Outlook and outcome – July 2004 to September 2004

Atmospheric circulation over New Zealand was more southwesterly than expected.

Normal rainfall was predicted for most of New Zealand. The outcome was drier than normal conditions in parts of the north and west of the North Island, Kaikoura, and Otago, and above average rain in Bay of Plenty, the southern North Island, and parts of Southland.

Air temperatures were lower than predicted across the country. River flows were expected to be generally normal.

River flows were below normal in the northern North Island and the South Island east coast, above normal in the eastern Bay of Plenty and the southern North Island, and near normal elsewhere.


The outcome maps shown here give the tercile rankings of the rainfall totals and mean temperatures that eventuated for these months. Terciles were obtained by dividing ranked July to September data from the past 30 years into three groups of equal frequency (lower, middle and upper one-third values) and assigning the data for the present year to the appropriate group. (Click to enlarge)

As an approximate guide, middle tercile rainfalls often range from 80 to 115% of the historical average. Middle tercile air temperatures typically occur in the range of the average plus or minus 0.5°C.