Category: Science

Source: NIWA – National Institute of Water and Atmospheric Research

An expedition to discover new species in one of the most remote parts of the deep ocean is departing from Wellington today. 

Led by The Nippon Foundation-Nekton Ocean Census Alliance, New Zealand’s National Institute of Water and Atmospheric Research (NIWA) and the Museum of New Zealand Te Papa Tongarewa, a team of scientists will spend 21 days investigating the unexplored Bounty Trough ocean system off the coast of New Zealand’s South Island. They will search depths down to 5000 metres for undiscovered marine species.

Ocean Census is a global alliance of the world’s leading marine science institutions with the ambitious goal of discovering and protecting 100,000 new species across the global ocean over the next decade.

Ocean Census Science Director Professor Alex Rogers says New Zealand’s Bounty Trough has been selected because it is one of the world’s least explored deep ocean ecosystems with significant potential for discovering new life.

“It’s urgent we survey the unexplored deep ocean for new life as human activities including climate change are now impacting this vast ecosystem. The ocean sequesters more carbon dioxide than rainforests and produces the majority of the oxygen we breathe. It supports the discovery of breakthrough medicines and provides a sustainable food source for billions of people.

“We chose to come to New Zealand because of its world-class marine scientists and their track record in deep ocean species discovery. The remarkable collections of species identified and housed by NIWA and Te Papa are among the marine science world’s greatest treasures,” says Rogers.

Although it’s estimated that between 1-2 million species inhabit our ocean, a staggering 75-90% remain undiscovered, making this mission crucial for marine biodiversity understanding.

NIWA marine biologist and voyage co-leader Sadie Mills says the partnership with Ocean Census is expanding the frontiers of knowledge in ways that would not otherwise be possible.

“Most of the area we’re surveying is still a mystery. It’s fascinating because it’s right between the Chatham Rise and the Sub Antarctic Zone, with a unique mix of conditions for discovering new marine fauna.

“The vision of The Nippon Foundation and Nekton to make this scientific mission possible is a gift to New Zealand and the world. We were selected because of the work of scientists in many New Zealand organisations. We see this as an accolade for the entire New Zealand marine science community,” says Sadie.

Te Papa Curator of Invertebrates, Kerry Walton, says the expedition will truly be exploring one of Earth’s final frontiers.

“The few points of information we have from the shallower margins of the Bounty Trough indicate an interesting array of life to be discovered.

“The collections at Te Papa and NIWA that result from expeditions like this are essential for understanding the vast diversity of life in the deep ocean,” says Walton.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Much of the North Island saw rainfall totals of 15-25 mm in the past week, along with some smaller pockets of 25-50 mm.
• However, Northland, much of Auckland, and parts of the lower east coast received 5 mm or less.
• This resulted in small to moderate soil moisture decreases in the central North Island, although decreases were more substantial in Northland.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in eastern Northland, while the wettest soils for this time of the year are found in southern Waikato.
• Hotspots are currently located in much of eastern Northland and parts of Wellington-Wairarapa.
• As of 5 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Northland, Auckland, and much of the lower North Island. Very dry to extremely dry conditions are located in southern Manawatū-Whanganui and Wellington.

South Island:

• Widespread rainfall amounts of more than 200 mm affected Fiordland in the past week, while the West Coast generally received 50-100 mm.
• Lower Southland received 30-60 mm, while the rest of Southland, Otago, and the upper South Island generally received up to 25 mm.  
• However, much of Canterbury received less than 10 mm.
• While many areas didn’t see much change in soil moisture in the past week, some increases were observed in the upper South Island and Southland, while central and southern Canterbury saw soil moisture decreases.  
• The driest soils across the South Island, when compared to normal for this time of the year, are found in Nelson, Marlborough and parts of Canterbury, while the wettest soils for this time of the year are found in the upper West Coast and western Tasman.  
• The previous hotspot in portions of southern Marlborough and northern Canterbury dissipated in the past week, and no other hotspots are currently present. However, parts of the upper and eastern South Island remain close to hotspot status.  
• As of 5 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Tasman, Nelson, Marlborough, Canterbury, Otago, and far northern Southland. Very dry to extremely dry conditions are located in eastern Tasman, Nelson, Marlborough, parts of Canterbury, and northern Otago, while small areas of meteorological drought are indicated in southern Marlborough and far northern Canterbury.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 5 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Northland, Auckland, much of the lower North Island, Tasman, Nelson, Marlborough, Canterbury, Otago, and far northern Southland. Very dry to extremely dry conditions are located in southern Manawatū-Whanganui, Wellington, eastern Tasman, Nelson, Marlborough, parts of Canterbury, and northern Otago, while small areas of meteorological drought are indicated in southern Marlborough and far northern Canterbury. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• Dry weather will continue on Thursday (8 February), followed by a few showers in the eastern and central North Island on Friday.
• Afternoon showers and isolated thunderstorms will impact much of the upper and central North Island on Saturday, with isolated showers possible into Sunday (11 February).
• However, from early next week another large area of high pressure will arrive, bringing multiple days of dry weather.
• Weekly rainfall totals could reach 15-25 mm in parts of the central North Island that see the heaviest showers and thunderstorms.
• However, meagre rainfall totals of 15 mm or less are likely in the rest of the North Island.
• Due to the expected rainfall in the next week, moderate soil moisture decreases may occur in much of the North Island, although generally minor change is expected in central regions.
• The current hotspots in eastern Northland and Wairarapa could both strengthen further in the next week.

South Island:

• A weakening front will continue moving up the West Coast on Thursday (8 February), with light showers farther east.
• After dry weather on Friday, another front will bring moderate rainfall totals to the lower and central South Island from Saturday afternoon to Sunday morning (10-11 February).
• From Sunday afternoon through the middle of next week, high pressure will bring mostly dry weather.
• Weekly rainfall totals of 40-80 mm are possible in the central and lower West Coast, including Fiordland, while much of Canterbury, Otago, and Southland will receive 15-30 mm.
• However, meagre rainfall amounts are expected in the upper South Island, where weekly totals may be 5 mm or less. 
• Due to the expected rainfall in the next week, additional soil moisture decreases are likely in the upper South Island, but areas from central Canterbury to Southland may see slight increases.
• Hotspots could re-emerge in Nelson, Marlborough, and northern Canterbury in the next week.

Long-term outlook (through early March):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios show drier or much drier than normal conditions across nearly the entire country.
• Even in the wetter (75^th percentile) scenario, below normal rainfall is still forecast for several regions across both islands.
• Such agreement across all three rainfall scenarios gives an increased confidence in drier than normal conditions in the coming weeks.
• Very dry soil conditions could affect the lower North Island and eastern South Island in all three rainfall scenarios, along with the upper North Island in the drier scenario. Areas of meteorological drought are indicated in parts of Wairarapa and the eastern South Island in the drier scenario.

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Substantial rainfall totals of 40-100 mm (with isolated totals up to 150 mm) occurred in the central North Island in the past week, along with Gisborne and Hawke’s Bay.
• However, the upper and lower North Island both received much less rainfall in the past week—generally less than 20 mm.
• This resulted in significant soil moisture increases in the central North Island, with generally little change observed elsewhere.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in parts of eastern Northland and Wairarapa, while the wettest soils for this time of the year are found in southern Waikato and coastal Hawke’s Bay.
• Hotspots are currently located in a portion of eastern Northland, the south coast of Taranaki, and parts of Wellington-Wairarapa.
• As of 29 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Northland and much of the lower North Island. Very dry to extremely dry conditions are located in southern Manawatū-Whanganui and Wellington.

South Island:

• Widespread rainfall amounts of 50-100 mm (with isolated higher amounts) occurred in the central and lower West Coast in the past week. The upper West Coast and western Tasman generally received 25-50 mm.
• While Southland and parts of Otago received 10-25 mm, meagre rainfall amounts of less than 5 mm again occurred in much of Nelson, Marlborough, and Canterbury.  
• This resulted in small soil moisture decreases across a majority of the South Island.  
• The driest soils across the South Island, when compared to normal for this time of the year, are found in interior Marlborough and northern Canterbury, while the wettest soils for this time of the year are found in the upper West Coast and western Tasman.  
• A hotspot remains in place in portions of southern Marlborough and northern Canterbury, while the remainder of these areas are close to hotspot status.  
• As of 29 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Tasman, Nelson, Marlborough, Canterbury, Otago, and far eastern Southland. Very dry to extremely dry conditions are located in Marlborough, parts of Canterbury, and interior Otago, while small areas of meteorological drought are indicated in southern Marlborough and far northern Canterbury.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 29 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Northland, much of the lower North Island, Tasman, Nelson, Marlborough, Canterbury, Otago, and far eastern Southland. Very dry to extremely dry conditions are located in southern Manawatū-Whanganui, Wellington, Marlborough, parts of Canterbury, and interior Otago, while small areas of meteorological drought are indicated in southern Marlborough and far northern Canterbury. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• Unsettled weather will affect much of the North Island from Friday afternoon through Saturday (2-3 February), producing areas of moderate to heavy rain in western and central regions.
• However, a large area of high pressure will move overhead thereafter, bringing several days of dry weather from Sunday (4 February).  
• Weekly rainfall totals could reach 30-50 mm in the western and central North Island.
• However, meagre rainfall totals of 15 mm or less are likely in all other regions.
• Due to the expected rainfall in the next week, substantial soil moisture decreases may occur in much of the North Island, although little change is expected in western and central regions.
• The current hotspots in eastern Northland and Wairarapa will likely strengthen and expand in the next week, while the hotspot located in Taranaki could ease at least slightly.

South Island:

• A front will bring heavy rain to the West Coast on Friday (2 February), with areas of showers and moderate rain east of the Alps. Showers and lighter rain will continue on Saturday (3 February).
• Thereafter, several days of dry weather are expected in the upper and eastern South Island.
• However, the lower West Coast and lower South Island will continue to see periods of moderate to heavy rainfall through the middle of next week as a moisture-rich front moves back and forth across those regions.
• Weekly rainfall totals of 150-300 mm are possible in the central and lower West Coast, including Fiordland, while the upper West Coast and western Tasman will receive up to 100 mm.
• Substantial rainfall is also possible in the lower South Island, where Southland and Otago could receive 50-75 mm.
• However, more modest amounts of 15-40 mm are likely in much of the eastern South Island.
• Due to the expected rainfall in the next week, additional soil moisture increases are likely in the West Coast and lower South Island, with some decreases possible elsewhere.
• The current hotspot in Marlborough and northern Canterbury could strengthen at least slightly in the next week.

Long-term outlook (through early March):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios show drier or much drier than normal conditions across the entire North Island and eastern South Island, although the West Coast and lower South Island would see near normal rainfall. Based on the agreement of the drier and middle scenarios, the North Island and eastern South Island have the highest chances of experiencing below normal rainfall.
• However, in the wetter (75^th percentile) scenario, near normal rainfall could occur across large portions of the country.
• Very dry soil conditions could affect the lower North Island and upper South Island in all three rainfall scenarios, along with Northland in the drier scenario. A small area of meteorological drought is indicated in the drier scenario in Wairarapa.

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Rainfall totals of 30-60 mm occurred in portions of the central North Island in the past week, along with the Coromandel Peninsula and East Cape. The rest of the central North Island generally received 15-25 mm.
• However, the upper and lower North Island generally received meagre rainfall totals of 5 mm or less.
• This resulted in small soil moisture decreases across much of the North Island, although small increases were observed in western and southern Waikato.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in southern Taranaki, while the wettest soils for this time of the year are found in southern Waikato.
• Hotspots are currently located in a small portion of eastern Northland, the south coast of Taranaki, and parts of Wellington-Wairarapa.
• As of 24 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of eastern Northland, central Waikato, and much of the lower North Island. Very dry to extremely dry conditions are located in southern Manawatū-Whanganui and Wellington.

South Island:

• Widespread significant rainfall amounts of 200-400 mm (with isolated higher amounts) occurred in the central and lower West Coast in the past week, resulting in areas of flooding. The upper West Coast and western Tasman generally received 50-100 mm.
• Southland, interior Otago, and far interior Canterbury received 25-50 mm, while the rest of the eastern South Island generally saw amounts of 10-25 mm. However, meagre amounts of less than 5 mm occurred in Marlborough and northern Canterbury.  
• This resulted in large soil moisture increases for much of the West Coast and western Southland, while small to moderate increases were observed in most other areas.  
• The driest soils across the South Island, when compared to normal for this time of the year, are found in interior Marlborough and far northern Canterbury, while the wettest soils for this time of the year are found along the West Coast and western Southland.
• Most South Island hotspots dissipated in the past week, although a hotspot remains in place in southern Marlborough.
• As of 24 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Tasman, Nelson, Marlborough, Canterbury, northern and interior Otago, coastal Southland, and Stewart Island. Very dry to extremely dry conditions are now located in Marlborough, parts of Canterbury, and interior Otago, while small areas of meteorological drought are indicated in far southern Marlborough and far northern Canterbury.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 24 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of eastern Northland, central Waikato, much of the lower North Island, Tasman, Nelson, Marlborough, Canterbury, northern and interior Otago, coastal Southland, and Stewart Island. Very dry to extremely dry conditions are now located in southern Manawatū-Whanganui, Wellington, Marlborough, parts of Canterbury, and interior Otago, while small areas of meteorological drought are indicated in far southern Marlborough and far northern Canterbury. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• An approaching front will bring showers to the lower and central North Island on Saturday (27 January). However, as this front stalls, more substantial rainfall is likely on Sunday afternoon and Sunday night.
• An area of low pressure forming north of the North Island will direct periods of at least moderate rainfall into the eastern North Island from Monday to Wednesday (29-31 January), although other regions will likely remain much drier.
• Late next week a brief period of drier weather may occur.
• Weekly rainfall totals could reach 75-100 mm along the east coast and Central Plateau, with isolated higher amounts.
• However, more modest amounts of 25-50 mm are likely in most other areas, although Northland and Auckland may only receive 15-25 mm.
• Due to the expected rainfall in the next week, substantial soil moisture increases may occur in the east coast, with small increases possible in most other areas. However, the upper North Island may see small soil decreases.
• The current hotspot in eastern Northland may strengthen at least slightly in the next week, while those in Taranaki and Wellington-Wairarapa could ease somewhat.

South Island:

• A potent front moving across the island on Friday night and Saturday morning (26-27 January) will bring heavy rain to the West Coast and light to moderate rain to the eastern South Island.  
• A round of showers and isolated thunderstorms will affect the West Coast and lower South Island on Sunday (28 January).  
• However, much drier weather is expected from Monday across the island, at least through late next week.
• Weekly rainfall totals of 100-250 mm are expected in the central and lower West Coast, with 50-75 mm possible in the upper West Coast along with western portions of Canterbury, Otago, and Southland.
• However, Marlborough and coastal Canterbury may see rainfall totals of less than 20 mm.
• Due to the expected rainfall in the next week, additional soil moisture increases may occur in many regions, but at least small decreases are possible in Marlborough and coastal Canterbury.
• The current hotspot in Marlborough could strengthen in the next week, with a chance for additional hotspots to emerge in Marlborough Sounds and northern Canterbury.

Long-term outlook (through late February):

• The drier (25th percentile) rainfall scenario shows drier or much drier than normal conditions across a majority of New Zealand, although in the middle (50th percentile) scenario, many areas see closer to normal rainfall, or even above normal rainfall in the eastern North Island. Based on the agreement of the drier and middle scenarios, the upper portions of both islands and the lower South Island have the highest chances of experiencing below normal rainfall.
• However, in the wetter (75th percentile) scenario, near normal to above normal rainfall could occur across the entire country.
• Very dry soil conditions could affect the lower North Island and upper South Island in all three rainfall scenarios.    

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A strong marine heatwave is contributing to New Zealand’s unusually hot weather, says NIWA.  

Meteorologist Ben Noll says that sea surface temperatures around Auckland are borderline tropical. 

“A rapidly intensifying marine heatwave has caused sea surface temperatures to reach a near-record 23-24˚C in some coastal areas in late January. It’s striking.”

“Since the first big marine heatwave back in 2017-18, they have become commonplace for New Zealand, happening in more summers than not. They seem to generate less and less fanfare, but this one is really standing out,” said Mr Noll. 

Marine heatwaves are periods of unusually warm ocean temperatures. They have far-reaching impacts, affecting everything from ecosystems to economics.  

They also influence weather patterns, priming the environment for tropical cyclones, like Tropical Cyclone Kirrily that has formed off the coast of Australia, while causing hotter and more humid conditions on land. 

This partly explains why the North Island is experiencing above normal humidity levels, which are keeping nighttime temperatures elevated.

“The fact that this marine heatwave is coinciding with the typical annual peak means it’s stacking a 2-3˚C anomaly on top of the ocean warming we normally see at this time of the year. Swimmers and surfers will have likely noticed the unusually warm waters,” said Mr Noll.

NIWA physical oceanographer Erik Behrens says the large warming around the North Island is unusual and does not align with the pattern which we would typically expect during El Nino.  

“The temperatures around the South Island are more aligned with our expectations, where stronger south westerly winds as part of El Nino cause coastal upwell of cold water, reducing the likelihood for marine heatwaves,” said Dr Behrens. 

2024 has already seen record-breaking temperatures, with places such as Wellington Airport recording its highest January temperature since records began in 1962, and over 50 locations tracking toward a near-record or record warm month. 

The marine heatwave intensity may ebb and flow over the next two weeks owing to more variable temperatures, wind flows, and cloud, but an intensification may occur from the second week of February. 

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Rainfall totals of 30-70 mm occurred in much of Gisborne and parts of the Central Plateau in the past week, with up to 25 mm in the rest of the upper North Island.
• However, the lower North Island once again received meagre rainfall amounts of less than 5 mm.
• This resulted in soil moisture increases across portions of the upper North Island (most notably in Gisborne), while the lower North Island saw small decreases.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in much of Wellington and southern Taranaki, while the wettest soils for this time of the year are found near Cape Reinga and in southern Waikato.
• Hotspots are currently located in a small portion of eastern Northland, the south coast of Taranaki, and around Wellington. In addition, Wairarapa is nearing hotspot status.
• As of 16 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of eastern Northland, central Waikato, and much of the lower North Island. Very dry to extremely dry conditions are now located in Wellington.

South Island:

• Rainfall amounts of 50-100 mm were generally observed in the West Coast in the past week (through early Friday morning), with some higher terrain seeing more than 150 mm.
• Southland received 25-40 mm, while the rest of the eastern South Island generally saw meagre amounts of 10 mm or less.
• This resulted in moderate soil moisture decreases from Nelson to Canterbury, while the West Coast and Southland saw soil moisture increases.
• The driest soils across the South Island, when compared to normal for this time of the year, are found in interior Marlborough and far northern Canterbury, while the wettest soils for this time of the year are found along the West Coast.
• South Island hotspots are now located in eastern Tasman, Nelson, much of Marlborough, and far northern Canterbury. The rest of Canterbury and northern Otago are nearing hotspot status.
• As of 16 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Tasman, Nelson, Marlborough, Canterbury, interior Otago, coastal Southland, and Stewart Island. Very dry to extremely dry conditions are now located in Marlborough, parts of Canterbury, and interior Otago, while a small area of meteorological drought is indicated in far southern Marlborough and far northern Canterbury.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 16 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of eastern Northland, central Waikato, much of the lower North Island, Tasman, Nelson, Marlborough, Canterbury, interior Otago, coastal Southland, and Stewart Island. Very dry to extremely dry conditions are now located in Wellington, Marlborough, parts of Canterbury, and interior Otago, while a small area of meteorological drought is indicated in far southern Marlborough and far northern Canterbury. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• Scattered showers and thunderstorms will occur daily through Tuesday (23 January), especially in the central North Island.
• In addition, an area of low pressure could bring some heavy rain to Gisborne and eastern Bay of Plenty on Monday (22 January).
• Generally drier weather is expected from about Wednesday next week.
• Weekly rainfall totals could reach or exceed 100 mm in parts of Gisborne, with localised amounts above 50 mm in the central North Island. However, lesser amounts are expected in Northland and Auckland.
• Due to the expected rainfall in the next week, small soil moisture increases will be possible in the central and northeastern North Island, but Northland and Auckland may see at least small decreases.
• The current hotspot in eastern Northland may strengthen at least slightly in the next week, while those in the lower North Island may not change significantly.

South Island:

• Very heavy rain will continue to affect the West Coast through Saturday morning (20 January), with moderate rain in the lower South Island.
• More unsettled weather will arrive from late Sunday through Tuesday (21-23 January), affecting not only the West Coast but parts of the eastern South Island also.  
• Generally drier weather is expected to arrive from Wednesday next week.
• Weekly rainfall totals (including Friday 19 January) of 200-500 mm or more are expected in the central West Coast, with 30-60 mm in the lower South Island, interior Otago, and interior Canterbury. However, Marlborough and coastal Canterbury may receive less than 25 mm.
• Due to the expected rainfall in the next week, additional soil moisture decreases may occur in Marlborough and coastal Canterbury, with some increases expected in most other areas.
• The current hotspots in the upper South Island may strengthen at least slightly in the next week, while there is a possibility for new hotspots to form in coastal Canterbury.  

Long-term outlook (through mid-February):

• The drier (25^th percentile) rainfall scenario shows drier or much drier than normal conditions across the western North Island and much of the South Island, although in the middle (50^th percentile) scenario, many areas see closer to normal rainfall, with a chance for above normal rainfall in the north-eastern North Island. Based on the agreement of the drier and middle scenarios, Northland, Otago, and Southland have the highest chances of experiencing below normal rainfall.
• However, in the wetter (75^th percentile) scenario, above normal rainfall could occur in large parts of the North Island and portions of the South Island.
• Very dry soil conditions could affect parts of the upper and eastern South Island in all three rainfall scenarios.    

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Meagre rainfall totals of 5 mm or less were observed in much of the western half of the North Island in the past week.
• Gisborne, Hawke’s Bay, and eastern Bay of Plenty generally received 10-25 mm in the past week, with small pockets up to 40 mm.   
• This resulted in significant soil moisture decreases across a majority of the North Island.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in eastern Northland, coastal Manawatū-Whanganui, and Wellington, while the wettest soils for this time of the year are found near Cape Reinga, southern Auckland, and interior Waikato.
• Hotspots are currently located in eastern Northland, coastal Manawatū-Whanganui, and western Wellington.
• As of 8 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Waikato and much of the lower North Island. Very dry to extremely dry conditions are also now located in Wellington.

South Island:

• Rainfall amounts of 25-75 mm were generally observed in the lower West Coast and Fiordland in the past week.
• However, elsewhere in the South Island rainfall amounts were minimal—generally less than 15 mm.
• This resulted in moderate to large soil moisture decreases in nearly all of the South Island.
• The driest soils across the South Island, when compared to normal for this time of the year, are found in the central West Coast, coastal Southland, and Stewart Island, while the wettest soils for this time of the year are found in coastal Tasman and far northern West Coast.
• South Island hotspots are now located in far northern Canterbury, interior South Canterbury, and coastal eastern Southland.
• As of 8 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Tasman, Nelson, Marlborough, Canterbury, Otago, coastal Southland, and Stewart Island. Very dry to extremely dry conditions are now located in Marlborough, parts of Canterbury, interior Otago, and Stewart Island.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 8 January, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Waikato, much of the lower North Island, Tasman, Nelson, Marlborough, Canterbury, Otago, coastal Southland, and Stewart Island. Very dry to extremely dry conditions are now located in Wellington, Marlborough, parts of Canterbury, interior Otago, and Stewart Island. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• High pressure will bring mostly dry weather through Sunday (14 January), with only isolated, light showers possible.
• A front will bring moderate to heavy rain to most locations on Monday (15 January), followed by scattered showers and isolated thunderstorms from Tuesday through Thursday.
• Weekly rainfall totals could reach 40-60 mm across much of the North Island, although totals could be somewhat lower along the east coast.
• Due to the expected rainfall in the next week, small soil moisture increases will be possible in much of the North Island.
• The current hotspots in the North Island may weaken at least slightly in the next week.

South Island:

• After a mostly dry Friday (12 January), a front will bring moderate to heavy rain to the West Coast and lower South Island from late Saturday through Sunday.
• After some additional showers on Monday (15 January), mostly dry weather will occur through Thursday.
• Weekly rainfall totals of 75-150 mm are possible in the West Coast, with 30-50 mm in the lower South Island. However, amounts less than 20 mm are likely elsewhere.
• Due to the expected rainfall in the next week, additional soil moisture decreases will be likely in Marlborough and Canterbury, with some increases possible in Otago and Southland.
• The current hotspot in Southland may weaken in the next week, while the hotspots in Canterbury will likely strengthen and expand.

Long-term outlook (through early February):

• The drier (25^th percentile) rainfall scenario shows drier or much drier than normal conditions across nearly all of New Zealand, although in the middle (50^th percentile) scenario, many areas see closer to normal rainfall.
• However, in the wetter (75^th percentile) scenario, above normal rainfall could occur in large parts of the North Island and upper South Island.
• Very dry soil conditions could affect parts of both islands in the drier rainfall scenario, along with a risk for meteorological drought to develop in the interior South Island.    

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

Large numbers of bluebottle jellyfish were reported on several of Auckland’s west coast beaches recently. Also called Portuguese man o’ war, they are only distantly related to true jellyfish. “The wind steers the majestic creatures onto the shore because they are light and have a gas-filled float,” Dr Gordon says.

Around 35 species of jellyfish are found in New Zealand waters. The three species most frequently seen on New Zealand beaches are moon jellyfish, lion’s mane and spotted jellyfish.

Moon jellyfish (Aurelia sp.) have a bell-shaped whitish body, about 25-40cm across, and have a fringe of short tentacles around the margin of the bell. Lion’s mane (Cyanea rosea) is New Zealand’s biggest species of jellyfish, growing up to an impressive two and a half metres in diameter and with tentacles of up to 36 metres in length. Spotted Jellyfish (Desmonema gaudichaudi) are dome-shaped with reddish-brown polka dots on the body.

If you come across a jellyfish this summer, Dr Gordon advises care. “Despite being really beautiful, the lion’s mane and spotted jellyfish can produce a very painful sting, as can the bluebottle.”

Stinging is caused by the thousands of microscopic stinger capsules (nematocysts) located on the surface of the tentacles. Upon contact, the nematocysts simultaneously discharge their venom, delivering a nasty sting – so it is best not to touch the tentacles. It is safe to touch the top of the bell.

If you see a jellyfish next to you in the water, the chances are you can out-swim it. “Those who do plan on getting in the water should be cautious and wear a wetsuit if it is known that there may be jellyfish in the area,” he says.

Common symptoms of a jellyfish sting include a burning sensation on your skin, a tingling or numbness where the sting occurred, and the sting area turning purple or red.

Most stings in New Zealand waters are not serious, however, the treatment of stings is exactly the same regardless of the type of jellyfish involved.

First, flush the sting area with seawater to remove the tentacles. Use a dry towel to remove the remaining tentacles. Then, immerse the stung area in hot (but comfortable) water for 15 to 20 minutes. Use pain relief or antihistamines if needed.

Using urine to relieve a jellyfish sting is a popular misconception. As there is no way of telling its pH and chemical makeup, it could actually make the pain worse.

“Jellyfish are enchanting, delicate creatures that should be appreciated, just not too close,” says Dr Gordon.

Source: NIWA – National Institute of Water and Atmospheric Research

2023 is tracking to be one of the top three hottest years on record for Aotearoa New Zealand.

NIWA meteorologist Tristan Meyers says 2022 was our warmest year on record, surpassing the record set the year before in 2021.

“Last month didn’t add to the record books, with it being the 34^th-warmest November since NIWA’s seven station temperature series began in 1909 and although the first half of December had mostly average temperatures, a sultry 33C temperature reading in North Canterbury yesterday [Wednesday] marked what would be a hot and humid finish to the year, helping to keep 2023 near the top of the rankings.”

“We’ll be confirming this in our annual climate summary issued early next month.”

In the meantime, Meyers says the Christmas outlook is a mixed bag.

“Showers and areas of rain look to affect the North Island, while a few showers are possible for the Southern Alps and east of the South Island. However, the West Coast looks drier. Parts of the eastern North Island look to also see some temperatures reach the high 20s or low 30s.”

He says while Australian wildfires will also keep raging, the smoke that’s being ferried to New Zealand is nowhere near as bad as the 2019-2020 fires, although he cautions Australians are looking at an above-average bushfire season.

“With the peak of the bushfire season still ahead of us, the recent smoke that’s made its way to New Zealand may be a sign of things to come later in the summer if more large fires break out.”