CLIMATOLOGICAL TABLE—Summary of the Records of Temperature, Rainfall, and Sunshine for March 1957—continued

†Observations for 25 days.

LATE RETURNS

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 MARCH 1957

General: March was warm and humid, and also rather wet. The rain was welcomed after the dry weather of the two previous months, and growth was considered to be good. Stock also benefited, but in parts of the Auckland and Hawke’s Bay Provinces it was found necessary to take precautions against facial eczema in sheep.

In the early morning of the 20th a small tornado caused considerable damage in New Plymouth. No less than five small tornadoes were reported during the month, of which three occurred on the 20th. A north-easterly gale caused some damage on the 19th.

Rainfall: Rainfall was appreciably above normal over the greater part of the country. It was double the usual value in eastern and inland districts from Dunedin to Cape Campbell, and also in parts of the Auckland Province.

Central Hawke’s Bay, Westland, and the Southland coast received appreciably less rain than usual.

Severe thunderstorms affected Canterbury and Wairarapa on the 7th. On the 18th, thunderstorms were widespread from Auckland to Westland and Canterbury.

Flooding was reported in the Whangarei - Bay of Islands area on the 8th, and in parts of Canterbury and Otago on the 20th.

Temperatures: As in the previous month, temperatures were above normal over the whole country, mainly by about three degrees. Departures were greatest in central districts.

Sunshine: Sunshine was below normal over the South Island and also over eastern districts of the North Island, mainly by about thirty hours. Western districts of the North Island were favoured with somewhat more sunshine than usual.

Weather Sequence: For the first three days of the month the weather was fine, under the influence of an anticyclone. From the 4th to the 7th pressures remained high to the south and east, but a shallow depression affected the South Island. Severe thunderstorms were reported in Canterbury and Wairarapa on the 7th.

For the next week pressures still remained high to the south and east, while a complex disturbance from the north-west caused unsettled weather over the greater part of the country. Warm humid north-easterlies prevailed throughout the period. The first depression moved southward over northern Northland on the 8th and 9th with thunderstorms and heavy rain over the Auckland Province; flooding occurred in Whangarei. For the next two days the depression moved south-westward, and most districts received some rain. There were some heavy falls in North Canterbury, with flooding in the Cheviot area. From the 12th to the 14th another depression affected mainly eastern districts of the Auckland Province.

The pattern changed on the 15th as a very deep depression passed far to the south-west and the associated trough of low pressure moved onto the South Island. Another depression soon developed over the North Tasman Sea, and as it deepened on the 16th and 17th rain commenced once again in districts exposed to north-easterly winds. The passage of this depression across the South Island from the 18th to the 20th caused considerable rain, with widespread thunderstorms. Flooding was reported in parts of Canterbury and Otago. For the next two days the weather was showery in places and generally much cooler.

By the 23rd, pressures were again high to the south and east, but another depression was centred over the eastern Tasman Sea. A shallow trough became stationary over the South Island, with rain as far north as Christchurch. North-easterlies again developed, with showers in some districts on the 24th and 25th. For the next four days a depression passing to the north affected the weather in parts of the Auckland Province; while on the 28th and 29th the passage of a depression to the south brought some rain to Otago and Southland. However, there was a general clearance on the last two days of the month as a large anticyclone moved on to the country. Temperatures became somewhat cooler.

M. A. F. BARNETT, Director.

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