Retrospective: July-September 2019 Outlook

For the July to September period, air pressure was forecast to be higher than normal to the northwest of New Zealand and lower than normal to the south. This was expected to be associated with more westerly quarter winds to start the season and mixed flow patterns later. A trend toward more unsettled weather was expected during the season, particularly in September. Actual pressures were lower than normal over and to the south of the country. This pressure set up resulted in more south-westerly flows than normal.

Predicted air temperature: Temperatures were forecast to be near average or above average for all regions of New Zealand, owing to warmer than average coastal and regional sea surface temperatures.

Outcome: Actual temperatures in the North Island were near average about Auckland, Northland, the Wairarapa and parts of Manawatu-Whanganui and above average for the remainder of the island. In the South Island, temperatures were above average for interior Canterbury and parts of Otago and near average for the remainder of the island.

Predicted rainfall: Rainfall was forecast to be near normal or below normal in the north of the North Island and north and east of the South Island. Near normal rainfall was forecast in all other regions of New Zealand.

Outcome: Actual rainfall was above normal about Auckland, Taranaki, Tasman, Nelson and Marlborough. Rainfall was below normal for parts of Gisborne, Hawke’s Bay and the Wairarapa. Rainfall was near normal elsewhere.