Three-month outlook

The outlook for January 2005 to March 2005

Lower than normal mean sea-level pressures to the south of New Zealand are expected, with stronger than normal west to southwest wind flow over the country. Sea surface temperatures around New Zealand are expected to be below average in January, but tending to average by March.

The average air temperature for the next three months is expected to be below the historical average everywhere except in the east of the North Island, where it is expected to be average.

Below normal or normal rainfall is expected in the north and east of the North Island. Rainfalls are expected to be near normal elsewhere.

A gradation of soil moisture levels and streamflows is expected across the country, ranging from below normal to normal conditions in the north and east of the North Island to normal or above normal conditions in the west and south of the South Island.

The present weak El Niño is likely to continue through the next three months. The chance of an ex-tropical cyclone affecting New Zealand over the summer is near the long-term average.

 

A. Climate models give no strong signals about how the climate will evolve, so we assume that there is an equal chance (33%) of the climate occurring in the range of the upper, middle or lower third (tercile) of all previously observed conditions.

B. There is a relatively strong indication by the models (60% chance of occurrence) that conditions will be below average, but, given the variable nature of climate, the chance of average or above-average conditions is also shown (30% and 10% respectively).