National Climate Summary – March 2005

NATIONAL CLIMATE CENTRE FRIDAY 1 APRIL 2005

National Climate Summary - March 2005

1. Rainfall: Above average over much of the North Island and the north and southwest of the South Island - below average in the north of the North Island

2. Temperature: Above average in the North Island - near average over much of the South Island

3. Sunshine: Above average in the north of both islands, including Buller and northern Westland - below average in the south of the North Island and southern South Island

4. Several destructive tornadoes

March 2005 was unsettled with above average rainfall over much of the North Island, especially Wairarapa. However, drier and sunnier than average conditions with significant soil moisture deficits occurred in Northland, Auckland, Waikato and Coromandel. Significant soil moisture deficits also affected the southwest of the North Island from Wanganui to Horowhenua, and Marlborough, Canterbury and Otago until the last week of March. March was also sunnier than average in Nelson, and northern Westland. Less sunshine than normal occurred in the south of the North Island, as well as West Otago, Fiordland, and Southland. It was warmer than normal in the North Island, as well as Nelson. However, near average temperatures prevailed elsewhere. Major weather phenomenon in March were the Greymouth tornado on the 10th (one of three in New Zealand during March), which was particularly severe, and potentially hazardous fog and low cloud which closed Wellington Airport several times over the 17-22nd of March resulting in severe disruption of flights. Depressions (“lows’) were often centred over central New Zealand during March, with most anticyclones (“highs’) usually well away, to the west or east, of the country.

Highlights:

1. The highest temperature for March 2005 was 32.9¢XC recorded at Darfield on the 5th. The lowest temperature for the month was -3.4¢XC, recorded at Middlemarch on the 31st.

2. A severe tornado tracked through Greymouth on the 10th. Many buildings, houses, and dozens of motor vehicles were severely damaged by the high winds and flying debris, with estimated damages exceeding 10 million dollars. About 30 people were left homeless, and three injured. Damaging tornadoes also struck parts of Bay of Plenty on the 25th, and tornado-like winds struck Blaketown (Westland) on the 8th, damaging three properties.

3. Huge waves generated by an offshore low pressure system and strong easterlies, resulted in flooding and damage in the Hawke’s Bay coastal settlement of Haumoana on the 17th.

4. Fog and low cloud closed Wellington Airport at times over the 17-18th and 20-22nd of March resulting in the disruption of more than 500 flights affecting tens of thousands of travellers.

5. Rainfall was extremely high in Fiordland over 5-10 March, with 306 mm recorded at Milford Sound on the 5th, and 702 mm for the 6-day period.

6. Of the four main centres Auckland was easily the warmest, sunniest and driest. Rainfall was above average in Wellington and Dunedin, and below average in Auckland and Christchurch. Temperatures were above average in Auckland and near average in the three other centres. Sunshine hours were well above average in Auckland, but below average in the three other main centres.

Rainfall: It was unsettled with above average rainfall over much of the North Island, as well as Nelson, Marlborough, coastal Otago, Fiordland, and Western Southland. At least 300 percent of normal rainfall occurred in parts of Wairarapa (due to substantial rainfall at the end of the month). However, rainfall was well below average (less than 25 percent of normal) in much of Northland, and less than 50 percent of normal in parts of Auckland. It was also drier than average in Waikato and Coromandel.

Temperature: Mean temperatures were 1.0¢XC or more above average in parts of Auckland, Western Bay of Plenty, Waikato, Gisborne, Manawatu, and the Kapiti coast, and also above average in most other North Island districts, as well as Nelson. Temperatures were near average elsewhere. The national average temperature for March was 16.0¢XC (0.3¢XC above normal).

Sunshine: Sunshine hours were above average in Northland, Auckland, Waikato, Coromandel, Nelson, Buller, and northern Westland, but below average in Wairarapa, Kapiti, Wellington, West Otago, Fiordland, and Southland.

ABOVE AVERAGE RAINFALL OVER MUCH OF THE NORTH ISLAND

AND THE NORTH AND SOUTHWEST OF THE SOUTH ISLAND

BELOW AVERAGE RAINFALL IN THE NORTH OF THE NORTH ISLAND

Rainfall was 125-200 percent of normal in Hawke’s Bay, inland Bay of Plenty, Taupo, north Taranaki, Wanganui, the Kapiti coast, Wellington, Nelson, Marlborough, coastal Otago, Fiordland, and Western Southland. It was very wet, with at least 300 percent of normal rainfall, in parts of Wairarapa. In contrast, rainfall was less than 25 percent of normal throughout much of Northland, less than 50 percent of normal in parts of Auckland, and less than 75 percent of normal rainfall in Waikato and Coromandel. Rainfall was near average elsewhere.

Near or record low March rainfall was recorded at:

Location March

rainfall

(mm) Percentage

of normal Year

Records began Comments

Cape Reinga 11 15 1920 Well below normal

Kaitaia Observatory 7 8 1986 Lowest

Kerikeri 26 20 1982 2nd lowest

Kaikohe 16 12 1973 3rd lowest

Whangarei Airport 16 11 1937 2nd equal lowest

Near or record high March rainfall was recorded at:

Location March rainfall

(mm) Percentage

of normal Year

Records began Comments

Mahia 156 212 1992 3rd highest

Castlepoint 278 307 1902 2nd highest

East Taratahi 208 424 1973 Highest

Wellington Airport 150 201 1960 4th highest

Lake Rotoiti 245 224 1934 2nd highest

ABOVE AVERAGE TEMPERATURES IN THE NORTH ISLAND, NEAR AVERAGE OVER MUCH OF THE SOUTH ISLAND

Mean temperatures were 1.0¢XC or more above average in parts of Auckland, Western Bay of Plenty, Waikato, Gisborne, Manawatu, and the Kapiti coast, and about 0.5¢XC above average in most other North Island districts, as well as Nelson. Temperatures were near average elsewhere.

ABOVE AVERAGE SUNSHINE IN THE NORTH OF BOTH ISLANDS, INCUDING BULLER AND NORTHERN WESTLAND

BELOW AVERAGE SUNSHINE IN THE SOUTH OF THE NORTH ISLAND, AND SOUTHERN SOUTH ISLAND

Sunshine hours were at least 110 percent of average in Northland, Auckland, Coromandel, Waikato, Nelson, Buller and northern Westland, but less than 90 percent of average in Wairarapa, Kapiti, Wellington, West Otago, Fiordland, and Southland. Hours of bright sunshine were near average elsewhere.

High March sunshine hours were recorded at:

Location March sunshine

(hours) Percentage

of normal Year

Records began Comments

Kaitaia Observatory 236 135 1986 3rd highest

Dargaville 231 135 1944 2nd highest

Auckland, Mangere 232 126 1963 3rd highest

Near or record low March sunshine hours were recorded at:

Location March sunshine

(hours) Percentage

of normal Year

Records began Comments

Martinborough 156 70 1987 2nd lowest

Queenstown 136 72 1930 3rd lowest

MARCH’S CLIMATE IN THE FOUR MAIN CENTRES

Of the four main centres Auckland was easily the warmest, sunniest and driest. Rainfall was above average in Wellington due to heavy rainfall (almost 100 mm) during the last two days, and also Dunedin, and below average in Auckland and Christchurch. Temperatures were above average in Auckland and near average in the three other centres. Sunshine hours were well above average in Auckland, and below average in the other main centres.

Location March

Mean

Temp.

(¢XC) Dep.

from normal

(¢XC) March

rainfall

(mm) % of

normal March Sunshine

(hours) % of

normal

Auckland 19.3a +0.7 Above average 26b 27 Well below average 232a 126 Well above average

Wellington 15.9 +0.1 Above average 142 154 Above average 164 86 Below average

Christchurch 14.9c -0.2 Near average 40c 71 Below average 164 90 Below average

Dunedin 13.6 -0.2 Near average 84 121 Above average 129 92 Below average

a-Mangere b Mt Albert c-Christchurch Airport

HIGHLIGHTS AND EXTREME EVENTS

- Temperature

The highest temperature during March 2005 was 32.9¢XC recorded at Darfield in hot northwesterly conditions on the 5th. The lowest temperature for the month was -3.4¢XC, recorded at Middlemarch on the 31st.

- Tornadoes

Tornado like winds struck Blaketown (Westland) about 6.15pm on the 8th, damaging three properties.

A severe, damaging, tornado tracked through parts of Greymouth just after 1pm on the 10th. Many buildings, houses, and dozens of motor vehicles were seriously damaged (some overturned) by the high winds and flying debris (roofs lifted and window panes smashed), with damages estimated to be at least $10 million. A power pole even snapped in half. About 30 people were left homeless, and three injured. There were no fatalities. The tornado left a 400-500 m wide and 4 km long track of damage from the river mouth, southeast through the township, toward the hills. Estimates of maximum wind speeds, based on the international Fujita tornado scale, range from 180 km/h to 250 km/h. The tornado was preceded by lightning.

More tornadoes struck parts of Bay of Plenty, damaging trees and properties near Kawerau on the 25th.

- High winds and high seas

The highest wind gust recorded during March 2005 was 148 km/h from the northwest, measured at Castlepoint on the 3rd.

Huge waves, with 6 m swells, generated by an offshore low pressure system northeast of Gisborne and strong easterlies, resulted in flooding and damage in the Hawke’s Bay coastal settlement of Haumoana on the 17th, six houses being evacuated, 60 being affected.

- Fog and low cloud

Persistent fog and low cloud occurred at Wellington Airport over the 17-18th and 20-22nd of March resulting in airport closures and the disruption of more than 500 flights affecting tens of thousands of travellers. Many flights had to be diverted to Palmerston North.

- High rainfall

Rainfall was extremely high in Fiordland from 5 through 10 March, with 306 mm recorded at Milford Sound on the 5th, and 702 mm for the 6-day period. Rainfall totalling 50-75 mm occurred in Bay of Plenty and Hawke’s Bay on the 17th. Rainfall on the 24th of March totalled 137, 96, and 50-60 mm at Lake Rotoiti (Nelson Lakes), Takaka, and Nelson respectively. Further high rainfall, totalling 60-100 mm occurred throughout much of Taranaki, Wairarapa and Wellington over the 29th-31st, some areas recording more than 100 mm. Six houses were evacuated after flooding occurred in the Riversdale-Castlepoint district. Torrential rainfall totalling 57 mm was recorded at Castlepoint between 5 and 6pm on the 30th, with 115 mm between 5and 8pm that evening. For the 24-hours to 9am on the 31st, Wellington Airport recorded its highest 1-day rainfall (94 mm) total since 1981.

http://www.niwa.co.nz/ncc

Copyright NIWA 2005. All rights reserved.

© Scoop Media