April 1981: April was a warm, sunny month for much of New Zealand. In the north of the country southwesterly winds were far more prevalent than is usual for April. Winds form the southwest or northwest also prevailed in the south. This was in direct contrast to the predominantly northeasterly flows of last month. Gale force winds affected many parts of the North Island on the 12th. Areas with wind damage included Waitemata harbour, where many craft were severely damaged, and in Te Aroha and Paraparaumu where roofs were lifted.
Rainfall: Dry conditions continued in central New Zealand with rainfall generally well below normal for the 4th consecutive month. Other areas with low rainfall were Northland and Central Otago. The rest of the country had higher than normal rainfall, especially Westland, Thames, Bay of Plenty, Gisborne and Hawkes Bay. A complex frontal system covered the country on the 11th-13th and an associated northeasterly flow brought heavy rain to districts in the north and east of the country. Exceptional falls were experienced around Coromandel and the Hauraki Plains. After heavy rain on the 12th the Ohinemuri River broke stopbanks and caused extensive flooding in Thames and Paeroa. Over 900 people were evacuated. Other towns badly affected were Waikino, where several buildings were swept away, and Te Aroha, where in addition to severe flooding gale force winds blew roofs off. Some 72-hour totals from 9am/11th-9am/14th were: Katikati 232mm, Whangamata 307mm, Coromandel 383mm, Waihi 520mm and Puriri 650mm. Heavy rain and gales also affected parts of Gisborne and Hawkes Bay, where falls for the same period ranged up to 270mm. For many places rainfall over this period contributed up to 90% of the month’s total, the rest being relatively dry.
Some totals: Waihi 541mm, Te Aroha 398mm, Gisborne 141mm, Greymouth 354mm, Milford 698mm; Nelson 33mm, Alexandra 15mm.
Temperatures: Mean temperatures were above normal by an average of 1C in the North Island and 2C in the South Island. Westport was 3.2C above normal, this being equalled only once in April since 1938. The first 10 days of the month were very warm in all areas, particularly in central and southern regions where they were frequently over 5C above normal. However by the end of the month temperatures over the whole country had become close to or slightly below normal.
27.7C maximum at Mangatu Forest on the 8th,
-4.4C minimum at Ophir on the 28th.
Sunshine: April was sunnier than normal in all areas except Westland, the southeast of the South Island, and the Nelson-Marlborough region where it was slightly below normal. For Westland it was the 3rd consecutive month with below normal sunshine. Gisborne had its 2nd highest April total since records began in 1938, and Ohakea its second highest since 1954 when records began. It was the sunniest April for New Plymouth since 1966.
[Some totals: Kaitaia 198, Dargaville 175, Waitangi 198, Auckland 191, Tauranga 195, Whakatane 214, Rotorua 191, Taupo 161, Hamilton 174, New Plymouth 198, Masterton 164, Dannevirke 154, Gisborne 223, Napier 211, Ohakea 194, Palmerston North 149, Levin 148, Wellington 181, Stratford 163, Wanganui 176, Westport 124, Hokitika 123, Greymouth 94, Nelson 187, Blenheim 193, Kaikoura 194, Mt Cook 110, Methven 161, Christchurch 166, Tekapo 158, Timaru 126, Oamaru Aero 116, Omarama 177, Palmerston 102, Dunedin 102, Te Anau 122, Queenstown 129, Alexandra 155, Gore 118, Invercargill 102.]
Sources: NZ Met. Misc. pub. 107 (Climatological table, NZ Gazette) and NZ Met. Misc. pub. 109 (Meteorological Observations).
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April 19, 2012, 07:27:35 PM