Retrospective – June to August 2015 Outlook

During June – August 2015, above normal pressure was forecast to the west of New Zealand, while below normal pressure was expected to the northeast of the country. This circulation pattern was likely to be accompanied with anomalous westerly to southwesterly wind flows.

Actual pressures were largely as forecast with higher than normal pressure over the North Island and lower than normal pressure to the south of New Zealand. This resulted in a westerly to southwesterly flow anomaly as anticipated.

Predicted rainfall: June – August 2015 rainfall totals were forecast to be in the near normal or below normal range for all regions of New Zealand except for the west of the South Island, where near normal rainfall was the most likely outcome.

Outcome: Actual rainfall was below normal in the north and east of the North Island as well as in the districts of Kaikoura and Hurunui. Conversely rainfall was above normal for the western regions of both islands and rainfall was near normal elsewhere.

Predicted air temperature: June – August 2015 temperatures were likely to be  average or above average in all regions of New Zealand except in the north of the North Island, where temperatures were most likely to be in the near average range.

Outcome: Actual temperatures were near average for the majority of the country with pockets of below average temperature recorded in the districts of Otorohanga, Tararua, Grey and Clutha.