19 JUNE]

THE NEW ZEALAND GAZETTE

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

LATE RETURNS.

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 MAY 1952

General.—For the first half of May the weather was predominantly fair and mild, but thereafter a succession of vigorous depressions provided cool unsettled weather with frequent rain in western districts. The previous two months had also followed a similar pattern, the better weather occurring in the first part of the month.

On the whole it appeared to be a reasonably favourable month for farmers, though more rain would have been welcome in eastern districts. In Hawke’s Bay, low rainfall and attacks by aphids pests have affected winter forage crops. Stock generally faced the winter in fair to good condition.

Rainfall.—Rainfall was below normal over most of the North Island and in eastern and southern districts of the South Island (except Banks Peninsula). The Hawke’s Bay and Gisborne districts received less than one-fifth of the normal rainfall, several stations reporting a record low rainfall for May. Greymouth, on the other hand, had more rain than has previously been recorded in May.

There was a moderate surplus over the remainder of the South Island, also about Wellington and the Tararuas and in the area north-westwards from the Ruahines to the North Taranaki Bight.

Temperatures.—Mean temperatures departed little from the normal. Though small, the departures had a negative tendency in the north and west, and were positive elsewhere. Two good snowfalls occurred on the high country, the first at the beginning of the month, and the second about the 23rd.

Sunshine.—Sunshine totals were high east of the main ranges, especially in Hawke’s Bay and Gisborne, the latter setting a new record for May. Elsewhere sunshine was below normal with a substantial deficit in west coast districts. Auckland repeated its performance of the previous month by setting a new low record for May. At Waipoua, also, the total was below the previous lowest figure for May.

Weather Sequence.—South-westerly winds and cold showery weather prevailed for the first few days as a deep depression located east of Otago moved slowly away to the south-east. The high country of both islands received its first substantial snowfall of the year.

Conditions improved somewhat on the 3rd when a large and intense anticyclone centred over New South Wales extended across the Tasman Sea towards New Zealand. Moving slowly eastward the centre of the anticyclone crossed Northland on the 8th, having decreased appreciably in intensity. During the passage of this anticyclone across the Tasman the weather in eastern districts was mainly fair, but a series of westerly depressions in the south was responsible for further showery weather elsewhere, especially in Westland.

A slow-moving trough which crossed the South Island on the 9th moved north-eastwards off the North Island on the 11th after depositing moderate rains in most districts with the exception of inland Otago and Hawke’s Bay.

From the 12th to the 16th an anticyclone covered the South Tasman Sea with a ridge extending north-eastwards across Northland. The weather became more settled, except in Southland and South Otago where disturbances far to the south-east caused unpleasant, south-westerly conditions. Strong southerly winds and brief showers also extended temporarily to other eastern districts on the 15th.

After a fine day on the 16th with severe frosts that night, there was a rapid deterioration next day when winds turned northerly ahead of a large and vigorous depression. The associated trough moved rapidly eastwards across New Zealand on the 18th accompanied by heavy rain, while the main centre passed close to Southland. Next day the weather cleared temporarily, apart from local showers in the north. A complex disturbance from the west brought a further period of unsettled weather. One centre filled up near Southland, but another which formed off Westland, crossed the middle of the country on the 22nd. Strong southerlies prevailed on the 23rd bringing further snow to the high country and cold showery weather elsewhere.

A brief improvement occurred with the passage of a weak ridge of high pressure on the 24th. Next day a broad belt of rain moved rapidly south-eastwards over the country ahead of a warm front. The centre of the associated depression crossed the Cook Strait area on the 26th, while a secondary depression crossed the South Island two days later. Both were very active and caused general rain with substantial falls over the northern half of the South Island.

The weather continued very unsettled for the remainder of the month. Moving rapidly eastwards the centre of another deep depression passed close to Southland on the night of the 29th. The trough produced heavy rain and some thunderstorms with north-westerly winds rising temporarily to gale force in exposed positions. At the end of the month, another depression was approaching rapidly from the Central Tasman Sea.

M. A. F. BARNETT, Director.

(M.O.N.Z. 107)