New Zealand - report from the drought zone

The map below shows that you almost have to travel to Fiordland to find an area that is NOT affected by drought.

Multiple fronts expected to bring wettest week of year

Radio NZ,

18 February, 2019

A front and a warm air mass will push onto the lower South Island bringing heavy falls for the next two days.

Meanwhile, NIWA says there's a chance that Tropical Cyclone Oma could directly impact New Zealand with heavy rain, wind, and rough seas heading into next week.

NIWA forecaster Ben Noll said the category two cyclone was making its way through the Pacific but might not bring immediate relief from the dry weather even if it reaches New Zealand.

Mr Noll said Cyclone Oma's path should be clearer by Wednesday.

At this stage, he said rain was expected for the Tasman region later this week.

"While rain is good, heavy rain, a lot of rain in a short period [of time] is not. What can happen is you can get a lot of rain and that will fall on our partched soils," Mr Noll said.

"The soils right now around New Zealand are kind of like concrete, so when that heavy rain falls on the soil it will just run off and that can actually lead to flooding issues," he said.

"But it's likely to produce some rainfall for New Zealand, and specifcally the top of the South Island, probably as we go through Thursday, especially Friday and maybe even Saturday.

"So a couple of days where the rain chances peak, depending on where that storm tracks there could be more signifcant impacts to parts of New Zealand, it remains unclear where that is going to be just yet."

Mr Noll said wind gusts today could reach as high as 50km/h in Tasman, but should ease back tomorrow and Wednesday.

A severe weather warning is in place for Fiordland and the MetService is keeping an eye on Westland south of Fox Glacier, and the Otago Headwaters until Wednesday morning.

The wet front over the South Island will weaken and rain will become confined to Westland by Wednesday evening.

MetService Meteorologist Mark Bowe said a ridge of high pressure remained over the North Island causing mostly fine and dry weather for today.

"Warm, moist air from the tropics will move over the upper North Island on Wednesday and produce some showers over parched areas of Northland, especially in eastern areas.

"On Thursday, warm moist air will continue to stream in over the North Island bringing very humid conditions with showers for many areas, which marks the start of wetter weather across much of New Zealand."

The wet weather is expected to spread further on Friday as warm tropical air continues to inundate the North Island with showers.

The frontal feature is likely to cause rain as it moves onto the South Island.

MetService tropical cyclone experts are keeping a close eye on the developments of Tropical Cyclone Oma.

"At this stage there is still some uncertainty across the weather model outputs regarding where Oma will move so there is no definitive answer on its exact path at this point but … we will still see some rain this weekend," Mr Bowe said.

Fire alert across the entire North Island

South Westland is the only area with a LOW fire alert

We just wanted to let you know that the roadside (arm and berm) mowing throughout the district will be put on hold until the fire danger reduces.

Stay safe everyone! Thank you for your understanding.

--Ruapehu Regional Council

Scott Steven Down here at the moment at Five Mile Bay in Taupo, its hot and dry as hell. We were among 100 motorhomes that had to evacuate the area a couple of days ago due to scrub fire, flared up twice after this photo, its still closed.

Strictest water restrictions in 18 years come into force in parts of Tasman -'We can't waste a drop'

Strict water restrictions have come into force in parts of Tasman today, as the region struggles through one of its driest summers in 18 years.

The district experienced 65 per cent water rationing in 2001, which was described by Tasman Mayor Richard Kempthorne as "really difficult then and challenging".

"But it was in March, so it was at least a month further down than this year. This year, the restriction is a lot earlier," Mr Kempthorne told 1 NEWS.

Waimea Plains apple grower David Easton has turned off his sprinkler system and has switched to a precision drip line.

"We can't waste a drop of water. We've got to use everything as efficiently as we can," Mr Easton said.

"The trees have used up all the water reserves in the ground and they're really just living on the little bit of irrigation we're giving them and so the fruits are not sizing like it would in a normal year."

Most outdoor water use is currently banned in Richmond, Mapua, Ruby Bay, Hope, Brightwater and Wakefield. Businesses in these areas must reduce their water use by 25 per cent.

The Wooden Spoon Café owner Nicky Woodbury says she has always made a point to conserve water, but this year has ramped up efforts.

"Everywhere we can, we catch water and keep it for a purpose. All of our chiller exhausts, our coffee machine - all go onto the garden so that's stopped us using fresh water that we would have quite happily used before," Ms Woodbury said.

Leaving nothing to waste, the cafe is encouraging customers to follow suit.

"We get anywhere between eight and 15 full glasses of beautiful, untouched water left on tables every day. That's always been a bit of an issue, but I guess now it's impacting everyone quite dramatically, it's more of a concern," she said.

A bund has also been built across the lower Waimea River to stop saltwater getting upstream and contaminating water supplies – with an estimated 4.6-metre king tide due at the end of the week.

Without a break in restrictions, the drought could cost Tasman more than $100 million.

With the Tasman fire still burning in the hills, the region is hopeful forecast rain for the weekend will hold true.

The devastation of a prolonged marine heatwave

The language is changing and a more realistic tone is being used compared with last year when a similar, but more serious, marine heatwave was simply put down to la-Nina.

Warm New Zealand seas could be 'devastating', NIWA warns

Newshub,

27 January, 2019

Craig Stevens and Ben Noll for The Conversation

Signs of another marine heat wave should direct attention to the serious impact of warming oceans, write Craig Stevens and Ben Noll of NIWA.

As New Zealanders are enjoying their days at the beach, unusually warm ocean temperatures look to be a harbinger of another marine heatwave.

Despite the exceptional conditions during last year's heatwave in the Tasman Sea, this summer's sea surface temperatures to the north and east of New Zealand are even warmer.

The latest NIWA climate assessment shows that sea surface temperatures in coastal waters around New Zealand are well above average. Marine heatwave conditions are already occurring in parts of the Tasman Sea and the ocean around New Zealand and looking to become the new normal.

What's in a name

Currently, marine heatwaves are defined as periods that last for five or more days with temperatures warmer than the 90th percentile based on a 30-year historical baseline. Given we are likely to experience many more such events as the oceans continue to warm, it is time to understand and categorise the intensity of marine heat.

The names Hurricane Katrina, tropical cyclone Giselle (which sank the ferry Wahine 50 years ago), tropical cyclone Winston give a malevolent personality to geophysical phenomena. Importantly they get graded into categories, so we can rapidly assess their potential impact.

An Australian team has developed a classification scheme for marine heatwaves. The team used an approach similar to that used for hurricanes and cyclones – changing conditions can be slotted into to a sequence of categories. 

At the moment it looks like we are in marine heat wave category one conditions, but potentially entering category two if it continues to warm

Turning the heat up on marine life

A marine heatwave is potentially devastating for marine ecosystems. It is also an indication that the hidden buffer in the climate system – the fact that the oceans have absorbed 93% of the excess heat – is starting to change. Individual warm seasons have always occurred, but in future there will be more of them and they will keep getting warmer.

The Great Barrier Reef has already been hit hard by a succession of marine heatwave events, bleaching the iconic corals and changing the structure of the ecosystem it supports.

Further south, off Tasmania's east coast, a number of species that normally occur in tropical waters have extended their range further south. A number of fish species, lobster and octopus species have also taken up residence along the Tasmanian coast, displacing some of the species that call this coast home. Mobile species can escape the warmer temperatures, but sedentary plants and animals are hardest hit.

In New Zealand, aquaculture industries will find it more difficult to grow fish or mussels as coastal waters continue to warm. If the same trends seen off Tasmania occur here, areas with substantial kelp canopies will struggle and start to be replaced by species normally seen further north. But the impacts will likely be very variable because the warming will be heavily influenced by wind and ocean currents and different locations will feel changes to a greater or lesser extent.

Predicting the seasons

As important as it is to identify a marine heatwave at the time, reliable predictions of developing conditions would help fishers, aquaculture companies and local authorities – and in fact anyone living and working around the ocean.

Seasonal forecasting a few months ahead is difficult. It falls between weather and climate predictions. In a collaboration between the National Institute of Water and Atmospheric Research and the Australian Bureau of Meteorology, we are examining how well long-term forecasts of ocean conditions around New Zealand stack up. Early forecasts suggested this summer would not be as warm as last year. But it now looks like this summer will again be very warm in the ocean.

One of the important points to keep in mind is that when we are at the beach, we are sampling only the surface temperature. The same is true of satellites – they monitor less than the top millimetre of the ocean.

Sea surface temperatures are several degrees above normal at the moment. But in deeper waters, because of the high heat content of water, even a tenth of a degree is significant. Temperature in the deeper ocean is monitored by a network of moored buoys on and off the continental shelf along the Australian coast. New Zealand has almost nothing that would be comparable.

Measuring temperature in real time

What we can look to, in the absence of moored buoys, is a fleet of ocean robots that monitor temperature in real time. Argo floats drift with ocean currents, sink to two kilometres every ten days and then collect data as they return to the surface.

These data allowed us to identify that the 2017/18 marine heatwave around New Zealand remained shallow. Most of the warmer water was in the upper 30 metres. Looking at the present summer conditions, one Argo robot off New Zealand’s west coast shows it is almost four degrees above normal in the upper 40 metres of the ocean. On the east coast, near the Chatham Islands, another float shows warmed layers to 20 metres deep. To the south, the warming goes deeper, down to almost 80 metres.

Our work using the Australian Bureau of Meteorology forecast model highlights how variable the ocean around New Zealand is. Different issues emerge in different regions, even if they are geographically close.

The research on categories of marine heatwaves shows we will have to keep shifting what we regard as a heat wave as the ocean continues to warm. None of this should come as a surprise. We have known for some time that the world’s oceans are storing most of the additional heat and the impacts of a warming ocean will be serious.

The Conversation.

Craig Stevens is Associate Professor in Ocean Physics, National Institute of Water and Atmospheric Research and Ben Noll is Meteorologist/forecaster, National Institute of Water and Atmospheric Research

This article is republished from The Conversation under a Creative Commons license. Read the original article.