Retrospective: May-July 2017 Outlook

During May-July, the atmospheric circulation around New Zealand was forecast to favour slightly more south-westerly flows than normal, but variable circulation regimes were to be expected over the course of the season. Actual pressures were higher than normal over the country, particularly to the south and east. This pressure set up led to more easterlies than normal.

Predicted air temperature: May – July 2017 temperatures were likely to be above average or near average for the north and west of the North Island and the north of the South Island and most likely to be near average for the remaining regions of New Zealand.

Outcome: Actual temperatures were near average for much of the country. Pockets of below average temperature were observed in coastal parts of Canterbury and Otago.

Predicted rainfall: May – July 2017 rainfall totals were most likely to be near normal in the north of the North Island and east of the South Island. Seasonal rainfall totals were likely to be below normal or near normal for the west and east of the North Island and the north and west of the South Island.

Outcome: Actual rainfall was above normal in Wairoa, Nelson, costal parts of Otago and coastal mid to south Canterbury. Below normal rainfall was observed in parts of Southland and the West Coast. Rainfall was near normal elsewhere.

Research subject: Climate