Retrospective - May to July Outlook

For May-July 2013 higher pressures than normal were forecast south of the country extending towards the east of the Chatham Islands. Lower pressures than normal were expected to the north of New Zealand. This circulation pattern was expected to produce weaker than normal westerly flows. Actual pressures for this 3-month period were weak across the New Zealand region, with strongly negative mean sea level anomalies to the south and more positive anomalies to west and east of the country. This mixed pattern resulted in weak south-west flows across southern areas and weak easterly flows across northern areas of New Zealand. 

Predicted rainfall: Rainfall is likely to be in the near normal range for all regions .

Outcome: Actual rainfall for this 3-month period was close to normal across all North Island regions as well as northern and western regions of the South Island. It was slightly drier than normal however across the Waitomo, Taupo, Whakatane and Opotiki Districts. In contrast, it was much wetter than expected in the east of the South Island where rainfall was more than 160 % of normal in coastal areas of Marlborough, south Canterbury and Otago. Above normal rainfall was also recorded in coastal areas of Central Hawkes Bay, Auckland and Wellington. 

Predicted air temperature: Temperatures are very likely to be above average across the entire country.

Outcome: The forecast was mostly correct for the east and west of both islands with slightly warmer than normal temperatures observed; however, closer to average temperatures were observed in Northland, Auckland, the Coromandel, East Cape, parts of the Waikato Region, southern Hawkes Bay, the Tasman District, and central South Island.