MAY 24] THE NEW ZEALAND GAZETTE 757

CLIMATOLOGICAL TABLE—continued

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

LATE RETURNS

| Taumarunui, Mar., 1951 | 560 | 74·4 | 50·0 | 62·2 | .. | 84·1 | 8 | 36·2 | 15 | 1·85 | 10 | .. | 0·63 | 23 | 184·0 |
| Golden Downs, Mar., 1951 | 900 | 67·0 | 46·2 | 56·6 | —0·2 | 75·0 | 18 | 33·0 | 27 | 4·51 | 9 | (+1·81) | 2·13 | 22 | .. |
| Tara Hills, Mar., 1951 | 1,600 | 69·2 | 43·8 | 56·5 | .. | 85·6 | 7 | 29·5 | 12 | 1·40 | 10 | .. | 0·58 | 22 | .. |
| Cromwell, Mar., 1951 | 720 | 72·4 | 47·6 | 60·0 | .. | 87·8 | 6 | 34·1 | 25 | 1·62 | 7 | .. | 0·73 | 10 | .. |

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 APRIL, 1951

General.—April’s weather was persistently unsettled with frequent rain. Cyclonic disturbances were very active in the New Zealand region, and the average barometric pressure reached a record low value for April.

Growth was well maintained under very mild conditions until a cold change occurred towards the end of the month. North Island dairy production continued at a high level, but conditions were not available for sheep farmers. Persistently damp conditions over the past few months have had an adverse effect on the health of sheep, and lambs have not fattened well. Reports of such ailments as foot-rot, facial eczema, blow-fly strike, &c., have been much more frequent than in recent years.

In Canterbury agricultural work has been seriously hampered, and little wheat is likely to be sown this autumn. Much damage remains to be repaired after the widespread flooding on the 17th and 18th.

Rainfall.—April was a wet month for the whole Dominion, with the exception of Southland and an area from the Bay of Plenty through to Hawke Bay where the rainfall was not quite up to normal.

In Canterbury the wettest April on record followed four successive wet months. The rainfall over most of the province was treble, and in some northern districts, five times the average amount. Continuous heavy rain during the 17th and 18th reached a maximum in the foothills and resulted in widespread flooding throughout the province. The longer rivers with sources in the Southern Alps were not seriously affected.

The surplus rainfall along the coast between Cape Palliser and Cape Kidnappers was also substantial.

Temperatures.—Mean temperatures were generally about a degree above normal, except in the interior of Otago and Canterbury and in the far north where there was a slight negative anomaly.

Sunshine.—In eastern districts from Hawke’s Bay to Otago, and about Nelson, the duration of sunshine was 20 to 30 hours or more below normal. At Waimate and Hanmer the deficiency was equivalent to two hours a day.

Over the remainder of the country totals were slightly above normal.

Weather Sequence.—At the beginning of the month an anticyclone lay to the south-east of the South Island and conditions were improving in South Canterbury after widespread heavy rains. With the approach of a tropical cyclone from the north-west, rain developed in Northland and gradually spread over the whole of the North Island. The cyclone moved slowly south-eastwards past North Cape, but when it was east of Gisborne on the 5th, another low-pressure centre moved south-eastwards across Southland. The trough associated with the latter crossed the Dominion from the west accompanied by heavy showers and some thunderstorms.

A passing ridge brought a brief clearance on the 6th, but conditions became generally unsettled again with the arrival of a large and complex disturbance late on the 7th. One low-pressure centre crossed the South Island on the 8th and southerlies advanced to Cook Strait soon afterwards. They became general when a second centre crossed Auckland early on the 10th. As the disturbance moved off to the east, a ridge brought a general clearance from the south and west. Cool, showery weather persisted, however, between Cook Strait and East Cape until the 12th.

The approach of a deep and extensive depression from the Tasman Sea on the 14th marked the beginning of a further period of very unsettled weather. One depression passed south of New Zealand on the 15th. A second, after remaining off Westland for several days during which easterly rains caused extensive flooding in Canterbury, finally moved across the middle of the North Island on the 19th. Heavy rainfalls were also recorded in Marlborough and Nelson.

On the 20th there was a temporary improvement over the central provinces, but an extensive depression covering the South Tasman was moving onto the South Island while another depression was forming near North Cape. The latter deepened rapidly and travelled south-eastwards to pass East Cape on the afternoon of the 21st. The main centre of the southern depression continued on an easterly course and passed south of Stewart Island on the 22nd. Strong westerly winds prevailed generally and gradually backed south-westerly in the South Island. Showers were frequent and heavy, except in a few sheltered east coast districts, and thunderstorms were reported over a wide area for several days.

Barometers began to rise slowly in the south on the 26th under the influence of a weak wedge which had extended across the South Tasman Sea. Winds turned more southerly and temperatures became colder. Fine weather prevailed in South Westland and later extended northwards to Nelson and Taranaki. Elsewhere the clearance was delayed by the arrival of another depression whose centre moved eastwards across the Auckland Province on the 28th. By the end of the month an anticyclone covered the South Island, and clear frosty weather extended over the greater part of the country. It remained cold and showery, however, between Banks Peninsula and East Cape. During the last few days substantial snowfall occurred at high levels in both Islands.

R. G. SIMMERS, Acting Director.

(N.Z.M.O. 107.)