Retrospective: July-September 2018 Outlook
The atmospheric circulation around New Zealand was expected to be characterized by mixed flow patterns along with periodic easterly quarter flows. Actual pressure were slightly lower than normal across the country with a westerly quarter flow anomaly.
Predicted air temperature: July – September temperatures were forecast to be near average or above average for the North Island and north of the South Island. Near average temperatures were expected for the east and west of the South Island.
Outcome: Actual temperatures were near average for the North Island and the top of the South Island with the exception being parts if Manawatu-Whanganui where temperatures were above average. Temperatures were above average for the remaining part of the South Island with the exception of coastal Canterbury where they were near average.
Predicted rainfall: July – September rainfall totals were forecast to be near normal or above normal in the north and east of the North Island. Normal rainfall was forecast in the west of the North Island as well as the north and east of the South Island with near normal or below normal rainfall expected in the west of the South Island.
Outcome: Actual rainfall was below normal for the north of the North Island, Canterbury and parts of the West Coast. Rainfall was largely near normal elsewhere with small pockets of above normal rainfall in Otago and Southland.