24 JAN.]

THE NEW ZEALAND GAZETTE

CLIMATOLOGICAL TABLE—continued

Summary of the Records of Temperature, Rainfall, and Sunshine for December 1951—continued

LATE RETURNS

Correction, Blenheim sunshine total for November should read 231·7 hours.

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, and the normals are partly interpolated.

NOTES ON THE WEATHER FOR DECEMBER 1951

General.—December's weather was cool and changeable with frequent rain. The season became very backward after three consecutive months of unsettled weather. Stone fruits and vegetables matured much later than usual. Except in Gisborne and parts of Hawke's Bay, conditions were very difficult for shearing and haymaking though there was plenty of hay to be harvested. In the south the sowing of root crops for winter fodder has been delayed. It has not been a good season for stock, and lambs have been slow in fattening.

Rainfall.—The monthly totals were generally above average though not excessively so, but there were small deficiencies in Northland, Bay of Plenty, northern Hawke's Bay, Gisborne, south Westland and western Otago.

Rain fell much more frequently than usual and there was considerable thunderstorm activity. An exceptionally severe hail-storm with stones larger than golf balls damaged crops and killed some poultry locally near Greendale, Canterbury, on the 7th.

Temperatures.—Mean temperatures were well below normal. The anomaly was 3°--4°F, in Canterbury, Marlborough, and the King-country; elsewhere it was about 2°F, but slightly less in Northland. Light frosts occurred over a wide area on the 9th and 10th.

Sunshine.—In Canterbury and Marlborough sunshine was near the average, elsewhere it was below average. The deficiency was generally equivalent to about half an hour a day, but in the south and about the western part of the Wellington Province it was about an hour a day.

Weather Sequence.—With pressures remaining very low to the south but relatively high to the north, the unsettled weather of the previous month continued on into December.

A depression which moved south-eastwards across the northern part of the South Island on the night of the 2nd was followed by a similar depression twenty-four hours later. There were widespread gales over the North Island on the 4th. A third depression passing close to Stewart Island on the 5th produced heavy showers over most of the country. Winds then turned south-westerly, but a change to much colder southerlies followed the passage of a depression across the South Island on the 7th. Hail and thunder were reported from most districts between the 4th and 7th.

Moving steadily eastwards a wedge brought a temporary improvement as it crossed the Dominion on the 9th, but unsettled showery weather again prevailed by the 11th with the arrival of a depression from the South Tasman Sea. When a new depression formed east of the South Island the original depression moved northwards from Southland to a position off Westland where it slowly dissipated. A weak ridge which developed between the two depressions gave a brief clearance on the 15th.

There was general rain during the passage of an extensive and slow-moving depression whose centre was over the South Island on the 16th. The associated cold front was very active when crossing the North Island on the 17th, and thunderstorms occurred as it moved eastwards off the Gisborne district next morning. After a temporary change to southerlies, due to the development of a secondary depression east of Hawke's Bay, an anticyclone brought light variable winds and improved weather on the 19th.

When a deep depression passed to the south on the 20th heavy rain fell in Westland and Southland. The accompanying frontal system became stationary across the middle of the country, due to the deepening of a new depression which arrived over the North Island from the Tasman Sea on the 22nd. Only light rain fell in the far north and south, but elsewhere there were substantial falls between the 21st and 23rd.

Cool south-westerlies prevailed on the 24th and showery weather continued in western districts. Next day winds rose to gale force in exposed coastal areas, while temperatures became colder and showers more widespread.

As an anticyclone from the Tasman Sea drew slowly nearer, winds decreased and the weather slowly improved until by the 27th only isolated showers were being reported. Another showery period occurred in the South Island on the 29th caused by a cold front from the south-west. The anticyclone then took a more northward course, the centre crossing Northland on the 31st. On the same day a very deep depression passed just south of the Dominion. Temperatures became milder, but changeable showery weather again developed in Westland and Southland.

M. A. F. BARNETT, Director.

(N.Z.M.O. 107)