21 SEPTEMBER
THE NEW ZEALAND GAZETTE
4021

THE WEATHER IN NEW ZEALAND IN JULY 1984

General—July was a mild, cloudy month for most areas. North-westerly winds were much more frequent than usual in the North of the country, with a corresponding decrease in the number of south-westerlies.

At Auckland Airport the frequency of north-westerly winds was the highest and south-westerlies the lowest for July since 1974. Apart from a slight increase in the frequency of north-easterlies, winds were very close to normal in the South.

Pressures were generally close to normal, being slightly lower than usual in central districts and the west of the South Island and slightly higher than usual elsewhere.

The mild conditions this month suited most farmers. Many North Island stations reported lambing and calving well under way by the end of the month, with fewer losses than usual and all stock in good condition. Farmers in the South Island also reported stock in good condition, although muddy conditions caused problems in some southern areas.

Rainfall and Snow—Coastal areas of South Canterbury, Southland and Otago and the north and east of the North Island had average or less rainfall for July, while the rest of the country was wetter than usual. The Cook Strait region and central and south-western areas of the South Island were especially wet with between 150 and 250 percent of normal rainfall.

Skifields throughout the country reported an unseasonable lack of snow at the beginning of the month. However, after two light falls on 2nd and 5–6th, very cold southerly winds between 14–16th brought widespread snow to low levels throughout the country, with reports of light snow as far north as the hills to the east of Kaikohe.

Falls were heavy in the high country and southern areas of the South Island and central areas of the North Island. Many roads were closed in these areas and 100 people were stranded in cars in the Porters Pass (Canterbury) area and about 200 rescued on the Desert Road. The overnight Auckland to Wellington express was halted for 2 hours by snow on the tracks and 2 Cook Strait Ferry sailings were cancelled due to high winds.

Temperatures—Temperatures were higher than normal over the whole country this month. The south and south-west of the South Island, East Cape and parts of Northland had mean temperatures between normal and 1 degree above normal and the rest of the country was between 1° and 2° above normal. Many stations in the North and West of the South Island had their warmest July (highest mean temperature) on record. These included (with start of record) Hokitika (1866), Westport (1937) and Nelson (1943). For much of the North Island it was the warmest since 1974.

Apart from the period between 14th and 17th there were few days when mean temperatures fell below average. During the first week of the month some stations in the Gisborne—Hawke’s Bay area and North Auckland recorded temperatures of 20°C or above. Riverhead Forest reached 20.1°C on the 2nd, the highest for July since opening in 1928 and the maximum of 20.4°C at Wairoa on the same day was the highest for July since 1967.

Sunshine—Apart from the north of the North Island, where sunshine hours were normal or above normal, much of the country was cloudier than usual for July. The west of the South Island and the area about Cook Strait were particularly dull, with stations in these areas recording 30–45 hours less sunshine than usual. Among those stations with greatest departures this month were: Westport (–31 hours) Blenheim (–31 hours), Kelburn (–38 hours), Nelson and Hokitika (–44 hours).

THE WEATHER SEQUENCE—JULY 1984

1–7 July
A complex trough covered New Zealand at the beginning of July. Two small depressions lay within the trough; these were centred east of North Cape and off the Otago Peninsula. Associated fronts brought rain to most parts of the country on the 1st. The northern depression moved south-eastwards during the 2nd, bringing heavier rain to western and central areas of both Islands but fine weather to eastern areas.

By the 3rd it lay off Fiordland and a west to north-west flow covered the country. Rain fell in the south-west of the South Island and some western areas of the North Island but the weather was otherwise fine. A depression developed near Lord Howe Island on the 4th. As this moved south-eastwards its associated frontal system brought rain to Northland on the 5th and to the whole country except the far south on the 6th and 7th. Temperatures remained higher than usual throughout this period.

8–14 July
The rain had cleared from most districts by the 8th, although temperatures became cool as a southerly airflow covered the country. An extensive anticyclone centred near Lord Howe Island began to extend a ridge onto the country during the 9th, bringing cool, clear weather to all districts during the 9th and 10th.

A cold front brought showers to many areas on the 11th, although the ridge still covered the country and temperatures were mild. A complex trough developed behind the front and as this moved over New Zealand between the 11th and 14th rain became widespread, with heavy falls at times in some western and central areas.

15–21 July
A second trough developed immediately behind the first and rain continued to fall in many areas on the 15th. Temperatures, which had been mild, fell rapidly as a cold south to south-westerly flow developed behind the trough. Snow fell in many parts of the country between the 14th and 17th with very heavy falls in the ranges and high country of the South Island. By the 18th an anticyclone had moved onto the country.

The weather remained clear and temperatures, which had been 4°–7°C below average, began to rise. A cold front approached the South Island during the 20th and rain fell in the south and west of the South Island and some western and north-western areas of the North Island on the 20th and 21st as the front remained slow moving off the west coast of the country.

22–31 July
A depression developed on the front and as this began to cross the country during the 22nd rain became widespread, with heavy falls in some northern areas of the North Island. The rain cleared from most districts on the 23rd although showers remained in isolated parts of the North Island and a belt of high pressure began to develop over the country as the depression weakened and moved away to the east.

However, further rain developed over the North Island and northern South Island as a cold front began to move onto the country. By the 26th this lay off the east coast and the weather became fine. An anticyclone situated in the Australian Bight moved rapidly eastwards and fine, cool weather prevailed until the 29th. A depression had begun to develop off the coast of Australia during the 28th and this moved eastwards to lie centred in the Tasman Sea on the 30th. An associated frontal system brought rain to most parts of the country apart from some eastern areas as the front crossed the country during the 30th and 31st.

PROPOSED DISCONTINUATION OF THE WEATHER SEQUENCE

Daily weather information, including maps, is now available through various media. The Meteorological Service is therefore proposing to discontinue publishing this Weather Sequence as above, though the Climatological Table and written summary will continue in the Supplement to the New Zealand Gazette.

People having a special need for the Weather Sequence as currently published are invited to write to:

The Director,
New Zealand Meteorological Service,
P.O. Box 722,
Wellington.

by 30 September 1984.

BY AUTHORITY: P. D. HASSELBERG, GOVERNMENT PRINTER, WELLINGTON, NEW ZEALAND—1984
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