Three-month outlook

The outlook for October 2004 to December 2004

Mean sea-level pressures are expected to be lower than normal to the south of New Zealand, with more west to southwest wind flow than usual over the country for the remainder of 2004. Sea surface temperatures are likely to remain slightly below average around New Zealand over the next three months.

Temperatures are expected to be average or below average in the north and west of the North Island, and near average elsewhere. Normal or below normal rainfall is expected in the north and east of the North Island, with normal or above normal rainfall for the west and south of the South Island. Near normal rainfalls are expected elsewhere.

Soil moisture levels are expected to be normal or below normal over most of the country, apart from normal or above normal conditions for the western South Island. Stream flows are expected to be below normal in the north and east of the North Island, normal or below normal in the eastern South Island, and normal or above normal elsewhere.

The tropical Pacific is presently in a weak El Niño state. It is likely that weak El Niño conditions will continue through the rest of 2004 and into early 2005.

 

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).