Retrospective - March to May Outlook

The mature La Niña event in place at the start of autumn 2012 was (correctly) forecast to have eased to neutral by the end of the season. A somewhat stormy Tasman Sea (with lower pressures than usual) was expected for March – May, with more frequent northeast winds than usual predicted over the country. Pressures were indeed generally below normal over the north Tasman Sea, as well as near Tasmania. Higher than normal pressures continued east of the Chatham Islands during autumn, and also extended across the South Island. More east to northeast winds affected New Zealand during autumn.
Predicted rainfall: Rainfall totals are likely to be normal or above normal in the north and east of the North Island, as well as the north of the South Island. In all other regions, near normal seasonal rainfall totals are likely.

Outcome: Autumn rainfall was correctly forecast for Northland, Auckland, Coromandel, and Bay of Plenty – but it was drier than forecast in Waikato and Waitomo (with areas of below average rainfall observed). Normal or above normal rainfall was forecast for the north of the South Island (but below normal rainfall was experienced). In all other regions, near normal seasonal rainfall totals were predicted. This was a correct forecast for Taranaki and Wellington, Marlborough and parts of north Canterbury – but over the bulk of the country, below normal rainfall was generally recorded.

Predicted air temperature: Temperatures are likely to be average or below average in eastern areas of both Islands, and near average elsewhere.

Outcome: Temperatures were below average in all eastern regions. Near average temperatures were observed in parts of Northland, Auckland, the Bay of Plenty, Golden Bay, the Buller District, parts of the West Coast, Southland and parts of inland Otago. Above average temperatures were recorded around Westport as well as for coastal Fiordland and coastal Southland. But it was cooler than forecast for the remainder of the country, with below average temperatures observed.