Three-month outlook

The outlook for April 2005 to June 2005

Over the next three months, atmospheric pressures at mean sea level are expected to be lower than their historical average to the west of New Zealand, with more northerly flows than usual over the country. Sea surface temperatures around New Zealand are expected to be near or above average.

Mean three-month air temperatures are expected to be near or above historical averages in all districts.

Mean rainfalls are likely to be near normal in all districts, but may be above normal in the northern North Island. Normal soil moisture levels and stream flows are expected in all regions.

The tropical Pacific should be in a neutral state (no El Niño or La Niña) for most of the period, ending the present weak El Niño event.

There is still a chance of an ex-tropical cyclone affecting New Zealand during April, but typically the cyclone season has ended by late April.

 

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).