29 MAY]

THE NEW ZEALAND GAZETTE

CLIMATOLOGICAL TABLE—continued
Summary of the Records of Temperature, Rainfall, and Sunshine for April 1952—continued

LATE RETURNS.

Waihi, March 1952 | 354 | 69·6 | 52·8 | 61·2 | -0·7 | 75·5 | 10 | 43·5 | 12 | 1·55 | 11 | -5·65 | 0·83 | 14 | 189·7
Whakatane, March 1952 | 6 | 71·2 | 53·0 | 62·1 | (+1·2) | 78·0 | 14 | 37·3 | 30 | 1·66 | 6 | (-2·49) | 0·71 | 14 | ...
Appleby, Nelson, March 1952 | 57 | 68·4 | 51·0 | 59·7 | -0·5 | 73·5 | 31 | 41·5 | 30 | 0·78 | 7 | (-1·30) | 0·41 | 25 | ...
Adair, March 1952 | 200 | 64·8 | 47·2 | 56·0 | (-0·3) | 81·0 | 25 | 34·8 | 18 | 0·45 | 6 | (-1·79) | 0·15 | 5 | ...
Gore, Feb. 1952 | 245 | 69·9 | 46·8 | 58·4 | +0·1 | 82·0 | 22 | 30·0 | 15 | 2·38 | 8 | -0·43 | 1·15 | 1 | ...
Gore, March 1952 | 245 | 63·6 | 44·2 | 53·9 | -1·5 | 78·0 | 14 | 34·0 | 23 | 4·32 | 20 | +1·21 | 0·68 | 25 | ...

NOTE.—At stations where departures from normal are in parentheses, the temperature record has been maintained for less than ten years, the rainfall record for less than twenty years. Rainfall normals have been revised and now refer to the standard period 1921–1950. Where observations are not available for the whole period, or where the site of the raingauge has been changed, the normals are partly interpolated.

NOTES ON THE WEATHER FOR APRIL 1952

General.—A mild, dry spell over the first half of the month gave place to unsettled and rather cooler weather after the 17th. Temporarily retarded through lack of rain, North Island pastures recovered later in the month. East of the South Island ranges, where there has been a significant rainfall deficiency over the past few months, crops and pastures made little growth and winter feed may be scarce in many districts. During the second quarter, several unusually dense and widespread fogs were reported from the southern part of the Auckland Province.

Rainfall.—As in the preceding month the rainfall, except in a few isolated areas, was well below normal. There was a small surplus in parts of North Taranaki, also near the Tararuas and the Tasman Ranges, and in the northern Sounds. With the exception of Westland, almost the whole of the month’s rainfall occurred after the 17th. In some districts of South Canterbury, rain has been deficient in each month of this year.

Temperatures.—In coastal districts from Invercargill to East Cape, mean temperatures were about 1° F. above normal; elsewhere there were no significant anomalies.

Sunshine.—The distribution of sunshine was most unusual. Westland, Northland, and western districts of the Wellington Province had a small deficiency, but from Taranaki to Auckland City the total duration was at least an hour a day below normal. Auckland had the lowest April sunshine since records commenced in 1910, this in spite of the low rainfall. At the other extreme, Dunedin’s figure of 177·5 hours was thirty hours better than the previous best April figure in thirty-nine years. Canterbury, too, and other districts of the South Island were all well favoured with sunshine.

Weather Sequence.—As an anticyclone moved away to the east, a weak ridge persisted over the North Island. There were showery periods in the west and south for the first few days of April, due to the influence of a series of deep depressions moving eastwards in subantarctic waters. Westerly gales were reported from Otago and Southland on the 2nd.

An intense anticyclone from the west brought a general improvement on the 6th, and the weather remained settled until rain developed again in Southland and Westland on the morning of the 10th. The cold front which produced this rain became weaker during its passage northwards. It was followed by a rapidly intensifying ridge which moved out to the east of Southland on the 12th.

Over the Auckland Province where easterly winds had already prevailed, showers developed in most districts on the 13th. Elsewhere there was a brief change to northerlies with the approach of a depression moving southwards through the Tasman Sea. The centre passed west of Southland at mid-day on the 13th, while the associated trough moved slowly eastwards across the Dominion causing brief rain in most districts.

Moderate southerlies and colder temperatures prevailed on the 15th ahead of an anticyclone advancing across the South Tasman Sea. Skies remained rather cloudy and rain continued intermittently over the Auckland Province. Altering course, the anticyclone moved north-eastward over New Zealand, the centre crossing the Wellington Province early on the 17th. Later that day there was a gradual deterioration from the north and west accompanied by a change to north-westerly winds caused by an extensive and complex disturbance in the western Tasman. A period of unsettled weather followed as the disturbance progressed steadily eastwards across the New Zealand area. Rain was general but falls were not excessive.

Cool southerlies advanced northwards on the 21st. Next day the weather cleared with the approach of an anticyclone from the west. By the 24th the anticyclone had crossed to the east of the Dominion and rain again developed in the north under the influence of another extensive depression covering the Central and North Tasman Sea. Rain spread southwards as far as Nelson and North Canterbury shortly before the main low-pressure centre moved across the centre of the North Island on the 26th. After a temporary improvement on the 27th, a secondary centre produced further rain over the Auckland and Hawke’s Bay provinces. Meanwhile, a weak ridge had given a spell of fair weather in the south.

During the night of the 29th the weather quickly deteriorated as the centre of a rapidly deepening depression sped southwards through the Tasman Sea to pass close to Puysegur Point on the afternoon of the 30th. About the same time the associated occlusion crossed the country from the west accompanied by a broad belt of heavy rain and northerly gales. Showery, westerly conditions then prevailed, though little rain penetrated to eastern districts sheltered by the main ranges.

M. A. F. BARNETT, Director.

[M.O. N.Z. 107]