National Climate Summary – April 2000
APRIL REPLENISHES DRY SOILS
VERY WET IN BAY OF PLENTY AND HAWKE’S BAY DRY ON THE KAIKOURA COAST AND IN SOUTHLAND VERY WARM IN THE NORTH ISLAND CLOUDY OVER THE NORTH ISLAND, BUT SUNNY IN SOUTHLAND
April replenished dry soils in many areas. Plentiful rainfall across most of the country recharged soil moisture levels in the previously at risk agricultural regions, especially Wanganui, Manawatu and in parts of the Waikato. Rainfall was very high throughout Bay of Plenty, especially in Tauranga where totals were more than three times normal. Hawke’s Bay was also very wet with at least twice the normal April rainfall. It was also wet in many other regions. In contrast, less than half normal rainfall occurred along the Kaikoura coast, and totals were less than 75 percent of normal in Southland, and parts of Wairarapa. It was very warm for April over many areas of the North Island with temperatures at least 1.0°C above normal. Much of the South Island experienced near normal temperatures. The national average temperature was 13.8°C, 0.5°C above normal. Although it was a sunny month in Southland, sunshine totals were well below average in most North Island regions.
April’s climate patterns were associated with more anticyclones (‘highs’) near Tasmania, and east of the Chatham Islands, and more depressions (‘lows’) to the south of the South Island. Westerlies were more prevalent to the south of New Zealand, but more variable windflow affected the North Island.
VERY WET IN BAY OF PLENTY AND HAWKE’S BAY
April was very wet throughout Bay of Plenty and Hawke’s Bay, where totals where at least 200 percent of normal. Most other central North Island regions, including Auckland, and Wellington, incurred totals ranging from 120 to 200 percent (double) of normal. Many South Island regions also experienced a wet month, with totals about 200 percent (double) of normal in parts of Nelson, and at least 120 percent of normal on the West Coast, central Marlborough, south Canterbury, and Central Otago. Extremely high April rainfall was recorded at Tauranga with 311 mm, 3 times the normal, and the 4th highest on record.
DRY ON THE KAIKOURA COAST AND IN SOUTHLAND
Rainfall was less than 50 percent (half) of normal along the Kaikoura coast, and less than 75 percent of normal in Southland, and parts of Wairarapa.
VERY WARM IN THE NORTH ISLAND
It was very warm in many areas of the North Island (Bay of Plenty, Waikato, Taupo, Tongariro, Hawke’s Bay) and parts of Nelson, where mean temperatures ranged from 1.0 to 1.5°C above normal. Other mild areas, with mean temperatures at least 0.5°C above normal, were southern Northland, Auckland, Taranaki, King Country, Gisborne, Wanganui, Manawatu, Wellington, central Marlborough and coastal south Canterbury. Mean temperatures were near normal elsewhere.
SUNNY IN SOUTHLAND, BUT CLOUDY IN THE NORTH ISLAND
April sunshine and solar radiation totals showed at least 125 percent of normal sunshine in Southland. However, it was much cloudier than usual in most North Island regions, especially Auckland, Bay of Plenty, Taranaki, and Horowhenua, where sunshine totals were about 70 to 80 percent of normal. Extremely low April sunshine hours were recorded at Auckland (113 hours, 3rd lowest), New Plymouth (127 hours, 2nd lowest) and Paraparaumm (115 hours, 3rd lowest).
Heavy rainfall occurred throughout eastern Coromandel and Bay of Plenty on the 9th. Extremely high falls were measured at Tauranga Airport, with rainfall totalling 166 mm in just eight hours from 3pm through midnight, and 51 mm in the hour to 8pm. Severe surface flooding occurred in parts of the city. Rainfall totalling more than 100 mm in 24 hours affected areas about and south of Wairoa on the 10th, with further flooding there.
Large hail and cold snap
Thundery conditions produced a severe, but localised hail storm bringing traffic to a standstill for a time during the evening on the 24th on SH1 north of Wellington between Tawa and Porirua, with hail stones up to golf ball size reported. A cold snap followed on the 25th, with snowfall on the Desert Road, and snow to a depth of 10cm recorded at the base of the Turoa skifield.
High winds Hurricane force southwesterlies battered exposed parts of coastal Otago on the 26th, with mean speeds as high as 120 km/h recorded at Taiaroa Head, and gusts to 153 km/h. Some trees toppled, damaging power lines, cutting power to about 2000 Dunedin residents. There were also reports of broken windows, and a roof lifted by the wind.
Extreme temperatures The lowest air temperature for April was –4.6oC recorded at Manapouri Airport during the morning of the 3rd. The lowest April air temperature for Manapouri is - 5.2oC.
The highest air temperature for the month was 27.0oC, recorded in Napier on the 4th. The record high April temperature for Napier is 29.2 oC.