In this newsletter:

 - NIWA climate report for Spring

 - CHRISTCHURCH WEATHER - SPRING 2007

 

Climate Summary for Spring 2007

Very windy mid spring, dry with significant soil moisture deficits at the end of the season

• Sunshine: One of the sunniest springs on record in Horowhenua, Wellington, Marlborough, and Nelson
• Rainfall: Below or near normal throughout New Zealand
• Soil moisture: Significant deficits in many regions at the end of the season
• Temperature: Near average everywhere

Spring 2007 was a mixed bag! The season started with snowfall to low levels in the east of the South Island, followed by one of the windiest Octobers on record, and ended with a very dry November.

The season was one of the sunniest on record in Horowhenua, Wellington, Marlborough, and Nelson. It was also sunnier than normal in many areas from Canterbury to Southland.

Rainfall was below normal in many North Island regions, as well as much of Marlborough, Nelson, and along the south Canterbury to North Otago coast, and near normal elsewhere. Significant soil moisture deficits developed toward the end of October in parts of Marlborough and Central Otago and spread to Nelson and Canterbury in November. Significant deficits also developed in November in Bay of Plenty, Taupo, Gisborne, Hawke’s Bay, Wanganui, and Wellington.

Mean temperatures were near average throughout the whole of New Zealand. The national average temperature of 11.9°C was 0.2°C below normal.

The overall spring climate pattern was dominated by more anticyclones in the Tasman Sea, with ridging extending over central New Zealand, producing more southerly quarter airflow than normal (although weak) over much of the country.

Major Highlights

• The lowest air temperature during spring was -6.0ºC recorded at Fairlie on 6 September and Hanmer on the 7 September. The highest temperature recorded during the spring was 32.8 °C recorded at Blenheim Airport on 25 November.
• There were relatively few high rainfall events – the worst being rainfall totalling 102 mm at Kaitaia on 19 September, surface flooding in the Hutt Valley on 7 October, and an overflow of the Waiau River (in North Canterbury) on 8 October after days of rainfall. Heavy rainfall occurred in the central North Island, with 30 mm recorded at Ohakune in an hour on 17 October.
• Snowfall occurred to low levels in the east of the South Island on 4 September, and occurred in many high country areas over 2–7 October, 10–11, 14–15, and 17–18 October.
• Gale force events on 4 and 23 October resulted in fallen trees, broken power lines, and difficulty for motorists, in several regions of the country. Wind gusts over 130 km/h were recorded on 13 days in October.
• Of the five main centres, Auckland was the warmest, Wellington the wettest and sunniest, Christchurch the driest, and Dunedin the coolest this spring.

Rainfall

Spring rainfall was below normal in many North Island regions, including Waikato, Coromandel, Bay of Plenty, Taupo, Taranaki, and Hawke’s Bay, as well as much of Marlborough, Nelson, and along the south Canterbury to North Otago coast. Rainfall was near normal elsewhere.

Temperature

Seasonal mean temperatures were near average throughout the whole of New Zealand.

Sunshine

Spring sunshine hours were above normal in Manawatu, Horowhenua, Wellington and much of the north and east of the South Island from Nelson to Southland, and near normal elsewhere.

Full report

• Full details of the Spring 2007 Climate Summary

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate
NIWA National Climate Centre – Auckland
Phone +64 9 375 2053
j.salinger@...

Stuart Burgess – Climatologist
NIWA National Climate Centre – Wellington
Phone +64 4 386 0569
s.burgess@...

Geoff Baird – Communications Manager
Phone +64 4 386 0543
g.baird@...

Acknowledgement of NIWA as the source is required.

 

 

 

·                             Rainfall: Below normal in many areas, near or above normal in the parts of Northland, east of the North Island, parts of Otago and Fiordland.

·                             Temperature: Above average in the north of the North Island, and parts of the South Island.

·                             Sunshine: Above average in the south west of the North Island, western and inland

·                             Wind: Less wind than normal

 

 

 

 

CHRISTCHURCH WEATHER - SPRING 2007

by Ben Tichborne

 

SEPTEMBER

 Temperatures varied greatly this month, but there wasn't much wet weather. The most significant weather of note was the cold outbreak early in the month. This brought very cold southerlies to Canterbury on the 4th, with snow to low levels on the Canterbury Plains; flurries reaching the outskirts of Christchurch (including the Airport) and the Port Hills, but not settling. Showers and sleet cleared from the city the next morning. More cold southerlies occurred from the 23rd-27th, but these gave no more than some light rain and drizzle to Christchurch, though light snow and hail fell to low levels further north (eg near Amberley) on the 26th. Generally, the weather was relatively settled for the time of year, with some frosty nights but also some warm days, when there were northerly or northwesterly flows.

 

OCTOBER

 This was an unsettled month, with a seemingly endless series of troughs and fronts crossing over. Temperatures varied greatly, with cold southerly changes alternating with some spells warmer west or northwesterlies. The northwesterlies reached gale in the early hours of the 7th, and were strong and gusty on some other occasions. The coldest outbreaks were on the 2nd/3rd and 18th, with some hail (and sleet on 3rd) in Christchurch and snow on higher hills of Banks Peninsula. Hail also fell on the outer peninsula on the 27th. During the brief fine spells, nights were often cold with some frosts, that of the 19th being particularly heavy for the time of year.

 

NOVEMBER

 This month was considerably more settled than October. While it was still changeable (and cold at times) during the first half, the second half was generally sunny and much warmer. It was cold and showery with a southerly on the 5th, but the southerly outbreak of the 13th/14th was more significant. Scattered thunder and hail affected some areas (especially Banks Peninsula) with the change on the afternoon of the 13th, with a waterspout coming ashore on Kaitorete Spit. (Lake Ellesmere) Showers and scattered hail continued through to the following afternoon, with snow dusting the higher hills of the peninsula.

By contrast, conditions felt summery at times later in the month (though there was a brief cold, wet southerly change late on the 27th), with maximums reaching into the high 20s on a few days and even warmer inland. This was due to westerly flows combined with warming sunshine.