80 Weather and Climate (1986) 6: 80-82

NEW ZEALAND WEATHER

BRIEF REVIEW OF THE WEATHER () with a mean daily temperature of 17.8 'C. The SUMMER 1985-86 (Fig. 1) warmest was 18.8°C during the summer of 1934-35. Records began in 1862. On a nationwide basis this summer Throughout this summer was warmer than usual. Mean daily temperatures ranged from 1 'C to 2 'C was the third equal warmest since records began in 1853. above average. For many places on the east coast of the In parts of Auckland this was the wettest summer for at North Island, in the Manawatu and in the Wairarapa this least ten years, and at Paraparaumu and Nelson Airports it was the warmest summer for many years. was the wettest for at least forty years. Westerlies prevailed over the North Island. North- Hours of bright sunshine were near or below average westerlies prevailed over the with their highest throughout the country, being about eighty-five percent of frequency since records began in 1956. Southwesterlies also average in coastal Otago and in Fiordland. had their lowest frequency on record over this part of the country for summer. MONTHLY SUMMARIES Over the North Island rainfall was well above average in DECEMBER 1985 - FEBRUARY 1986 Auckland and the Manawatu, and below average in Gisborne and Hawkes Bay. Over the South Island rainfall December was cloudy and wetter than usual in most was well above average in Nelson. places, with above average temperatures over the whole country. Northwesterlies prevailed and strong winds were This summer was the third warmest on record in Kelburn less frequent than usual. Southwesterlies had their lowest SUMMER 1985/86 A RAINFALL TEMPERATURE C SUNSHINE (DECEMBER - FEBRUARY)

Well above normal Above normal Normal Below normal Well below normal Fig. I: Summer 1985/86. Rainfall (A) and temperature (B) departure maps based on observations from 46 stations; sunshine (C) based on observations from 23 stations. New Zealand Weather 81 frequency over the south of the South Island for almost Island apart from Gisborne, Hawkes Bay and the thirty years. Mean sea level pressures were above average Wairarapa. Rainfall totals for the Gisborne region ranged throughout New Zealand. Rainfall was above average over from 45 to 60 percent of average. Record January rainfalls most of the country and several records were set for were recorded at , Kinleith, Auckland monthly rainfall in December at Whenuapai, Auckland City, Hamilton Airport and Nelson Airport. Over the City, and Ohakea. Rainfall at these places South Island rainfall was generally near average, apart was well over 200 percent of normal. In Taranaki, from Buller, Marlborough and Nelson where it ranged Gisborne, Hawkes Bay and in Southland rainfall was below from 150 to over 300 percent of average. Nationwide average. Mean daily temperatures were at least 0.5 'C above January was one of the warmest months ever. Mean average, and mostly 1.5 "C above average over the whole temperatures were 2 'C above the long term averages, country. On the West Coast of the South Island mean daily making it the second warmest month since records began in temperatures were 2.0 "C above average. It was a cloudy the 1860's. The mean daily temperature was 2.5 "C above month in the South Island. Southland's sunshine was just average in the King Country, Wellington, South Canter- above average, while in Canterbury, Otago and Westland bury and Central Otago. At the mean sunshine hours were only 70 percent of average. Kaikoura daily maximum temperature averaged 27.4 "C, which is the recorded the least sunshine there for December on record. second highest there since records began in 1938. Throughout the whole of the country hours of bright January was much warmer than average throughout New sunshine ranged between 85 and 105 percent of normal. The Zealand. Northwesterlies also prevailed this month, with region with the least amount of sunshine was in Southern their highest frequency over the South Island since records Hawkes Bay. Mean sea level pressures were 1 to 2 hPa began in 1956. Flooding occurred in a number of places in above average. the North Island from the 4th to the 6th, resulting in many people being evacuated from their homes. The worst February was slightly warmer and wetter than usual in most affected places were Pawarenga (Northland), Ngongotaha places. Southwesterlies prevailed over the North Island with (near Rotorua), Tarawera, and the Henderson Valley. more strong winds than usual, while northwesterlies Floods resulted again after heavy rain in Nelson City on the prevailed over the south of the South Island. Over the 25th, causing major damage to some houses, bridges and South Island the frequency of southeasterlies was the the sewage system, together with severe slips causing roads highest on record which accounted for some of the record out of the city to be blocked. Approximately 150 people in high rainfalls on the East coast. There was a lack of strong the Brightwater and Matai regions evacuated their homes. winds over the South Island. Record high February Rainfall was well above average throughout the North rainfalls were recorded at Blenheim Airport, Timaru AUTUMN 1986 TEMPERATURE C SUNSHINE (MARCH - MAY)

Well above normal Mom. Above normal Normal Below normal Well below normal Fig. 2: As Fig. 1, but for Autumn 1986. 82 New Zealand Weather

Airport, Roxburgh and . At Kaitaia North Island and in Nelson. Temperatures were about 1 'C Airport 159 mm fell in the 24 hours to 9 a.m, on the 16th. above average on the West Coast of the South Island and in Mean sea level pressures were 3 to 4 hPa below average over Southland and Central Otago. March was a particularly the whole of New Zealand. Hours of sunshine were gen- sunny month over most of New Zealand. Record high erally near normal. In parts of Canterbury and Westland hours of sunshine were recorded in many western North sunshine was ten percent above average, while the Mana- Island regions from Taranaki to Auckland, where sunshine watu had one of the lowest sunshine totals for February ranged between 120 to 140 percent of average. since records began. There was also less sunshine than usual in Otago. April was a dry sunny month. Many clear nights in east BRIEF REVIEW OF THE WEATHER coast regions from Gisborne to South Canterbury were an AUTUMN 1986 (Fig. 2) advantage for people who wished to view Halley's Comet. Strong winds occurred with twice their usual frequency over This autumn was sunnier, slightly warmer, and drier than the south of the South Island, the greatest for April for over average in most places. Easterlies were generally less ten years. Northwesterlies were predominant over the South frequent than usual. There were less strong winds than usual over the North Island, and more strong winds over Island and had their highest frequency since records began the south of the South Island. Rainfall was above average in 1956. Southwesterlies prevailed over the North Island with their usual frequency and it was less windy than usual. in Canterbury, North Otago; and parts of Southland. Over Mean sea level pressures ranged from near normal in the North Island rainfall in most places ranged from 50 to Southland to over 4 hPa above normal in Northland. 75 percent of average. Rainfall was less than fifty percent of Rainfall was above average on the West Coast of the South normal in Whangarei, Auckland City and at Tauranga and Island, in Fiordland and in Southland. Invercargill Gisborne Airports. Mean daily maximum temperatures recorded 160 percent of normal rainfall for April. were between 0.5 ' and 1.0 'C above average in most places, Throughout the remainder of the country rainfall was well and up to 1.5 "C above average in Gisborne, Hawkes Bay below average, especially on the east coast of both islands, and in some places in Canterbury and North Otago. Mean and in most places to the north of Hamilton. Record low daily minimum temperatures were about 0.5 "C below April rainfalls were recorded at (25 average in the North Island, apart from eastern regions mm), Warkworth (20 mm), Whenuapai (38 mm), East Cape from Taranaki to Wellington, and between 0.5 ' to 1.0 "C (11 mm), Napier Airport (4 mm), Hastings (6 mm), and above average over much of the South Island. After a Waingawa (17 mm). The mean daily maximum temperature cloudy summer throughout most of New Zealand, autumn was about 1 'C above average in most regions of the North was particularly sunny, with Auckland, Wellington and Island. On the east coast from Gisborne to southern Canterbury regions recording between 120 and 130 percent Wairarapa the mean daily maximum temperature was 2 ' to of average sunshine. Auckland City recorded the sunniest 3 'C above average. Mean daily minimum temperatures autumn period for at least 24 years, Waingawa 44 years, were near to 1 'C below average in most regions apart from Paraparaumu Airport 34 years, Kelburn (Wellington) 57 Wellington, the Manawatu and Taranaki, where it was 1 'C years and 38 years. Total hours of above average. In the South Island maximum daily sunshine for autumn were below average in Southland and on the West Coast of the South Island, temperatures were near to 1 'C below average on the West Coast and in Fiordland, and up to 3.5 "C above average in MONTHLY SUMMARIES Canterbury and North Otago. Mean daily minimum MARCH - MAY 1986 temperatures were about 1 "C above average, except at where it was 8.0 "C (2.4 "C above March was a sunny month, especially over the North normal), the highest there for April since records began in Island. Strong winds were less frequent than usual. 1949. Mean daily maximum temperatures for many places Southwesterlies prevailed over the North Island and in Hawkes Bay, Canterbury, Otago and Southland were the northwesterlies prevailed over the south of the South highest on record for April. Sunshine hours were well above Island. Mean sea level pressures were 1 hPa above average average on the east coast of both islands from East Cape to in the North Island, and up to 3 hPa above average in the North Otago, including Wellington and Marlborough, South Island. Heavy rainfall occurred in South Canterbury ranging from 120 to 150 percent of average and in these in the 24 hours to 9 a.m, on the 13th, when an almost regions nearly equalling or exceeding the previous record stationary depression had developed in the Tasman Sea and for April. a convergent easterly airstream existed over the Canterbury The sunny mild weather continued into May. Westerlies region. Serious flooding resulted. The worst affected township was Pleasant Point where 1200 people were prevailed over the whole country. Strong winds were less evacuated as the Tengawai river burst its banks and water frequent than usual over the North Island. Southwesterlies were predominant over the South Island with their highest up to 1.5 metres deep flooded the town. The total cost of the damage due to the floods was estimated to be $39 frequency since November. Mean sea level pressures were near normal over the south of the South Island, and up to 2 million. Rainfall was below average throughout the North hPa above normal over the North Island. Total rainfall was Island apart from the Wairarapa and Wellington. Only 16 above average in the Waikato, elsewhere in the North mm was recorded at Whangarei and 12 mm at Taupo Airport. 188 mm (247 percent of normal) was recorded at Island it was near or below average. Rainfall was about 70 percent of average in most east coast regions, including Waingawa. In the South Island it was drier than average in Nelson and on the West Coast north of Hokitika, with Wellington, and only about 50 percent of average in the Wairarapa. Over the South Island rainfall was above rainfall between 50 to 70 percent of average. On the east average in most places in Inland Canterbury, Otago and coast from Cape Campbell to Dunedin, monthly totals were Southland. For most regions on the West Coast and in much higher than average. The total of 187 mm (328 Southland it was drier, with rainfall being between 70 and percent of normal) for Timaru Airport was the highest on 80 percent of average. It was very dry at Kaikoura, record. Records began there in 1956. Mean daily Christchurch Airport and at where the temperatures werre generally slightly below average over the Weather and Climate (1986) 6: 83 83 month's rainfall was only 31, 29 and 22 mm respectively. Mean daily minimum temperatures were near average in There was no rain in Whakatane, Christchurch or Timaru most places. Some severe frosts were recorded in until the 17th. The mean daily maximum temperature was Canterbury and Otago between the 5th and the 8th and also near average over most of the country. Daily maximum from the 23rd to the 26th, due to cold southwesterlies which temperatures averaged 1 on the east coast of the North had covered the country, followed by fine cold nights. It Island, in the Waikato, Wellington, Marlborough and at was sunny in most regions, particularly in Auckland. At Christchurch. A maximum temperature of 24.5 'C was Auckland City this was the sunniest May for at least sixteen reached during the afternoon of the 4th at Napier Airport, years. There was less sunshine than usual in Southland. which is the highest there for May for at least 17 years. S. BURGESS RECENT PUBLICATIONS OF THE NEW ZEALAND METEOROLOGICAL SERVICE

1. INFORMATION PUBLICATIONS No. 175(6): N.Z. Meteorological Service, 1986: Climatic No. 13. Smith, R. A., 1985: Cloud forms. map series part six: annual rainfall.

2. METEOROLOGICAL OFFICE NOTES 4. SCIENTIFIC REPORTS No. 140. Revell, C. G., 1985: Tropical cyclone 'Saba'. No. 13. Auer, A. H., 1985: Use of satellite imagery in the From Weather and Climate, v. 5 no. 2: p. 42-52. recognition of deformation zones over Australasia. No. 141. Reid S. J., 1985: Manawatu wind studies: speed- No. 14. Heine, R. W., Curran, P. S., 1985: Measurement up over a ridge. From Weather and Climate, v. 5 no. 2: of temperature profiles under inversion conditions in p. 52-64. Hawkes Bay. No. 142. Kidson, J. W., 1985: Index cycles in the No. 15. Renwick, J. A., 1985: Modification of the objective northern hemisphere during global weather experiment. max/min temperature forecasting scheme. From Monthly Weather Review, v. 113 no. 4: p. No. 16. Lechner, I. S., Larsen, H. R., Fisher, G. W., 607-623. 1985: Droplet distributions observed in a pileus and No. 143. Laing, A. K., 1985: An assessment of wave underlying rotor cloud. observations from ships in southern oceans. From No. 17. Burgess, S. M., Holmes, V., 1986: The Thames- Journal of Climate and Applied Meteorology, v. 24 no. Coromandel floods of February 1985. 5: p. 481-494. No. 18. Wratt, D. A., Bromley, A. M., Lewthwaite, E. W. No. 144. Fisher, G. W., Larsen, H. R., Lechner, I. S., D., 1986: Meteorological measurements under 1985: Agricultural spray droplet measurement. From temperature inversion conditions at the Tauhara New Zealand Journal of Technology, v. 1: p. 169-175. geothermal power station site. No. 145. Steiner, J. T., Clarkson, T. S., 1985: Heavy No. 19. Simpson, I. R., Clarkson, T. S., 1986: Dryplum: a metals in the New Zealand atmosphere. From Journal computer model for predicting the behaviour of plumes of the Royal Society of New Zealand, v. 15 no. 4: p. in the atmosphere. 389-398. No. 20. Renwick, J. A., 1986: Objective guidance forecasts No. 146: Laing, A. K., 1985: A computer model for fore- based on prognoses from the European centre for casting ocean wave parameters at specific sites around medium range weather forecasts. the New Zealand coast. From New Zealand Journal of No. 21. Nichol, S. E., Basher, R. E., 1986: Analysis of Marine and Freshwater Research, v. 9: p. 517-533. three years' measurements of erythema' ultraviolet No. 147. Neale, A. A., Steiner, J. T., Maunder, W. J., radiation at Invercargill, New Zealand. Fitzharris, B. B., 1986: New Zealand weather and climate some key areas for the future. From proceedings 5. TECHNICAL INFORMATION CIRCULAR of the Royal Society of New Zealand, v. 113: p. 146-153. No. 201. Renwick, J. A., 1985: Verification of subjective max/min temperature forecasts, December 1982- No. 148. Salinger, M. J., 1986: Meteorological patterns of November 1983. importance to land use in Marlborough. From No, 202. Salinger, M. J., 1985: Climatic inputs to Proceedings of the Soil Dynamics and Land Use agriculture and agricultural research needs by MAF and Seminar, Blenheim, May 1985. DSIR. No. 149. Holden, R., Clarkson, T. S., 1986: Acid rain: a No. 203. N.Z. Meteorological Service, 1985; Greenhouse New Zealand viewpoint. From Journal of the Royal gases and climate. A conference statement approved by Society of New Zealand, v. 16 no. 1: p. 1-15. the UNEP/WMO/ICSU meeting on 'An assessment of No. 150. Gordon, N. D., 1986: The southern oscillation the role of carbon dioxide and of other greenhouse gases and New Zealand weather. From Monthly Weather in climate variations and associated impacts' Austria, Review, v. 114 no. 2: p. 371-387. 1985. No. 204. Salinger, M. J., 1986: Agrometeorology in the 3. MISCELLANEOUS PUBLICATIONS New Zealand Meteorological Service.

No. 109. N.Z. Meteorological Service, 1986: 6. OTHER PUBLICATIONS Meteorological observations for 1984. No. 110. N.Z. Meteorological Service, 1986: Rainfall N.Z. Meteorological Service: Proceedings of the workshop observations for 1984. on atmospheric chemistry in New Zealand 23-24 May No. 175(4): N.Z. Meteorological Service, 1985: Climatic 1985, Wellington. map series part four: air temperatures. K. JOHNSON