19 DECEMBER
THE NEW ZEALAND GAZETTE
5785

THE WEATHER IN NEW ZEALAND IN OCTOBER 1984

General—October was a dry, sunny month.
Winds from a southerly quarter were more frequent than usual in the north while southern areas had more westerlies than normal. There were fewer very strong winds than usual for the time of year. Pressures were higher than normal in northern and western areas and slightly lower than usual in the south.

Apart from the south and west of the South Island most farmers reported that conditions were too dry for good growth this month. Very little hay and silage are being made and stock are reported to be just holding condition in many areas. Feed is particularly scarce in parts of Canterbury and North Otago.

Very low temperatures and frost affected much of the country on the 1st and 2nd and there were reports of damage to kiwifruit vines from Bay of Plenty, Nelson and Marlborough.

Intense frontal activity brought thunderstorms, hail and strong winds to Wellington and Hawkes Bay on the 22nd. Light snow showers fell in parts of Hawkes Bay and orchards and vineyards were severely affected in some areas.

Rainfall—The North Island and the north and east of the South Island were much drier than usual this month. Apart from the south of the North Island, which had between 70 and 90 percent of normal rainfall, rainfalls were generally less than half the average for October. Northland, Bay of Plenty, areas of central and northern Hawkes Bay, South Canterbury and Otago were exceptionally dry, with many stations in these areas receiving less than 10 mm rainfall making this their driest October (and in some northern areas, driest month) on record.

Southern Westland, Fiordland and Southland were wetter than usual this month. Rainfalls were generally only slightly above normal in Southland but up to twice normal in southern Westland and Fiordland. Milford Sound was particularly wet with 1004 mm of rain this month, of which 964 mm fell in the 17 days between the 5th and 21st.

Temperatures—Temperatures were between normal and 0.5°C below normal in the North Island and south and west of the South Island, and up to 1°C warmer than normal in northern and eastern areas of the South Island this month.

The first 3 days of the month were very cold, with mean temperatures 4–6°C below average, and maxima 10°C below average in some areas. Frosts were very widespread.

There were 2 especially mild periods this month. The period from the 14th to 17th, particularly in northern and eastern areas of both Islands and central Otago, was unseasonably warm. Maximum temperatures exceeded 20°C on several days in these areas during this time, and mean temperatures were up to 7°C above average. The end of the month was also very mild, with mean temperatures up to 6°C above average over the whole country on the 29th and in the North Island on the 30th–31st. Many places again recorded maxima above 20°C.

Sunshine—October was a very sunny month. While stations in the south and west of the South Island had normal or slightly below normal sunshine hours this month the rest of the country was much sunnier than usual, with many stations recording between 40 and 60 hours more sunshine than usual for October. This was the second sunniest October on record for many places, being exceeded only by October 1954.

Among those stations with the greatest sunshine departures this month were: Tauranga (+60 hrs), Timaru (+56 hrs), Auckland (+52 hrs), Gisborne (+51 hrs), Rotorua (+50 hrs) and Wellington (+47 hrs).

THE WEATHER SEQUENCE, OCTOBER 1984

1–7 October
A complex trough covered New Zealand on the 1st, with small fronts lying over eastern areas of both Islands and a strong southerly flow over most of the country. Temperatures were cool and there were showers in eastern areas of both Islands on the 1st and 2nd. By the 3rd the trough lay to the east and an extensive anticyclone, centred in the Tasman Sea, began to move on to the country. Temperatures remained cool, but the showers cleared from most areas during the next 2 days. The anticyclone covered the country by the 5th and the weather became generally fine and milder.

A depression developed to the south-west of the South Island and a cold front associated with this began to cross the south-west of the South Island on the 6th. Rain fell in Fiordland and Westland on the 6th and spread to other western areas and central districts on the 7th as a complex trough developed with the front and began to cross the country.

8–14 October
The frontal system lay to the east by the 8th, with a south-westerly flow on to the country. Rain continued in southern and western areas of both Islands. A strong, moist, north-westerly flow associated with a deep depression near MacQuarie Island brought heavy rain to western and southern areas of the South Island between the 12th and 14th. An anticyclone moved on to the North Island on the 13th and fine, warm weather prevailed over the North Island and the north and east of the South Island on the 13th and 14th.

15–21 October
Rain continued to affect the south and west of the South Island on the 15th and 16th as a series of fronts, travelling within the westerly flow, crossed the country. Over the rest of the country the weather was generally fine and mild. During the 17th a complex trough began to move on to the country and the rain spread into southern areas of the North Island.

Rain became widespread during the 18th as the trough began to cross the country. This system moved quickly eastward and by the 20th a disturbed westerly flow again covered the country. Rainfall continued to be widespread over the South Island, apart from isolated eastern areas, and there were lighter falls over many parts of the North Island during the 20th and 21st. Temperatures were generally cool.

22–31 October
The trough lay just to the east of New Zealand on the 22nd, with a following strong south-westerly flow over the country. Temperatures were very cool and there were showers in many areas. The whole country had fine, settled weather between the 23rd and 28th, due to a large anticyclone which moved on to the country.

Although initially cool, temperatures had become mild by the 26th. The high pressure belt remained over the north of the country until the end of the month, bringing mild, settled weather to the North Island. However, rain fell in Westland and Fiordland on the 29th as a cold front crossed these areas and in northern and eastern areas on the 30th as the front moved eastwards. Fine, settled weather prevailed on the 31st as the field of high pressure extended southwards.

J. S. HICKMAN, Director.

Price 50c
BY AUTHORITY: P. D. HASSELBERG, GOVERNMENT PRINTER, WELLINGTON, NEW ZEALAND—1984
27232F—84PT