CLIMATOLOGICAL TABLE-Summary of the Records of Temperature, Rainfall, and Sunshine for September 1956-continued

†Observations for 25 days.

LATE RETURNS

Akaroa, Aug. 1956.. | 150 | 52·5 | 38·8 | 45·6 | -0·8 | 69·8 22 | 30·2 9 | 3·26 | 17 | -0·72* | 0·68 | 11 | 141
Mossburn, Aug. 1956.. | 961 | 50·1 | 33·1 | 41·6 | .. | 60·0 15 | 22·8 9 | 2·85 | 17 | .. | 0·42 | 10 | ..

NOTE.-At stations where departures from normal have an asterisk, 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 1921-50. Where observations are not available for the whole period, or where the site of the rain gauge has been changed, the normals are partly interpolated.

NOTES ON THE WEATHER FOR SEPTEMBER 1956

By contrast, it was an unusually cloudy month for Otago and Southland. Gore and Invercargill both received the lowest September sunshine in forty years of records.

September was a dry, warm month and also rather sunny in most districts, especially during the first three weeks. In the Auckland Province some areas had not yet recovered from the very wet winter. Elsewhere the weather was mainly favourable for farming, but in a few districts more rain would have been appreciated. Lambing conditions varied considerably; in the South Island losses occurred during cold south-westerly weather from the 13th to the 15th.

Two small local tornadoes were reported on the 12th, one at Greymouth, the other near Waitara in North Taranaki.

Weather Sequence: For the first three days of the month the weather was fine, under the influence of an anticyclone centred at first near Cook Strait, later near the Chatham Islands. On the 4th a weak trough of low pressure affected western and southern districts of the South Island. Meanwhile a depression had been developing over the North Tasman Sea, and during the next three days it moved to the north and east of Northland, bringing rain to the Auckland Province. From the 8th to 10th another anticyclone covered the country, and the weather was again fair or fine.

Rainfall: Rainfall was less than three-quarters of the normal value, except over Canterbury, North Otago, and northern and eastern districts of the Auckland Province. The greatest deficit was on the West Coast, which experienced the driest September since 1935.

There was a deterioration on the 11th as a depression over the Tasman Sea moved south-eastward past Southland and deepened rapidly. On the 12th a vigorous cold front brought a change to south-westerlies, which persisted for another three days. Showery conditions prevailed generally and snow fell on the high country of both islands. From the 16th to the 22nd an anticyclone moved slowly from the North Tasman Sea across the North Island and to the east of the country. Fine weather prevailed for the whole of this week except in Fiordland and parts of Westland, which received some rain for the first few days.

For Banks Peninsula and parts of coastal Canterbury it was a comparatively wet month. A few stations in this area received double their usual rainfall.

A shallow depression affected the Gisborne district on the 23rd, and at the same time rain began again on the West Coast with the approach of a trough of low pressure from the west. For the last week of the month a depression over the North Tasman Sea moved slowly eastward and on to the country. The moist northerly airstream brought cloudy conditions, with rain at times in most districts. Some heavy falls were reported in parts of coastal Canterbury on the 26th.

A number of rather violent thunderstorms were reported in the North Island from the 27th to the 29th, and caused local heavy downpours in Auckland and Dannevirke on the 27th.

Temperatures: Mean temperatures were above normal, mainly by 1 to 2 degrees.

Snow fell on the high country of both Islands during a spell of south-westerly winds from the 13th to the 15th.

Sunshine: The greater part of the country received more sunshine than usual by about an hour a day. The Wellington-Manawatu-Wanganui area was particularly favoured. For Wellington city, with 221 hours, it was the sunniest September since 1910.

M. A. F. BARNETT, Director.

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