2312
THE NEW ZEALAND GAZETTE
No. 104

CLIMATOLOGICAL TABLE—Summary of the Records of Temperature, Rainfall, and Sunshine for August 1976—continued
LATE RETURNS AND CORRECTIONS—continued

The “normal” refers to the present site of the instruments. Standard period for normals is 1941–1970. No normals are available for stations with only short records.

*Indicates that the sunshine recorder is not located at the station but is in the near vicinity.

A rain day is a day with rainfall equal to or greater than 0.1 mm.

Where the extremes of temperature and rainfall have occurred more than once during the month, the date of the first occurrence is given.

NOTES ON THE WEATHER FOR AUGUST 1976

General—In August barometric pressures were low over New Zealand and comparatively high to the south; and an unusually high frequency of winds from an easterly quarter brought considerable cloud and rain to eastern and northern districts of the South Island. In these areas and in some southern districts of the North Island conditions were not favourable for lambing, and both lambs and ewes were lost in cold rains and in snow on the high country. By contrast, over most of the North Island conditions were relatively mild for August, resulting in good growth and favourable conditions for stock and especially for lambing.

Rainfall—Rainfall was above normal over the greater part of the North Island and also in most northern and eastern districts of the South Island. It was more than double the normal value in Dunedin with a considerable part of North and Central Otago, and also in the Lyttelton-Banks Peninsula area. Rainfall was less than three-quarters of the normal value over a considerable area extending eastward from Westland and Fiordland over the Southern Lakes district, the Alps, and part of the Canterbury high country. In the Christchurch-Banks Peninsula area more than half the rain fell on the 26th and 27th, amounting in some stations to over 200 mm for the two days. Flooding affected part of Christchurch.

Temperatures—In most northern and some western districts of the North Island temperatures were more than a degree C above normal. Elsewhere in the North Island and in Nelson and Marlborough they were about half a degree above normal. In the rest of the South Island they were close to normal. The coldest periods were the first eight days and the last five days. On the 26th and 27th considerable snow was reported in the high country of Canterbury and Otago.

Sunshine—Sunshine was below normal in northern and eastern districts of the South Island by 30–60 hours, except in the Mackenzie Country, where it was well above normal. Timaru’s total of 85 hours and Dunedin’s 87 hours were the lowest August values on record for these cities. In Wairarapa and most of Hawke’s Bay sunshine was below normal by about 30 hours.

WEATHER SEQUENCE

On the first two days of August pressures were low to the east while a ridge of high pressure extended over the North Island from an anticyclone to the north. In the cold south-westerlies showers were reported, mainly in the Manawatu-Wanganui-Taranaki area. During the next three days a deep depression crossed the South Island and the associated trough of low pressure moved over the North Island. The winds turned to cold southerlies over the South Island and southern districts of the North Island with fairly general showers. From the 6th to the 8th the depression remained centred to the east and a belt of high pressure initially extending from about latitude 30° over New Zealand to latitude 55° moved slowly eastward. Some scattered light showers were reported at times but the weather was mainly settled. However, temperatures remained cold over most of the South Island.

From the 9th to the 14th a deep depression over the Tasman Sea moved very slowly southward, losing intensity. By the 14th there were two centres, one still over the Tasman Sea and the other to the east of the South Island. Rain was general over the North Island and also in northern and western districts of the South Island. Some considerable falls were reported in Northland and Bay of Plenty from the 9th to the 11th. Temperatures became warm. During the next two days pressures remained low over New Zealand and a trough of low pressure crossed the North Island rather slowly, bringing rain mainly to the North Island and the northern half of the South Island. Some considerable falls were again reported in Bay of Plenty besides Nelson. By the 17th the centre of low pressure was moving away to the east and conditions improved under the influence of a ridge of high pressure.

From the 18th to the 24th a belt of high pressure extended from an anticyclone west of the North Island to another one east of the South Island, but a depression passed close to Northland from the 19th to the 21st and a weak trough crossed the South Island on the 24th. This was a period of settled and mild weather in most districts. However, rain was reported in Northland on the 20th and 21st, and in Gisborne on the 22nd; and also on the West Coast and the Southland coast on the 23rd and 24th.

During the 25th and 26th a depression crossed the South Island associated with a trough of low pressure. As pressures rose to the west and south, strong cold southerlies set in over Otago and Southland from the 26th. Rain was general, with some heavy falls in Otago and Southland, causing flooding around Christchurch. Snow was reported to comparatively low levels, adversely affecting sheep. On the following day the cold southerlies spread over the remainder of the South Island and parts of the North Island, but the rain was scattered and somewhat lighter. During the last four days of the month the depression to the east moved slowly north-eastward and the cold southerlies persisted. In the South Island the rain affected mostly eastern districts, but in the North Island it was fairly general. Some considerable falls were reported in the Wairarapa and southern Hawke’s Bay on the 29th.

J. F. DE LISLE, Director.

(N.Z. Met. S. Pub. 107)