnz.org/Newsletter/clipsnov2008.pdf 

MetService shrugs off Far North mayor's icy blast

Saturday Nov 01, 2008 By Angela Gregory NZ Herald

Wayne Brown. Photo / Northern Advocate

Each year the MetService aims to detect and warn of at least 75 per cent of all significant wind, rain or snow events.

And each year it outdoes itself, says weather ambassador Bob McDavitt.

This week the weather forecast service came in for a blasting from Far North Mayor Wayne Brown, who blamed it and television news for thousands of holiday cancellations in Northland over Labour weekend.

Mr Brown was scathing of television reports of a "Noah-like storm" that he said were based on MetService information. He demanded an apology from the service, which he argued was ultimately responsible for the negative predictions.

The MetService has denied any wrongdoing, saying its weather warning played down the significance of any wild weekend weather.

Mr McDavitt said yesterday that MetService records showed it was well exceeding its targets for detecting 75 per cent of heavy rain, snow or wind events. In the 12 months to June it had detected 95 per cent of heavy rain events, 87 per cent of severe snow and 94 per cent of severe gales.

Mr McDavitt said the service was also beating other targets, including that no more than 40 per cent of its warnings turned out to be false alarms. There were just 27 per cent false alarms for heavy rain, 29 per cent for heavy snow and 20 per cent for severe gales. "We are doing okay but we want to do better."

Mr McDavitt said the MetService was therefore changing its targets with an aim to achieve in the next four years a minimum 95 per cent prediction of severe rain warnings.

Philip Duncan, head weather analyst at Weather Watch, said he generally found the MetService to be accurate. He said there had been some heavy localised downpours in Northland over Labour weekend but a lot of the rain had fallen out to sea.

Ozone hole the size of North America

 Wednesday Nov 05, 2008 NZ Herald By Angela Gregory

The blue and purple colours represent the area with the least ozone. Photo / NASA

The Antarctic ozone hole grew to the size of North America in September, the fifth largest recorded in nearly 30 years.

The information released yesterday by the United States National Oceanic and Atmospheric Administration (NOAA) said the ozone hole fluctuated in response to temperature and sunlight.

It had grown to the size of North America in a one-day maximum in September, making it the fifth largest since NOAA satellite records began in 1979.

The primary cause of the ozone hole was human-produced compounds called chlorofluorocarbons, or CFCs, which released ozone-destroying chlorine and bromine into the atmosphere.

Earth's protective ozone layer acted like a giant umbrella, blocking the sun's ultraviolet-B rays. Though banned for the past 21 years to reduce their harmful build-up, CFCs still took many decades to dissipate.

The NOAA scientists found that colder than average temperatures in the stratosphere played a part in allowing the ozone hole to develop more fully this year.

Nasa satellites measured the maximum area of this year's ozone hole at 27.2 million sq km and 6.4 km deep on September 12.

Bryan Johnson, a scientist at NOAA's Earth System Research Laboratory in Boulder, Colorado, which monitors ozone, ozone-depleting chemicals and greenhouse gases around the globe, said weather was the most important factor in the fluctuation of the size of the hole from year to year.

"How cold the stratosphere is and what the winds do determine how powerfully the chemicals can perform their dirty work."

Greg Bodeker, Niwa principal scientist, told the Herald the ozone hole was shrinking, but very slowly. He said the chemicals that mostly depleted ozone, chlorine and bromine, were decreasing at about 1 per cent a year but there were annual variations.

Dr Bodeker said it was estimated that ozone would return to 1980 levels in the next 60 to 70 years. Increases in greenhouse gases had contributed to the problem as they trapped infra-red radiation which warmed up the lower atmosphere, or troposphere, up to 15km altitude.

The upper atmosphere, or stratosphere, became cooler as a result, which promoted Antarctic ozone depletion and delayed the recovery of the ozone hole.

Caution urged on South Island roads

Nov 5, 2008  TVNZ

South Islanders have woken to some unlikely spring weather with snow falling for the first time in years in downtown Invercargill.

Snow fell in Invercargill right down to sea level, covering the city with one to two centimetres of powder.

MetService says it's unusual for this time of the year.

Snow's also fallen in Southland through to Southern Otago and Dunedin.

Weather Forecaster Leigh Matheson says motorists should expect snow on roads.

Matheson says the snow is a result of a cold snap and it will continue through the day.

Motorists in the southern South Island are being warned to drive with caution following a dumping of snow.

The Manawatu Gorge also remains closed on Wednesday after a large slip closed both lanes of State Highway 3.

Snow to make way for fine, frosty Election Day

The Press | Friday, 07 November 2008  The Press

David Hallett

Snowvember: Unseasonable weather brought snow overnight to the Port Hills.

Snow is falling in parts of Canterbury this morning but meteorologists are predicting fine, sunny conditions for election day.

Metservice weather ambassador Bob McDavitt says there will be a frosty start to the day for many South Island and central North Island areas.

"Temperatures on Saturday will still be somewhat on the cool side of average. Wellington, Christchurch and Dunedin are forecast to reach a mere 12 degrees and Auckland 17.

Over 100 lightning strikes in hour

PAUL EASTON and BRITTON BROUN - The Dominion Post | Fri, 07 November 2008

MATT VELDE

WHITE ROAD: Hail on the Wellington motorway this afternoon as storm hits.

Surface flooding has been reported between Tawa and Porirua following a sudden storm, which broke hit Wellington, Marlborough and Wairarapa and included more than 100 lightning strikes in hour.  Metservice spokesman Andy Downs said hail had fallen around Wellington, including the suburbs of Johnsonville and Karori. More than 100 lightning strikes had been recorded around Wellington, Marlborough and Wairarapa between 2pm to 3pm.

Canterbury vintners on edge

Nov 7, 2008  TVNZ

The next few mornings will have vintners on edge as they anticipate frosty starts.

MetService is forecasting a fine but frosty start around Canterbury at least Saturday morning and maybe on Sunday as well.

Pools take a pounding as heat of summer hits SC

South Canterbury | Monday, 17 November 2008 Timaru Herald

NATASHA MARTIN/Timaru Herald

COOL TIME: The Caroline Bay paddling pool was the perfect place to cool off yesterday. Enjoying a splash are, from left: Jorja Peterson, Georgia McLean, Tylah and Maison Laplanche.

SUMMER arrived. South Canterbury sweltered.

Yes, the MetService had predicted high 20s for Saturday, and yes, they delivered - all 31C.

There was no need to tell South Cantabrians that summer had arrived just in time for the annual Geraldine Arts and Plants Festival, summer sports and social events.

The maximum temperature recorded at the Timaru Airport on Saturday was 31C, the warmest temperature recorded this month.

It wasn't just Timaru that was in the heat on Saturday. The Shell service station at Twizel recorded a temperature of 27C on Saturday, while yesterday by 1.30pm it had reached 20C. Cashier Grace Butler said there was a record number of people pumping petrol into their boats to enjoy a day out on the water.

Hailstorm causes severe, expensive damage in Ashburton

Walnut-sized hailstones

Tue, 18 Nov 2008    3News

Walnut-sized hailstones have pounded Ashburton causing millions of dollars worth of damage.

The hailstorm only lasted five minutes, but it will take lettuce grower Rodger Withell months to recover.

While his glass houses are wrecked and his produce has been showered in debris, it is the noise from yesterday's storm that sticks in his mind.

“It just sounded like bullets going off. You couldn't hear. It was just that noisy it was like bullets going off,” explains Mr Withell. “The hailstones were about as big as good 50 cent pieces.”

Within hours half a dozen clips of the storm had been posted on YouTube.

For Ashburton's gardeners it has been a difficult spring.

“Last week the town suffered from a severe frost that damaged nurseries and vegetable crops,” says Laura Bootham. “What the frost didn't destroy, yesterday's hail finished off.”

For commercial growers the storm came at a cost as damaged produce will need to be thrown out.

“You can't eat glass with lettuce,” explains Mr Withell.

Experts say hailstorms usually hit in December, but they were surprised at the damage this one did.

“There's not many times when hailstorms in New Zealand cause significant damage to cars for instance by denting them,” states Blue Skies Weather Forecaster Tony Trewinnard.

Local panel beaters seem to have benefited from the weather event.

Aden Pulham has secured an extra 18 months work repairing more than $1 million worth of damage.“I got here early this morning and the first customer was already waiting pretty much and the phone hasn't stopped ringing,” says Mr Pulham.

Tornado hits farm 

Mark Story  Hawke’s Bay Today  18.11.2008

Senior Constable Alan Daly Dexter McGhie examine the vine netting.

Haumoana farmer Dexter McGhie now intends to make hay only when the sun shines.

Struggling to get his hay crop in during yesterday's mid-afternoon rain, the part-time secondary school teacher grabbed his dog and jumped into a ditch to avoid a "mini tornado" heading in his direction.

Minutes earlier, working in a paddock on his Tukituki Road property, Mr McGhie noticed a sudden drop in temperature.

"There was this weird cooling sensation, and next thing you know this vortex full of hay and dirt was headed my way," he said.

"It was like something off TV, and really scary when you know the potential of these things.

I wanted nothing to do with it, so I moved pretty quickly."

Seventy-five metres of bird netting fell from the sky as the vortex changed its northerly direction and headed south towards Haumoana.

"Two or three guys couldn't lift this netting, so it shows what sort of power we're talking about," Mr McGhie said.

"I don't know of any netting used near this property, so I'm guessing it could have come all the way from the other side of the river. This would have to rate as the most unusual event of my life."

Neighbour Mark Johnson also witnessed the phenomenon, which he said flew slowly over his house. "With the netting inside it, it looked like a big swirling spider web. It was huge, very impressive."

Metservice forecaster Ian Miller said the reports were surprising, given tornadoes were typically associated with thunder and lighting.

"Yet they're (tornadoes) not always the result of stormy weather. In this case, it's more likely it was caused by strong winds flying over rugged terrain, which can often give rise to these eddies.

"Essentially we're talking about turbulence on a big scale."

Takaka hit by worst flooding in 20 years

By STAFF REPORTERS - Nelson | Wednesday, 26 November 2008

HAYLEY GALE/Nelson Mail

WATER WORLD: Commercial St, Takaka, seen when the flood was around its peak, at about 8pm on Monday.

MARION VAN DIJK/Nelson Mail

SLIP-SLIDING: Adela Knottenbelt, 17, left and Jess Bygate, 16, both of Nelson, had fun in a puddle at the Maitai Cricket Ground.

Mopping up began Tuesday morning after what is described as the worst flood to hit Takaka since 1986.

In Nelson, a timely break in the weather saved the city from major flooding during Monday's downpour.

As the flood peaked in Takaka at 7.30 Monday night, water poured down Commercial St, which had been closed to traffic, and seeped into low-lying shops. Some shopkeepers placed sandbags around the doors to try to prevent floodwaters going inside.

Takaka was cut off from 4.45pm with both State Highway 60 in the Takaka Valley and Waitapu Bridge towards Collingwood closed by heavy flooding.

Schools in Takaka closed early on Monday to enable children in the worst-affected areas to return home safely.

Council hydrologist Matt McLarin said 300 millimetres of rain fell in the Anatoki high country within 24 hours from 6pm on Sunday to 6pm Monday. At Kotinga, just above Takaka, 200mm of rain fell in the same 24-hour period.

The Takaka River has a base flow rate of around 20 cubic metres per second at Kotinga bridge, but when the flood peaked, the flow rate reached 1500 cumecs, he said.

One of Nelson's main weather monitoring sites in Stoke received about 90mm of rain during the past three days. The average rainfall for November is about 79mm.

Forecasting advance tipped as lifesaver

By PAUL GORMAN - The Press | Friday, 21 November 2008

Millions of lives could be saved from natural disasters around the world by the biggest revolution in weather forecasting since the introduction of computers.

Weather forecasters from all corners of the globe, including New Zealand, are joining forces to push back the prediction limits of severe weather such as tropical cyclones, thunderstorms and tornadoes, torrential rain, heatwaves and heavy snow.

Extreme weather cannot be forecast accurately beyond two or three days at present but the 10-year Thorpex (The Observing System Research and Predictability Experiment) study is effectively thumbing its nose at that.

Its aim is to develop a system that will give extended-range warnings up to two weeks ahead, providing more time for communities and governments to prepare for life-threatening events.

A giant "ensemble" computer model is being developed that will combine all the best points of dozens of models used in everyday weather forecasting and, hopefully, increase the accuracy of predictions.

Thorpex Southern Hemisphere regional co-chairman Neil Gordon, of MetService, told this week's joint Meteorological Society of New Zealand and New Zealand Hydrological Society conference that New Zealand had an important role to play in the programme.

This was due to its expertise on the region's complex, chaotic weather systems and of Antarctic weather patterns.

"This will lead to a fundamental change in the way forecasting is done around the world."

Thorpex was focused on providing the best weather warnings to lessen the loss of life and property.

Gordon told The Press weather was a mixture of predictability and chaos, which meant that beyond a certain period it was almost impossible to know what the atmosphere would do.

However, Thorpex was breaking new ground.

"We are pushing back the bounds of chaos.

"We are learning more and more how to exploit chaos, in the sense that it is not completely chaotic and there are probabilities we can use. But there's a limit to how far we can do that."

The hope was the new forecast system would be specific enough to enable environmental-hazard predictions to be made, such as where landslips might occur after heavy rain, Gordon said.

Severe weather predictions of the future would likely involve probabilities, stating there was, for example, a 20 per cent chance something would happen.

Rain is pennies from heaven

By WAYNE MARTIN - Nelson | Thursday, 27 November 2008 The Nelson Mail

COLIN SMITH

GREEN FINGERS: Greenacres Golf Club course superintendent Craig Westley, left, and head greenkeeper Nick Van Leeuwen.

Nelson's unseasonably wet spring has meant utter frustration for most casual club golfers.

But for Greenacres Golf Club course superintendent Craig Westley, head greenkeeper Nick Van Leeuwen and his apprentice Hamish Campbell, the ever-present rain has been like liquid gold as they continue their final preparations for next week's Toro men's interprovincial golf tournament.

"The weather's been brilliant; we couldn't have asked for anything better," said Westley.

Floods won't keep boy from mum

Maike van der Heide - The Marlborough Express | Wednesday, 26 November 2008

CHRISTINE CORNEGE/The Marlborough Express

SWIMMING FOR MUM: Canvastown youngster James Hodgson, 10, swam through floodwaters to reach his Mother, Mary, after she became stuck on Wakamarina Road which was swamped by the river on Monday night.

A pyjama-clad 10-year-old swam through rising floodwaters to be with his mother who was trapped in her car on a flooded Canvastown road on Monday night.

Torrential rain had caused the Wakamarina River to break its banks and spill over the lower Wakamarina Rd and surrounding properties.

James Hodgson was at home when his mother Mary called from her cellphone to say she was trapped in the rising water near their home.

James and his father Mark drove to her in their four-wheel-drive but by then the water was too deep to drive into.

James said he argued with his father about what to do, but he wanted to be with his mother. He waded in, then swam to his mother's side. Although he was not afraid, James said the current was quite strong where bushes did not block the flow.

The pair were rescued a short time later by a friend in a larger vehicle.

Wakamarina Rd farmer Tony Mathews, who was yesterday clearing fallen tree branches from Wakamarina Rd, said his Niwa rain gage showed 117.5mm of rain fell in the 24 hours from 9am Monday. The day before, just 40mm fell.

Winds play havoc with Cape pointers

Thursday Nov 27, 2008 NZ Herald / Northern Advocate

DoC says aluminium signs had struggled to withstand the strong winds over the year. Photo / Northern Advocate

A famous signpost at Cape Reinga is due for a makeover after all 10 signs pointing to cities around the world were ripped off by high winds.

The signpost, next to the lighthouse, stands bare after Department of Conservation staff say wild weather throughout this year stripped the attraction of its famous pointers.

DOC visitor asset manager William Macrae said the aluminium signs had struggled to withstand the strong winds over the year and, due to metal fatigue, had been torn off in blustery gales.

"It's a tough environment up there and is subjected to sand blasts, strong winds and sea salt. The wind is so bad some days you have to be there to believe it."

Niwa records show the strongest wind gust at Cape Reinga in the past 12 months was 174km/h on July 26, from the southwest.