Three-month outlook

The outlook for October to December 2003

Late spring is expected to be mild, with average or above average temperatures in all districts. Normal rainfall is expected in the upper North Island and eastern South Island, with normal or above normal rainfall in all western areas and the north of the South Island, and normal or below normal rainfall in the east of the North Island.

Soil moisture levels and river flows are expected to be normal or above normal, except for the east of the South Island, where normal or below normal river flows are likely.

Local circulation patterns are expected to favour below average mean sea-level pressures and enhanced westerly-quarter winds. The tropical Pacific has moved into a neutral state and is expected to remain neutral (no El Niño or La Niña) through to the end of summer 2003–04.

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).