Three-month outlook

The outlook for May 2005 to July 2005

Below average sea-level pressures are expected to the south of New Zealand, with enhanced westerly or northwesterly air flows over the country. Sea surface temperatures around New Zealand are likely to be near or above average to the end of July.

Air temperatures are expected to be above average in all districts. Associated with this, a decreased risk of frosts is likely in many places for early winter.

Rainfalls are likely to be normal or above normal in western districts, but tending towards below normal in the eastern North Island, with near normal falls expected in the northern North Island and eastern South Island. Normal or below normal soil moisture levels and streamflows are expected in the north and east of the North Island, while normal conditions are expected in the southwest of the North Island and for all the South Island.

The tropical Pacific is in a neutral but borderline El Niño state. Although conditions may stay in the neutral range, there is a significant chance of an El Niño developing by spring.

 

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).